I can convert wav file to pcm
ffmpeg -i file.wav -f s16le -acodec pcm_s16le file.pcm
How can I revert this operation?
ffmpeg -f s16le -ar 8000 -ac 2 -i out.pcm -ar 44100 -ac 2 out.wav
Below code should be work:
ffmpeg -f s16le -ar 8000 -ac 2 -i out.pcm -ar 44100 -ac 2 out.wav
The wav container just adds a simple header to the raw PCM data. The header includes the format, sample rate, and number of channels. Since the raw PCM data does not include this information, you will need to specify it on the command line. Options are specified before the file they apply to, so options before the input file may be used to specify the format of the input file, and options after the input file and before the output file may be used to specify the desired format of the output file. If you want the same bits/sample, sample rate, and number of channels in the output file then you don't need any output options in this case; the wav container format is already indicated by the file extension.
Example to convert raw PCM to WAV:
ffmpeg -f s16le -ar 44.1k -ac 2 -i file.pcm file.wav
-f s16le
… signed 16-bit little endian samples-ar 44.1k
… sample rate 44.1kHz-ac 2
… 2 channels (stereo)-i file.pcm
… input filefile.wav
… output fileBe careful with RAW data format
-f u8 is unsigned 8 bit, s16 is signed just in case there are others
$ ffmpeg -formats | grep PCM
DE alaw PCM A-law
DE f32be PCM 32-bit floating-point big-endian
DE f32le PCM 32-bit floating-point little-endian
DE f64be PCM 64-bit floating-point big-endian
DE f64le PCM 64-bit floating-point little-endian
DE mulaw PCM mu-law
DE s16be PCM signed 16-bit big-endian
DE s16le PCM signed 16-bit little-endian
DE s24be PCM signed 24-bit big-endian
DE s24le PCM signed 24-bit little-endian
DE s32be PCM signed 32-bit big-endian
DE s32le PCM signed 32-bit little-endian
DE s8 PCM signed 8-bit
DE u16be PCM unsigned 16-bit big-endian
DE u16le PCM unsigned 16-bit little-endian
DE u24be PCM unsigned 24-bit big-endian
DE u24le PCM unsigned 24-bit little-endian
DE u32be PCM unsigned 32-bit big-endian
DE u32le PCM unsigned 32-bit little-endian
DE u8 PCM unsigned 8-bit