[FFmpeg-devel] Command-line parameters used too latefor has_codec_parameters()

Luca Abeni lucabe72
Fri Jan 16 14:23:54 CET 2009

Hi Alexandre,

>> I think parameters like width, height, and pixel format are encoded in the
>> H.263 bitstream... In particular, I suspect pix_fmt is always PIX_FMT_YUV420P.
>> Such value is immediately set in ff_h263_decode_init() (which, if I understand
>> well, is called as soon as you start decoding the bitstream). Hence, I think
>> that if you see PIX_FMT_NONE after parsing more than 1 frame there is a
>> problem somewhere.
> OK but if it can be forced (to the same value of course), then the 
> command-line param pix_fmt could be used immediately, before reading any 
> frame. I understand this is not currently the case in ffmpeg.c, but it 
> could be, couldn't it ?

According to the documentation in avcodec.h, in decoding pix_fmt is set by
libavcodec so no, I do not think it is possible (and I think setting pix_fmt
before reading any frame would not make much sense).


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