Saving Wav to Disk

General JUCE discussion
1

Hey,

I just recently started using JUCE and have found it very useful so far but I’m having a problem saving a .wav file to disk. The code giving me trouble is is:

//save the filtered output ScopedPointer<WavAudioFormat> wavFormat = new WavAudioFormat(); File output("C:\\DEV\\FFT2\\filtered_output.wav"); FileOutputStream *fost = output.createOutputStream(); AudioSampleBuffer write_to_disk(&float_output, 1, M + P - 1); ScopedPointer<AudioFormatWriter> writer = wavFormat->createWriterFor(fost, 44100, 1, 16, StringPairArray(), 0); writer->writeFromAudioSampleBuffer(write_to_disk, 0, M + P - 1);
I know the data in float_output is good because I wrote it to a .txt file and imported it in Matlab to verify. I’m not sure if I’m opening the file/creating the streams/or calling write correctly.

Matlab gives the following output.

>> output = wavread('filtered_output.wav'); ??? Error using ==> wavread at 166 Incorrect chunk size information in WAV file.
Any help would be greatly appreciated.

Thanks,
Graham

2

Does your writer object definitely get deleted? That’s usually the cause when you see unfinished files being written.

3

If it’s a scoped pointer shouldn’t it get deleted automatically?

4

Yes, but your code snippet doesn’t show what happens after you created it.

5

[code] //save the filtered output
ScopedPointer wavFormat = new WavAudioFormat();
File output(“C:\DEV\FFT2\filtered_output.wav”);
FileOutputStream *fost = output.createOutputStream();
AudioSampleBuffer write_to_disk(&filtered_output, 1, M + P - 1);
ScopedPointer writer = wavFormat->createWriterFor(fost, 44100, 1, 16, StringPairArray(), 0);
writer->writeFromAudioSampleBuffer(write_to_disk, 0, M + P - 1);

std::cout << "The Kehoe Nation rules! (Press enter)" << std::endl;
std::cin.ignore(1);
return 0;[/code]

Writing the file to disk is the last thing the program does before exiting. I give a prompt telling me it’s finished and then it waits for me to hit enter.

6

yeah… but the writer is still in scope when you do your std::cin stuff.

7

ScopedPointer<WavAudioFormat> wavFormat = new WavAudioFormat(); File output("C:\\DEV\\FFT2\\filtered_output.wav"); FileOutputStream *fost = output.createOutputStream(); AudioSampleBuffer write_to_disk(&filtered_output, 1, M); AudioFormatWriter* writer = wavFormat->createWriterFor(fost, 44100, 1, 16, StringPairArray(), 0); if(writer->writeFromAudioSampleBuffer(write_to_disk, 0, M)) { std::cout << "Saving .wav succeeded" << std::endl; } else { std::cout << "Saving .wav failed" << std::endl; } delete writer;

Even when I delete the writer Matlab gives me the same error and I can’t play the file in Windows Media Player. Is there something else I’m doing wrong?

8

Are you deleting the file before you write to it? Otherwise, you’ll just be sticking your new data on the end of the existing file…

9

That was precisely the problem! Thanks a bunch.

10

I’m trying to get this to work. What is the datatype of filtered_output?

11

FYI be careful copying the code above - there’s some really bad C++ style in there. Search the juce repo for writeFromAudioSampleBuffer and I’m sure you’ll find some better example code to copy.

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