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Issue metadata

Status: WontFix
Owner:
Last visit > 30 days ago
Closed: Sep 2016
Cc:
Components:
EstimatedDays: ----
NextAction: ----
OS: Mac
Pri: 1
Type: Bug



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on Mac, buffer time for high resolution video source is very low so video playback becomes very choppy

Project Member Reported by yini...@chromium.org, Sep 20 2016

Issue description

Version: 55.0.2859.0
OS: Mac

I only see this issue happen on Mac OS. it not repro when switch to 30fps. It repro on both 720p60fps and 1080p60fps while the latter is even worse. The buffered time is usually < 3 seconds, so there are lots of choppy in playback. 
This issue happen on both H264 and VP9 video

What steps will reproduce the problem?
(1)navigate to any of these two videos, switch to 1080p60fps 
https://www.youtube.com/watch?v=SFeA13_15-M
https://www.youtube.com/watch?v=MbiOazijZVQ
(2) bring up Stat for Nerd by right click

What is the expected output?
buffer health value shows good healthy buffer time, playback is smooth

What do you see instead?
buffer time is usually < 3 seconds, very choppy playback
 
one found, this issue also happens on CrOS with build 55.0.2858.0

Comment 2 by hubbe@chromium.org, Sep 20 2016

Youtube uses MSE, and the buffering is controlled by javascript in their player. This is a bug that should be filed against youtube I think.

Cc: strobe@chromium.org
Summary: on Mac, buffer time for high resolution video source is very low so video playback becomes very choppy (was: on Mac, buffer time for 60fps video source is very low so video playback becomes very choppy)
change title remove 60fps. I actually see this issue happen to 24fps as well. It seems easily repro on high resolution(>=720) video but sometimes repro on low resolution (480p) as well.
Here are two 24fps repro video
https://www.youtube.com/watch?v=OPf0YbXqDm0  (H264)
https://www.youtube.com/watch?v=09R8_2nJtjg (vp9)

Comment 5 by strobe@google.com, Sep 20 2016

Can't repro. Please post a Debug Info from the player.
Status: WontFix (was: Assigned)
I don't see this issue anymore on the same device with the same Chrome build. It seems YouTube fixed it.
For posterity:

There was some suspsicion that this is caused by incorrect firing of the "waiting" and "timeupdate" events, discussed here [0]. These events may cause spinners to be seen when the decoder is struggling to keep up (but buffer is otherwise healthy). 

However fixes for that bug were not landed on Sep 21st (when repro went away), so not sure what to make of this. 

[0] https://bugs.chromium.org/p/chromium/issues/detail?id=648710#c30

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