Opened 13 years ago

Last modified 12 years ago

#1947 new defect

Audio cuts out with AC3 output at 256kb/s

Reported by: subjunk@… Owned by: reimar
Priority: normal Component: core
Version: HEAD Severity: normal
Keywords: Cc: cehoyos
Blocked By: Blocking:
Reproduced by developer: no Analyzed by developer: no

Description

Tested with r33877.
Using the following input, the sound is perfect:

mencoder input.avi -oac lavc -of mpeg -ovc lavc -lavcopts acodec=ac3:abitrate=224 -o output.mpeg

It's also fine when the abitrate value is changed to 448, 192 and I'm sure others that I didn't try.
However, using the following input there are occasional gaps in the audio:

mencoder input.avi -oac lavc -of mpeg -ovc lavc -lavcopts acodec=ac3:abitrate=256 -o output.mpeg

The gaps sound different depending on which media player plays them. VLC produces loud clicking sounds, MPC-HC just skips quietly, as does MPlayer.

MPlayer gives some information on the errors when it plays the file. When the gap occurs it outputs:

[ac3 @ 00e9ee10]exponent out-of-range
[ac3 @ 00e9ee10]error decoding the audio block
[ac3 @ 00e9ee10]new coupling coordinates must be present in block 0
[ac3 @ 00e9ee10]error decoding the audio block

The files I have noticed it happening with have all been avi files with mp3 audio.

Attachments (1)

256.txt (2.3 KB ) - added by subjunk@… 13 years ago.
Complete MEncoder output

Download all attachments as: .zip

Change History (7)

comment:1 by cehoyos, 13 years ago

Cc: cehoyos@… added

While I cannot reproduce your problem with the command lines you provided (they both produce a working file for me) and I wonder if ASP in PS really makes sense, please at least provide complete, uncut output of mencoder (when muxing fails).

by subjunk@…, 13 years ago

Attachment: 256.txt added

Complete MEncoder output

comment:2 by subjunk@…, 13 years ago

comment:3 by subjunk@…, 13 years ago

I've attached the complete MEncoder output to this ticket, and I've uploaded 10 second video comparisons to http://www.spirton.com/uploads/Unsorted/20110712-VideosAC3.zip so you can hear the bug for yourself.
224.mpeg is how the original sounds, while 256.mpeg has the bug.

comment:4 by cehoyos, 13 years ago

The needed sample is input.avi, please consider attaching it here.

comment:5 by subjunk@…, 13 years ago

comment:6 by subjunk@…, 12 years ago

Did you manage to download the file before it was deleted? I can re-upload it

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