1120017 - Make MediaDecoderStateMachine::DispatchDecodeTasksIfNeeded operate properly while doing first-frame decodes

Status: RESOLVED FIXED

(Core :: Audio/Video, defect)

Comment 1

[Bobby Holley (:bholley)]

Attachment: Make the DispatchDecodeTasksIfNeeded path handle DECODER_STATE_DECODING_FIRSTFRAME. v1

Once we make MP4Reader reject with WAITING_FOR_DATA, we end up with the following scenario:

DecodeFirstFrame requests audio data, and then it gets rejected with WAITING_FOR_DATA.
So OnAudioNotDecided does WaitForData, which eventually causes us to be called back in
MediaDecoderStateMachine::WaitForDataResolved. That does DispatchDecodeTasksIfNeeded, which
currently bails out of our state is DECODER_STATE_DECODING_FIRSTFRAME.

The other way to do this would be to add a separate specialized path through all this
asynchronicity for DECODER_STATE_DECODING_FIRSTFRAME. But it's not clear to me what that
buys us.

Comment 2

[Bobby Holley (:bholley)]

https://hg.mozilla.org/integration/mozilla-inbound/rev/02ab5234c39e

Comment 3

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/02ab5234c39e

Comment 4

[Ralph Giles (:rillian)]

Comment on attachment 8546933 [details] [diff] [review]
Make the DispatchDecodeTasksIfNeeded path handle DECODER_STATE_DECODING_FIRSTFRAME. v1

Approval Request Comment
[Feature/regressing bug #]: MSE
[User impact if declined]: Youtube video stalls and sync issues. Less consistent testing.
[Describe test coverage new/current, TBPL]: Landed on m-c.
[Risks and why]: This does affect non-MSE playback.
[String/UUID change made/needed]: None.

Comment 5

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/releases/mozilla-beta/rev/aa8cdb057186