[Ffmpeg-devel] [Ffmpeg-devel-old] SVCD bug

Michel Bardiaux mbardiaux
Mon Jan 30 10:31:25 CET 2006

M?ns Rullg?rd wrote:
> Colin Ward <lists at codehq.org> writes:
>>M?ns Rullg?rd wrote:
>>>I can think of many reasons to want a proper MPEG file rather than a
>>>encapsulated one.  The OP's file apparently causes problems for ffmpeg.
>>>>   I have a VCD related problem that I have been meaning to look into.
>>>>I have a couple of .dat files from a couple of different VCDs.  One of
>>>>them plays in my FFMPEG based program and the other causes either
>>>>av_open_input_file() or av_find_stream_info() to return an "unknown
>>>>format" error.  I can't remember exactly at the moment as I am not in
>>>>front of my development computer.
>>>>   Why would one VCD .dat file be playable and not the other?
>>>Post some samples, please.
>>   Sorry for the delay, I haven't been home for a few days to upload
>>   the samples.  They can be found here:
>>   http://www.codehq.org/Robots.dat
>>   http://www.codehq.org/Legue.dat
>>   They are both the first 1 MB from the respective .dat files on the
>>   VCD.  As I said, one of them opens successfully and the other
>>   returns an "unknown format" error.  And yet they both open
>>   successfully with MPlayer.
> Those files are both unmunged MPEG1 system streams, except for one
> thing.  The one that fails (Legue.dat) starts with a block of 0x11058
> zeros.  That is more junk than lavf searches when checking the file
> format.
Stricto sensu, a bug, since the standard does not place any restriction 
on the amount of zero-stuffing.

Michel Bardiaux
R&D Director
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