AudioQueue bytes to ffmpeg understandable WAV format

Question

I got the recorded AudioQueueBufferRef buffer using the following code.

NSData *data = [NSData dataWithBytes:inBuffer->mAudioData length:inBuffer->mAudioDataByteSize];

And then, I send the data to my server. However, FFMPEG isn't able to read that because the data is not in any audio standard format.

It's just plain data.

So, how do I do either on iPhone or backend ffmpeg to convert that raw buffer to WAV?

Thank so much.

William Rosenbloom · Answer 1 · 2015-12-24T09:24:46.003

0

You could write the WAV headers yourself. However, in a similar situation I chose to use the sox command line tool. This is better for server side. You can take your raw audio data, save it to a file, and then execute the following command.

sox -r <your sample rate> -b <bytes per frame> -c <number of channels> -e <your sample encoding> <your raw audio file> <your-output-file.wav>

Your raw audio file must have a .raw file extension.

edited Dec 24 '15 at 09:24

answered Dec 24 '15 at 06:16

William Rosenbloom

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What would the sample encoding be? – moeseth Dec 24 '15 at 07:23
It depends how your audio is encoded, but generally it is either `signed-integer` or `unsigned-integer` for PCM samples. – William Rosenbloom Dec 24 '15 at 07:32

AudioQueue bytes to ffmpeg understandable WAV format

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