1198588 - A/V sync is broken for media playback when AudioStream is opened in LowLatency mode

Status: RESOLVED FIXED

(Core :: Audio/Video: MediaStreamGraph, defect)

Description

[Matthew Gregan [:kinetik]]

Discovered while testing, and not a high priority as media playback never uses AudioStream with LowLatency, but this should still work:

If AudioStream is opened with LatencyRequest::LowLatency, A/V sync is broken.  cubeb_stream_init is still opened with the default (high) latency of 100ms, so the only behaviour differences are in AudioStream itself.  There are a bunch of special cases for LowLatency, most suspect of which is the initial buffer prefill.

Comment 1

[Paul Adenot (:padenot)]

I was going to remove the LowLatency option for AudioStream, since it's not very useful: you're opening a stream in low latency mode, but you sticking a massive buffer in from of the callback, so it kind of defeats the purpose.

Comment 2

[Matthew Gregan [:kinetik]]

Oh right, this code is no longer used since MSG moved to the callback based architecture.  In that case, it looks like we can delete ~450 LOC from AudioStream.

Comment 3

[Matthew Gregan [:kinetik]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=a9139eab256f

Comment 4

[Matthew Gregan [:kinetik]]

Attachment: bug1198588_v0.patch

Ignore the first (now cancelled) try push, I missed removing another ~50 LOC.

This removes the following from AudioStream, all of which were added and used only for MSG purposes:

- Low latency mode
- Latency logger
- Async OpenCubeb
- Output panning for shared headset/mic devices on OS X

Comment 5

[Matthew Gregan [:kinetik]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=f7d660263c8e

Comment 6

[Paul Adenot (:padenot)]

Comment on attachment 8653240 [details] [diff] [review]
bug1198588_v0.patch

Review of attachment 8653240 [details] [diff] [review]:
-----------------------------------------------------------------

Cool !

Comment 7

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/b12b9840d67b

Comment 8

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/b12b9840d67b