[pulseaudio-discuss] Pulseaudio Delay with Mythtv

[Lennart Poettering]

On Sun, 19.04.09 12:00, Colin Guthrie (gmane at colin.guthr.ie) wrote:

>
> 'Twas brillig, and Mark Greenwood at 19/04/09 11:02 did gyre and gimble:
>> This must be something that has been recently introduced. I run a mythtv box with pulseaudio (using PA 0.9.10 and mythtv 0.21) and have no sync issues at all.
>>
>> That setup simply has the default ALSA output configured to be 'pulse' and mythtv is configured to use  ALSA:default as its output. Have you tried that? Maybe it works better..??
>
> Yeah I had a little play on my 0.21 install and it seemed to work fine  
> for me on movie playback etc, although the logs were full of underrun  
> errors, I didn't really hear any problems.
>
> The direct pulse plugin did cause a noticeable delay tho', so I'd like  
> to see if I can make it work better to see if it get down to the low  
> latency of 20-50ms that Daniel is keen to see.

I don't know if I follow here.

I don't  see why low latency would matter for MythTV. This is not a
VoIP tool or a music application! Selecting needlessly short latencies
increases CPU load and the likeliness of drop-outs. To save power and
to minimize drop-outs MythTV should configure the longest latency
possible!

What does matter for MythTV is that the current latency/playback
position is known, so that video frames can be synced to it.

A latency of 20-50ms for a video playing application is
counterproductive and misses the point!

Lennart

-- 
Lennart Poettering                        Red Hat, Inc.
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