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Old 29th November 2020, 15:17   #1  |  Link
nivedhya
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How to identify stereo wave file fit for 5.1 upmix?

I took a wave stereo, split it to 6 mono wave. Found except FL & FR all other 4 are silent including Center. Hence I presume this stereo wave is unfit for 5.1 upmix and think vocal also recorded with L& R & unable to take out seperately.

So my question is how to identify or select a wave stereo fit for 5.1 conversion and split?

Is there any other way to use my above file for 5.1 upmix or no way?
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Old 29th November 2020, 23:53   #2  |  Link
Richard1485
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Your question is confusing. If you have a 2.0 file, you can't split it into six wavs. But some 5.1 tracks are really 2.0 because only two channels have content: I've come across this with some HDTV broadcasts, and it might be what you are describing.

Take the two channels that have content and merge them into a single wav. Once you have a 2.0 wav, you can upmix it like any other.
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Old 2nd December 2020, 10:58   #3  |  Link
nivedhya
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Quote:
Originally Posted by Richard1485 View Post
Your question is confusing. If you have a 2.0 file, you can't split it into six wavs. But some 5.1 tracks are really 2.0 because only two channels have content: I've come across this with some HDTV broadcasts, and it might be what you are describing.

Take the two channels that have content and merge them into a single wav. Once you have a 2.0 wav, you can upmix it like any other.
My question is very simple. I have some songs in stereo. Originally they were recorded only in stereo since 5.1 not so famous or familiar in 80's.

Same songs converted by somebody to DTS which means 5.1 & I have that one too. Same songs both in 2 channel & 5.1 channel.

Even stereo can be played as Multichannel stereo in 5 speakers except LFE & what I say above is not that one.It is very clear 5,1 with LFE filtered, vocals boosted & in Center separate & similarly Music boosted & in SL & SR.

Likewise if I have to convert some other stereo to 5.1 what are the requirement. Hope my message & goal clear.
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Old 2nd December 2020, 11:02   #4  |  Link
nivedhya
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Quote:
Originally Posted by Richard1485 View Post
Your question is confusing. If you have a 2.0 file, you can't split it into six wavs. But some 5.1 tracks are really 2.0 because only two channels have content: I've come across this with some HDTV broadcasts, and it might be what you are describing.

Take the two channels that have content and merge them into a single wav. Once you have a 2.0 wav, you can upmix it like any other.
OK.If my question is confusing let me give a way to split stereo song of 70's or 80's file with voice separate & music separate & LFE separate. Rest boosting & all I take care
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Old 2nd December 2020, 17:30   #5  |  Link
tebasuna51
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You have a Sticky: GUIDE LIST: Stereo-to-Surround Conversion Guides with many options.

I recommend you this one https://forum.doom9.org/showthread.p...51#post1640451
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Old 3rd December 2020, 01:21   #6  |  Link
Richard1485
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Quote:
Originally Posted by nivedhya View Post
My question is very simple.
No, it wasn't. For example, you said...

Quote:
I took a wave stereo, split it to 6 mono wave.
...which is not possible, because splitting a 2.0 file won't result in six mono wavs. In the original post, it wasn't clear what sort of files you were dealing with.

Quote:
I have some songs in stereo. Originally they were recorded only in stereo since 5.1 not so famous or familiar in 80's.
Right, so your files are 2.0. Try one of the methods to which tebasuna linked.

Quote:
Even stereo can be played as Multichannel stereo in 5 speakers except LFE & what I say above is not that one.It is very clear 5,1 with LFE filtered, vocals boosted & in Center separate & similarly Music boosted & in SL & SR.
This makes it sound as if you want more than simple upmixing, which will not leave you with just vocals in the center and music in the surround channels: the vocals will bleed into the other channels, and there will be music in the center. You can try to extract the vocals from the rest of the mix with Audacity, but even that won't be perfect.

Your original question was about identifying stereo tracks that are suitable for upmixing. That's not really something that can be worked out by examining a file's metadata. Some tracks upmix better than others, but most of the time you just have to try it and see what the results are like.
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Old 3rd December 2020, 08:43   #7  |  Link
nivedhya
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Quote:
Originally Posted by Richard1485 View Post
No, it wasn't. For example, you said...



...which is not possible, because splitting a 2.0 file won't result in six mono wavs. In the original post, it wasn't clear what sort of files you were dealing with.



Right, so your files are 2.0. Try one of the methods to which tebasuna linked.



This makes it sound as if you want more than simple upmixing, which will not leave you with just vocals in the center and music in the surround channels: the vocals will bleed into the other channels, and there will be music in the center. You can try to extract the vocals from the rest of the mix with Audacity, but even that won't be perfect.

Your original question was about identifying stereo tracks that are suitable for upmixing. That's not really something that can be worked out by examining a file's metadata. Some tracks upmix better than others, but most of the time you just have to try it and see what the results are like.
Thank You. Understood. I had problem with my source file recording in which music & vocal not got separated & all recordings totally in center & duplicated in side channel. Took another stereo file. With center_cut_GUI got music alone as side & vocals with music as center almost to my expectation. Now I can try LFE filtering & surround files with these.Tq anyhow.
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Old 3rd December 2020, 10:51   #8  |  Link
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Quote:
Originally Posted by nivedhya View Post
...Now I can try LFE filtering & surround files with these.Tq anyhow.
I can't recommend you create a LFE chanel from a stereo file.
You can create a 5.0 or a 5.1 with the LFE empty because:

- The LFE is the Low Frequency Effects but not the low frequency from all channels. In a stereo source don't exist Effects, only low frequencies.

- All audio surround equipment can be configured to send the low frequencies from all channels to the subwoofer (and by default is recommended do so). Don't mistake LFE channel with the subwoofer in your system.

- Let your audio equipment do the filter of low frequencies to the subwoofer to avoid interferences between the rest in all channels and the extracted by you.
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Old 5th December 2020, 06:53   #9  |  Link
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A while ago I added a few 2ch -> 6ch upmix algorithms to my Wavi_Mod plugin for AVStoDVD. Just the other day I noticed that the channel mapping for the final output.ac3 file looked wrong when decoded with LAV Audio.

I had used this channel merge command (taken from an old post by Selur):
Quote:
#merge channels
sox -S -V -M front_left.wav front_right.wav rear_left.wav rear_right.wav center.wav lfe.wav multichannel.wav
But the center and LFE channels were mapped wrong according to the LAV Audio status window.

I found this old post by Jenyok where he posted 4 different output mapping schemes for different output formats:
https://forum.doom9.org/showthread.p...87#post1624087

Are these mapping methods correct?

I always convert the stereo source to 6-ch WAV, and the conversion to AC3 happens later independently from the upmix routine. To make LAV Audio happy I need to use this mapping which is supposed to be meant for WAV output:
Quote:
#merge channels
sox -S -V -M front_left.wav front_right.wav center.wav lfe.wav rear_left.wav rear_right.wav multichannel.wav
The following conversion to AC3 (using FFmpeg) seems to handle the mapping correctly, at least this is what LAV Audio thinks.

So do you think this is the correct channel mapping?


Cheers
manolito

Last edited by manolito; 5th December 2020 at 07:09.
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Old 5th December 2020, 12:48   #10  |  Link
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Quote:
Originally Posted by manolito View Post
...
I found this old post by Jenyok where he posted 4 different output mapping schemes for different output formats:
https://forum.doom9.org/showthread.p...87#post1624087

Are these mapping methods correct?
They are all correct, but the internal order than each encoder (AC3, DTS, AIFF, AAC,...) use is useless for us.

We only need know the order inside AviSynth than is the same than the WAV order FL,FR,FC,LFE,SL,SR

All encoders accept the uncompressed audio in the standard WAV order, if you supply monowavs (like with sox or ffmpeg) the order must be the same, no mather the internal order of the compressed output format.
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Old 5th December 2020, 13:05   #11  |  Link
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