[mythtv-users] Raspberry Pi Improvements

[Joseph Fry]

On Tue, Aug 9, 2016 at 5:32 PM Joseph Fry <joe at thefrys.com> wrote:

> On Tue, Aug 9, 2016 at 3:59 PM Peter Bennett <cats22 at comcast.net> wrote:
>
>> On 08/09/2016 01:08 PM, jrh wrote:
>> > Nothing I do eliminate the stutter.
>> >
>> I have not seen the speedup and slowdown problem except with the Dolby
>> passthrough. Normally if there is a slowdown you consistently get video
>> behind audio messages. Probably you will have to try the full raspbian.
>> Use the latest one from May 2016 and install updates after setting up
>> the SD card.
>>
>> Some other things to try -
>>
>> For audio playback you can try various ALSA entries from the list, or
>> you can try OpenMAX:hdmi. If ALSA is not working you can try using the
>> raspi-config advanced audio to force audio to HDMI. Changes you make
>> with that will affect the ALSA default but will not affect OpenMAX:hdmi.
>>
>> Make sure in the audio that you select Stereo speakers and not 5.1 or
>> 7.1 - even if you actually have surround speakers.
>>
>> In setup video playback, try both openmax normal and openmax high
>> quality. Do they both give the problem?
>>
>> I have not tried it with Raspbian Lite. The dependencies in the package
>> are based on the normal Raspbian. It is possible that Raspbian Lite is
>> missing some OpenGL component and using a software emulation of OpenGL
>> instead. That causes problems. The package is designed to look for the
>> correct OpenGL libraries but if they are not in the expected place it
>> may instead use the emulation libraries. The OpenMAX high quality
>> profile uses OpenGL.
>>
>> Peter
>>
>
> I have tried all of the OpenMax vs alsa settings, and manually typed in
> ALSA:Default as mentioned on the wiki... I have tried Normal and High video
> profiles and tweaking all of the relevant settings... even disabling
> deinterlacing made little if any difference with 1080i content.
>
> I do notice that content other than the H264 coming from my HDPVR's seems
> fine, so perhaps if I switched to 720p the problem would go away.
>
> I really suspect it is like you say, something in the Rasbian Lite that is
> missing.  I will take a closer look at the logs to see if its failing to
> detect something (OpenGL, realtime threads, etc).  I know that enabling the
> realtime threads option triggers mythfrontend to attempt several different
> methods, and its possible that the full Rasbian allows them but Lite does
> not?  Either way I will test and report back.
>
> I would greatly appreciate it if you could update the package at some
> point to work on Raspbian Lite .  Would make mythtv-light even light-er.
> My complete. mostly working. frontend fits in 1.7GB, which allows me to use
> an old 2GB SD card that would be thrown away otherwise.  I have spent
> exactly $35 on this frontend (cardboard case and I had cables), sucks
> dropping $10 on a larger SD card just to store apps that will never be used.
>

So enabling realtime threads (rlimits) didn't do much.  Didn't have any
time to check the logs for other problems.  I did however change my STB to
output a 720p signal instead of 1080i, and other than dropping about 10 fps
the video and audio are smooth (at least its not doing the Curly Shuffle
anymore).  I may need to tweak my HDPVR a bit (bitrate,vbr/cbr,etc)?:

2016-08-10 10:33:46.897511 I [633/633] CoreContext mythplayer.cpp:1906
(AVSync) - Player(0): A/V predict drop frame, dropping frame to catch up.
2016-08-10 10:33:46.992916 I [633/633] CoreContext mythplayer.cpp:1906
(AVSync) - Player(0): A/V predict drop frame, dropping frame to catch up.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mythtv.org/pipermail/mythtv-users/attachments/20160810/6d155a67/attachment.html>