Blender Git Loki

Fix T37198: Vorbis encoding is broken

Issue was caused by wrong PTS calculation. This commit
makes this calculation closer to what's happening in
FFmpeg itself.

Seems everything is working now including newer FFmpeg,
but there's one thing which still doesn't work: writing
avi files with h264 codec and Vorbis audio doesn't play
correct in mplayer here. But didn't manage to get this
working even using FFmpeg CLI, so this might be just a
bug in FFmpeg/mplayer. Since this file works fine in
blender just fine wouldn't consider this is crucial thing
to look into at this moment.