Export Multiple 5.1 channel

[ppw1]

Hello,

I have a FLAC file with 6 channels (tracks) and multiple regions that I have marked using a label track. Using "Export Multiple..." from the File menu, Audacity automatically downmixes the 6 tracks in the marked region into one mono track. This happens even if "custom mix" is enabled in the Import/Export Preferences dialog, and the channel settings otherwise appear when exporting a track. The format for exporting is FLAC which supports 6 channels. Is this a bug?


Thanks for any answers

[kozikowski]

The Audacity instructions expect this to work and we have had postings from people where it did.

http://manual.audacityteam.org/man/Adva ... ng_Options

You should give us all your versions of everything. Which Windows, Which Audacity, etc. Stay from adjectives like "the latest." Do you have FFMpeg and lame installed? The only experiences I remember are exporting to AC3 and I think you need FFMpeg for that.

Koz

[ppw1]

Windows: 7 SP1 x64
Audacity: 2.0.3 (Jan 18 2013), x86
FFmpeg: F(52.64.2),C(52.72.2),U(50.15.1)
LAME: 3.99.3

[ppw1]

Oh no.

"Currently there is no support for exporting multichannel files when using File > Export Multiple...."

Well that sucks. How hard can it be to implement anyway?

[kozikowski]

How hard can it be to implement anyway?

Are you volunteering to write it?
The real question is how hard is it to get on the Audacity Patch List along with about half a billion other changes. Remember this isn't a corporation with a polished circular driveway and a fountain in the middle. It's a rag-tag group of volunteer programmers.

Koz

[steve]

How hard can it be to implement anyway?

I don't know, how hard is it to implement? Have you written a patch for it?

[ppw1]

I'm not a professional programmer, but if there's a routine to pick up two tracks (to export multiple stereo regions), shouldn't it be relatively easy to extend it to 6?

[steve]

if there's a routine to pick up two tracks (to export multiple stereo regions), shouldn't it be relatively easy to extend it to 6?

Probably not.
The Audacity "audio track" format supports mono or stereo tracks. Multi-channel export is achieved by mapping channels in the Audacity Project to output file channels. There are various different standards for how the audio channels should be mapped, so the Export Multiple dialogue would need to be extended to cover different channel mappings.

There is also error handling - more channels means more complexity and more opportunities for user errors - The code would need to be able to handle every possible user error in a sensible way (for example: what happens if the project has 4 stereo tracks and 5 mono tracks and the user chooses to export in 5.1 format?)

If Audacity were to support 5.1, then of course it should also support 2.1, 2.2, 4.0 (quad), 4.0 (surround), 4.1, 7.1 and so on. Someone would need to decide how that should be implemented.

How does file naming work when exporting multiple tracks with Export Multiple based on track names? Does it use the name of the first track, the centre channel, a separate user text field, some other way?

Just bolting on extra features is rarely a good way to design anything. All of the above and probably a lot more would need to be considered before anyone even starts coding it. How much do we estimate the development cost to be for this feature, based on say $50k pa for one experienced developer?

I'm sure that it could be done, given the necessary resources and the will to do it, so it is perfectly reasonable as a "feature request", but that does not mean that it will actually be done any time soon.

I'll move this topic to the "Adding Features" section.

[Gale Andrews]

I would guess Export Multiple by labels is relatively easy conceptually to extend to multi-channel tracks (which may not mean it is easy to code from what is there now).

The user would choose channel mapping after pressing "Export" in Export Multiple. The user can of course do it themselves by selecting a region at a time then File > Export Selection .

Export Multiple by track would be very complex for multi-channel export. It would seem to make more sense to implement the most useful feature to export multiple multi-channel by labels and then see if there was really any demand for export multiple multi-channel by tracks.


Gale