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Topic: Surround sound mapping in Audacity (Read 9265 times) previous topic - next topic
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Surround sound mapping in Audacity

Hello.
Firstly, let me appologise if this is in the wrong area of the forum.
Secondly, let me further appologise that this post may seem quite specific to Audacity (and yes I have tried the Audacity forums too).
I am begining to think that my problem is more Windows 7 (32 bit) based but can't for the life of me find a rouge setting in any windows mixer/control panel settings.

Here goes with the problem.
I have created an 8 channel recording in Audacity 2.03, and wish to render this to 6 channels for export as 5.LFE (not .1 as it will be 44.1 sample rate, for the moment).
In Audacity's  Edit:Preferences Export/Import I have selected the multi-channel option and channel mapper (and metadata). When exported the resulting file has 6 channels 4 of which are silence but channels 3 and 6 have the audio assigned from the channel mapper during export.
What am I doing wrong?

Does any one here know Audacity, or windows sufficiently to give me a further clue?

Hope you can help.

Surround sound mapping in Audacity

Reply #1 –
What mapping do you want to use for rendering the input 8 channels into the output 6 channels?

Surround sound mapping in Audacity

Reply #2 –
Quote from: phofman on
What mapping do you want to use for rendering the input 8 channels into the output 6 channels?


Hi
The 8 inputs consist of
Track 1: Bass guitar,
Track 2: rhythm 1,
Track 3: rhythm 2,
Track 4: Sub bass,
Track 5: Lead 1,
Track 6: Lead 2,
Track 7 intro lead 1,
Track 8 Intro lead 2.
The audacity mapping I want to achieve is
Output 1 (Lfront): Track 5 and Track 7,
Output 2 (Rfront) Track 6 and Track 8,
Output 3 (centre channel) Track 1 (don't ask why,long story, I know its not conventional layout),
Output 4 (Lsurround) Track 2,
Output 5 (Rsurround) Track 3.
Output 6 (LFE, not sub-sampled yet this is to remain full BW until AC3 or AAC encoding for web use later in the mean timeall channels are sampled at 44.1) Track 4.

I'm following the AES/EBU, DPP, EBU, SMPTE surround track channel layout as this is for use with a pro desk.

Cheers

Surround sound mapping in Audacity

Reply #3 –
Hi, Flingle_Bunt.

Do you mean something like this ?



If so, make sure you have "use custom mix" enabled in Audacity's Import/Export options:



HTH,
Maggi

Surround sound mapping in Audacity

Reply #4 –
Hi Maggi

Thanks for the quick responce thats exactly how it is arranged and thats the channel map I create, I have the options set as you show and it still creates silence on all channels but 3 and 6. So I'm at a bit of a loss as to why this is happening, I'm not sure if Windows is the problem, I cannot find any surround sound settings in Control panel, which makes me think that Windows mixer is only stereo. If so I'm a bit stuck.
Any thoughts?

Thanks again

Surround sound mapping in Audacity

Reply #5 –
Quote from: Flingle_Bunt on
Thanks for the quick responce thats exactly how it is arranged and thats the channel map I create, I have the options set as you show and it still creates silence on all channels but 3 and 6. So I'm at a bit of a loss as to why this is happening, I'm not sure if Windows is the problem, I cannot find any surround sound settings in Control panel, which makes me think that Windows mixer is only stereo. If so I'm a bit stuck.
Any thoughts?

Thanks again


That's odd, because it works just fine on my end ... 
(using Audacity v2.0.3)

How did you check the resulting file ? By opening it in Audacity again ?

Surround sound mapping in Audacity

Reply #6 –
That's odd, because it works just fine on my end ... 
(using Audacity v2.0.3)

How did you check the resulting file ? By opening it in Audacity again ?
[/quote]
Hi again.
I'm using the latest Audacity, down loaded it yesterday and replaced V1.3 unicode.
I save any mods to the project as an aup, then export as a WAV, map the channels, fill in the metadata, save the file. Close Audacity and re-open to check the saved file and it is as described, silence on 4 tracks active on 2 of them, the .aup file is fine.
  ?

Thanks

Surround sound mapping in Audacity

Reply #7 –
sorry, I have no idea what's going wrong on your end ... 

Surround sound mapping in Audacity

Reply #9 –
I don't know what's going on with Audacity, but you might try REAPER ($60 USD for personal or small business use).  For mixing, a DAW (Digital Audio Workstation)* is more appropriate than an audio editor.  The downside is the long learning curve. 

Quote
...wish to render this to 6 channels for export as 5.LFE (not .1 as it will be 44.1 sample rate, for the moment).
What?  I'm not following that...  The "point one" channel should have the same sample rate as everything else (usually 48kHz for DVD).  On a DVD, it's all in one 48kHz AC3 file, multiplexed with the video in an MPEG-2 A/V file. 

FYI - LFE is supposed to be for effects.  The other 5 channels should contain the "regular" musical bass.  On a typical home theater system, the 5 surround speakers are small so your receiver has bass management to optionally route all of the bass to the subwoofer, but the DVD's point-one channel should contain only effects (booms & explosions).

When you play-back a surround DVD on a 2-channel stereo system, the 5.1 to 2.0 mix-down does not include the LFE.    So, if you want Track-4 to be included in stereo-playback, don't put in in the LFE.  That also means that at least some of the "booms & explosions" sound needs to be mixed into the other channels (probably left & right front).



* There are other DAWs, but REAPER is low-cost, the 60-day trial version is fully-functional, the $60 version is identical to the full-commercial "pro version" (just a different user-licence), and the upgrade policy is generous.

Surround sound mapping in Audacity

Reply #10 –
Windows has nothing to do with generating the export of audacity, so you will do yourself a favour if you look elsewhere.

You haven't said to what format are you exporting the audio (Indicate exactly the file type and whatever extra configuration you have in the options button).
I'd say it doesn't matter, but also tell about the sampling rates of the tracks and the one of the project. at last, are the tracks mono or stereo? (so, you have 8 or 16 sources?)

Tests done here generate audio on all channels (with the required mixing on those that have more than one source), and I have a stereo soundcard.
 

Surround sound mapping in Audacity

Reply #11 –
Just as a blind shot ...

Maybe you need to install the ffmpeg library for Audacity ?
http://manual.audacityteam.org/index.php?t...s#installffmpeg

I have it installed, because I need to extract audio from QTs on a regular basis, but maybe it's needed for proper multi channel export as well.

Cheers,
Maggi