[Webkit-unassigned] [Bug 221553] New: Audio is STILL distorted when using createMediaElementSource!

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=221553

            Bug ID: 221553
           Summary: Audio is STILL distorted when using
                    createMediaElementSource!
           Product: WebKit
           Version: Safari 14
          Hardware: All
                OS: All
            Status: NEW
          Severity: Blocker
          Priority: P2
         Component: Web Audio
          Assignee: webkit-unassigned at lists.webkit.org
          Reporter: luigi at luigipulcini.com
                CC: cdumez at apple.com

Hello,

I have just confirmed this is still a problem in the new Safari Technology Preview 119, released on January 27, 2021.

This issue has emerged more than a year ago and, every time someone reports it (bug #211394, bug #215314), the report gets listed as RESOLVED FIXED very hastily and without verifying whether the fix is really effective or not. Whatever was the patch believed to have fixed this, it has not.

The problem appears to be affecting the audio more heavily with audio files sampled at 48kHz, while it seems to be less relevant when the audio file is sampled at 44.1kHz. In any case, this seems to prove there is still an issue with the audio resampling. In the previous bug report (bug #215314), we possibly detected the source of the issue being within the test case http://trac.webkit.org/changeset/267014/webkit

Particularly this:
> When the context's sample rate differs from the hardware sample rate, instantiate a MultiChannelResampler and use it in render() to do the resampling.


How to reproduce the issue (even in Safari Technology Preview 119) with your MacOS/OSX computer:
– go to https://www.waveplayer.info/createmediaelementsource-test/
– play any track (you will notice the waveform animating, which proves the WebAudio API is working)
– open the "Audio MIDI Setup" app (under /Applications/Utilities)
– while the track is still playing, change the sample rate of the audio device
– you should hear the audio distorting more or less heavily depending on which sample rate you selected for your device

You can watch a video demonstrating the issue here:
https://www.youtube.com/watch?v=KYtb-FnjbpQ&t=62
(what for it at 1:12!!!)

The first part of the same video shows that none of this is an issue in Chrome that can perfectly resample the audio, no matter what sample rate the audio device or the audio files are set to.

Thanks,
Luigi.

-- 
You are receiving this mail because:
You are the assignee for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.webkit.org/pipermail/webkit-unassigned/attachments/20210208/76d00a2b/attachment.htm>