Can the frame size be cropped during decoding using libavcodec?

Question

I've followed Dranger's tutorial for displaying video using libav and FFMPEG. http://dranger.com/ffmpeg/

avcodec_decode_video2 seems to be the slowest part of the video decoding process. I will occasionally have two videos decoding simultaneously but only displaying half of each video side by side. In other words, half of each video will be off-screen. In order to speed up decoding, is there a way to only decode a portion of a frame?

Answer 1

No.

Codecs using interframe prediction need whole reference frames, so there's no way this could possibly work.