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BUG: stereo -> mono not working
Posted: 15 May 2007 11:49
by mhavo
Hi!
I'm trying to transcode audio from soundcard to mono mp3. Not working... "channel=1" setup is not recognized. Audio is always joint-stereo. Version is 0.8.6.b
Posted: 15 May 2007 12:06
by DJ
If I may be so bold to ask the stupid question? How are you determining this?
Posted: 15 May 2007 15:05
by mhavo
Code: Select all
vlc.exe --intf rc dshow:// :dshow-vdev="" :dshow-adev="" :dshow-size="" :sout="#duplicate{dst='transcode{acodec=mp3,ab=192,channels=2}:duplicate{dst=std{access=file,mux=raw,dst="C:\test192.mp3"}}',dst='transcode{acodec=mp3,ab=128,channels=1}:duplicate{dst=std{access=file,mux=raw,dst="C:\test128.mp3"}}'}"
Both files are joint-stereo. Am I missing something?
Posted: 18 May 2007 08:33
by mhavo
Well I'm not the only one with this problem.
viewtopic.php?t=35687&sid=f11de573814cd ... c2024b525a
So it would be nice if developers say at least something about this.
Posted: 18 May 2007 08:45
by DJ
I'm doing this from memory as I seldom do mono MP3 files. There are 2 options in the format (rather confusing as I recall) Joint stereo was designed for stereo files where as stereo was designed for by lingual files (Mono). Left channel is the default language and Right channel is optional. I know this works in VLC because occasionally I get files that default to the left channel and were encoded in the wrong way. Also VLC plays mono through both speakers. Personally I believe this is incorrect. While most people do like and want this.
Posted: 18 May 2007 08:50
by mhavo
Ok?
But how do I encode stereo input to mono mp3? And how do I tell to encoder to produce real stereo? (Not joint-stereo) Am I still missing something? (Yes I do
)
Posted: 18 May 2007 09:31
by DJ
I know that the default for the decoder is Stereo and NOT Joint-stereo. But a flag in the file will change this to what it needs to be.
As far as the encoding goes, I don't know what the default is. I assume it is Joint-stereo or the stereo would default to the left channel and not do a real stereo. There are no options to change this that I am aware of, other than the 1 channel option in the Stream output menu. I have tried to go the other direction and do multi-channel when the source is multi-channel, but that doesn't work either. I suspect that this option was never finished.
Posted: 18 May 2007 10:26
by mhavo
Posted: 18 May 2007 10:51
by DJ
Posted: 18 May 2007 11:56
by mhavo
Thank you so much!
Posted: 04 Jun 2007 09:02
by mhavo
04.06.2007: The status of Ticket #1198 is still in 'Not started' state... too sad.
21.08.2007: Still not started. Still waiting.
Re: BUG: stereo -> mono not working
Posted: 21 Aug 2007 08:43
by mhavo
It would be great if we can hear at least something about this from the coders. I can guess that this issue is not so big to fix in the code...
Re: BUG: stereo -> mono not working
Posted: 22 Aug 2007 01:53
by funman
unfortunately nobody in the team has time/knowledge to work on this item
try aenc=twolame in the transcode chain
Re: BUG: stereo -> mono not working
Posted: 22 Aug 2007 02:19
by funman
by the way mono encoding works fine for me (using nightly build)
Code: Select all
file in.mp3
in.mp3: MPEG ADTS, layer III, v1, 128 kBits, 44.1 kHz, JntStereo
this looks like stereo
Code: Select all
./vlc/bin/vlc -I dummy -vvv --color in.mp3 --sout "#transcode{acodec=mp3,channels=1}:standard{access=file,mux=raw,dst=out.mp3}" vlc:quit
and then this looks like mono:
Code: Select all
file out.mp3
out.mp3: MPEG ADTS, layer III, v1, 64 kBits, 44.1 kHz, Monaural
listening is fine
can you please try a nightly build ? you can get one at
http://nightlies.videolan.org
the bug may have resolved itself, so let us know !
Re: BUG: stereo -> mono not working
Posted: 19 Sep 2007 17:11
by fouj@x
Actually, it works when converting a stereo file to mono, but not when trying to get a dshow input and save it as a mono file.
