Blender Git Loki

== FFMPEG ==

This fixes a rather subtle seeking issue with ffmpeg and Sony
XDCAM-footage.

Problem is: MPEG2 streams within an MP4 container can contain a start
time - at several places. There is a starttime within the video
and audio streams and one within the container.

FFMpeg commandline tool only uses the container starttime and we used
the stream starttime.

The world would be a better place, if those two timestamps always match
up, since in XDCAM-footage those two starttimes differ in 4
frames - and the container has the right one.

We now always use the container start time as ffmpeg commandline tool
does (in the hope, that there is a good explaination for this and this
is the right thing(tm) to do).

I tested this also with HDV footage, which seems to work with the new
code, too.

Additional fix: disabled seek_by_bytes again, since it will only work
correctly, if ffmpeg guessed the HDV bitrate right (which it doesn't).
If you have seeking issues with HDV and have an older version of ffmpeg
installed, please upgrade, newer versions have some fixes in them.