[Libav-user] Decoding specific formats?

[Patrick Zielinski]

Ok, firstly please bare with me, up until two weeks ago I didn't even know
what codec were and how encoding worked. Also, this code is ported within a
C++ framework so it might not comply with your usual coding standards.

Essentially here is the code that I have written which resembles closely to
the libav decoding example with minor tweaks due to deprecated functions. I
actually have a different version in our code, but it's mostly just working
with the buffer and the image data to add to our own structure.

http://pastebin.ca/2120920

I'd like to have either tips on how I could make this more robust, or what
steps I should take to extract each frame from different formats. I've
taken a look at ffmpeg.c, but not as much as I wanted.

On Wed, Feb 22, 2012 at 11:22 AM, Alex Cohn <alexcohn at netvision.net.il>wrote:

> On Tue, Feb 21, 2012 at 23:24, Patrick Zielinski <dzeesea at gmail.com>
> wrote:
> > Hello all, I have integrated decoding with libavformat and libavcodec a
> > basic decoder. It works for H264 encoded video's and also I converted one
> > into avi, it also works.
> >
> > But for some reason when I try other formats like .mkv I receive this
> > error:
> >
> > [h264 @ 05f32a80] no frame!
> >
> > I've encoded  the mkv's with x264 so I'm having a hard time understand
> how
> > it cannot find a frame, it occurs when I call
> >
> > avcodec_decode_video2(pCodecCtx, pFrame, &gotFrame, &packet);
> >
> >
> > What kind of details am I missing, because the different structs seem to
> > have correct data.
>
> You probably have metadata missing, e.g. SPS/PPS, if MKV container
> keeps this information not with the frames that you push into
> avcodec_decode_video2(). Please make sure that your mkv can be played
> by command-line ffmpeg. If this simple test succeeds, please make your
> initialization code available (e.g. via pastebin).
>
> BR,
> Alex
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