MP3 incorrect time and distortion




3 years ago
3 years ago


(Reporter: jamie, Unassigned)



44 Branch
Mac OS X
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Firefox Tracking Flags

(Not tracked)





3 years ago
When attempting to play the MP3 file at, Firefox plays a horrible distorted noise and shows the incorrect time of 2:51:15, instead of 59:59 (or 1:00:00 depending on how it is rounded) and playing normally.

The MP3 file opens fine in other software (such as Audacity, QuickTime/native, and VLC), so I am not sure why it does not play in Firefox. The MP3 file does not appear to be corrupt, and passes a basic integrity check in VLC.


3 years ago
Component: File Handling → Audio/Video: Playback
Product: Firefox → Core

Comment 1

3 years ago
Could you attach the MP3 file to the bug report (or in the cloud), the website is not reachable.
Flags: needinfo?(jamie)

Comment 2

3 years ago
It's a very large MP3 file, so I put it on another machine (

The MP3 file itself is 137MB in size, so it seems like it would be a bit inconsiderate to upload it to Mozilla's servers.
Flags: needinfo?(jamie)

Comment 3

3 years ago
I'm not able to play it locally. Maybe bad encoding.

Complete name                            : 2016-02-13-18.mp3
Format                                   : MPEG Audio
File size                                : 137 MiB
Duration                                 : 59mn 59s
Overall bit rate mode                    : Constant
Overall bit rate                         : 320 Kbps
Writing library                          : LAMEªª±

Format                                   : MPEG Audio
Format version                           : Version 1
Format profile                           : Layer 3
Mode                                     : Joint stereo
Duration                                 : 59mn 59s
Bit rate mode                            : Constant
Bit rate                                 : 320 Kbps
Channel(s)                               : 2 channels
Sampling rate                            : 48.0 KHz
Compression mode                         : Lossy
Stream size                              : 137 MiB (100%)
Writing library                          : LAMEªª±

Comment 4

3 years ago
Anyway the playback regressed. Before 44, the playback was fine on Win 7 even if the total duration displayed was wrong (playback jumped directly from 0:59:59 to 1:10:58).
Blocks: 1209410
Flags: needinfo?(jyavenard)
Keywords: regression
Version: unspecified → 44 Branch

Comment 5

3 years ago
The MP3 is probably poorly encoded (it is essentially a real-time stream), but yes, that should not affect playback - other players tested recover/play without issue.
I'm guessing another mp3 that changes sampling rate or something like that
Flags: needinfo?(jyavenard) → needinfo?(esawin)
Yes, looks like another case of oscillating sample rate.
Flags: needinfo?(esawin)
Also, some frames are mono.
The patch from bug 1256590 seems to fix the playback problems. Although I haven't listened to whole of it, the first few minutes play back fine, and seeking to the end of the file works, too. If the sample rate is indeed oscillating at some point, there might be some residual problems (skipped frames, because they won't pass the VerifyFrameConsistency() check) left, though, so I'm not sure whether this bug should closed as a duplicate or not.
If some of the frames are mono then this will depend on bug 1248861.
Depends on: 1248861
Is this issue still reproducible?
Fixed by bug 1256590 and 1264199.
Last Resolved: 3 years ago
Resolution: --- → WORKSFORME
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