911468 - Media Encoder - Audio recorded is in lower quality than the original opus audio file

Status: RESOLVED INVALID

(Core :: Audio/Video: Recording, defect)

Description

[Jason Smith [:jsmith]]

STR

1. Go to http://mozilla.github.io/qa-testcase-data/webapi/mediarecorder/index.html
2. Select Setup under music_orig.opus
3. In console - run mediaRecorderList[0].start();
4. Select play for each set of media controls
5. Wait for the song to finish recording (~1 min and 31 sec)
6. In console - run mediaRecorderList[0].stop();
7. Playback the blob recorded

Expected

The sound quality should be the same as the original audio file.

Actual

When you compare playback of the original audio file vs. recorded audio file, you'll notice a regression in sound quality. The sound playback sounds slightly muffled at points of playback of the opus file recorded. You won't hear that playing back the original opus file.

Comment 1

[Jason Smith [:jsmith]]

Attachment: Recorded Opus File

Comment 2

[Jason Smith [:jsmith]]

Attachment: Original Opus File

Comment 3

[Jason Smith [:jsmith]]

Actually disregard - I messed up here. This is a problem with VLC media player that happens with the original and recorded audio file.

Comment 4

[Timothy B. Terriberry (:derf)]

(In reply to Jason Smith [:jsmith] from comment #3)
> Actually disregard - I messed up here. This is a problem with VLC media
> player that happens with the original and recorded audio file.

Out of curiousity, what is the problem? I have a bunch of VLC developers handy here.

Comment 5

[Jason Smith [:jsmith]]

(In reply to Timothy B. Terriberry (:derf) from comment #4)
> (In reply to Jason Smith [:jsmith] from comment #3)
> > Actually disregard - I messed up here. This is a problem with VLC media
> > player that happens with the original and recorded audio file.
> 
> Out of curiousity, what is the problem? I have a bunch of VLC developers
> handy here.

If you playback the opus media file attached in VLC media player on Windows, you'll hear the sound slightly muffled. If you play that same opus media file in the browser, you won't hear the muffled sound - the sound comes out clearly.

Comment 6

[Timothy B. Terriberry (:derf)]

Can you try with the 2.1.0 prerelease of VLC?
http://download.videolan.org/pub/videolan/testing/vlc-2.1.0-pre2/

Apparently the audio output system has been completely redone.

Comment 7

[Jason Smith [:jsmith]]

(In reply to Timothy B. Terriberry (:derf) from comment #6)
> Can you try with the 2.1.0 prerelease of VLC?
> http://download.videolan.org/pub/videolan/testing/vlc-2.1.0-pre2/
> 
> Apparently the audio output system has been completely redone.

Looks like the muffling isn't present on the vlc-2.1.0-pre2 build. Works fine in comparison to playing the same opus file in Desktop Firefox.