Jerky playback with shield on certain interlaced content

[mspieth]

Some recordings are giving extremely jerky playback.

The log shows that the video is being re-initialized around twice every second.

[Peter Bennett]

Fix for repeated video reinitialization bug

[Peter Bennett]

The logic is continuously flipping between 25fps and 50fps and each time is re-initializing video.

The fix changes the order of fields used to determine framerate to give r_frame_rate a lower priority. r_frame_rate is described as the lowest possible frame rate. not the actual frame rate and was showing as 50. I think the description actually means highest possible frame rate, lowest frame interval

This fixes playback for Mark's sample file.

[mspieth]

Tested with another 2 programs which is still very jerky. Tried at 1.0 and 1.5x.

1013_20190303003000.ts (another sports 6.5h)

also another style of program

1013_20190303100000.ts (chat show style) 1h

[Peter Bennett]

Replacement for the previous patch. Hopefully this fixes it for all recordings.

[Peter Bennett]

This bug actually manifests on all decoders that have built in deinterlace - medicodec, nvdec, vaapi2. It also manifests on avsync as well as avsync2.

The new patch fixes it on the original video as well as the two new videos from Mark.

[mspieth]

Looks good so far.

[Peter Bennett <pbennett@…>]

In 0e7e57f9c2/mythtv:

Playback: Fix jerkiness with codec-deinterlaced content

Remove unneeded setting of m_fps that was overwriting the correct
value. m_fps is suppsed to contain the framerate before deinterlacing.

Fixes #13419

[Peter Bennett <pbennett@…>]

In 76ea9755b/mythtv:

Playback: Fix jerkiness with codec-deinterlaced content

Remove unneeded setting of m_fps that was overwriting the correct
value. m_fps is suppsed to contain the framerate before deinterlacing.

Fixes #13419

(cherry picked from commit 0e7e57f9c2eb0e2c4f47dcb30788a4e54d6808ba)