MultimediaWiki - User contributions [en]

Indeo 5

2006-08-15T14:35:13Z

FyKnight: /* Block header */ added conditions and loops info

* FOURCCs: IV50
* Company: [[Intel]], then [[Ligos]]
* Samples: [http://samples.mplayerhq.hu/V-codecs/IV50/ http://samples.mplayerhq.hu/V-codecs/IV50/]

== General description ==

=== Frame layout ===

The general indeo5 frames layout is composed of one global header, followed by the content of the three YUV plans.

In this document, the global header is split into 3 parts:
* [[#Frame_header|Frame header]]: describe the kind of frame (I/P/B)
* [[#GOP_header|GOP header]]: some data which is true for all the frame in this GOP (present only in the first (I) frame of the GOP)
* [[#More_header|More header]]: some more data which is true only for this single frame

Each YUV plan begin with a [[#Plan_header|Plan header]], containing values which are valid only for this single plan.

=== Encoding ===

This codec is based on the slant transform. Other used standard techniques are huffman coding and motion compensation.

=== Conventions ===

Headers are described in some tables. Each row of those tables describes a value which may be read from the frame. Those tables and rows are presented in the order of appearance in the frame.

Here are the meaning of each columns:
* '''size''': The size of this value in bits. Bits are counted in LSB to MSB order. As an example, with the byte 01110000b, reading 3 bits then 5 bits will return 000b then 01110b. Reading more than 8 bits thus reads as a little-endian value. Think of the get_bits function as filling up the return value from its LSB, using the bits from each byte starting from their LSB.
* '''name''': Kind of variable name, used to reference the value. When a value is named valueX, it generally means we don't know it's purpose. Lines named alignmentX means that bits reader need to skip bits until next byte boundary.
* '''condition''': The value is present in the frame only if this condition is matched. No condition means that the value is always present.
* '''nb times''': How many times the value is repeated.
* '''comments''': Some details about the content of the value. It may also explain that a value is repeated until a certain condition is reached.

== Headers ==

=== Frame header ===

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| 5 || const1 || || || = 0x1F always
|-
| 3 || frame_flags || || ||
* frame_flags & 0x01 => backward predictive
* frame_flags & 0x02 => forward predictive
* frame_flags & 0x04 => null frame
common values:
* 0 => I frame
* 1 => P frame
* 3 => B frame
* 6 and 7 are illegal
|-
| 8 || id_in_gop || || || frame number in GOP (0 for I frame)
|}

null frames don't contain anything else than this header.

=== GOP header ===

This header is present in I frames only. The values in this header are valid during the whole GOP starting at this frame.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 8 || gh_flags || || || [[#gh_flags|gh_flags]] & 0x02 => YV12 (default YVU9)
|-
| align="right" | 16 || value1 || [[#gh_flags|gh_flags]] & 0x01 || || discard in decoding
|-
| align="right" | 32 || value2 || [[#gh_flags|gh_flags]] & 0x20 || ||
|-
| align="right" | 2 || value3 || [[#gh_flags|gh_flags]] & 0x40 || ||
|-
| align="right" | 3 || value4 || || || legal values are 0, 1, 2 and 6
|-
| align="right" | 4 || res_id || || || see [[#Resolution_table|Resolution table]]
|-
| align="right" | 13 || height || rowspan="2" | [[#res_id|res_id]] == 15 || || frame height
|-
| align="right" | 13 || width || || frame width
|-
| align="right" | 6 || value5 || || rowspan="2" | 2*n (n == 1 always?) ||
|-
| align="right" | 2 || value6 || [[#value5|value5]] >> 3 || need to be = 0
|-
| align="right" | 4 || value7 || rowspan="2" | [[#gh_flags|gh_flags]] & 0x08 || ||
|-
| align="right" | 24 || value8 || ||
|-
| align="right" | ?? || alignment1 || || || align bits reader on next byte
|-
| align="right" | 24 || value9 || || ||
|-
| align="right" | 16 || value10 || [[#value9|value9]] & 0x800000 || || loops while value10 & 0x8000 (probably some kind of VLC ?)
|}

=== More header ===

This header is present in all kinds of frame except null.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 8 || mh_flags || || ||
|-
| align="right" | 24 || frame_size || [[#mh_flags|mh_flags]] & 0x01 || || tolal size of frame data
|-
| align="right" | 16 || value11 || [[#mh_flags|mh_flags]] & 0x10 || ||
|-
| align="right" | 8 || counter1 || rowspan="2" | [[#mh_flags|mh_flags]] & 0x20 || || rowspan="2" | this whole block loops while [[#counter1|counter1]] != 0
|-
| align="right" | 8 || value12 || [[#counter1|counter1]]
|-
| align="right" | 3 || value13 || [[#mh_flags|mh_flags]] & 0x40 || ||
|-
| align="right" | 4 || counter2 || rowspan="2" | [[#value13|value13]] == 7 || ||
|-
| align="right" | 4 || value14 || [[#counter2|counter2]] ||
|-
| align="right" | 3 || value15 || || ||
|-
| align="right" | ?? || alignment2 || || || align bits reader on next byte
|}

=== Plane header ===

This header is present at the beginning of every plane.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 8 || ph_flags || || ||
|-
| align="right" | 24 || plan_size || [[#mh_flags|mh_flags]] & 0x80 || || tolal size of plan data
|-
| align="right" | 8 || counter3 || rowspan="3" | [[#ph_flags|ph_flags]] & 0x10 || || must be < 0x3E
|-
| align="right" | 8 || value16 || rowspan="2" | [[#counter3|counter3]] ||
|-
| align="right" | 8 || value17 ||
|-
| align="right" | 3 || value18 || [[#ph_flags|ph_flags]] & 0x40 || ||
|-
| align="right" | 3 || table1_id || [[#ph_flags|ph_flags]] & 0x80 || || see [[#Table_1|Table 1]]
|-
| align="right" | 4 || counter4 || rowspan="2" | [[#table1_id|table1_id]] == 7 || || rowspan="2" | used instead of [[#Table1|Table1]]
|-
| align="right" | 4 || value19 || [[#counter4|counter4]]
|-
| align="right" | 1 || value20 || || ||
|-
| align="right" | 16 || value21 || [[#value20|value20]] || ||
|-
| align="right" | 5 || value22 || || ||
|-
| align="right" | ?? || alignment3 || || || align bits reader on next byte
|-
| align="right" | 8 || counter5 || rowspan="4" | [[#ph_flags|ph_flags]] & 0x20 || || rowspan="3" | all of this is repeated as long as [[#value23|value23]] is true
|-
| align="right" | 8 || skip1 || [[#counter5|counter5]]
|-
| align="right" | 1 || value23 ||
|-
| align="right" | ?? || alignment4 || || align bits reader on next byte
|}

== Planes ==
=== Plane data ===

Needs more analysis. Follows plane header.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 1 || value24 || || ||
|-
| align="right" | 1 || value25 || ! [[#value24|value24]] || || plan_data_size = value25
|-
| align="right" | 8 || value26 || [[#value25|value25]] == 1 || || plan_data_size = value26
|-
| align="right" | 24 || value27 || [[#value26|value26]] == 0xFF || || plan_data_size = value27
|}

=== Block header ===

Each plane is split into a number of blocks in the x and y directions. There is one of these headers one after another for each block in the plane.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 1 || value28 || || ||
|-
| align="right" | vlc || value29 || value28 && plane_state17 || ||
|-
| align="right" | 1 || value30 || !value28 && plane_state12 && plane_state1 || ||
|-
| align="right" | 4 || value31 || !value28 && four_blocks || ||
|-
| align="right" | 1 || value32 || !value28 && !four_blocks || ||
|-
| align="right" | vlc || value33 || !value28 && plane_state14 && !plane_state13 && (plane_state17 <nowiki>||</nowiki> value31/2) || ||
|-
| align="right" | vlc || value34 || rowspan=2 | !value28 && !(block_state4 & 2) && !plane_state12 || ||
|-
| align="right" | vlc || value35 || ||
|}

The 'plane_state' states come from plane parsing; they are yet to be connected to the previous data.

block_state4 is too complicated to explain here, sorry!

=== Block data ===

Follows block header. One of these for each plane that has 'plane_flags&1'. The variable 'run' starts at -1 and carries over from one coded plane to the next. I don't really know what I'm doing with vlc's so the names might not be correct... but their functional description is.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | vlc || vlc || || rowspan=4 valign=top | while (vlc != vlcEnd) ||
|-
| align="right" | vlc || run_add || rowspan=3 | vlc == vlcEsc || run += run_add + 1
|-
| align="right" | vlc || lindex_lo || rowspan=2 | lindex = lindex_lo <nowiki>|</nowiki> (lindex_hi<<6)
|-
| align="right" | vlc || lindex_hi
|}

If vlc != vlcEsc then run_add is run_table[vlc], lindex is lindex_table[vlc].

After each loop, stored coefficient is: block[ scan_table[run] ] = level_tables[run][lindex-1].

The values of vlcEnd and vlcEsc are variable, as is the vlc table itself. However, they are all fixed for all the planes in the same block. run_table, lindex_table, scan_table are also fixed-per-block. level_tables is per-plane.

== Annexes ==

=== Resolution table ===

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
! bgcolor="#f0f0f0" | res_id
| 0 || 1 || 2 || 3 || 4 || 5 || 6 || 7 || 8 || 9 || 10 || 11
|-
! bgcolor="#f0f0f0" | width
| 640 || 320 || 160 || 704 || 352 || 352 || 176 || 240 || 640 || 704 || 80 || 88
|-
! bgcolor="#f0f0f0" | height
| 480 || 240 || 120 || 224 || 240 || 288 || 144 || 180 || 240 || 240 || 60 || 72
|}

=== Table 1 ===

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
! bgcolor="#f0f0f0" | table1_id
| 0 || 1 || 2 || 3 || 4 || 5 || 6 || default
|-
! bgcolor="#f0f0f0" | counter4
| 10 || 11 || 12 || 13 || 11 || 13 || 13 || 9
|-
! valign="top" bgcolor="#f0f0f0" | value19
| valign="top" |
{| border="0"
| 1
|-
| 2
|-
| 3
|-
| 4
|-
| 4
|-
| 7
|-
| 5
|-
| 5
|-
| 4
|-
| 1
|}
| valign="top" |
{| border="0"
| 2
|-
| 3
|-
| 4
|-
| 4
|-
| 4
|-
| 7
|-
| 5
|-
| 4
|-
| 3
|-
| 3
|-
| 2
|}
| valign="top" |
{| border="0"
| 2
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 4
|-
| 4
|-
| 3
|-
| 1
|-
| 1
|}
| valign="top" |
{| border="0"
| 3
|-
| 3
|-
| 4
|-
| 4
|-
| 5
|-
| 6
|-
| 6
|-
| 4
|-
| 4
|-
| 3
|-
| 2
|-
| 1
|-
| 1
|}
| valign="top" |
{| border="0"
| 3
|-
| 4
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 5
|-
| 4
|-
| 2
|-
| 2
|}
| valign="top" |
{| border="0"
| 3
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 4
|-
| 3
|-
| 3
|-
| 2
|-
| 1
|-
| 1
|}
| valign="top" |
{| border="0"
| 3
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 5
|-
| 4
|-
| 3
|-
| 3
|-
| 2
|-
| 1
|-
| 1
|}
| valign="top" |
{| border="0"
| 3
|-
| 4
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 5
|-
| 5
|}
|}

default is used when !([[#ph_flags|ph_flags]] & 0x80)

[[Category:Undiscovered Video Codecs]]
[[Category:Video Codecs]]

Indeo 5

2006-08-15T08:39:58Z

FyKnight: Block header: might or might not be huffman but is definitely a vlc

* FOURCCs: IV50
* Company: [[Intel]], then [[Ligos]]
* Samples: [http://samples.mplayerhq.hu/V-codecs/IV50/ http://samples.mplayerhq.hu/V-codecs/IV50/]

== General description ==

=== Frame layout ===

The general indeo5 frames layout is composed of one global header, followed by the content of the three YUV plans.

In this document, the global header is split into 3 parts:
* [[#Frame_header|Frame header]]: describe the kind of frame (I/P/B)
* [[#GOP_header|GOP header]]: some data which is true for all the frame in this GOP (present only in the first (I) frame of the GOP)
* [[#More_header|More header]]: some more data which is true only for this single frame

Each YUV plan begin with a [[#Plan_header|Plan header]], containing values which are valid only for this single plan.

=== Encoding ===

This codec is based on the slant transform. Other used standard techniques are huffman coding and motion compensation.

=== Conventions ===

Headers are described in some tables. Each row of those tables describes a value which may be read from the frame. Those tables and rows are presented in the order of appearance in the frame.

Here are the meaning of each columns:
* '''size''': The size of this value in bits. Bits are counted in LSB to MSB order. As an example, with the byte 01110000b, reading 3 bits then 5 bits will return 000b then 01110b. Reading more than 8 bits thus reads as a little-endian value. Think of the get_bits function as filling up the return value from its LSB, using the bits from each byte starting from their LSB.
* '''name''': Kind of variable name, used to reference the value. When a value is named valueX, it generally means we don't know it's purpose. Lines named alignmentX means that bits reader need to skip bits until next byte boundary.
* '''condition''': The value is present in the frame only if this condition is matched. No condition means that the value is always present.
* '''nb times''': How many times the value is repeated.
* '''comments''': Some details about the content of the value. It may also explain that a value is repeated until a certain condition is reached.

== Headers ==

=== Frame header ===

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| 5 || const1 || || || = 0x1F always
|-
| 3 || frame_flags || || ||
* frame_flags & 0x01 => backward predictive
* frame_flags & 0x02 => forward predictive
* frame_flags & 0x04 => null frame
common values:
* 0 => I frame
* 1 => P frame
* 3 => B frame
* 6 and 7 are illegal
|-
| 8 || id_in_gop || || || frame number in GOP (0 for I frame)
|}

null frames don't contain anything else than this header.

=== GOP header ===

This header is present in I frames only. The values in this header are valid during the whole GOP starting at this frame.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 8 || gh_flags || || || [[#gh_flags|gh_flags]] & 0x02 => YV12 (default YVU9)
|-
| align="right" | 16 || value1 || [[#gh_flags|gh_flags]] & 0x01 || || discard in decoding
|-
| align="right" | 32 || value2 || [[#gh_flags|gh_flags]] & 0x20 || ||
|-
| align="right" | 2 || value3 || [[#gh_flags|gh_flags]] & 0x40 || ||
|-
| align="right" | 3 || value4 || || || legal values are 0, 1, 2 and 6
|-
| align="right" | 4 || res_id || || || see [[#Resolution_table|Resolution table]]
|-
| align="right" | 13 || height || rowspan="2" | [[#res_id|res_id]] == 15 || || frame height
|-
| align="right" | 13 || width || || frame width
|-
| align="right" | 6 || value5 || || rowspan="2" | 2*n (n == 1 always?) ||
|-
| align="right" | 2 || value6 || [[#value5|value5]] >> 3 || need to be = 0
|-
| align="right" | 4 || value7 || rowspan="2" | [[#gh_flags|gh_flags]] & 0x08 || ||
|-
| align="right" | 24 || value8 || ||
|-
| align="right" | ?? || alignment1 || || || align bits reader on next byte
|-
| align="right" | 24 || value9 || || ||
|-
| align="right" | 16 || value10 || [[#value9|value9]] & 0x800000 || || loops while value10 & 0x8000 (probably some kind of VLC ?)
|}

=== More header ===

This header is present in all kinds of frame except null.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 8 || mh_flags || || ||
|-
| align="right" | 24 || frame_size || [[#mh_flags|mh_flags]] & 0x01 || || tolal size of frame data
|-
| align="right" | 16 || value11 || [[#mh_flags|mh_flags]] & 0x10 || ||
|-
| align="right" | 8 || counter1 || rowspan="2" | [[#mh_flags|mh_flags]] & 0x20 || || rowspan="2" | this whole block loops while [[#counter1|counter1]] != 0
|-
| align="right" | 8 || value12 || [[#counter1|counter1]]
|-
| align="right" | 3 || value13 || [[#mh_flags|mh_flags]] & 0x40 || ||
|-
| align="right" | 4 || counter2 || rowspan="2" | [[#value13|value13]] == 7 || ||
|-
| align="right" | 4 || value14 || [[#counter2|counter2]] ||
|-
| align="right" | 3 || value15 || || ||
|-
| align="right" | ?? || alignment2 || || || align bits reader on next byte
|}

=== Plane header ===

This header is present at the beginning of every plane.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 8 || ph_flags || || ||
|-
| align="right" | 24 || plan_size || [[#mh_flags|mh_flags]] & 0x80 || || tolal size of plan data
|-
| align="right" | 8 || counter3 || rowspan="3" | [[#ph_flags|ph_flags]] & 0x10 || || must be < 0x3E
|-
| align="right" | 8 || value16 || rowspan="2" | [[#counter3|counter3]] ||
|-
| align="right" | 8 || value17 ||
|-
| align="right" | 3 || value18 || [[#ph_flags|ph_flags]] & 0x40 || ||
|-
| align="right" | 3 || table1_id || [[#ph_flags|ph_flags]] & 0x80 || || see [[#Table_1|Table 1]]
|-
| align="right" | 4 || counter4 || rowspan="2" | [[#table1_id|table1_id]] == 7 || || rowspan="2" | used instead of [[#Table1|Table1]]
|-
| align="right" | 4 || value19 || [[#counter4|counter4]]
|-
| align="right" | 1 || value20 || || ||
|-
| align="right" | 16 || value21 || [[#value20|value20]] || ||
|-
| align="right" | 5 || value22 || || ||
|-
| align="right" | ?? || alignment3 || || || align bits reader on next byte
|-
| align="right" | 8 || counter5 || rowspan="4" | [[#ph_flags|ph_flags]] & 0x20 || || rowspan="3" | all of this is repeated as long as [[#value23|value23]] is true
|-
| align="right" | 8 || skip1 || [[#counter5|counter5]]
|-
| align="right" | 1 || value23 ||
|-
| align="right" | ?? || alignment4 || || align bits reader on next byte
|}

== Planes ==
=== Plane data ===

Needs more analysis. Follows plane header.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 1 || value24 || || ||
|-
| align="right" | 1 || value25 || ! [[#value24|value24]] || || plan_data_size = value25
|-
| align="right" | 8 || value26 || [[#value25|value25]] == 1 || || plan_data_size = value26
|-
| align="right" | 24 || value27 || [[#value26|value26]] == 0xFF || || plan_data_size = value27
|}

=== Block header ===

One of these for each block after plane data. Conditions/loops not yet investigated.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 1 || value28 || || ||
|-
| align="right" | vlc || value29 || || ||
|-
| align="right" | 1 || value30 || || ||
|-
| align="right" | 4 || value31 || || ||
|-
| align="right" | 1 || value32 || || ||
|-
| align="right" | vlc || value33 || || ||
|-
| align="right" | vlc || value34 || || ||
|-
| align="right" | vlc || value35 || || ||
|}

=== Block data ===

Follows block header. One of these for each plane that has 'plane_flags&1'. The variable 'run' starts at -1 and carries over from one coded plane to the next. I don't really know what I'm doing with vlc's so the names might not be correct... but their functional description is.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | vlc || vlc || || rowspan=4 valign=top | while (vlc != vlcEnd) ||
|-
| align="right" | vlc || run_add || rowspan=3 | vlc == vlcEsc || run += run_add + 1
|-
| align="right" | vlc || lindex_lo || rowspan=2 | lindex = lindex_lo <nowiki>|</nowiki> (lindex_hi<<6)
|-
| align="right" | vlc || lindex_hi
|}

If vlc != vlcEsc then run_add is run_table[vlc], lindex is lindex_table[vlc].

After each loop, stored coefficient is: block[ scan_table[run] ] = level_tables[run][lindex-1].

The values of vlcEnd and vlcEsc are variable, as is the vlc table itself. However, they are all fixed for all the planes in the same block. run_table, lindex_table, scan_table are also fixed-per-block. level_tables is per-plane.

== Annexes ==

=== Resolution table ===

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
! bgcolor="#f0f0f0" | res_id
| 0 || 1 || 2 || 3 || 4 || 5 || 6 || 7 || 8 || 9 || 10 || 11
|-
! bgcolor="#f0f0f0" | width
| 640 || 320 || 160 || 704 || 352 || 352 || 176 || 240 || 640 || 704 || 80 || 88
|-
! bgcolor="#f0f0f0" | height
| 480 || 240 || 120 || 224 || 240 || 288 || 144 || 180 || 240 || 240 || 60 || 72
|}

=== Table 1 ===

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
! bgcolor="#f0f0f0" | table1_id
| 0 || 1 || 2 || 3 || 4 || 5 || 6 || default
|-
! bgcolor="#f0f0f0" | counter4
| 10 || 11 || 12 || 13 || 11 || 13 || 13 || 9
|-
! valign="top" bgcolor="#f0f0f0" | value19
| valign="top" |
{| border="0"
| 1
|-
| 2
|-
| 3
|-
| 4
|-
| 4
|-
| 7
|-
| 5
|-
| 5
|-
| 4
|-
| 1
|}
| valign="top" |
{| border="0"
| 2
|-
| 3
|-
| 4
|-
| 4
|-
| 4
|-
| 7
|-
| 5
|-
| 4
|-
| 3
|-
| 3
|-
| 2
|}
| valign="top" |
{| border="0"
| 2
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 4
|-
| 4
|-
| 3
|-
| 1
|-
| 1
|}
| valign="top" |
{| border="0"
| 3
|-
| 3
|-
| 4
|-
| 4
|-
| 5
|-
| 6
|-
| 6
|-
| 4
|-
| 4
|-
| 3
|-
| 2
|-
| 1
|-
| 1
|}
| valign="top" |
{| border="0"
| 3
|-
| 4
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 5
|-
| 4
|-
| 2
|-
| 2
|}
| valign="top" |
{| border="0"
| 3
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 4
|-
| 3
|-
| 3
|-
| 2
|-
| 1
|-
| 1
|}
| valign="top" |
{| border="0"
| 3
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 5
|-
| 4
|-
| 3
|-
| 3
|-
| 2
|-
| 1
|-
| 1
|}
| valign="top" |
{| border="0"
| 3
|-
| 4
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 5
|-
| 5
|}
|}

default is used when !([[#ph_flags|ph_flags]] & 0x80)

[[Category:Undiscovered Video Codecs]]
[[Category:Video Codecs]]

Indeo 5

2006-08-15T08:35:40Z

FyKnight: Block data: prettified; little extra info on tables

* FOURCCs: IV50
* Company: [[Intel]], then [[Ligos]]
* Samples: [http://samples.mplayerhq.hu/V-codecs/IV50/ http://samples.mplayerhq.hu/V-codecs/IV50/]

== General description ==

=== Frame layout ===

The general indeo5 frames layout is composed of one global header, followed by the content of the three YUV plans.

In this document, the global header is split into 3 parts:
* [[#Frame_header|Frame header]]: describe the kind of frame (I/P/B)
* [[#GOP_header|GOP header]]: some data which is true for all the frame in this GOP (present only in the first (I) frame of the GOP)
* [[#More_header|More header]]: some more data which is true only for this single frame

Each YUV plan begin with a [[#Plan_header|Plan header]], containing values which are valid only for this single plan.

=== Encoding ===

This codec is based on the slant transform. Other used standard techniques are huffman coding and motion compensation.

=== Conventions ===

Headers are described in some tables. Each row of those tables describes a value which may be read from the frame. Those tables and rows are presented in the order of appearance in the frame.

Here are the meaning of each columns:
* '''size''': The size of this value in bits. Bits are counted in LSB to MSB order. As an example, with the byte 01110000b, reading 3 bits then 5 bits will return 000b then 01110b. Reading more than 8 bits thus reads as a little-endian value. Think of the get_bits function as filling up the return value from its LSB, using the bits from each byte starting from their LSB.
* '''name''': Kind of variable name, used to reference the value. When a value is named valueX, it generally means we don't know it's purpose. Lines named alignmentX means that bits reader need to skip bits until next byte boundary.
* '''condition''': The value is present in the frame only if this condition is matched. No condition means that the value is always present.
* '''nb times''': How many times the value is repeated.
* '''comments''': Some details about the content of the value. It may also explain that a value is repeated until a certain condition is reached.

== Headers ==

=== Frame header ===

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| 5 || const1 || || || = 0x1F always
|-
| 3 || frame_flags || || ||
* frame_flags & 0x01 => backward predictive
* frame_flags & 0x02 => forward predictive
* frame_flags & 0x04 => null frame
common values:
* 0 => I frame
* 1 => P frame
* 3 => B frame
* 6 and 7 are illegal
|-
| 8 || id_in_gop || || || frame number in GOP (0 for I frame)
|}

null frames don't contain anything else than this header.

=== GOP header ===

This header is present in I frames only. The values in this header are valid during the whole GOP starting at this frame.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 8 || gh_flags || || || [[#gh_flags|gh_flags]] & 0x02 => YV12 (default YVU9)
|-
| align="right" | 16 || value1 || [[#gh_flags|gh_flags]] & 0x01 || || discard in decoding
|-
| align="right" | 32 || value2 || [[#gh_flags|gh_flags]] & 0x20 || ||
|-
| align="right" | 2 || value3 || [[#gh_flags|gh_flags]] & 0x40 || ||
|-
| align="right" | 3 || value4 || || || legal values are 0, 1, 2 and 6
|-
| align="right" | 4 || res_id || || || see [[#Resolution_table|Resolution table]]
|-
| align="right" | 13 || height || rowspan="2" | [[#res_id|res_id]] == 15 || || frame height
|-
| align="right" | 13 || width || || frame width
|-
| align="right" | 6 || value5 || || rowspan="2" | 2*n (n == 1 always?) ||
|-
| align="right" | 2 || value6 || [[#value5|value5]] >> 3 || need to be = 0
|-
| align="right" | 4 || value7 || rowspan="2" | [[#gh_flags|gh_flags]] & 0x08 || ||
|-
| align="right" | 24 || value8 || ||
|-
| align="right" | ?? || alignment1 || || || align bits reader on next byte
|-
| align="right" | 24 || value9 || || ||
|-
| align="right" | 16 || value10 || [[#value9|value9]] & 0x800000 || || loops while value10 & 0x8000 (probably some kind of VLC ?)
|}

=== More header ===

This header is present in all kinds of frame except null.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 8 || mh_flags || || ||
|-
| align="right" | 24 || frame_size || [[#mh_flags|mh_flags]] & 0x01 || || tolal size of frame data
|-
| align="right" | 16 || value11 || [[#mh_flags|mh_flags]] & 0x10 || ||
|-
| align="right" | 8 || counter1 || rowspan="2" | [[#mh_flags|mh_flags]] & 0x20 || || rowspan="2" | this whole block loops while [[#counter1|counter1]] != 0
|-
| align="right" | 8 || value12 || [[#counter1|counter1]]
|-
| align="right" | 3 || value13 || [[#mh_flags|mh_flags]] & 0x40 || ||
|-
| align="right" | 4 || counter2 || rowspan="2" | [[#value13|value13]] == 7 || ||
|-
| align="right" | 4 || value14 || [[#counter2|counter2]] ||
|-
| align="right" | 3 || value15 || || ||
|-
| align="right" | ?? || alignment2 || || || align bits reader on next byte
|}

=== Plane header ===

This header is present at the beginning of every plane.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 8 || ph_flags || || ||
|-
| align="right" | 24 || plan_size || [[#mh_flags|mh_flags]] & 0x80 || || tolal size of plan data
|-
| align="right" | 8 || counter3 || rowspan="3" | [[#ph_flags|ph_flags]] & 0x10 || || must be < 0x3E
|-
| align="right" | 8 || value16 || rowspan="2" | [[#counter3|counter3]] ||
|-
| align="right" | 8 || value17 ||
|-
| align="right" | 3 || value18 || [[#ph_flags|ph_flags]] & 0x40 || ||
|-
| align="right" | 3 || table1_id || [[#ph_flags|ph_flags]] & 0x80 || || see [[#Table_1|Table 1]]
|-
| align="right" | 4 || counter4 || rowspan="2" | [[#table1_id|table1_id]] == 7 || || rowspan="2" | used instead of [[#Table1|Table1]]
|-
| align="right" | 4 || value19 || [[#counter4|counter4]]
|-
| align="right" | 1 || value20 || || ||
|-
| align="right" | 16 || value21 || [[#value20|value20]] || ||
|-
| align="right" | 5 || value22 || || ||
|-
| align="right" | ?? || alignment3 || || || align bits reader on next byte
|-
| align="right" | 8 || counter5 || rowspan="4" | [[#ph_flags|ph_flags]] & 0x20 || || rowspan="3" | all of this is repeated as long as [[#value23|value23]] is true
|-
| align="right" | 8 || skip1 || [[#counter5|counter5]]
|-
| align="right" | 1 || value23 ||
|-
| align="right" | ?? || alignment4 || || align bits reader on next byte
|}

== Planes ==
=== Plane data ===

Needs more analysis. Follows plane header.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 1 || value24 || || ||
|-
| align="right" | 1 || value25 || ! [[#value24|value24]] || || plan_data_size = value25
|-
| align="right" | 8 || value26 || [[#value25|value25]] == 1 || || plan_data_size = value26
|-
| align="right" | 24 || value27 || [[#value26|value26]] == 0xFF || || plan_data_size = value27
|}

=== Block header ===

One of these for each block after plane data. Conditions/loops not yet investigated.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 1 || value28 || || ||
|-
| align="right" | huffman || value29 || || ||
|-
| align="right" | 1 || value30 || || ||
|-
| align="right" | 4 || value31 || || ||
|-
| align="right" | 1 || value32 || || ||
|-
| align="right" | huffman || value33 || || ||
|-
| align="right" | huffman || value34 || || ||
|-
| align="right" | huffman || value35 || || ||
|}

=== Block data ===

Follows block header. One of these for each plane that has 'plane_flags&1'. The variable 'run' starts at -1 and carries over from one coded plane to the next. I don't really know what I'm doing with vlc's so the names might not be correct... but their functional description is.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | vlc || vlc || || rowspan=4 valign=top | while (vlc != vlcEnd) ||
|-
| align="right" | vlc || run_add || rowspan=3 | vlc == vlcEsc || run += run_add + 1
|-
| align="right" | vlc || lindex_lo || rowspan=2 | lindex = lindex_lo <nowiki>|</nowiki> (lindex_hi<<6)
|-
| align="right" | vlc || lindex_hi
|}

If vlc != vlcEsc then run_add is run_table[vlc], lindex is lindex_table[vlc].

After each loop, stored coefficient is: block[ scan_table[run] ] = level_tables[run][lindex-1].

The values of vlcEnd and vlcEsc are variable, as is the vlc table itself. However, they are all fixed for all the planes in the same block. run_table, lindex_table, scan_table are also fixed-per-block. level_tables is per-plane.

== Annexes ==

=== Resolution table ===

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
! bgcolor="#f0f0f0" | res_id
| 0 || 1 || 2 || 3 || 4 || 5 || 6 || 7 || 8 || 9 || 10 || 11
|-
! bgcolor="#f0f0f0" | width
| 640 || 320 || 160 || 704 || 352 || 352 || 176 || 240 || 640 || 704 || 80 || 88
|-
! bgcolor="#f0f0f0" | height
| 480 || 240 || 120 || 224 || 240 || 288 || 144 || 180 || 240 || 240 || 60 || 72
|}

=== Table 1 ===

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
! bgcolor="#f0f0f0" | table1_id
| 0 || 1 || 2 || 3 || 4 || 5 || 6 || default
|-
! bgcolor="#f0f0f0" | counter4
| 10 || 11 || 12 || 13 || 11 || 13 || 13 || 9
|-
! valign="top" bgcolor="#f0f0f0" | value19
| valign="top" |
{| border="0"
| 1
|-
| 2
|-
| 3
|-
| 4
|-
| 4
|-
| 7
|-
| 5
|-
| 5
|-
| 4
|-
| 1
|}
| valign="top" |
{| border="0"
| 2
|-
| 3
|-
| 4
|-
| 4
|-
| 4
|-
| 7
|-
| 5
|-
| 4
|-
| 3
|-
| 3
|-
| 2
|}
| valign="top" |
{| border="0"
| 2
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 4
|-
| 4
|-
| 3
|-
| 1
|-
| 1
|}
| valign="top" |
{| border="0"
| 3
|-
| 3
|-
| 4
|-
| 4
|-
| 5
|-
| 6
|-
| 6
|-
| 4
|-
| 4
|-
| 3
|-
| 2
|-
| 1
|-
| 1
|}
| valign="top" |
{| border="0"
| 3
|-
| 4
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 5
|-
| 4
|-
| 2
|-
| 2
|}
| valign="top" |
{| border="0"
| 3
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 4
|-
| 3
|-
| 3
|-
| 2
|-
| 1
|-
| 1
|}
| valign="top" |
{| border="0"
| 3
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 5
|-
| 4
|-
| 3
|-
| 3
|-
| 2
|-
| 1
|-
| 1
|}
| valign="top" |
{| border="0"
| 3
|-
| 4
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 5
|-
| 5
|}
|}

default is used when !([[#ph_flags|ph_flags]] & 0x80)

[[Category:Undiscovered Video Codecs]]
[[Category:Video Codecs]]

Indeo 5

2006-08-15T08:31:06Z

FyKnight: Block data info

* FOURCCs: IV50
* Company: [[Intel]], then [[Ligos]]
* Samples: [http://samples.mplayerhq.hu/V-codecs/IV50/ http://samples.mplayerhq.hu/V-codecs/IV50/]

== General description ==

=== Frame layout ===

The general indeo5 frames layout is composed of one global header, followed by the content of the three YUV plans.

In this document, the global header is split into 3 parts:
* [[#Frame_header|Frame header]]: describe the kind of frame (I/P/B)
* [[#GOP_header|GOP header]]: some data which is true for all the frame in this GOP (present only in the first (I) frame of the GOP)
* [[#More_header|More header]]: some more data which is true only for this single frame

Each YUV plan begin with a [[#Plan_header|Plan header]], containing values which are valid only for this single plan.

=== Encoding ===

This codec is based on the slant transform. Other used standard techniques are huffman coding and motion compensation.

=== Conventions ===

Headers are described in some tables. Each row of those tables describes a value which may be read from the frame. Those tables and rows are presented in the order of appearance in the frame.

Here are the meaning of each columns:
* '''size''': The size of this value in bits. Bits are counted in LSB to MSB order. As an example, with the byte 01110000b, reading 3 bits then 5 bits will return 000b then 01110b. Reading more than 8 bits thus reads as a little-endian value. Think of the get_bits function as filling up the return value from its LSB, using the bits from each byte starting from their LSB.
* '''name''': Kind of variable name, used to reference the value. When a value is named valueX, it generally means we don't know it's purpose. Lines named alignmentX means that bits reader need to skip bits until next byte boundary.
* '''condition''': The value is present in the frame only if this condition is matched. No condition means that the value is always present.
* '''nb times''': How many times the value is repeated.
* '''comments''': Some details about the content of the value. It may also explain that a value is repeated until a certain condition is reached.

== Headers ==

=== Frame header ===

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| 5 || const1 || || || = 0x1F always
|-
| 3 || frame_flags || || ||
* frame_flags & 0x01 => backward predictive
* frame_flags & 0x02 => forward predictive
* frame_flags & 0x04 => null frame
common values:
* 0 => I frame
* 1 => P frame
* 3 => B frame
* 6 and 7 are illegal
|-
| 8 || id_in_gop || || || frame number in GOP (0 for I frame)
|}

null frames don't contain anything else than this header.

=== GOP header ===

This header is present in I frames only. The values in this header are valid during the whole GOP starting at this frame.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 8 || gh_flags || || || [[#gh_flags|gh_flags]] & 0x02 => YV12 (default YVU9)
|-
| align="right" | 16 || value1 || [[#gh_flags|gh_flags]] & 0x01 || || discard in decoding
|-
| align="right" | 32 || value2 || [[#gh_flags|gh_flags]] & 0x20 || ||
|-
| align="right" | 2 || value3 || [[#gh_flags|gh_flags]] & 0x40 || ||
|-
| align="right" | 3 || value4 || || || legal values are 0, 1, 2 and 6
|-
| align="right" | 4 || res_id || || || see [[#Resolution_table|Resolution table]]
|-
| align="right" | 13 || height || rowspan="2" | [[#res_id|res_id]] == 15 || || frame height
|-
| align="right" | 13 || width || || frame width
|-
| align="right" | 6 || value5 || || rowspan="2" | 2*n (n == 1 always?) ||
|-
| align="right" | 2 || value6 || [[#value5|value5]] >> 3 || need to be = 0
|-
| align="right" | 4 || value7 || rowspan="2" | [[#gh_flags|gh_flags]] & 0x08 || ||
|-
| align="right" | 24 || value8 || ||
|-
| align="right" | ?? || alignment1 || || || align bits reader on next byte
|-
| align="right" | 24 || value9 || || ||
|-
| align="right" | 16 || value10 || [[#value9|value9]] & 0x800000 || || loops while value10 & 0x8000 (probably some kind of VLC ?)
|}

=== More header ===

This header is present in all kinds of frame except null.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 8 || mh_flags || || ||
|-
| align="right" | 24 || frame_size || [[#mh_flags|mh_flags]] & 0x01 || || tolal size of frame data
|-
| align="right" | 16 || value11 || [[#mh_flags|mh_flags]] & 0x10 || ||
|-
| align="right" | 8 || counter1 || rowspan="2" | [[#mh_flags|mh_flags]] & 0x20 || || rowspan="2" | this whole block loops while [[#counter1|counter1]] != 0
|-
| align="right" | 8 || value12 || [[#counter1|counter1]]
|-
| align="right" | 3 || value13 || [[#mh_flags|mh_flags]] & 0x40 || ||
|-
| align="right" | 4 || counter2 || rowspan="2" | [[#value13|value13]] == 7 || ||
|-
| align="right" | 4 || value14 || [[#counter2|counter2]] ||
|-
| align="right" | 3 || value15 || || ||
|-
| align="right" | ?? || alignment2 || || || align bits reader on next byte
|}

=== Plane header ===

This header is present at the beginning of every plane.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 8 || ph_flags || || ||
|-
| align="right" | 24 || plan_size || [[#mh_flags|mh_flags]] & 0x80 || || tolal size of plan data
|-
| align="right" | 8 || counter3 || rowspan="3" | [[#ph_flags|ph_flags]] & 0x10 || || must be < 0x3E
|-
| align="right" | 8 || value16 || rowspan="2" | [[#counter3|counter3]] ||
|-
| align="right" | 8 || value17 ||
|-
| align="right" | 3 || value18 || [[#ph_flags|ph_flags]] & 0x40 || ||
|-
| align="right" | 3 || table1_id || [[#ph_flags|ph_flags]] & 0x80 || || see [[#Table_1|Table 1]]
|-
| align="right" | 4 || counter4 || rowspan="2" | [[#table1_id|table1_id]] == 7 || || rowspan="2" | used instead of [[#Table1|Table1]]
|-
| align="right" | 4 || value19 || [[#counter4|counter4]]
|-
| align="right" | 1 || value20 || || ||
|-
| align="right" | 16 || value21 || [[#value20|value20]] || ||
|-
| align="right" | 5 || value22 || || ||
|-
| align="right" | ?? || alignment3 || || || align bits reader on next byte
|-
| align="right" | 8 || counter5 || rowspan="4" | [[#ph_flags|ph_flags]] & 0x20 || || rowspan="3" | all of this is repeated as long as [[#value23|value23]] is true
|-
| align="right" | 8 || skip1 || [[#counter5|counter5]]
|-
| align="right" | 1 || value23 ||
|-
| align="right" | ?? || alignment4 || || align bits reader on next byte
|}

== Planes ==
=== Plane data ===

Needs more analysis. Follows plane header.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 1 || value24 || || ||
|-
| align="right" | 1 || value25 || ! [[#value24|value24]] || || plan_data_size = value25
|-
| align="right" | 8 || value26 || [[#value25|value25]] == 1 || || plan_data_size = value26
|-
| align="right" | 24 || value27 || [[#value26|value26]] == 0xFF || || plan_data_size = value27
|}

=== Block header ===

One of these for each block after plane data. Conditions/loops not yet investigated.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 1 || value28 || || ||
|-
| align="right" | huffman || value29 || || ||
|-
| align="right" | 1 || value30 || || ||
|-
| align="right" | 4 || value31 || || ||
|-
| align="right" | 1 || value32 || || ||
|-
| align="right" | huffman || value33 || || ||
|-
| align="right" | huffman || value34 || || ||
|-
| align="right" | huffman || value35 || || ||
|}

=== Block data ===

Follows block header. One of these for each plane that has 'plane_flags&1'. The variable 'run' starts at -1 and carries over from one coded plane to the next. I don't really know what I'm doing with vlc's so the names might not be correct... but their functional description is.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | vlc || vlc || || while (vlc != vlcEnd) ||
|-
| align="right" | vlc || run_add || vlc == vlcEsc || || run += run_add + 1
|-
| align="right" | vlc || lindex_lo || vlc == vlcEsc || || rowspan=2 | lindex = lindex_lo <nowiki>|</nowiki> (lindex_hi<<6)
|-
| align="right" | vlc || lindex_hi || vlc == vlcEsc || ||
|}

If vlc != vlcEsc then run_add is run_table[vlc], lindex is lindex_table[vlc].
After each loop, stored coefficient is: block[ scan_table[run] ] = level_tables[run][lindex-1].
The values of vlcEnd and vlcEsc are variable, as is the vlc table itself. However, they are all fixed for all the planes in the same block.

== Annexes ==

=== Resolution table ===

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
! bgcolor="#f0f0f0" | res_id
| 0 || 1 || 2 || 3 || 4 || 5 || 6 || 7 || 8 || 9 || 10 || 11
|-
! bgcolor="#f0f0f0" | width
| 640 || 320 || 160 || 704 || 352 || 352 || 176 || 240 || 640 || 704 || 80 || 88
|-
! bgcolor="#f0f0f0" | height
| 480 || 240 || 120 || 224 || 240 || 288 || 144 || 180 || 240 || 240 || 60 || 72
|}

=== Table 1 ===

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
! bgcolor="#f0f0f0" | table1_id
| 0 || 1 || 2 || 3 || 4 || 5 || 6 || default
|-
! bgcolor="#f0f0f0" | counter4
| 10 || 11 || 12 || 13 || 11 || 13 || 13 || 9
|-
! valign="top" bgcolor="#f0f0f0" | value19
| valign="top" |
{| border="0"
| 1
|-
| 2
|-
| 3
|-
| 4
|-
| 4
|-
| 7
|-
| 5
|-
| 5
|-
| 4
|-
| 1
|}
| valign="top" |
{| border="0"
| 2
|-
| 3
|-
| 4
|-
| 4
|-
| 4
|-
| 7
|-
| 5
|-
| 4
|-
| 3
|-
| 3
|-
| 2
|}
| valign="top" |
{| border="0"
| 2
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 4
|-
| 4
|-
| 3
|-
| 1
|-
| 1
|}
| valign="top" |
{| border="0"
| 3
|-
| 3
|-
| 4
|-
| 4
|-
| 5
|-
| 6
|-
| 6
|-
| 4
|-
| 4
|-
| 3
|-
| 2
|-
| 1
|-
| 1
|}
| valign="top" |
{| border="0"
| 3
|-
| 4
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 5
|-
| 4
|-
| 2
|-
| 2
|}
| valign="top" |
{| border="0"
| 3
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 4
|-
| 3
|-
| 3
|-
| 2
|-
| 1
|-
| 1
|}
| valign="top" |
{| border="0"
| 3
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 5
|-
| 4
|-
| 3
|-
| 3
|-
| 2
|-
| 1
|-
| 1
|}
| valign="top" |
{| border="0"
| 3
|-
| 4
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 5
|-
| 5
|}
|}

default is used when !([[#ph_flags|ph_flags]] & 0x80)

[[Category:Undiscovered Video Codecs]]
[[Category:Video Codecs]]

Indeo 5

2006-08-07T05:47:20Z

FyKnight: First version of block header and data. s/plan/plane

* FOURCCs: IV50
* Company: [[Intel]], then [[Ligos]]
* Samples: [http://samples.mplayerhq.hu/V-codecs/IV50/ http://samples.mplayerhq.hu/V-codecs/IV50/]

== General description ==

=== Frame layout ===

The general indeo5 frames layout is composed of one global header, followed by the content of the three YUV plans.

In this document, the global header is split into 3 parts:
* [[#Frame_header|Frame header]]: describe the kind of frame (I/P/B)
* [[#GOP_header|GOP header]]: some data which is true for all the frame in this GOP (present only in the first (I) frame of the GOP)
* [[#More_header|More header]]: some more data which is true only for this single frame

Each YUV plan begin with a [[#Plan_header|Plan header]], containing values which are valid only for this single plan.

=== Encoding ===

This codec is based on the slant transform. Other used standard techniques are huffman coding and motion compensation.

=== Conventions ===

Headers are described in some tables. Each row of those tables describes a value which may be read from the frame. Those tables and rows are presented in the order of appearance in the frame.

Here are the meaning of each columns:
* '''size''': The size of this value in bits. Bits are counted in LSB to MSB order. As an example, with the byte 01110000b, reading 3 bits then 5 bits will return 000b then 01110b. Reading more than 8 bits thus reads as a little-endian value. Think of the get_bits function as filling up the return value from its LSB, using the bits from each byte starting from their LSB.
* '''name''': Kind of variable name, used to reference the value. When a value is named valueX, it generally means we don't know it's purpose. Lines named alignmentX means that bits reader need to skip bits until next byte boundary.
* '''condition''': The value is present in the frame only if this condition is matched. No condition means that the value is always present.
* '''nb times''': How many times the value is repeated.
* '''comments''': Some details about the content of the value. It may also explain that a value is repeated until a certain condition is reached.

== Headers ==

=== Frame header ===

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| 5 || const1 || || || = 0x1F always
|-
| 3 || frame_flags || || ||
* frame_flags & 0x01 => backward predictive
* frame_flags & 0x02 => forward predictive
* frame_flags & 0x04 => null frame
common values:
* 0 => I frame
* 1 => P frame
* 3 => B frame
* 6 and 7 are illegal
|-
| 8 || id_in_gop || || || frame number in GOP (0 for I frame)
|}

null frames don't contain anything else than this header.

=== GOP header ===

This header is present in I frames only. The values in this header are valid during the whole GOP starting at this frame.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 8 || gh_flags || || || [[#gh_flags|gh_flags]] & 0x02 => YV12 (default YVU9)
|-
| align="right" | 16 || value1 || [[#gh_flags|gh_flags]] & 0x01 || || discard in decoding
|-
| align="right" | 32 || value2 || [[#gh_flags|gh_flags]] & 0x20 || ||
|-
| align="right" | 2 || value3 || [[#gh_flags|gh_flags]] & 0x40 || ||
|-
| align="right" | 3 || value4 || || || legal values are 0, 1, 2 and 6
|-
| align="right" | 4 || res_id || || || see [[#Resolution_table|Resolution table]]
|-
| align="right" | 13 || height || rowspan="2" | [[#res_id|res_id]] == 15 || || frame height
|-
| align="right" | 13 || width || || frame width
|-
| align="right" | 6 || value5 || || rowspan="2" | 2*n (n == 1 always?) ||
|-
| align="right" | 2 || value6 || [[#value5|value5]] >> 3 || need to be = 0
|-
| align="right" | 4 || value7 || rowspan="2" | [[#gh_flags|gh_flags]] & 0x08 || ||
|-
| align="right" | 24 || value8 || ||
|-
| align="right" | ?? || alignment1 || || || align bits reader on next byte
|-
| align="right" | 24 || value9 || || ||
|-
| align="right" | 16 || value10 || [[#value9|value9]] & 0x800000 || || loops while value10 & 0x8000 (probably some kind of VLC ?)
|}

=== More header ===

This header is present in all kinds of frame except null.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 8 || mh_flags || || ||
|-
| align="right" | 24 || frame_size || [[#mh_flags|mh_flags]] & 0x01 || || tolal size of frame data
|-
| align="right" | 16 || value11 || [[#mh_flags|mh_flags]] & 0x10 || ||
|-
| align="right" | 8 || counter1 || rowspan="2" | [[#mh_flags|mh_flags]] & 0x20 || || rowspan="2" | this whole block loops while [[#counter1|counter1]] != 0
|-
| align="right" | 8 || value12 || [[#counter1|counter1]]
|-
| align="right" | 3 || value13 || [[#mh_flags|mh_flags]] & 0x40 || ||
|-
| align="right" | 4 || counter2 || rowspan="2" | [[#value13|value13]] == 7 || ||
|-
| align="right" | 4 || value14 || [[#counter2|counter2]] ||
|-
| align="right" | 3 || value15 || || ||
|-
| align="right" | ?? || alignment2 || || || align bits reader on next byte
|}

=== Plane header ===

This header is present at the beginning of every plane.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 8 || ph_flags || || ||
|-
| align="right" | 24 || plan_size || [[#mh_flags|mh_flags]] & 0x80 || || tolal size of plan data
|-
| align="right" | 8 || counter3 || rowspan="3" | [[#ph_flags|ph_flags]] & 0x10 || || must be < 0x3E
|-
| align="right" | 8 || value16 || rowspan="2" | [[#counter3|counter3]] ||
|-
| align="right" | 8 || value17 ||
|-
| align="right" | 3 || value18 || [[#ph_flags|ph_flags]] & 0x40 || ||
|-
| align="right" | 3 || table1_id || [[#ph_flags|ph_flags]] & 0x80 || || see [[#Table_1|Table 1]]
|-
| align="right" | 4 || counter4 || rowspan="2" | [[#table1_id|table1_id]] == 7 || || rowspan="2" | used instead of [[#Table1|Table1]]
|-
| align="right" | 4 || value19 || [[#counter4|counter4]]
|-
| align="right" | 1 || value20 || || ||
|-
| align="right" | 16 || value21 || [[#value20|value20]] || ||
|-
| align="right" | 5 || value22 || || ||
|-
| align="right" | ?? || alignment3 || || || align bits reader on next byte
|-
| align="right" | 8 || counter5 || rowspan="4" | [[#ph_flags|ph_flags]] & 0x20 || || rowspan="3" | all of this is repeated as long as [[#value23|value23]] is true
|-
| align="right" | 8 || skip1 || [[#counter5|counter5]]
|-
| align="right" | 1 || value23 ||
|-
| align="right" | ?? || alignment4 || || align bits reader on next byte
|}

== Planes ==
=== Plane data ===

Needs more analysis. Follows plane header.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 1 || value24 || || ||
|-
| align="right" | 1 || value25 || ! [[#value24|value24]] || || plan_data_size = value25
|-
| align="right" | 8 || value26 || [[#value25|value25]] == 1 || || plan_data_size = value26
|-
| align="right" | 24 || value27 || [[#value26|value26]] == 0xFF || || plan_data_size = value27
|}

=== Block header ===

One of these for each block after plane data. Conditions/loops not yet investigated.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 1 || value28 || || ||
|-
| align="right" | huffman || value29 || || ||
|-
| align="right" | 1 || value30 || || ||
|-
| align="right" | 4 || value31 || || ||
|-
| align="right" | 1 || value32 || || ||
|-
| align="right" | huffman || value33 || || ||
|-
| align="right" | huffman || value34 || || ||
|-
| align="right" | huffman || value35 || || ||
|}

=== Block data ===

Follows block header. Conditions/loops not yet investigated.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | huffman || value35 || || ||
|-
| align="right" | huffman || value36 || || ||
|-
| align="right" | huffman || value37 || || ||
|-
| align="right" | huffman || value38 || || ||
|}

== Annexes ==

=== Resolution table ===

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
! bgcolor="#f0f0f0" | res_id
| 0 || 1 || 2 || 3 || 4 || 5 || 6 || 7 || 8 || 9 || 10 || 11
|-
! bgcolor="#f0f0f0" | width
| 640 || 320 || 160 || 704 || 352 || 352 || 176 || 240 || 640 || 704 || 80 || 88
|-
! bgcolor="#f0f0f0" | height
| 480 || 240 || 120 || 224 || 240 || 288 || 144 || 180 || 240 || 240 || 60 || 72
|}

=== Table 1 ===

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
! bgcolor="#f0f0f0" | table1_id
| 0 || 1 || 2 || 3 || 4 || 5 || 6 || default
|-
! bgcolor="#f0f0f0" | counter4
| 10 || 11 || 12 || 13 || 11 || 13 || 13 || 9
|-
! valign="top" bgcolor="#f0f0f0" | value19
| valign="top" |
{| border="0"
| 1
|-
| 2
|-
| 3
|-
| 4
|-
| 4
|-
| 7
|-
| 5
|-
| 5
|-
| 4
|-
| 1
|}
| valign="top" |
{| border="0"
| 2
|-
| 3
|-
| 4
|-
| 4
|-
| 4
|-
| 7
|-
| 5
|-
| 4
|-
| 3
|-
| 3
|-
| 2
|}
| valign="top" |
{| border="0"
| 2
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 4
|-
| 4
|-
| 3
|-
| 1
|-
| 1
|}
| valign="top" |
{| border="0"
| 3
|-
| 3
|-
| 4
|-
| 4
|-
| 5
|-
| 6
|-
| 6
|-
| 4
|-
| 4
|-
| 3
|-
| 2
|-
| 1
|-
| 1
|}
| valign="top" |
{| border="0"
| 3
|-
| 4
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 5
|-
| 4
|-
| 2
|-
| 2
|}
| valign="top" |
{| border="0"
| 3
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 4
|-
| 3
|-
| 3
|-
| 2
|-
| 1
|-
| 1
|}
| valign="top" |
{| border="0"
| 3
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 5
|-
| 4
|-
| 3
|-
| 3
|-
| 2
|-
| 1
|-
| 1
|}
| valign="top" |
{| border="0"
| 3
|-
| 4
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 5
|-
| 5
|}
|}

default is used when !([[#ph_flags|ph_flags]] & 0x80)

[[Category:Undiscovered Video Codecs]]
[[Category:Video Codecs]]

Indeo 5

2006-08-06T16:56:00Z

FyKnight: Fixed bit order description since it's little-endian. Added a few remarks.

* FOURCCs: IV50
* Company: [[Intel]], then [[Ligos]]
* Samples: [http://samples.mplayerhq.hu/V-codecs/IV50/ http://samples.mplayerhq.hu/V-codecs/IV50/]

== General description ==

=== Frame layout ===

The general indeo5 frames layout is composed of one global header, followed by the content of the three YUV plans.

In this document, the global header is split into 3 parts:
* [[#Frame_header|Frame header]]: describe the kind of frame (I/P/B)
* [[#GOP_header|GOP header]]: some data which is true for all the frame in this GOP (present only in the first (I) frame of the GOP)
* [[#More_header|More header]]: some more data which is true only for this single frame

Each YUV plan begin with a [[#Plan_header|Plan header]], containing values which are valid only for this single plan.

=== Encoding ===

This codec is based on the slant transform. Other used standard techniques are huffman coding and motion compensation.

=== Conventions ===

Headers are described in some tables. Each row of those tables describes a value which may be read from the frame. Those tables and rows are presented in the order of appearance in the frame.

Here are the meaning of each columns:
* '''size''': The size of this value in bits. Bits are counted in LSB to MSB order. As an example, with the byte 01110000b, reading 3 bits then 5 bits will return 000b then 01110b. Reading more than 8 bits thus reads as a little-endian value. Think of the get_bits function as filling up the return value from its LSB, using the bits from each byte starting from their LSB.
* '''name''': Kind of variable name, used to reference the value. When a value is named valueX, it generally means we don't know it's purpose. Lines named alignmentX means that bits reader need to skip bits until next byte boundary.
* '''condition''': The value is present in the frame only if this condition is matched. No condition means that the value is always present.
* '''nb times''': How many times the value is repeated.
* '''comments''': Some details about the content of the value. It may also explain that a value is repeated until a certain condition is reached.

== Headers ==

=== Frame header ===

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| 5 || const1 || || || = 0x1F always
|-
| 3 || frame_flags || || ||
* frame_flags & 0x01 => backward predictive
* frame_flags & 0x02 => forward predictive
* frame_flags & 0x04 => null frame
common values:
* 0 => I frame
* 1 => P frame
* 3 => B frame
* 6 and 7 are illegal
|-
| 8 || id_in_gop || || || frame number in GOP (0 for I frame)
|}

null frames don't contain anything else than this header.

=== GOP header ===

This header is present in I frames only. The values in this header are valid during the whole GOP starting at this frame.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 8 || gh_flags || || || [[#gh_flags|gh_flags]] & 0x02 => YV12 (default YVU9)
|-
| align="right" | 16 || value1 || [[#gh_flags|gh_flags]] & 0x01 || || discard in decoding
|-
| align="right" | 32 || value2 || [[#gh_flags|gh_flags]] & 0x20 || ||
|-
| align="right" | 2 || value3 || [[#gh_flags|gh_flags]] & 0x40 || ||
|-
| align="right" | 3 || value4 || || || legal values are 0, 1, 2 and 6
|-
| align="right" | 4 || res_id || || || see [[#Resolution_table|Resolution table]]
|-
| align="right" | 13 || height || rowspan="2" | [[#res_id|res_id]] == 15 || || frame height
|-
| align="right" | 13 || width || || frame width
|-
| align="right" | 6 || value5 || || rowspan="2" | 2*n (n == 1 always?) ||
|-
| align="right" | 2 || value6 || [[#value5|value5]] >> 3 || need to be = 0
|-
| align="right" | 4 || value7 || rowspan="2" | [[#gh_flags|gh_flags]] & 0x08 || ||
|-
| align="right" | 24 || value8 || ||
|-
| align="right" | ?? || alignment1 || || || align bits reader on next byte
|-
| align="right" | 24 || value9 || || ||
|-
| align="right" | 16 || value10 || [[#value9|value9]] & 0x800000 || || loops while value10 & 0x8000 (probably some kind of VLC ?)
|}

=== More header ===

This header is present in all kinds of frame except null.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 8 || mh_flags || || ||
|-
| align="right" | 24 || frame_size || [[#mh_flags|mh_flags]] & 0x01 || || tolal size of frame data
|-
| align="right" | 16 || value11 || [[#mh_flags|mh_flags]] & 0x10 || ||
|-
| align="right" | 8 || counter1 || rowspan="2" | [[#mh_flags|mh_flags]] & 0x20 || || rowspan="2" | this whole block loops while [[#counter1|counter1]] != 0
|-
| align="right" | 8 || value12 || [[#counter1|counter1]]
|-
| align="right" | 3 || value13 || [[#mh_flags|mh_flags]] & 0x40 || ||
|-
| align="right" | 4 || counter2 || rowspan="2" | [[#value13|value13]] == 7 || ||
|-
| align="right" | 4 || value14 || [[#counter2|counter2]] ||
|-
| align="right" | 3 || value15 || || ||
|-
| align="right" | ?? || alignment2 || || || align bits reader on next byte
|}

=== Plan header ===

This header is present at the beginning of every plan.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 8 || ph_flags || || ||
|-
| align="right" | 24 || plan_size || [[#mh_flags|mh_flags]] & 0x80 || || tolal size of plan data
|-
| align="right" | 8 || counter3 || rowspan="3" | [[#ph_flags|ph_flags]] & 0x10 || || must be < 0x3E
|-
| align="right" | 8 || value16 || rowspan="2" | [[#counter3|counter3]] ||
|-
| align="right" | 8 || value17 ||
|-
| align="right" | 3 || value18 || [[#ph_flags|ph_flags]] & 0x40 || ||
|-
| align="right" | 3 || table1_id || [[#ph_flags|ph_flags]] & 0x80 || || see [[#Table_1|Table 1]]
|-
| align="right" | 4 || counter4 || rowspan="2" | [[#table1_id|table1_id]] == 7 || || rowspan="2" | used instead of [[#Table1|Table1]]
|-
| align="right" | 4 || value19 || [[#counter4|counter4]]
|-
| align="right" | 1 || value20 || || ||
|-
| align="right" | 16 || value21 || [[#value20|value20]] || ||
|-
| align="right" | 5 || value22 || || ||
|-
| align="right" | ?? || alignment3 || || || align bits reader on next byte
|-
| align="right" | 8 || counter5 || rowspan="4" | [[#ph_flags|ph_flags]] & 0x20 || || rowspan="3" | all of this is repeated as long as [[#value23|value23]] is true
|-
| align="right" | 8 || skip1 || [[#counter5|counter5]]
|-
| align="right" | 1 || value23 ||
|-
| align="right" | ?? || alignment4 || || align bits reader on next byte
|}

== Plan data ==

This is where the actual data is, but this still need to be reverse engineered :-(

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 1 || value24 || || ||
|-
| align="right" | 1 || value25 || ! [[#value24|value24]] || || plan_data_size = value25
|-
| align="right" | 8 || value26 || [[#value25|value25]] == 1 || || plan_data_size = value26
|-
| align="right" | 24 || value27 || [[#value26|value26]] == 0xFF || || plan_data_size = value27
|-
| align="right" | ?? || ... || || || more data to analyze
|}

== Annexes ==

=== Resolution table ===

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
! bgcolor="#f0f0f0" | res_id
| 0 || 1 || 2 || 3 || 4 || 5 || 6 || 7 || 8 || 9 || 10 || 11
|-
! bgcolor="#f0f0f0" | width
| 640 || 320 || 160 || 704 || 352 || 352 || 176 || 240 || 640 || 704 || 80 || 88
|-
! bgcolor="#f0f0f0" | height
| 480 || 240 || 120 || 224 || 240 || 288 || 144 || 180 || 240 || 240 || 60 || 72
|}

=== Table 1 ===

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
! bgcolor="#f0f0f0" | table1_id
| 0 || 1 || 2 || 3 || 4 || 5 || 6 || default
|-
! bgcolor="#f0f0f0" | counter4
| 10 || 11 || 12 || 13 || 11 || 13 || 13 || 9
|-
! valign="top" bgcolor="#f0f0f0" | value19
| valign="top" |
{| border="0"
| 1
|-
| 2
|-
| 3
|-
| 4
|-
| 4
|-
| 7
|-
| 5
|-
| 5
|-
| 4
|-
| 1
|}
| valign="top" |
{| border="0"
| 2
|-
| 3
|-
| 4
|-
| 4
|-
| 4
|-
| 7
|-
| 5
|-
| 4
|-
| 3
|-
| 3
|-
| 2
|}
| valign="top" |
{| border="0"
| 2
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 4
|-
| 4
|-
| 3
|-
| 1
|-
| 1
|}
| valign="top" |
{| border="0"
| 3
|-
| 3
|-
| 4
|-
| 4
|-
| 5
|-
| 6
|-
| 6
|-
| 4
|-
| 4
|-
| 3
|-
| 2
|-
| 1
|-
| 1
|}
| valign="top" |
{| border="0"
| 3
|-
| 4
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 5
|-
| 4
|-
| 2
|-
| 2
|}
| valign="top" |
{| border="0"
| 3
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 4
|-
| 3
|-
| 3
|-
| 2
|-
| 1
|-
| 1
|}
| valign="top" |
{| border="0"
| 3
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 5
|-
| 4
|-
| 3
|-
| 3
|-
| 2
|-
| 1
|-
| 1
|}
| valign="top" |
{| border="0"
| 3
|-
| 4
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 5
|-
| 5
|}
|}

default is used when !([[#ph_flags|ph_flags]] & 0x80)

[[Category:Undiscovered Video Codecs]]
[[Category:Video Codecs]]

Indeo 5

2006-07-24T10:28:05Z

FyKnight: Fixed link to samples.

* FOURCCs: IV50
* Company: [[Intel]], then [[Ligos]]
* Samples: [http://samples.mplayerhq.hu/V-codecs/IV50/ http://samples.mplayerhq.hu/V-codecs/IV50/]

== General description ==

=== Frame layout ===

The general indeo5 frames layout is composed of one global header, followed by the content of the three YUV plans.

In this document, the global header is split into 3 parts:
* [[#Frame_header|Frame header]]: describe the kind of frame (I/P/B)
* [[#GOP_header|GOP header]]: some data which is true for all the frame in this GOP (present only in the first (I) frame of the GOP)
* [[#More_header|More header]]: some more data which is true only for this single frame

Each YUV plan begin with a [[#Plan_header|Plan header]], containing values which are valid only for this single plan.

=== Encoding ===

This codec is based on the slant transform. Other used standard techniques are huffman coding and motion compensation.

=== Conventions ===

Headers are described in some tables. Each row of those tables describes a value which may be read from the frame. Those tables and rows are presented in the order of appearance in the frame.

Here are the meaning of each columns:
* '''size''': The size of this value in bits. Bits are counted in MSB to LSB order. As an example, with the byte 01110000b, reading 3 bits then 5 bits will return 011b then 10000b.
* '''name''': Kind of variable name, used to reference the value. When a value is named valueX, it generally means we don't know it's purpose. Lines named alignmentX means that bits reader need to skip bits until next byte boundary.
* '''condition''': The value is present in the frame only if this condition is matched. No condition means that the value is always present.
* '''nb times''': How many times the value is repeated.
* '''comments''': Some details about the content of the value. It may also explain that a value is repeated until a certain condition is reached.

== Headers ==

=== Frame header ===

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| 3 || frame_flags || || ||
* frame_flags & 0x01 => backward predictive
* frame_flags & 0x02 => forward predictive
* frame_flags & 0x04 => null frame
common values:
* 0 => I frame
* 1 => P frame
* 3 => B frame
|-
| 5 || const1 || || || = 0x1F always
|-
| 8 || id_in_gop || || || frame number in GOP (0 for I frame)
|}

null frames don't contain anything else than this header.

=== GOP header ===

This header is present in I frames only. The values in this header are valid during the whole GOP starting at this frame.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 8 || gh_flags || || || [[#gh_flags|gh_flags]] & 0x02 => YV12 (default YVU9)
|-
| align="right" | 16 || value1 || [[#gh_flags|gh_flags]] & 0x01 || ||
|-
| align="right" | 32 || value2 || [[#gh_flags|gh_flags]] & 0x20 || ||
|-
| align="right" | 2 || value3 || [[#gh_flags|gh_flags]] & 0x40 || ||
|-
| align="right" | 3 || value4 || || ||
|-
| align="right" | 4 || res_id || || || see [[#Resolution_table|Resolution table]]
|-
| align="right" | 13 || height || rowspan="2" | [[#res_id|res_id]] == 15 || || frame height
|-
| align="right" | 13 || width || || frame width
|-
| align="right" | 6 || value5 || || rowspan="2" | 2*n (n == 1 always?) ||
|-
| align="right" | 2 || value6 || [[#value5|value5]] >> 3 || need to be = 0
|-
| align="right" | 4 || value7 || rowspan="2" | [[#gh_flags|gh_flags]] & 0x08 || ||
|-
| align="right" | 24 || value8 || ||
|-
| align="right" | ?? || alignment1 || || || align bits reader on next byte
|-
| align="right" | 24 || value9 || || ||
|-
| align="right" | 16 || value10 || [[#value9|value9]] & 0x800000 || || loops while value10 & 0x8000 (probably some kind of VLC ?)
|}

=== More header ===

This header is present in all kinds of frame except null.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 8 || mh_flags || || ||
|-
| align="right" | 24 || frame_size || [[#mh_flags|mh_flags]] & 0x01 || || tolal size of frame data
|-
| align="right" | 16 || value11 || [[#mh_flags|mh_flags]] & 0x10 || ||
|-
| align="right" | 8 || counter1 || rowspan="2" | [[#mh_flags|mh_flags]] & 0x20 || || rowspan="2" | this whole block loops while [[#counter1|counter1]] != 0
|-
| align="right" | 8 || value12 || [[#counter1|counter1]]
|-
| align="right" | 3 || value13 || [[#mh_flags|mh_flags]] & 0x40 || ||
|-
| align="right" | 4 || counter2 || rowspan="2" | [[#value13|value13]] == 7 || ||
|-
| align="right" | 4 || value14 || [[#counter2|counter2]] ||
|-
| align="right" | 3 || value15 || || ||
|-
| align="right" | ?? || alignment2 || || || align bits reader on next byte
|}

=== Plan header ===

This header is present at the beginning of every plan.

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 8 || ph_flags || || ||
|-
| align="right" | 24 || plan_size || [[#mh_flags|mh_flags]] & 0x80 || || tolal size of plan data
|-
| align="right" | 8 || counter3 || rowspan="3" | [[#ph_flags|ph_flags]] & 0x10 || || must be < 0x3E
|-
| align="right" | 8 || value16 || rowspan="2" | [[#counter3|counter3]] ||
|-
| align="right" | 8 || value17 ||
|-
| align="right" | 3 || value18 || [[#ph_flags|ph_flags]] & 0x40 || ||
|-
| align="right" | 3 || table1_id || [[#ph_flags|ph_flags]] & 0x80 || || see [[#Table_1|Table 1]]
|-
| align="right" | 4 || counter4 || rowspan="2" | [[#table1_id|table1_id]] == 7 || || rowspan="2" | used instead of [[#Table1|Table1]]
|-
| align="right" | 4 || value19 || [[#counter4|counter4]]
|-
| align="right" | 1 || value20 || || ||
|-
| align="right" | 16 || value21 || [[#value20|value20]] || ||
|-
| align="right" | 5 || value22 || || ||
|-
| align="right" | ?? || alignment3 || || || align bits reader on next byte
|-
| align="right" | 8 || counter5 || rowspan="4" | [[#ph_flags|ph_flags]] & 0x20 || || rowspan="3" | all of this is repeated as long as [[#value23|value23]] is true
|-
| align="right" | 8 || skip1 || [[#counter5|counter5]]
|-
| align="right" | 1 || value23 ||
|-
| align="right" | ?? || alignment4 || || align bits reader on next byte
|}

== Plan data ==

This is where the actual data is, but this still need to be reverse engineered :-(

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
|- bgcolor="#f0f0f0" |
! size !! name !! condition !! nb times !! comments
|-
| align="right" | 1 || value24 || || ||
|-
| align="right" | 1 || value25 || ! [[#value24|value24]] || || plan_data_size = value25
|-
| align="right" | 8 || value26 || [[#value25|value25]] == 1 || || plan_data_size = value26
|-
| align="right" | 24 || value27 || [[#value26|value26]] == 0xFF || || plan_data_size = value27
|-
| align="right" | ?? || ... || || || more data to analyze
|}

== Annexes ==

=== Resolution table ===

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
! bgcolor="#f0f0f0" | res_id
| 0 || 1 || 2 || 3 || 4 || 5 || 6 || 7 || 8 || 9 || 10 || 11
|-
! bgcolor="#f0f0f0" | width
| 640 || 320 || 160 || 704 || 352 || 352 || 176 || 240 || 640 || 704 || 80 || 88
|-
! bgcolor="#f0f0f0" | height
| 480 || 240 || 120 || 224 || 240 || 288 || 144 || 180 || 240 || 240 || 60 || 72
|}

=== Table 1 ===

{| border="1" cellpadding="5" style="border-collapse: collapse; border-style: dashed; border-color: #2f6fab;"
! bgcolor="#f0f0f0" | table1_id
| 0 || 1 || 2 || 3 || 4 || 5 || 6 || default
|-
! bgcolor="#f0f0f0" | counter4
| 10 || 11 || 12 || 13 || 11 || 13 || 13 || 9
|-
! valign="top" bgcolor="#f0f0f0" | value19
| valign="top" |
{| border="0"
| 1
|-
| 2
|-
| 3
|-
| 4
|-
| 4
|-
| 7
|-
| 5
|-
| 5
|-
| 4
|-
| 1
|}
| valign="top" |
{| border="0"
| 2
|-
| 3
|-
| 4
|-
| 4
|-
| 4
|-
| 7
|-
| 5
|-
| 4
|-
| 3
|-
| 3
|-
| 2
|}
| valign="top" |
{| border="0"
| 2
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 4
|-
| 4
|-
| 3
|-
| 1
|-
| 1
|}
| valign="top" |
{| border="0"
| 3
|-
| 3
|-
| 4
|-
| 4
|-
| 5
|-
| 6
|-
| 6
|-
| 4
|-
| 4
|-
| 3
|-
| 2
|-
| 1
|-
| 1
|}
| valign="top" |
{| border="0"
| 3
|-
| 4
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 5
|-
| 4
|-
| 2
|-
| 2
|}
| valign="top" |
{| border="0"
| 3
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 4
|-
| 3
|-
| 3
|-
| 2
|-
| 1
|-
| 1
|}
| valign="top" |
{| border="0"
| 3
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 5
|-
| 4
|-
| 3
|-
| 3
|-
| 2
|-
| 1
|-
| 1
|}
| valign="top" |
{| border="0"
| 3
|-
| 4
|-
| 4
|-
| 5
|-
| 5
|-
| 5
|-
| 6
|-
| 5
|-
| 5
|}
|}

default is used when !([[#ph_flags|ph_flags]] & 0x80)

[[Category:Undiscovered Video Codecs]]
[[Category:Video Codecs]]