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WAV writer: note about WAVE_FORMAT_EXTENSIBLE

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Martin Pulec
2021-10-01 15:24:40 +02:00
parent 43679c09fe
commit 5bf46b2de7
1 changed files with 19 additions and 2 deletions
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21
src/audio/wav_writer.c
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@@ -37,8 +37,25 @@
/**
* @file
* WAV file format is taken from:
* http://www-mmsp.ece.mcgill.ca/Documents/AudioFormats/WAVE/WAVE.html
* References:
* [1]: http://www-mmsp.ece.mcgill.ca/Documents/AudioFormats/WAVE/WAVE.html
* [2]: http://www-mmsp.ece.mcgill.ca/Documents/AudioFormats/WAVE/Docs/multichaudP.pdf
* [3]: https://docs.microsoft.com/en-us/windows/win32/api/mmeapi/ns-mmeapi-waveformatex
*
* WAV file format is taken from [1].
*
* Note that this page states that WAVE_FORMAT_EXTENSIBLE should be used if:
*
* - PCM data has more than 16 bits/sample.
* - The number of channels is more than 2.
* - The actual number of bits/sample is not equal to the container size.
* - The mapping from channels to speakers needs to be specified.
*
* However, the document [2] doesn't mention this and there is no ambiguity for UG - we do
* not specify channel layout, bits per sample matches container size and is never padded.
* Resource [3] also suggests this use but strictly speaking this is documentation of system
* API, not file format. flac(1) complains if the original format is used, FFmpeg RIFF writter
* also follows the above rules.
*/
#ifdef HAVE_CONFIG_H