1721847 - Audio stuttering on udemy (DRM protected content) and AWS deepcomposer (one or multiple MIDI tracks)

Status: RESOLVED DUPLICATE of bug 1718223

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

Description

[basakpromit]

Attachment: Annotation 2021-07-22 221412.png

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:89.0) Gecko/20100101 Firefox/89.0

Steps to reproduce:

1. Go to udemy.com and play a video.
2. Go to AWS deepcomposer, compose an audio using GAN and play all 4/5 track together.

Actual results:

1. The audio is okay at the beginning and starts stuttering to some extent after 30 seconds to 1 minute on udemy.
2. The audio is okay at the beginning, but after a few playbacks, the audio was absent, only heard some noise.

Expected results:

The audio should be clear and understandable.
(This problem did not occur with other browsers on the same device)

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Core::Audio/Video: Playback' component, and is moving the bug to that component. Please revert this change in case you think the bot is wrong.

Comment 2

[John Lin [:jhlin][:jolin]]

Chunmin, this sounds like an audio issue. Could you please help? Thanks a lot!

Comment 3

[C.M.Chang[:chunmin]]

I guess we need to adjust the parameters in libsoundtouch. I'll circle back to this issue once I am available. Keep the NI for now.

Comment 4

[vedansh.garg.7]

I previously thought this was a Udemy bug, but then I tried playing other DRM protected videos on 2x on both Firefox and Chrome to compare..... and Yes, audio(specially speech) crackles in video on playback on 2x.
Reference DRM video :
https://bitmovin.com/demos/drm
Try playing the above video in 2x speed and observe the voice crackle. Does not occur on Chrome and Edge

Comment 5

[Alastor Wu [:alwu]]

This seems same as bug1718223. Would you mind to try adjusting media.eme.max-throughput-ms to a larger value and see if it helps?
Thank you.

Comment 6

[vedansh.garg.7]

Wow, that was a easy fix. Increased the value to 500 and all the audio crackling is gone. Was using Chrome specially for watching Udemy due to this bug XD.

Any side-effects for using a high value? If not, why not change the default value to 500 since many people on reddit seems to be mad at Udemy for the crackling (LOL)
https://www.reddit.com/r/Udemy/comments/mvpqts/drm_on_udemy_videos_since_march_breaks_legitimate/
https://www.reddit.com/r/firefox/comments/n1t0iy/crackling_while_while_playing_back_udemy_videos/

Anyways, thanks a lot. I no longer have to keep 2 browsers.

Comment 7

[Alastor Wu [:alwu]]

I didn't involve the discussion of why we need to set it to 200, so I don't really know the reason. I will let our DRM expert to answer this question (who is currently away, so I can't NI him. But I CCed him instead) and to re-evaluate if we need to change the default value.