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2022-10-15T09:27:47Z

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* Company: Lore Design Limited

This in an FMV format used in an unpublished PC game [https://www.mobygames.com/game/jaguar/highlander-the-last-of-the-macleods Highlander: The Last of the MacLeods]. It contains 320x240 frames using fixed palette and 22kHz 8-bit PCM audio.

== File format ==

FMV file contains a sequence of chunks prefixed with 4-byte chunk type and 32-bit little-endian chunk size. There are only four known chunk types:
* <code>FMV*</code> - file header (no data)
* <code>AUD1</code> - PCM data
* <code>VID3</code> - video frame
* <code>END*</code> - end of data

== Video compression ==

Frame data is compressed twice with history-based compression (first 32 bits of the frame data are the size of compressed data) and contains commands to paint 4x4 blocks of the frame.

=== History-based compression ===

This is a simple compression method that reads flags (one byte at once, LSB first) and depending on flag value either reads new output value from the stream or reuses a value from history buffer:

prev = 0;
pprev = 0;
while there's still data {
flags = *src++;
for (i = 0; i < 8; i++) {
hist_idx = (pprev << 7) ^ prev;
if ((flags >> i) & 1)
hist[hist_idx] = *src++;
*dst++ = hist[hist_idx];
pprev = prev;
prev = hist[hist_idx];
}
}

=== Block painting commands ===
There are nine commands to paint blocks in rather dithered form. First byte of the stream is command index, the following 1-16 bytes are pixel values:

* 0 - read pixel value, fill block with it
* 1 - read two pixel values, paint block as
0 1 0 1
1 0 1 0
0 1 0 1
1 0 1 0
* 2 - read two pixel values, paint block as
0 1 0 1
1 1 1 1
0 1 0 1
1 1 1 1
* 3 - read two pixel values, paint block as
0 1 0 1
0 0 0 0
0 1 0 1
0 0 0 0
* 4 - read two pixel values, paint block as
0 0 0 0
0 1 0 1
0 0 0 0
0 1 0 1
* 5 - read two pixel values, paint block as
1 1 1 1
0 1 0 1
1 1 1 1
0 1 0 1
* 6 - read five pixel values, paint block as
0 1 0 2
1 3 1 4
0 1 0 2
2 4 2 4
* 7 - read eight pixel values, paint block as
0 1 2 3
1 0 3 2
4 5 6 7
5 4 7 6
* 8 - read 16 pixels for block contents

[[Category:Game Formats]]
[[Category:Video Codecs]]

Highlander FMV - Revision history

Kostya: fill description