[Ffmpeg-devel] Re: Problems Decoding DivX

[Colin Ward]

Hello Michael,

On 02/09/05, you wrote:
>

  [Snip]

>>   I have some AVI files that I believe were encoded with DivX.  These
>> files played fine on the old source code from March (it was just a CVS
>> snapshot) and they also play fine on Windows Media Player and on the
>> Amiga port of MPlayer.  However, the new libavcodec source spews forth a
>> screenful of debug data and won't decode them.  Take a look at the
>> attached file which shows the debug output.  Does anyone have any ideas
>> as to what is causing this?
>
> hmm, could you upload (part of the) the file somewhere so we can take a
> look  

  Ok, the first MB or so can be found at:

  http://www.codehq.org/Tripping.avi

  This works on the latest Amiga version of MPlayer and also on my player
when I was using an old libavcodec and libavformat.  It doesn't work with
the latest libraries and my configuration.

  [Snip]

>> Because that crashes when decoding the comments at the start of the
>> file.  It might be the Theora code or it might be my makefile;  I don't
>> know.
> 
> upload debugger output from ffmpeg_g and upload the theora file too if it
> fails on linux too

  I can't check this on Linux as I won't have access to a Linux box until
Monday.  But I will try to do it then.  In the meantime I have uploaded the
first MB or so of the crashing file to my website.  It can be found at:

  http://www.codehq.org/Sahara.ogg

  This does also fail on the Amiga version of MPlayer as well as on my
player.  Actually, this is an interesting file that you might want to do
some testing with anyway.  I used to work for the CSIRO on a project called
Annodex (http://www.annodex.net) which took Theora + Vorbis Ogg files and
added an extra stream to them, which contaned metadata.  The file mentioned
above contains just such a stream.  Plus not only does it contain an extra
stream but they developed their own Ogg container reading and writing
routines as they didn't like xiph.org's ones.  So maybe this file (and
others created by this system) are just slightly different to Ogg Theora +
Vorbis files created with FFMPEG or the xiph.org libogg implementation.

  Also, the stack trace for this crash can be found at:

  http://www.codehq.org/StackTrace.txt

  That crash happens on line 365 of bitstream.h, in the function
unaligned32_be().  I thought that it was an alignment problem at first as I
wasn't using CONFIG_ALIGN and I am compiling for PPC (can't quite remember
the alignment rules ATM) but it is still crashing now.

  Any ideas would be greatly appreciated!  :-)

/-------------------------------------------------------------------\
[Hitman/Code HQ - 6502/z80/68000/604e/80x86/ARM coder - Amiga rulez!]
[VZ-200/VIC-20/MZ-700/c16/c64*10/c128*8/Plus-4/CPC464/CD32/500*2    ]
[600/1000/1200*2/A4000/SNES/N64/Dreamcast/Athlon 1100/AmigaOne      ]
[Assembly Language: The most fun you can have with your clothes on! ]
\-------------------------------------------------------------------/
????????