WIP: Enhancing Multichannel / Fix Single Channel Recording

[Giermann]

Hi all,

driven by Gale while discussing on the developer mailinglist, I'm going to publish my work-in-progress on enhancing Multichannel recordings with Audacity. I started to implement Record Profiles to address the following:

• remove both limitations mentioned in the Multichannel Recording Wiki
• implement the following Feature Requests
  Allocate specific channels to specific Audacity tracks,
  Allow nonconsecutive set of input channels to be selected
• BTW this could be a possible solution to the Pending Feature Request "Recording single channels"

For now there's no possibility to create Record Profiles within the Preferences GUI, so one would have to manually change the audacity.cfg, but when you are working with Multichannel capture devices and/or argue about Downmix of 2 channels when you try to capture just one channel, this current version might be helpful for you.
On the other hand it would enable me to test my changes at a wider range of systems/hardware. I am using it for weeks now on Windows with ASIO driver for Tascam US-1800, which works okay!

So please tell me, if you are interested in testing - or just join the discussion at audacity-devel or read previous messages here: http://sourceforge.net/mailarchive/mess ... d=30524473

Sven.

UPDATE:
Uploaded the patch to compile Audacity with Record Profiles support:

ChannelMapping_v5b.patch

04Mar13: Current patch to support Record profiles.

(32.38 KiB) Downloaded 249 times

For all non-developers, there's a Windows build ready to use, but without ASIO support which might be needed for many devices to support multiple input channels. I had to upload it to my Dropbox, since it exceeds the maximum upload file size here:
@Dropbox: Audacity_2.0.4-alpha_Win32.zip
(simply replace the EXE in your existing Audacity 2.0.3 installation!)

As a quick start simply add these lines to your audacity.cfg to create and enable the first profiles, that should appear in the capture channel selection dropdown on the next Audacity start:

Code: Select all

[AudioIO/RecordProfile1]
MaxRecordChannels=2
Name=Left(1) only
Channel1=1
ChannelName1=Left

[AudioIO/RecordProfile2]
MaxRecordChannels=2
Name=Right(2) only
Channel1=2
ChannelName1=Right

[AudioIO/RecordProfile3]
MaxRecordChannels=2
Name=Swap Mono
Channel1=2
ChannelName1=Right
ChannelType1=R
Channel2=1
ChannelName2=Left
ChannelType2=L

For the location of audacity.cfg, see http://manual.audacityteam.org/o/man/pr ... tml#stored . Quit Audacity before editing the .cfg file.

[Edgar]

Hi Sven!

My name is Ed Musgrove and I saw that Gale suggested that I might be able to help you in beta testing your work. I am an active member of Audacity's manual editors team and I have also had a small amount of code committed in re. bug fixes. I compile Audacity from SVN HEAD frequently and also provide custom Audacity solutions for end-users. I have compiled Audacity with ASIO in the past but do not currently do so. My primary audio device is an external FireWire Echo AudioFire4 which has four balanced mic inputs plus two SPDIF inputs as well as four balanced line level outputs plus two SPDIF outputs.

While I have skimmed the discussion on -devel, I am not really up on what you are trying to accomplish; however, I would be happy to do any testing of which I am capable. Other than its GUI, I am not really extremely familiar with Audacity's code base but I am capable of running Audacity under the Visual Studio debugger and am quite comfortable with C++.

Let me know how I may be of help!

[ragnar.jensen]

Hi!
I'm Ragnar Jensen and I'd be very interested in testing the fruits of your labor. I've been building on Windows from HEAD at least weekly for about a year now, both with and without ASIO. I have two multichannel interfaces, a Zoom R16 (8 input/2 output channels) and a Motu Ultralite Mk3 hybrid (10 in/14 out). Now and then I construct an 8-channel aggregate device out of four 2-channel USB interfaces and Virtual Audio Cable. The Zoom needs ASIO to work reliably but with the Motu and my VAC device I would be able to test using MME and DirectSound too.
I haven't tried Audacity on Linux yet, I'm not sure if my interfaces work there, but I could give that a go too if need be.

I've just joined audacity-devel

--
Ragnar

[Edgar]

Given the inherent difficulty of searching through the -devel mailing list looking for the most current patch, it might make some sense for Sven to edit the initial post in this thread and attach each new patch as it becomes available. Since only editing an old post may not trigger the "New Post" messaging system of this bulletin board it would also be a good idea to post a reply to this thread stating that a new patch is available in the initial post.


The most current patch I could find is 5a but there appear to be two different patches with that number:
ChannelMapping_v5a.patch
ChannelMapping_v5a-ignore-whitespace.patch


I grabbed both of these but have not looked at them yet. I am assuming that I will need to compile SVN HEAD with ASIO as otherwise Audacity only recognizes two channels of my Echo AudioFire4 - is that correct? Do I need to apply both of these patches and, if so, is there a specific order?

[steve]

Do I need to apply both of these patches and, if so, is there a specific order?

I think it's either/or.
Both patches look to be essentially the same but the ChannelMapping_v5a-ignore-whitespace.patch is smaller because it is a diff ignoring white space changes.
The larger ChannelMapping_v5a.patch may apply more easily.

ChannelMapping_v5a-ignore-whitespace.patch built OK on Linux, but I get an error when adding profiles to audacity.cfg (which Sven is already aware of).

[Giermann]

Yes, Steve is right.
I just added the two versions, because the "ignore-whitespace" one is easier to read, if one would like to review the DIFF manually before applying.
I will only attach the normal version in future, since one could also do another "ignore whitespace" diff after applying the normal one.

@Ed: It seems I'm not allowed to edit any of my posts (yet), but I'm going to add a more recent patch from the current HEAD, maybe already with the problem you identified when I selected profile is not valid anymore on the next Audacity start. But this is not going to be before next week...

[steve]

It seems I'm not allowed to edit any of my posts (yet),

We *much* prefer that people post updates as a new post. In the past it was a very frequent and confusing occurrence for forum users to edit their posts after they had been replied to, making nonsense of the replies (also people posting just enough to get past having posts moderated and then coming back and changing their posts to spam). Sorry if this is occasionally inconvenient.

[Edgar]

It seems I'm not allowed to edit any of my posts (yet),

We *much* prefer that people post updates as a new post.

I see; then the forum is probably not the appropriate repository for "work in progress" patches. Back in the dark ages we had a formal repository for this kind of patch but it was superseded by Bugzilla… ah yes:
http://wiki.audacityteam.org/index.php?title=Patches
since it has been abandoned by the Developers maybe we could borrow it.

Another potential solution would be to start a new thread each time a new patch was published; this has both drawbacks and advantages but I am not sure which way the balance falls.

[steve]

Giermann should be able to edit his own posts once the forum software recognises that he's a regular user.
@Giermann: let me know if this does not happen.

For things like "work in progress patches", then yes they can be updated, but if doing so please also make a note that it has been updated both in the original topic and send a new post - as topics get long it is awkward to have to go back several pages just to see if the first post has been updated.

Suggestions:
1) When updating an attachment it could be worth adding the date of the update, either to the file name or in the associated text. For example:
myreallygoodpatch.patch Updated 1/02/2013.

2) If a patch is added as an attachment to a post, Firefox allows right click to copy the link location (I'm sure other browsers have something similar), then the link can be pasted into a new post which will be chronologically the most recent.

since it has been abandoned by the Developers maybe we could borrow it.

That could be a possibility but upload would only be available to people with a wiki account.

[Gale Andrews]

I don't think patches should be a big problem if we do like Steve suggests (including update the first topic with the latest patch for people coming new to the topic). This works with topics about Nyquist plug-ins as far as I know.


Gale