[Ffmpeg-devel] Strange nb_streams value

Måns Rullgård mru
Fri Mar 24 14:46:16 CET 2006

Wiese, Hendrik said:
> Hi hi... Sorry for writing over and over again, but I still
> urgently (!) need help and I want to let you know my newest
> experiences with the libs as I'm going to dispair.
> I tried FFMPEG-0.4.9_pre1 because it is the newest revision
> that gave me a valid nb_streams value in my AVFormatContext
> (given by av_open_input_file). My next problem is, that the
> codec_id in my AVFormatContext is always (!) CODEC_ID_NONE,
> no matter which input file I use. It just has to be an AVI
> file. I'm really going to dispair...
> With the current CVS I get an annoying missbehaviour... The
> nb_streams value (and other fields) of the FormatContext
> given by av_open_input_file is invalid! It contains
> 0xCCCCCCCC instead of the correct number of frames. Just
> before av_open_input_file returns, the value of nb_streams
> (and others) is VALID! But back in the function that called
> av_open_input_file, I can't work with these fields, because
> they aren't valid anymore.
> For info: I'm working with Windows. I tried
> ffmpeg-0.4.9_pre1 and the current CVS. I compiled them with
> MinGW (gcc-3.4.2). FFMPEG-0.4.9_pre1 compiled without any
> errors. The current CVS compiled with some undefined
> references to fseeko and similar. My program (that uses
> ffmpeg) is compiled using MSVC++ 6.0.
> And sorry for telling you again: I really need help with
> this!
> If you can't help me, please tell me why! I'll see, what
> I can do to give you all required informations.

Everything you say points at an error of some kind in your application.
Could you post the shortest possible test case that shows the problem?
Then maybe someone will be able to tell you what you did wrong.  Needless
to say, libavformat is working well for most of us.

M?ns Rullg?rd
mru at inprovide.com

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