[mythtv] Jitter with time stretch

Peter Bennett pb.mythtv at gmail.com
Mon Jul 16 15:59:46 UTC 2018

On 07/16/2018 11:37 AM, David Engel wrote:
>> I already have a flag stored in the decoder and accessed from mythplayer
>> using "decoder->GetfpsMultiplier()" It takes values 1 or 2, 1=normal,
>> 2=doubled frames as with mediacodec.
> Excellent!
>> I am currently using fpsMultiplier only in AVSync where frame_delay is
>> calculated from frame_interval. I need to take that out and change the
>> calculation of frame_interval itself to use fpsMultiplier instead.
> So are you going to make the avsync_predictor_enabled change then or
> do you want me to do it?  I have time for it today.
I have created a new patch that changes frame_interval calculation, and 
attached it to the ticket. I also set the buffers to 8 instead of 4. 
With 4 buffers there still was a slight jiggle in the 2x speedup 
playback, that is gone with 8 buffers. See what you think.

FF seems to be working OK with this patch. The failure is rather random. 
The re-init handles it with a slight pause when it does happen. Do you 
think there is any point in trying to change FF to use software decoding?

I think I am almost ready to commit this. First I will do some testing 
on Linux with different playback profiles, and on raspberry Pi, to make 
sure nothing got broken. I want to split it into a few commits to 
separate some things that were not exclusively for mediacodec, and 
separate out the FFmpeg fix. Anything that is logically separate I will 
make a separate commit. I see no sign that Aman plans to commit the 
FFmpeg fix. That needs to be committed to the MythTV private FFmpeg 
repository as well.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mythtv.org/pipermail/mythtv-dev/attachments/20180716/d5c5617f/attachment.html>

More information about the mythtv-dev mailing list