S = t × f × C × b / 8
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How does this tool work?
Split the left and right channels of a stereo file into two independent mono WAV files. This is useful when each channel contains a different source or signal.
FFmpeg/WASM applies two pan operations: the left channel becomes the only channel in the first WAV, then the right channel becomes the only channel in the second. The tool therefore expects material with at least two usable channels; it cannot create two independent sources from a genuinely mono recording. Outputs copy existing channels; they do not intelligently isolate instruments or voices. A vocal mixed into both sides of a song remains in both files. For a mono recording, this engine writes silence on the right because no independent second channel exists. For multichannel sources, only channel indices 0 and 1 are extracted: this is not a complete surround-track export. Your browser may request permission for the second download; separate recovery buttons remain available in the panel. Keep the source if you need its other channels or metadata.
How to use this tool
Import a stereo file
Choose audio that contains two channels.
Split the channels
The engine produces one left mono WAV and one right mono WAV.
Reuse the outputs
Download both files or continue processing them in Workspace.
Split audio channels — Calculation reference
- S
- PCM payload in bytes, excluding headers
- t
- Duration in seconds
- f
- Sample rate in Hz
- C
- Channel count, dimensionless
- b
- Bits per sample
Use cases
Two-channel interview
Separate two speakers recorded independently on the left and right channels.
Stereo analysis
Compare what information is present in each channel.
Independent processing
Apply different processing to the left and right channels afterwards.
Examples
An interview recorded on separate sides
Each output contains 30 × 48,000 × 2 bytes. Speakers remain separate only when the recording actually placed them in separate channels.
Input
30 s, 48,000 Hz, stereo 16-bit PCMResult
Two WAV files with 2,880,000 PCM bytes eachIdentical source channels
Extraction does not invent differences between channels that already contain identical samples.
Input
Left and right contain the same signal for 10 sResult
Two identical 10-second mono signalsTips and best practices
- Check that the source is genuinely stereo and contains different information on both channels.
- Both outputs keep the same duration as the source.
- To simply downmix stereo to mono, use the mono/stereo converter instead.
Sources and references
- FFmpeg project, FFmpeg Filters Documentation (opens in a new tab)Page in English
- Microsoft, WAVEFORMATEX structure (mmeapi.h) (opens in a new tab)Page in English
Frequently asked questions
What happens with a mono file?
A mono source produces audio on the left and silence on the right here, since there is no second channel to extract.
Are both files mono?
Yes. Each WAV output contains one channel taken from the original left or right side.
Can I merge the two outputs later?
Yes, but ordinary merging places files one after another; it does not automatically rebuild a stereo pair.
Can left/right splitting isolate vocals from a song?
No. It copies channels without recognizing musical sources. A centred vocal will generally remain in both output files.
What happens to audio with more than two channels?
Only the first and second channels are exported. Additional channels are omitted, so retain the original if the complete multichannel programme matters.
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