CODEWITHSUNDEEP
windows-phone-8.1win-universal-app
thpitsch
thpitsch

Reputation: 2036

Play part of an audio file

I have to play an audio part out of a big file (300MB+).

This is my code:

// Media source is a local file.
// datName = "sound.dat"
// pointer = position in file
// length  = length of the part to play

try
{
    file = await StorageFile.GetFileFromApplicationUriAsync
          (new Uri(@"ms-appx:///Data/" + datName));
    // Get the media source as a stream.
    IRandomAccessStream stream = 
          await file.OpenAsync(FileAccessMode.Read);
    stream.Seek((ulong)pointer); // This is working, position changes from 0 to pointer
    stream.Size = (ulong)length; // Is not working, Size remains unchanged at total file size
    media.SetSource(stream, file.ContentType);
    media.Play();
}
catch (Exception ex)
{
    if (ex is FormatException || ex is ArgumentException)
    {
        //ShowFileErrorMsg();
    }
}

Please note the comments on stream Seek and Size. The file is played from position zero.

How can I play the sound from pointer to pointer + length?

Upvotes: 1

Views: 207

Answers (1)

thpitsch
thpitsch

Reputation: 2036

I've solved my problem by using the binary reader. I read the required area in a byte buffer and convert it to an IRandomAccessStream.

StorageFile file = await StorageFile.GetFileFromApplicationUriAsync(new Uri(@"ms-appx:///Data/" + fileName));
using (Stream stream = (await file.OpenReadAsync()).AsStreamForRead())
using (BinaryReader reader = new BinaryReader(stream))
{
    reader.BaseStream.Position = pointer;
    byte[] buffer = reader.ReadBytes((int)length);
    IRandomAccessStream nstream = new MemoryStream(buffer).AsRandomAccessStream();
    media.SetSource(nstream, "");
    media.Play();
}

This version is now working.

Upvotes: 1

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