[Ffmpeg-devel] [Ffmpeg-devel-old] SVCD bug
Thu Feb 2 03:11:02 CET 2006
Colin Ward wrote:
> M?ns Rullg?rd wrote:
>>>>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
> So by "unmunged" I assume that you mean standard MPEG1 files, rather
> than files converted to the VCD format?
>>>Stricto sensu, a bug, since the standard does not place any restriction
>>>on the amount of zero-stuffing.
>>I know, but how far is it reasonable to search for a start code? Lavf
>>passes the first 2048 bytes of the file to each demuxer when checking the
>>What's the purpose of those leading zeros anyway?
> Who knows! But they are certainly annoying. The one thing that I
> know is that no matter what VCD I try they almost all contain these
> "unmunged" MPEG1 files with huge arrays of empty zeros at the start! In
> other words, very few VCDs work with my media player.
> I need to learn a bit more about MPEG 1/2/4, VCDs and DVDs. Any
> suggestions of a good book that covers these on a file format level?
It has been a while since I've messed with VCD, but if I remember
correctly, the leading zeros might have something to do with the
2-second lead-in gap on the VCD track. I think it depends on how the
*.dat file was extracted from the VCD.
You might want to take a look at
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