E4L Export Utility - EnvelopSound/EnvelopForLive GitHub Wiki

E4L Export Utility is a utility device that can be used to facilitate exporting the output of the decoder section on the E4L Master Bus device via Ableton's native Export Audio/Video workflow.

This is just a utility device, it performs no actual audio processing. It is recommended to place an instance of the E4 Export Utility on the track which contains your E4L Master Bus. Make sure that it is added after the master bus.

Use the Export Channels dropdown to choose how many channels you wish to export. This is typically a function of what decoder you are using in the E4L Master Bus. For instance, if you're using a Quad decoder you would want to export 4 channels, the Octo decoder would export 8, and the full AmbiX decoder would export 16. Export Channels are always a multiple of two, as Ableton exports the channels in stereo pairs. If you have an odd number of decoder channels, round up.

Export Procedure

  1. Click Create Tracks to automatically create a set of Ableton dummy tracks for export. These tracks will be automatically configured to receive the output from the E4L Master Bus decoder. No changes to channel settings or routing should be necessary. The Ableton tracks will be named E4L Export 1-2, E4L Export 3-4, etc.

  2. Select all the dummy tracks that you wish to export, using shift-click.

  3. Now, select Export Audio/Video from the Ableton File menu, and use the Selected Tracks Only option in the Rendered Track dropdown.

  4. Your channels will now be rendered to your file system with the name you selected and the suffixes E4L Export 1-2, ...

Merging Output Channels

FFmpeg

One typical workflow is to use the AmbiX decoder setting with 16 export channels to create a full 3rd-order Ambisonics render of your project. The 8 separate stereo files may be merged using the following Terminal command with ffmpeg from the folder where your project was exported.

NAME="<file name prefix>"; ffmpeg \
 -i "$NAME E4L Stem 1-2.wav" \
 -i "$NAME E4L Stem 3-4.wav" \
 -i "$NAME E4L Stem 5-6.wav" \
 -i "$NAME E4L Stem 7-8.wav" \
 -i "$NAME E4L Stem 9-10.wav" \
 -i "$NAME E4L Stem 11-12.wav" \
 -i "$NAME E4L Stem 13-14.wav" \
 -i "$NAME E4L Stem 15-16.wav" \
 -filter_complex "[0:a][1:a][2:a][3:a][4:a][5:a][6:a][7:a] amerge=inputs=8[a]" \
 -map "[a]" output.wav

The resulting output.wav is a single 16-channel 3rd-order Ambisonics file.

Audacity

If you do not feel comfortable with using the command-line ffmpeg command, you can use the free, cross-platform Audacity software to merge the stereo files instead, using the following steps:

  1. Import all 8 stereo files into a new Audacity project so that they are increasingly ordered, e.g., E4L Stem 1-2, E4L Stem 3-4, etc.
  2. For all eight stereo tracks, open the menu (downward caret) on each track and select Split Stereo Track. You should now have 16 mono tracks in your project.
  3. Open Audacity Preferences, click Import / Export, and ensure Use Advanced Mixing Options is selected.
  1. Select Export -> Export as WAV, and type a new file name. When you click Save, you will be presented with an option to export all 16 tracks, like so:

The resulting output file is a single 16-channel 3rd-order Ambisonics file.

Cleanup

When you are done with your export, if you wish to clean up your project you may optionally click Delete Tracks to remove the auto-generated dummy tracks. It is also perfectly fine to delete or rename the export tracks manually. Note that if you have renamed the export tracks, the output filenames will be different from what is shown above.