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Gear / Technical Help => Post-Processing, Computer / Streaming / Internet Devices & Related Activity => Topic started by: voltronic on March 08, 2024, 07:51:43 PM
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I have finally found an easy solution to splitting polyphonic WAV files to stereo tracks without having to split to mono files and then recombine those to stereo.
EDIT: This is most useful for 32-bit float PolyWAV files. For 16/24-bit fixed, WaveAgent is the easier choice (see here (https://taperssection.com/index.php?topic=204546.msg2410355#msg2410355)).
1. Install FFMPEG (https://ffmpeg.org/download.html).
2. Copy/move the WAV to the directory containing ffmpeg.exe, or copy ffmpeg.exe to the directory containing the WAV file.
3. Open a command prompt and navigate to the directory containing your WAV and FFMPEG.
4. Enter the appropriate command based on how many channels your PolyWAV contains, replacing [inputfilename] with the name of your WAV:
*FOR 8 CHANNELS*
ffmpeg -i inputfilename.wav -filter_complex "[0]pan=stereo|c0=c0|c1=c1[a]; [0]pan=stereo|c0=c2|c1=c3[b]; [0]pan=stereo|c0=c4|c1=c5[c]; [0]pan=stereo|c0=c6|c1=c7[d]" -map "[a]" 1_2.wav -map "[b]" 3_4.wav -map "[c]" 5_6.wav -map "[d]" 7_8.wav
*FOR 6 CHANNELS*
ffmpeg -i inputfilename.wav -filter_complex "[0]pan=stereo|c0=c0|c1=c1[a]; [0]pan=stereo|c0=c2|c1=c3[b]; [0]pan=stereo|c0=c4|c1=c5[c]" -map "[a]" 1_2.wav -map "[b]" 3_4.wav -map "[c]" 5_6.wav
*FOR 4 CHANNELS*
ffmpeg -i inputfilename.wav -filter_complex "[0]pan=stereo|c0=c0|c1=c1[a]; [0]pan=stereo|c0=c2|c1=c3[b]" -map "[a]" 1_2.wav -map "[b]" 3_4.wav
You can run the 8-channel command on a file containing fewer channels without problems. Just be aware you'll be left with silent stereo files for the channels that were not recorded.
I adapted this from one of the solutions found here (https://superuser.com/questions/1241474/ffmpeg-splitting-an-8-channels-wav-into-4-stereo-wav-files). The other solutions listed there all returned errors, as did the syntax found in the official documentation (https://trac.ffmpeg.org/wiki/AudioChannelManipulation#Arbitrarychannelreductionmapping).
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Next task is to verify that this works for 32-bit float files.
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Why not use WaveAgent for 24-bit files?
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Why not use WaveAgent for 24-bit files?
I was not able to get WaveAgent to export directly to stereo tracks. Fortunately a user on GS Remote just showed me what I was doing wrong. I will likely go back to using WaveAgent now... :facepalm:
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Ha, ha! It is really simple, but not clearly documented. Another nice feature is that you can drop multiple files into WaveAgent (if there were auto-splits or different sets/bands or whatever) and do the same split on all simultaneously.
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Reaper will also explode Poly files. I started with Wave Agent but kinda got used to Reaper already so I'll probably stick with it.
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iZotope RX makes it real easy as well!
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iZotope RX makes it real easy as well!
Only if you have Advanced. I have standard, and it only supports mono or stereo files.
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ffmpeg is awesome for lots of stuff. I primarily use it to cut/extract snippets from original (long run) mp4 video files.
Really quick for repeated tasks once you get the syntax figured out.
Gordon
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Why not use WaveAgent for 24-bit files?
I was not able to get WaveAgent to export directly to stereo tracks. Fortunately a user on GS Remote just showed me what I was doing wrong. I will likely go back to using WaveAgent now... :facepalm:
Care to share?
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In the split / combine window, clear the default selections. Then select the first two tracks in column 1, the next two tracks in column 2, etc.
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If you're willing to pay, Adobe Audition makes it very easy to directly export stereo wave files from polywav, but really appreciate the alternate applications that can do this Voltronic!