5.1 MPEG-4 AAC audio - speakers issue

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5.1 MPEG-4 AAC audio - speakers issue

Postby efj » Sun Jun 14, 2009 11:07 am

Dears,

First of all I want to congratulate the people involved in this project
This is by far the most working and the most easy to use solution for PS3 Upnp media streaming.

Anyway, here's the problem I encounter:
While playing MP4 video files using the MPEG-4 AAC auddio codec with 5.1 sound, speakers tracks seems to be mixed up. I get center audio on the right speaker for instance.

Is there an easy fix that solves this?

Many thanks for your help,

Cheers,

Eric
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Re: 5.1 MPEG-4 AAC audio - speakers issue

Postby meskibob » Sun Jun 14, 2009 3:48 pm

Audio channels getting swapped (specifically center->right) has been asked several times. Please use the search function to find your answer.
I provide NO application support via PM or email, so please post your question to the forum per the Forum Rules.
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Re: 5.1 MPEG-4 AAC audio - speakers issue

Postby efj » Sun Jun 14, 2009 5:55 pm

I did that before asking.

[*]I have compiled the latest mplayer/ffmpeg-mt/mencoder.
[*]I have played with the 3 options (remux AC3, keep DTS audio in stream, DTS/FLAC -> LPCM remux), but whether those are checked or not, I get center channel audio on my right speaker.

I have no problem whatsoever with any other kind of video files with 5.1 sound, only mp4.

My question is rather: is there any way to manually define the speakers order in PMS, for specific extensions?
Like a set of options that could be forwarded to mencoder?

Many thanks for your help,

Eric
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Re: 5.1 MPEG-4 AAC audio - speakers issue

Postby krister » Mon Jul 20, 2009 11:58 pm

Eric, I'm suffering from a similar problem.

When i play an mkv file that is not with DTS audio i get center in my right back speaker.

You asked if there is someway of manually changing the speaker setup, on older builds you could use the option -af channels=6:6:0:0:1:2:2:3:3:5:4:1:5:4 in the mencoder config page.

not sure if this works in newer builds though.
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Re: 5.1 MPEG-4 AAC audio - speakers issue

Postby efj » Tue Jul 21, 2009 11:13 am

Hi Krister,

Many thanks for your post. This is the exact same problem that I have.

Indeed, the channels order is messed up, having sound from center coming out of rear right speaker.

I am using
I installed mencoder-mt and mplayer-mt from there, made symbolic links to those 2 by using
cd /usr/bin
sudo ln -s mencoder-mt mencoder
sudo ln -s mplayer-mt mplayer

Thanks to that little trick, I am able to transcode 720p movies with 5.1 channels using only an Intel Atom 330.
But this is not the point anyway ...

When looking in the man pages for mencoder-mt, it describes the "-af channels" option just like you mentionned in your post, so yes it is compatible with the latest builds.

Regarding PMS configuration:

What I did was go into expert settings, set the following line:
channels == 6 :: -af channels=6:6:0:0:1:2:2:3:3:5:4:1:5:4
I could refine this by setting acodec == ac3 too, maybe this problem is only ac3 related.

When I look in what's currently ongoing when playing the file, this is what I get:
mencoder -ss 0 -quiet /mnt/raid/Movies/video_file.mkv -quiet -quiet -oac lavc -of mpeg -lavfopts format=asf -mpegopts format=mpeg2:muxrate=500000:vbuf_size=1194:abuf_size=64 -ovc lavc -channels 6 -lavdopts debug=0:threads=2 -lavcopts autoaspect=1:vcodec=mpeg2video:acodec=ac3:abitrate=640:threads=2:keyint=1:vqscale=1:vqmin=2 -subcp cp1252 -subfont /usr/share/fonts/truetype/msttcorefonts/Arial.ttf -subfont-text-scale 3 -subfont-outline 1 -subfont-blur 1 -subpos 98 -quiet -quiet -sid 100 -quiet -quiet -ofps 24000/1001 -sub /mnt/raid/Movies/video_file.srt -af channels=6:6:0:0:1:2:2:3:3:5:4:1:5:4 -mc 0 -noskip -af lavcresample=48000 -srate 48000 -o /tmp/javaps3media/mencoder1248170282327

Anyway, it just seems to not take this channels mapping into account at all.

Is there anything I am missing here?

Krister: Would you mind posting the content of your PMS.conf file please? It would help me a lot.

Thanks in advance,

Eric
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Re: 5.1 MPEG-4 AAC audio - speakers issue

Postby qweac » Thu Jul 30, 2009 8:47 pm

krister wrote:Eric, I'm suffering from a similar problem.

When i play an mkv file that is not with DTS audio i get center in my right back speaker.



Got the same problem, but I get center audio in my right front speaker. Both back speakers are mute... I'm on Arch Linux, so everything should be up to date.
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Re: 5.1 MPEG-4 AAC audio - speakers issue

Postby shagrath » Thu Jul 30, 2009 11:46 pm

something in channels management has changed in the latest libavcodec code (the windows builds have the same "issue" I think, I'm still keeping the old ones from january)
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Re: 5.1 MPEG-4 AAC audio - speakers issue

Postby heddhunter » Fri Jul 31, 2009 9:47 pm

shagrath wrote:something in channels management has changed in the latest libavcodec code (the windows builds have the same "issue" I think, I'm still keeping the old ones from january)


would this affect tsmuxer as well? i don't transcode video at all and i am having the swapped channels problem.

if the answer is yes, what's the subversion revision of your version of mplayer/mencoder? i can check out an old one and rebuild for this purpose.
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Re: 5.1 MPEG-4 AAC audio - speakers issue

Postby shagrath » Fri Jul 31, 2009 11:24 pm

heddhunter wrote:would this affect tsmuxer as well? i don't transcode video at all and i am having the swapped channels problem.


I would think these two words are unrelated ;)
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Re: 5.1 MPEG-4 AAC audio - speakers issue

Postby heddhunter » Sun Aug 02, 2009 7:21 pm

shagrath wrote:
heddhunter wrote:would this affect tsmuxer as well? i don't transcode video at all and i am having the swapped channels problem.


I would think these two words are unrelated ;)


fair enough, but what i meant was - if i am using tsmuxer and not mencoder, does the mencoder channel problem still apply?

and again, what version of mencoder are you using? this swapped channels thing is driving me crazy. pms on linux is unusable until i get it fixed.
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