1701612 - Twitter.com and pscp.tv video stream does not play in normal view, but once it has been played in PiP, it can be played in normal view.

Status: RESOLVED WORKSFORME

(Core :: Audio/Video: Playback, defect, P3)

Description

[Alice0775 White]

Reproducible: The video won't play in Firefox. Chrome can.

Steps to reproduce:

1. Open https://twitter.com/i/broadcasts/1lDGLpawdDkGm

Actual Results:
Loading spinner spines forever.
Interestingly, Once going to PiP (ctrl+shift+]) and click play button, then the video can play in PiP(though orientation is incorrect). After that, close PiP, then the video can play in normal view.

Expected results:
the video can play.

Comment 1

[Alice0775 White]

And also this video won't play in Firefox:

• https://twitter.com/momowgp/status/1352919317961003008

Comment 2

[Alice0775 White]

And this video :

• https://www.pscp.tv/w/1mnxeaYqAyYxX

Comment 3

[C.M.Chang[:chunmin]]

I can reproduce it on my Nightly 89.0a1 (2021-04-02) (64-bit) and Release 87.0 (64-bit) on Ubuntu 20.04.

From the log captured by MOZ_LOG="MediaDemuxer:5, MediaDecoder:5", it seems Firefox encounters this error:

[Child 14727: MediaDecoderStateMachine #1]: V/MediaDecoder MediaDecoderStateMachine[7f935ae8b000] Decoder=7f93598c7c00 OnAudioNotDecoded ErrorName=NS_ERROR_DOM_MEDIA_WAITING_FOR_DATA Message=

When entering PIP mode, it seems MediaDecoderStateMachine is forced to enter SEEKING and somehow audio is not able to be decode(got an OnAudioDecoded)

[Child 16159: MediaDecoderStateMachine #1]: D/MediaDecoder MediaDecoderStateMachine[7f5168057000] state=DECODING_FIRSTFRAME Changed state to SEEKING (to 617981)
[Child 16159: MediaDecoderStateMachine #1]: D/MediaDecoder MediaDecoderStateMachine[7f5168057000] state=DECODING_FIRSTFRAME change state to: SEEKING_ACCURATE
[Child 16159: MediaDecoderStateMachine #1]: D/MediaDecoder MediaDecoderStateMachine[7f5168057000] Decoder=7f5164794000 StopPlayback()
[Child 16159: MediaDecoderStateMachine #1]: V/MediaDecoder MediaDecoderStateMachine[7f5168057000] Decoder=7f5164794000 UpdatePlaybackPositionInternal(617981)
[Child 16159: MediaDecoderStateMachine #1]: D/MediaDecoder MediaDecoderStateMachine[7f5168057000] Decoder=7f5164794000 MediaDecoderStateMachine::Reset
[Child 16159: Main Thread]: D/MediaDecoder MediaDecoder[7f5164794000] Changed mNextFrameStatus to NEXT_FRAME_UNAVAILABLE_SEEKING
[Child 16159: MediaDecoderStateMachine #1]: V/MediaDecoder MediaDecoderStateMachine[7f5168057000] Decoder=7f5164794000 Queueing video task - queued=0, decoder-queued=0, stime=0
[Child 16159: MediaDecoderStateMachine #1]: V/MediaDecoder MediaDecoderStateMachine[7f5168057000] Decoder=7f5164794000 Queueing audio task - queued=0, decoder-queued=0
[Child 16159: MediaDecoderStateMachine #1]: V/MediaDecoder MediaDecoderStateMachine[7f5168057000] Decoder=7f5164794000 OnAudioDecoded [567981,591200]
[Child 16159: MediaDecoderStateMachine #1]: V/MediaDecoder MediaDecoderStateMachine[7f5168057000] Decoder=7f5164794000 Queueing audio task - queued=0, decoder-queued=0
[Child 16159: MediaDecoderStateMachine #1]: V/MediaDecoder MediaDecoderStateMachine[7f5168057000] Decoder=7f5164794000 OnAudioDecoded [591201,614420]

Comment 4

[C.M.Chang[:chunmin]]

Attachment: log.txt

Raw log captured by MOZ_LOG="MediaDemuxer:5, MediaDecoder:5"

Comment 5

[C.M.Chang[:chunmin]]

Hi Bryce,

Do you have any idea why audio cannot be decoded in first place? Any thing weird in MoofParser? There is several Couldn't read next moof, returning false message like this, before it's played in the PIP mode, is it a normal log?

Comment 6

[Bryce Seager van Dyk [:bryce] (he/him) - Not reading bugmail]

Nothing is jumping out at me. It's possible the moof parser is having problems, but I'd need to debug more to figure out if something is going wrong. I'll see if I can get some more time to investigate and will hold the NI for now.

I notice for both the twitter videos if we call $('video').play() in the console they will start playing. I suspect that this is a similar mechanism to the pip steps in comment 0.

Comment 7

[Bryce Seager van Dyk [:bryce] (he/him) - Not reading bugmail]

I can no longer repro this.