Ticket #7496 (closed enhancement: fixed)
Opened 4 years ago
Last modified 3 years ago
pulseaudio A/V sync
|Reported by:||Alan Calvert <cal@…>||Owned by:||jyavenard|
|Component:||MythTV - Audio Output||Version:||head|
As requested by danielk (ref #5473), a ticket to focus efforts to improve pulseaudio sync/latency.
So far the approach to buffer setup has been to choose params that seem comfortable for myth, then try to persuade pulseadio to conform. Pulseadio has some wonderful attributes, but "accommodating" is not necessarily one of them. Patch pulse-latency-001.patch goes the other way - try to set pulseaudio latency to what's required, and have myth's fragment_size & soundcard_buffer_size conform to pulseaudio's ultimate choice of buffer metrics.
PA_STREAM_ADJUST_LATENCY has limited utility in myth's quest for "out of the box" performance. It depends on having tsched=1 in the load-module module-alsa-sink params, which according to the above reference "... is the default for most modern distributions, with the infamous exception of Ubuntu" . Since ubuntu is possibly the main reason for even bothering with pulseaudio in myth, that's inconvenient. I've tried this with both tsched=1 and tsched=0, and sync does seem to be a little tighter in both cases. The experience of others would be interesting.
comment:1 Changed 4 years ago by Colin Guthrie <mythtv@…>
comment:2 Changed 3 years ago by robertm
- Milestone changed from 0.23 to unknown
comment:3 Changed 3 years ago by geoffp@…
comment:4 Changed 3 years ago by stuartm
- Ticket locked set
comment:5 Changed 3 years ago by jyavenard
- Status changed from new to closed
- Resolution set to fixed
- Ticket locked unset