Write a .wav file from buffer example

General JUCE discussion
1

Is there a current example of how to simply write an AudioBuffer to a wave file?

Somehow I can’t find anything. Thanks.

1 Like
2

That’s the code:

AudioBuffer<float> buffer;
WavAudioFormat format;
std::unique_ptr<AudioFormatWriter> writer;
writer.reset (format.createWriterFor (new FileOutputStream (file),
                                      48000.0,
                                      buffer.getNumChannels(),
                                      24,
                                      {},
                                      0));
if (writer != nullptr)
    writer->writeFromAudioSampleBuffer (buffer, 0, buffer.getNumSamples());

Hope that helps

1 Like
3

Thanks, but I’m getting errors…

  • Allocating an object of abstract class type ‘juce::OutputStream’
  • No member named ‘createWriter’ in ‘juce::WavAudioFormat’
  • Unknown type name ‘OutputFileStream’; did you mean ‘OutputStream’?
4

Should be FileOutputStream, and createWriteFor() :wink:

5

Sloppy me, shouldn’t write out of my head… :slight_smile: thanks, I’ll edit the code above

6

Thanks, gents.

I’m still a little stunned that I couldn’t find an example of writing a wav file anywhere on the forum or docs.

7

Here is some code, just a little more elaborate:

1 Like
Wav File Header Data not being created properly
AAX_CHostProcessor support
8

Thanks, but your first example is exactly what I needed. I found quite a few streaming examples but I just needed to write an AudioBuffer. Thanks again.

9

Trying to write wav file, what am I doing wrong?

AudioBuffer<float> buffer(1, singleChannelAudio.size());

auto ptr = buffer.getWritePointer(0);

for (int f = 0; f < singleChannelAudio.size(); ++f)
    ptr[f] = float(singleChannelAudio[f]);

WavAudioFormat format;
std::unique_ptr<AudioFormatWriter> writer;
writer.reset(format.createWriterFor(new FileOutputStream(path), sampleRate, 1, bitDepth, {}, 0));

if (writer == nullptr)
    return false;

writer->writeFromAudioSampleBuffer(buffer, 0, buffer.getNumSamples());    

return true;

this gives error:

image
image.png740×154 8.1 KB

10

That code works for me (with the obvious additions to allow it to compile). There’s probably some problem with the file path you are using. Maybe trying to write to a directory that doesn’t exist or the directory doesn’t have write permissions.

1 Like
11

file wasn’t created due to bad file name

12

In the example, the active writer thread is using inputChannelData, which is a float** and not a buffer.
activeWriter.load()->write (inputChannelData, numSamples);
(JUCE/AudioRecordingDemo.h at 90e8da0cfb54ac593cdbed74c3d0c9b09bad3a9f · juce-framework/JUCE · GitHub)

How can I use a buffer to write directly using the thread like so, so that the modified buffer is written to the wav file via the stream:
activeWriter.load()->write (buffer, numSamples);

Thanks

13

You can always get the raw float pointers from a buffer using getArrayOfReadPointers():

activeWriter.load()->write (buffer.getArrayOfReadPointers(), buffer.getNumSamples());

HTH