[mythtv] mediacodec status

[David Engel]

On Sat, Jun 23, 2018 at 06:52:14PM -0400, Peter Bennett wrote:
> 
> The fact that mediacodec returns multiple frames for one packet is causing
> problems in many areas. I think I have most of that solved now.
> 
> MythTV playback with mediacodec is having some timing issues with interlaced
> content. The content is interlaced 29.97 fps. Mediacodec is returning 59.96
> deinterlaced frames per second. We are playing it OK but the elapsed
> playback time increments at double speed because it assumes there are 29.97
> frames per second. You can see this in the seconds displayed by the osd
> status during playback.
> 
> There are many calculations done in MythTV that use the frame count and
> assume that it matches the frames per second returned by the stream context.
> I still need to figure out a solution to this. Hopefully I can get the
> correct framerate from the Codec Context and use that instead of the value
> from the Stream.

How do we handle the frame rate doubling with existing, 2x
deinterlacers?  I know it's not exactly the same thing since the
doubling is occuring during decoding here and during deinterlacing in
the other cases.  Might a dummy, 2x deinterlacer that really doesn't
do anything work?  If not, we might need something like a new "fps
scales during decoding" variable added to all calculations.  It gets
set to 1 by default and is changed to 2 for mediacodec.

Also, if I remember what Aman said at one time, not all mediacodec
implementations do the rate doubling or even deinterlcing.  We'll
likely have to eventually look up by platform and adjust our behavior
accordingly.

David

> Rewind and FF are still to be tackled.
> 
> Peter

-- 
David Engel
david at istwok.net