https://wiki.multimedia.cx/index.php?action=history&feed=atom&title=NUVisionNUVision - Revision history2026-04-18T09:34:25ZRevision history for this page on the wikiMediaWiki 1.39.5https://wiki.multimedia.cx/index.php?title=NUVision&diff=15703&oldid=prevKostya: fill information2023-07-08T09:11:02Z<p>fill information</p>
<p><b>New page</b></p><div>* Company: Zoran Ltd.<br />
* FOURCCs: <code>NTN1</code>, <code>NTN2</code>, <code>NTN3</code><br />
<br />
This is rather simple video codec based on delta coding. Frame is split into lines, line is split into slices of width 24, 16 or 8 and each is coded using its own prediction method and delta quantisation.<br />
<br />
Frame consists of frame header and line data packed into chunks. Word is 16-bit little-endian value (or two-byte pair when used for mode/delta coding).<br />
<br />
=== Frame header ===<br />
word - should be 0x55 0xAA<br />
byte - header size (normally 12)<br />
byte - frame sequence number (reset with each new frame group)<br />
word - unknown, probably CRC<br />
byte - unknown <br />
byte - probably intra frame flag (should be 0x80)<br />
word - frame width<br />
word - frame height<br />
<br />
=== Line chunks ===<br />
1 byte - should be always 0x5A<br />
1 byte - chunk size in 16-bit words<br />
1 byte - line number<br />
luma slices coding modes<br />
chroma slices coding modes<br />
luma slice data<br />
chroma slice data (may be just one component per line)<br />
<br />
=== Line chunk coding ===<br />
As mentioned above, line is split into 24-pixel slices plus a tail. Each slice can be coded using one of four different modes that are packed into bytes as two-bit variables (MSB first) and padded to the even length (the same coding is used for deltas).<br />
<br />
Slice coding modes:<br />
* 0 - do not update slice from the previous frame<br />
* 1 - unpack deltas and add them to the slice from the previous frame<br />
* 2 - copy top slice (should not be present for the first line)<br />
* 3 - unpack deltas and use top slice for prediction (or do horizontal prediction for the first line)<br />
<br />
Delta values are coded in the following manner:<br />
1 byte - quantiser<br />
packed delta modes<br />
escape values<br />
<br />
There are four delta modes: -1, 0, 1 and escape. So when e.g. delta mode 2 is read, the output value is equal to the quantiser value. And in case of delta mode 3 the actual value is stored right after the whole mode flags.<br />
<br />
[[Category:Video Codecs]]<br />
[[Category:Incomplete Video Codecs]]</div>Kostya