Fix T89153: Follow Path for empty works only in negative values

The old code only clamped cyclic curves

Fix T89153: Follow Path for empty works only in negative values

The old code only clamped cyclic curves

Fix: VSE seeking with proxy strips would fail on certain frames

If the last decoded frame had the same timestamp as the GOP current
packet, then we would skip over this frame when fast forwarding and we
would seek until the end of the file.

This would could only be triggered reliably in single threaded mode.

Reviewed By: Richard Antalik

Differential Revision: http://developer.blender.org/D11601

Fix: VSE search in mpegts files would fail

ffmpeg_generic_seek_workaround did work properly and our start pts
calculation was wrong.

Reviewed By: Richard Antalik

Differential Revision: http://developer.blender.org/D11562

Fix: VSE indexer seeking not working correctly

Because of the added sanity checks in rB14508ef100c9 (D11492), seeking
in proxies would not work correctly any more. This is because it wasn't
working as intended before, but in most cases this wouldn't be
noticeable. However now when the sanity checks are tripped it is very
noticeable that something is wrong

The indexer tried to use dts values for time stamps when we used pts in
our decode functions to get the time positions. This would make it
start in the wrong GOP frames when searching. Now that we enforce no
crossing of GOP frames when decoding after seek, this would lead to
issues.

Now we correctly use pts (or dts if pts is not available) and thus we
don't have any seeking issues because of time stamp format missmatch.

Reviewed By: Richard Antalik

Differential Revision: http://developer.blender.org/D11561

Fix: VSE timecodes being used even when turned off.

Reviewed By: Richard Antalik

Differential Revision: http://developer.blender.org/D11567

Fix: Prevent small memory leak in VSE indexer

We need to unref the packet to tell ffmpeg it is ok to free it after
use.

Fix: Wrong logic for checking if we can reuse decoded frame

We should only check if the new pts value lies inside the duration of
the current frame.

FFmpeg: Fix seeking not returning the correct frame when not using TC index

Fixed the logic for seeking in ffmpeg video files.
The main fix is that we now apply a small offset in ffmpeg_get_seek_pos
to make sure we don't get the frame in front of the seek position when
seeking backward.

The rest of the changes is general cleanup and untangling code.

Reviewed By: Richard Antalik

Differential Revision: http://developer.blender.org/D11492

Fix T88623, T87044: Make encoded videos play correctly in VLC

The issue was two fold. We didn't properly:

1. Initialize the codec default values which would lead to VLC
complaining because of garbage/wrong codec settings.

2.Calculate the time base for the video. FFmpeg would happily accept
this but VLC seems to assume the time base value is at least somewhat
correct and couldn't properly display the frames as the internal time
base was huge. We are talking about 90k ticks (tbn) for one second of
video!

This patch initializes all codecs to use their default values and fixes
the time base calculation so it follows the guidelines from ffmpeg.

Reviewed By: Sergey, Richard Antalik

Differential Revision: http://developer.blender.org/D11426