[FFmpeg-devel] Chinese AVS file format (with upload)

Baptiste Coudurier baptiste.coudurier
Mon Jun 23 01:55:32 CEST 2008

Stefan Gehrer wrote:
> Hi,
> yesterday I got the "AvsTranscoder_2.0" available at
> http://www.avs.org.cn/DownSys/download.asp?id=6
> running on a virtual XP box.
> In case anyone is interested to do so and has problems with the
> user-friendly interface (see attachment for how it looked for me :) )
> the five buttons at the top are Add/Remove/Clear/Setup/About and the
> lower two Run/Quit.
> This program is said to produce container files according to AVS1 part 9
> (file format). Now this might come as a surprise to many, but this
> standard is widely based on a well-established ISO standard, in this
> case ISO 14496-12.
> Our own MOV demuxer can parse the file and the MP3 audio track is played
> back, but the video track is not recognized. The debug output of
> demuxing is below.
> I uploaded such a file to incoming/AVSFileFormat/AVSFileFormat.mp4
> together with another file which contains the same video stream in ES
> format. I looked at both in a hex editor and would describe the muxing
> process of the video ES into the file as follows:
> - cut ES into chunks starting with the 0x000001 prefix and get rid
> of this prefix
> - put a 32bit size value and an 8bit unknown value in front of
> the chunk
> - put the chunk in the mdat atom of the container file
> I played around a bit with mov.c but basically have no idea about it.
> If anybody is interested in this and could help me feeding the chunks
> to my video decoder I would be glad.
> But I could also imagine that some people are not very happy to see
> yet another bastardization of this file format :)

It uses generic isom container as far as I could see, I added demuxing
support, now you get extradata which is what was stored in 'avss' atom,
and codec recognized. It's up to you now :)

Beware that this is file seems weird though because some stts have
duration 0 which means somes samples have same dts. This is really _bad_.


Baptiste COUDURIER                              GnuPG Key Id: 0x5C1ABAAA
Smartjog USA Inc.                                http://www.smartjog.com
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