[MEncoder-users] How important are B-frames?

[Scott W. Larson]

On Fri, 2012-05-04 at 17:39 -0600, James Hastings-Trew wrote:
> B-frames allow for a greater amount of compression because they 
> represent a diff from both following frames and previous frames, in both 
> temporal directions. Therefore they are not essential, and basically for 
> years I used mencoder to create mp4 files with zero b-frames with no ill 
> visual effect. Just slightly larger files.

When I encode AVC at highest quality, a majority of the frames in the
video are encoded in B-frames. On average a B-frame takes only one
fourth the space of a P-frame. This results in a substantial decrease in
file size and no decrease in quality.

I do not own any devices which can't decode AVC video with B-frames.