[FFmpeg-user] Alter YUV values of AVFrames

[Carl Eugen Hoyos]

killkenny64 <kennethjjgibson <at> gmail.com> writes:

> I tried just altering the first frame of a video stream. I decoded the
> frame, added 100 to each Y value in the AVFrame->data[0], encoded the frame
> again and saved it into the video.
> 
> However when I play the video back, it is not only the first frame that has
> been altered, but the first 30 frames.

Sounds as if the codec the original video was encoded with used a gop-size 
of 30.

Try rawvideo or an intra-only codec (or try forcing a gop-size of 1).

Carl Eugen