[mythtv] 20180705 Android Observations

David Engel david at istwok.net
Fri Jul 6 15:58:41 UTC 2018

On Fri, Jul 06, 2018 at 11:45:40AM -0400, Peter Bennett wrote:
> On 07/06/2018 11:17 AM, John P Poet wrote:
> > A little bit of a tangent...
> > 
> > My local CBS and FOX stations are now both on the same transport -- 13.1
> > (1080i) and 13.2 (720p).  In addition, they have added another SD
> > channel at 13.3.  All jammed into 19 mbit.  The result is that the
> > quality of those channels is pathetic to say the least.
> > 
> > When using VDPAU for decoding those mpeg2 stream, I now get lots of
> > pixelization when watching CBS and some when watching FOX.  I have found
> > that I can get rid of the pixelization if I use VDPAU for the renderer
> > but Standard for the decoder.  ffmpeg seems to be much more tolerant of
> > the errors than VDPAU.
> > 
> See https://lists.gt.net/mythtv/users/609271#609271
> This was the inspiration for 538f99e0a6. Using that new feature I now have
> my playback profile set (on the frontends that use VDPAU) so that they use
> standard decoding for mpeg2 and VDPAU decoding for other video formats.
> > When using the standard (ffmpeg) decoder, though, I do see "residue"
> > frames being shown (flickering) when jumping to another position.  This
> > does not happen when using VDPAU for decoding.  It sounds like this the
> > same same thing that David is seeing on the Shield.  I figured I would
> > relay this story just in case it helps to understand the issue.
> > 
> I don't recall seeing that. Maybe it is associated with deinterlacing. Is it
> only with recordings from those stations? I actually watch most of my NBC
> recordings on a raspberry pi (openmax decoder) and this does not have the
> pixellation problem that I see with VDPAU. Do you actually see a wrong frame
> displayed?

I've only seen it on my Oreo Shield with 1080i content.  720p is fine.
I didn't try 480i, but will try to remember to do it.  I did not see
it on my Nougat Mecool.

It looks like part of a seemlingly random frame gets inserted for
about 1/30 or 1/60 of a second.  I can take a video of it with my
phone and send it to you if you like.

David Engel
david at istwok.net

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