[mythtvnz] Time stretch audio skipping

[Nick Rout]

On Tue, May 27, 2014 at 9:24 AM, Aaron Pelly <apelly at monkeymasters.co.nz> wrote:
> On 26/05/14 16:43, Duncan Kennington wrote:
>
> On 26 May 2014 15:30, Steve Hodge <stevehodge at gmail.com> wrote:
>>
>> On Mon, May 26, 2014 at 2:40 PM, Aaron Pelly <apelly at monkeymasters.co.nz>
>> wrote:
>>>
>>> Hi,
>>>
>>> I'm down to my last couple of minor issues. Thanks for the help so far!
>>>
>>> I have audio set to alsa:default. Above about 1.1x time stretch there is
>>> some noticeable skipping/clicking in recorded playback audio. I have not had
>>> this issue with mplayer which also uses alsa. Admittedly this is a pretty
>>> minor.
>>>
>>> Ubuntu audio has been fairly well behaved for the last few years, but
>>> earlier experience tells me this can be a real can of worms.
>>>
>>> Log attached.
>>>
>>> Am I missing something obvious?
>>
>>
>> What's you CPU usage like when timestretch is 1.2? You're getting buffer
>> underruns so Myth is not supplying data to ALSA fast enough.
>
>
> Agree, I have only seen this on underpowered frontends or where the VDPAU
> hasn't been enabled in playback profiles.
> http://www.mythtv.org/wiki/VDPAU#Enabling_VDPAU_in_MythFrontend
>
> CPU use is negligible.
>
> Broad specs gleaned from lshw:
>
>        description: Motherboard
>        product: Z87X-D3H-CF
>        vendor: Gigabyte Technology Co., Ltd.
>
>        description: System Memory
>        size: 16GiB
>
>        description: CPU
>        product: Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz
>
>        description: VGA compatible controller
>        product: GK110 [GeForce GTX 780]
>
> VDPAU is in use.
>
> It is possible the on-board sound is some shit chipset:
>
>     00:1b.0 Audio device: Intel Corporation 8 Series/C220 Series Chipset
> High Definition Audio Controller (rev 04)
>     Subsystem: Gigabyte Technology Co., Ltd Device a002
>     Flags: bus master, fast devsel, latency 0, IRQ 46
>     Memory at f3130000 (64-bit, non-prefetchable) [size=16K]
>     Capabilities: <access denied>
>     Kernel driver in use: snd_hda_intel
>
> I admit I'm on the fringes of my comprehension here, but is it possible that
> I've got some issue or conflict with Nvidia/Intel sound?

Where is your sound going? Out the HDMI port or the analogue output
from the Intel onboard sound chip or out an SPDIF interface attached
to the Intel onboard sound chip?