[mythtv-users] Video is behind audio, dropping frames to catch up (VDPAU, HD content)

[Mike Perkins]

On 28/02/13 12:15, Paul Gardiner wrote:
> On 28/02/2013 12:01, Mike Perkins wrote:
>> On 28/02/13 08:23, Paul Gardiner wrote:
>>> On 27/02/2013 22:04, Thomas Börkel wrote:
>>>> HI!
>>>>
>>>> I have now tried many things, but I am running out of ideas.
>>>>
>>>> * it happens usually every 2-10 minutes
>>>> * it happens for HD h264 and SD MPEG2, just for HD a little more often
>>>> * it happens with and without VDPAU
>>>> * it happened on old and upgraded hardware (only sound card identical)
>>>> * it happens on 0.26 and earlier versions
>>>> * I have tried all VDPAU profiles
>>>> * I have disabled logging over NFS (> /dev/null)
>>>> * I have enabled realtime prio (but it is not mentioned in the log)
>>>> * I have reniced mythfrontend to -2 and X to -12
>>>> * I have set the GPU to max. frequency all the time, so no switching
>>>> * I have disabled the often crashing mythlcdserver
>>>> * I have tried different kernel and NVidia driver versions
>>>>
>>>> What else can I try? What more info should I provide?
>>>>
>>>> Probably, something needs a little CPU time every now and then and this
>>>> probably causes that little "jump" in playback and the log entry from
>>>> the subject, but I don't know what it is and why MythTV is so sensitive
>>>> on such hardware specs (Core i3, 3.1 GHz)?
>>>>
>>>> Or does it probably have something to do with the fact that this is a
>>>> diskless PXE frontend?
>>>>
>>>> Any hints would be greatly appreciated.
>>>
>>> None of the myth systems I've built have ever synchronized AV correctly.
>>> I've always had to pause and unpause every now and then to regain sync
>>> and even then it's to get it to a consitentish 100ms which I then
>>> correct within my AV receiver. It's odd, because every other player I've
>>> tried with my recordings or downloads show them correctly in sync.
>>>
>> My diskless PXE frontend has never had problems with AV sync. I use NFS
>> to mount the root but not for media directories. On the other hand, my
>> sound comes out the TV. Perhaps it is the "AV receiver" which is the
>> common variable?
>
> I have wondered that. I will test, although several of the myth systems
> I was referring to were connected direct to speakers, and the sync was
> always variable and depended on the last user command. I think my
> current frontend may be pretty much ok when I'm not using different
> screen modes for different video resolutions, but I'm not sure of that.
> Need to do more testing.
>
> What CPU are you running?
>
My current front end is one of these:

http://www.newegg.com/Product/Product.aspx?Item=N82E16813131663

That outputs via HDMI. A previous incarnation had a C7 VIA chip which output 
using VGA and 3.5 mm stereo into the TV. No problems either way.

-- 

Mike Perkins