[mythtv-users] Intel i965 video buffers errors on, frontend

James Linder jam at tigger.ws
Sat Jul 8 00:56:17 UTC 2017



On 7/7/17 8:00 pm, mythtv-users-request at mythtv.org wrote:
>> I'm having difficult problems with playback in the frontend version
>> 0.28.1-3 and would love some help please!
>>
>>
>> I've been building a new media PC which will mainly be used for MythTV.
>> I deliberately chose to use intel graphics, to avoid the trouble of
>> binary proprietary drivers, for lower power consumption and as no
>> additional noisy cooling fans are required.
>>
>> I first tried using VDPAU but the frontend refuses to work with it,
>> erroring out each time with an unhelpful A/V sync error.  (Packages
>> installed include libva-vdpau-driver-0.7.4-14, libvdpau-va-gl-0.4.2-2 &
>> libvdpau-1.11-3 )
>>
>> So I switched to VAAPI, despite it lacking deinterlacing.  I'm still
>> having playback problems with stuttering, especially with live TV.  My
>> PC also has Intel HD audio (Realtek ALC892).
>>
>> Although playback works, when I enable debug logging I see multiple
>> occurrences of both:
>>
>> <date> <time> I  Player(0): Waiting for video buffers...
>>
>> and:
>>
>> <date> <time> I  Player(0): Video is 3.54437 frames ahead of audio,
>>                          doubling video frame interval to slow down.
>>
>> I've searched the internet, including archives of this mailing list, and
>> these problems have previously been called driver issues.  Kodi doesn't
>> seem to have any issues though.  I'm running Fedora 25 with a recent
>> kernel which should contain the latest stable Intel drivers anyway.  I'm
>> not sure what I can do?  Do you have any ideas, please?
>>
>> Thanks in advance!
>> evade.
> When playing back the recording pull up the playback data screen
> (m > playback > playback data)
>
> and have a look at the data there. It's a little complex, but
> you need to check a few things.
>
> - cpus usage, check it's not maxed out
> - storage to buffer and buffer to decoder figures.
>    You want storage to buffer figures to be significantly higher than
>    the buffer to decoder figures (not just a little bit higher)
> - available buffer. this figure is upside down, should really say "used
>    buffer", the closer to 100% this is the better.
> - frames decoded / free, frames decoded really should be greater than 10
>    for consistent viewing.
>
Opinion Please:

Suddenly (last week or so) my HD recordings are experiencing minor skips 
with associated lip sync issues

All the data looks ok except FPS steady at 25 suddenly glitches to 15 or 
so. a/v sync around 0.1 suddenly glitches to 15.0 or so.

Methinks that this is not myth related but OTA signal related and I 
should redo the schedule to use SD not HD.

CODEC is H264, MPEG-2 at 720 seems flawless. CPU is N/A but elsewhere 
CPU usage is < 10%

James


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