B-frames causing weird pixelation.

[electrodaveultra]

Hi all,

I followed the ffmpegx guide for converting to XviD using MPEG4[.AVI] (mencoder) and found that when I add the "Use B-frames" option I get flashes of pixelation in my video. I understand that B-frames can cause compatibility issues in some hardware players, but can this apply to playback with Quicktime and DivX Player as well?

[Case]

Flashes of pixelation may happen if the bitrate is too low and/or the quantizer parameter is too high. QuickTime 7 with the DivX® Component or the DivX Player should have no problem with B-frames per se on a normal 10.4 system.

By the way, MPEG4 [.AVI] (mencoder) is not XviD, but libavc mpeg-4 codec. Very similar, but not the same.
Are you using ffmpegX 0.0.9x r2 (current version)? Just checking, as you didn't mention a version number.

[electrodaveultra]

I am using 0.0.9x r2. I found that if I use XviD[.AVI](mencoder) with the same settings there is no problem using B-frames. I didn't think there was that big a difference as they both use mencoder.

Thanks for your help.