[Libav-user] Extracting I-Frame intra-prediction modes

[Misha Penkov]

On 26 June 2012 18:05, Rouhi Amirhossein2 <amir.rouhi at rmit.edu.au> wrote:
>
> Hi
> You know that in h264, a methos is used for compression which is called
> intra prediction method. totally we have 9 intra prediction modes which
> showing different direction of top and left side pixels of 4x4 blocks. I
> want to extract such modes in any frame that uses intra prediction such as
> I-Frames and IDR,s. Do you know how can i achive this purpose?
> In JM software i did the same in decoder, do you think it should be done in
> FFplay as a decoder or it can be done by FFmpeg?

AFAIK, H.264 I-frames and keyframes are the same thing.  Once you have
an AVFrame, you can check its key_frame member.  It will be non-zero
if it's a keyframe (I-frame).

For full code, have a look here:

https://github.com/mpenkov/sandpit/blob/master/ffmpeg/keyframes.c

Provided that you're using MP4 as the container, you can confirm that
the keyframes extracted are indeed I-frames by using the mp4videoinfo
utility (http://mpeg4ip.sourceforge.net/documentation/index.php).

> Thanks for your expert advice.
> Amir
>
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