[mythtv] 20180705 Android Observations

Peter Bennett pb.mythtv at gmail.com
Tue Jul 10 21:46:43 UTC 2018

On 07/10/2018 02:31 PM, David Engel wrote:
> On Tue, Jul 10, 2018 at 01:58:09PM -0400, Peter Bennett wrote:
>> On 07/08/2018 03:15 PM, David Engel wrote:
>>> I bumped the number of buffers up a little bit and 1080i at 1x was
>>> very smooth, but any timestretching made it more jerky than it should
>>> be.  I think something in the video display timing doesn't know that
>>> the video is being deinterlaced at 2x.  720p content at 60 fps is as
>>> smooth as it can be at any speed, so 1080i content deinterlaced to 60
>>> fps should be the same.  The only thing that could prevent that is if
>>> the decoder or deinterlacer can just barely do their jobs at 1x with
>>> no extra margin. and don't believe that's the case.
>> David
>> Please share with me what you found to be the best buffer values. For the
>> meantime I should add them to the patch with an #ifdef for android.
>> Then I can work on timestretch with those buffer values.
> I don't have the best values yet.  Bumping them by roughly 50 to 100%
> (vbuffers.Init(8, true, 1, 4, 3, 2)) got the 1x playback smooth, but
> didn't make any difference at speeds greater than 1x.  I've since
> changed course and want to try to get the >1x playback smooth first.
> To do that, I reset the buffer values back to original and captured
> some playback logs at 1x and 1.5x for 720p and 1080i yesterday.  I
> still need to analyze those logs.
> David
Look at the new patch. I don't know if it will help with the time 
stretch, but maybe, since I fixed a time calculation. The FF is still 
problematic but at least hopefully does not fail any more. See the 
comments in the ticket.

I did not actually get to look at your logs yet, so maybe I will still 
be able to fix it better once i have seen them.

Jury duty tomorrow so not much will get done until that is over.


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