[Libav-user] av_frame_is_writable

Nicolas George george at nsup.org
Sun Mar 13 20:54:31 CET 2016

Le tridi 23 ventôse, an CCXXIV, Tom Deseyn a écrit :
> When decoding an H264 file after setting refcounted_frames to 1, the
> decoded frames are not writable. Is this due to the input format?

In part, but this will happen with a lot of codecs.

In video encoding, most frames are coded as the difference from the previous
one. Or ones, or even next ones with B-frames.

That means the decoder needs frame N in order to decode frame N+1. If you
were to apply changes to frame N, they would change frame N+1 too, in an
unpredictable way.


  Nicolas George
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 819 bytes
Desc: Digital signature
URL: <http://ffmpeg.org/pipermail/libav-user/attachments/20160313/fdf078b8/attachment.sig>

More information about the Libav-user mailing list