1433113 - 24 Hz Video output has judder/jerkiness as compared to Safari.

Status: RESOLVED INCOMPLETE

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

Description

[Mischa Davey]

Attachment: Troubleshooting Information.xhtml

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:58.0) Gecko/20100101 Firefox/58.0
Build ID: 20180118215408

Steps to reproduce:

Use a Macbook Pro 15" mid '15 with High Sierra. Output 1080p24 video via HDMI to TV with laptop output set to 24 Hz. Mirror the display. Play any 24 Hz content on Amazon prime video or Youtube for example. Remedial steps performed after contacting Mozilla support:
-Disable GPU switching. (Use AMD discreet GPU exclusively)
-Clearing all history.
-Restart system.
-Reducing content processes to 1 in preferences.
-Disabling hardware acceleration.
-'Refresh Firefox', then trying again with default options.


Actual results:

Intermittent judder/jerkiness when playing fullscreen or not. Visible on both the TV & the laptop display. Especially evident with a change of scene or panning. None of the above steps changed anything.  Firefox is great with 50/60 Hz content (output at that frequency) all the way up to 4K/2160p. So the 24 Hz problem is curious. Sync or timing issue?


Expected results:

Should have displayed smooth 24p motion, similar to a Bluray. Also played the same videos in Safari with very rarely any stutter or judder.  

I'm sure you've got one of these Macbook Pro's around. Please try and reproduce this by watching a few minutes of 1080p24 content output to a TV at 24 Hz.

Comment 1

[Mischa Davey]

Please ask if you require more information.

Comment 2

[Ralph Giles (:rillian)]

Thanks for the report. That sounds bad! Is the jerkiness worse than playing a 24 fps movie with output set to 50/60 fps?

Dan, can you reproduce this on your mac?

Comment 3

[Mischa Davey]

Yes, the jerkiness is much worse when output at 24 Hz. 

Here are some very obvious examples:

https://www.youtube.com/watch?v=D6tC1pyrsTM

'The Marvelous Mrs Maisel' on primevideo.com

Play the videos at at least 1080p with 24 Hz output to a TV.

Comment 4

[Mischa Davey]

In the national park video above, it's especially visible whilst the car is touring.

Comment 5

[u480271]

Ralph,

I was able to reproduce some noticeable stuttering on my A1398 rMBP when playing the YT video linked above on my TV @ 24Hz. It was easy to see and reproducible in the 1m35s to 1m45s section when looking at the oncoming cars.  It's harder to see, but still there, when I see TV output to 60Hz.

:jya might be able to provide more technical details, but it could be an issue with the timing of the compositor display logic.

Comment 6

[Mischa Davey]

Attachment: Troubleshooting Information.xhtml

26-8-19

Comment 7

[Mischa Davey]

This problem is still present, 2 years later in that Zion National Park video above which is now 480p. Originally it was 4K.

Another example of a 1080p24 video, is this one below. Constant panning in this one, so it's really obvious.

https://www.youtube.com/watch?v=p6ULvPFPLIY

Same as before; no problems with 50 or 60 Hz videos all the way up to 4K on this machine. Albeit, there is a lot of fan; no hardware decode for VP9 or AV1. 24Hz output on Safari is close to flawless.

Have attached Troubleshooting Information. Webrender is on. That's the major change, since the last report. In general Webrender is amazing for general browsing. But, I don't think it's had any effect good or bad, with this defect.

Please have another look using Macbook Pro 15", mid '15, Radeon M370X 2GB. Automatic graphics switching off.

Comment 8

[Wayne Mery (:wsmwk)]

Reporter,
Does this still reproduce for you?

I'm not sure I see a difference between Firefox and Safari.

Comment 9

[BugBot [:suhaib / :marco]]

Redirect a needinfo that is pending on an inactive user to the triage owner.
:jimm, since the bug has recent activity, could you have a look please?

For more information, please visit auto_nag documentation.

Comment 10

[Phoenix]

Resolved per whiteboard