[mythtv] [patch] Fix for sluggish pause

[Bruce Markey]

David Engel wrote:
...
> Here's my first cut.

Only found one serious bug. Press ">" or "<" one or more times
then press Pause. Video goes to normal forward speed with no
audio while the OSD reports "Paused" with the progress bar
advancing. Pausing in slo/fast-mo or stretch don't seem to
have this problem.

Seems to do all the right stuff. Jump, skip, sticky, slo-mo
fast-mo and plus or minus stretch keys all respond quickly
and start from the correct frame. Changing speeds are all
responsive and don't lose there place. Changing slo-mo speeds
continues to consecutive frames. Pause to frame advance keeps
it's place and frame retreat does minimum reads and can backup
past keyframes. The response time compensation when leaving
sticky mode works at any speed in either direction and holding
down the skip keys stops when the key is released. All modes
other than fast-mo use less CPU than normal playback and network
throughput is not a problem at any high speed for remote
playback. Framerates are always equal to or greater than
the previous lower speed giving the users the impression that
they are going faster at higher speed factors. Also, I haven't
seen it play consecutive frames when it should have a high
skip value.

Pressing "E" to enter edit mode always settles at a keyframe
(MM:SS:01) one to three seconds previous to the playback
position when the key is pressed. It also moves back when
switching from pause to edit. Positioning on a keyframe may
be a good thing and intentional. However, skipping to a keyframe
before the immediate previous keyframe seems like it may be a
minor trivial bug. Switching to the 1 frame interval moves to
the correct frame on the first step and it seems to move
correctly at all other intervals.

The debug output is also very clean and reassuring but that
shouldn't be a factor for testing ;-).

Are there any other possible regressions that I've overlooked
and are there any border cases where you are concerned about
race conditions?

Also, bob should only be in effect for playback at 1.0. Any
other speed, including (or especially ;-) stretch adjustments
will bounce horribly. I believe that 2X fast-motion with bob
incorrectly results in normal speed with no audio. The right
fix would be to go back to full frames and speed relative to
the full frame interval.

-- bjm