Sound regression playing aac files in Lucid

[matthewbpt]

I currently have a problem with all my Lucid installs, whereby certain aac files (.m4a extension) cannot play properly anymore. When played the songs skip constantly and play high-pitched noise every split second between the real audio. I tested the same files in Arch, in a Karmic live cd and in Windows and they plays fine in all of them. I have tested this on 3 Lucid installs, one an upgrade, the other two fresh installs, and the problem is present in all of them.

Funny thing that I just discovered, the files are unplayable in Rhythmbox, Vlc, Totem and Audacious, but play perfectly in XBMC and Aqualung. What is different about how these players play the audio files?

Here's a link to one of the offending files http://drop.io/lwx4fgt , anyone with more expertise with sound problems care to help, it's quite an annoying bug as I have hundreds of music files with the same problem. I want to post a bug in launchpad but i dont know that to post the bug against,

Matt

EDIT: I've submitted a bug report, https://bugs.launchpad.net/ubuntu/+s...er/+bug/575798 , can anyone else confirm the bug?

[matthewbpt]

bump

[mc4man]

Not exactly sure what's up with your file(s) yet.

Of interest - the sample plays fine in browser, but not locally as you described.

But if it's decoded with ffaac it will play fine (vs. faad or libfaad which most players will default to.

So ffplay will decode ok as will mplayer as such

mplayer -ac ffaac '/home/doug/Downloads/new.m4a'

[matthewbpt]

That's interesting, so this is a bug in faad then? Should I change the affected package to faad in the bug report?

[mc4man]

edit - wrong assumption

Complete name : /home/doug/Downloads/new.m4a
Format : MPEG-4
Format profile : Apple AAC audio with iTunes info
Codec ID : M4A
File size : 161 KiB
Duration : 10s 7ms
Overall bit rate : 132 Kbps
Writing application : Lavf52.31.0

Audio
ID : 1
Format : AAC
Format/Info : Advanced Audio Codec
Format version : Version 4
Format profile : Main
Codec ID : 40
Duration : 10s 7ms
Bit rate mode : Variable
Bit rate : 129 Kbps

[matthewbpt]

Hmm, well I encoded the affected files before Lucid was released, so I didn't encode them with Lucid's ffmpeg. I think I used Rhythmbox inbuilt CD ripper.

[mc4man]

Hmm, well I encoded the affected files before Lucid was released, so I didn't encode them with Lucid's ffmpeg. I think I used Rhythmbox inbuilt CD ripper.

Well playing your sample with pretty much the same mplayer builds in karmic and lucid - it decodes properly in karmic, not in lucid. ( mplayer doesn't use the system libfaadX

Your best bet long term is not to use gstreamer apps to encode to m4a ( or at least if the gstreamer profile is using Main instead of LC.


Edit : what the difference is on lucid don't know - but changing the gstreamer profile to encode to Main, the resultant .m4a shows the decoding problem in lucid with all players except ffplay inc. mplayer. (unless mplayer uses ffaac.
So don't think the issue is libfaad2, just something about lucid

[andrew.46]

Hi,

I will admit that I am not testing this file on Lucid but the svn MPlayer can play it with either faad or ffaac:

andrew@skamandros~/Desktop$ mplayer -ac faad new.m4a 
MPlayer SVN-r31137-4.3.3 (C) 2000-2010 MPlayer Team

Playing new.m4a.
libavformat file format detected.
[lavf] stream 0: audio (aac), -aid 0, -alang und
Clip info:
 major_brand: M4A 
 minor_version: 512
 compatible_brands: isomiso2
 encoder: Lavf52.31.0
==========================================================================
Forced audio codec: faad
Opening audio decoder: [faad] AAC (MPEG2/4 Advanced Audio Coding)
AUDIO: 44100 Hz, 2 ch, s16le, 128.6 kbit/9.11% (ratio: 16070->176400)
Selected audio codec: [faad] afm: faad (FAAD AAC (MPEG-2/MPEG-4 Audio))
==========================================================================
AO: [oss] 44100Hz 2ch s16le (2 bytes per sample)
Video: no video
Starting playback...
A:   9.7 (09.6) of 10.0 (10.0)  6.9% 

Exiting... (End of file)

andrew@skamandros~/Desktop$ mplayer -ac ffaac new.m4a 
MPlayer SVN-r31137-4.3.3 (C) 2000-2010 MPlayer Team

Playing new.m4a.
libavformat file format detected.
[lavf] stream 0: audio (aac), -aid 0, -alang und
Clip info:
 major_brand: M4A 
 minor_version: 512
 compatible_brands: isomiso2
 encoder: Lavf52.31.0
==========================================================================
Forced audio codec: ffaac
Opening audio decoder: [ffmpeg] FFmpeg/libavcodec audio decoders
AUDIO: 44100 Hz, 2 ch, s16le, 128.6 kbit/9.11% (ratio: 16070->176400)
Selected audio codec: [ffaac] afm: ffmpeg (FFmpeg AAC (MPEG-2/MPEG-4 Audio))
==========================================================================
AO: [oss] 44100Hz 2ch s16le (2 bytes per sample)
Video: no video
Starting playback...
A:   9.7 (09.6) of 10.0 (10.0)  1.1% 

Exiting... (End of file)

I would be interested to see what the Lucid problem is...

Andrew

[mc4man]

I would be interested to see what the Lucid problem is...

It's a weird one for sure - the bug report is in the first post

On lucid, mplayer will only play with ffaac, yet the same mplayer build will play Main profile aac on anything but lucid.

Redid a vlc 1.0.6 build on lucid that was statically linked to the karmic libfaad (libfaad0), same thing - plays LC aac fine, Main profile is not decoded properly, exact same build on karmic is fine.

And it's not something in matthewbpt file(s) - I set rhythmbox to encode to Main, same thing.

The issue then is people who trusted gstreamer to encode aac in the past (when it used Main), are now left with unplayable files in lucid (well they play - so un-listenable - if that's even a word...

[matthewbpt]

I wasn't aware of the existence of these different profiles within the aac codec, what exactly is the difference between them?

Edit: This bug is getting more and more annoying, I didn't realise how many files I encoded using this "Main" profile, this needs a fix!