New Post: How to use FFT?

February 16, 2013, 11:17 am

≫ Next: New Post: DirectX and ASIO Recording

Hi Mark,

In your article, this code:

float sample = ((oldIndex < 0) ? prevBuffer[frames + 
            corr += (sample * buffer[i]);

it shows errors,
"Cannot implicitly convert type 'float' to 'int'. An explicit conversion exists (Are you missing a cast?)"
"Syntax error, ']' expected"

Any idea?

↧

New Post: DirectX and ASIO Recording

February 16, 2013, 9:48 pm

≫ Next: New Post: Adpcm to WAV

≪ Previous: New Post: How to use FFT?

Hi all,

I've been reading through the source and demos and I'm looking for a few things. I may just be missing them, so if I am can you point me in the right direction?

ASIO recording with mixer playback. i.e. multiple samples played while recording.
DirectX recording... ok, basically the same thing as the ASIO question. I don't see any DX recording at all.

Excellent API you've developed.

Thanks,
Tony

↧

New Post: Adpcm to WAV

February 17, 2013, 4:59 pm

≫ Next: New Post: Ima Adpcm to PCM

≪ Previous: New Post: DirectX and ASIO Recording

Hi,

I'm trying to convert an IMA Adpcm stream into a WAV stream.
This is my latest attempt:

            var bytes = File.ReadAllBytes(@"c:\temp\bytes.bin");
            using (var stream = new MemoryStream(bytes))
            {
                RawSourceWaveStream rawStream = new RawSourceWaveStream(stream, new ImaAdpcmWaveFormat(8000, 1, 4));
                WaveFormatConversionStream convertStream = new WaveFormatConversionStream(new WaveFormat(8000, 16, 1), rawStream);
                var buffer = new byte[640];
                convertStream.Read(buffer, 0, buffer.Length);
            }

This attempt has failed because the WaveFormatConversionStream is trying to create an AcmStream which in turn doing sourceBufferSize -= (sourceBufferSize % sourceFormat.BlockAlign);
Since ImaAdpcmWafeFormat initializes BlockAlign to be 0, I get DivisionByZeroException.
I fixed that by doing this: sourceBufferSize -= sourceFormat.BlockAlign != 0 ? (sourceBufferSize % sourceFormat.BlockAlign) : 0;
So I passed this line.
Now it fails while calling acmStreamOpen with the error: "AcmNotPossible calling acmStreamOpen".
I don't understand why. When I enumerate my codecs I see the Microsoft IMA ADPCM CODEC and the following:
===========================================
Format 0: 8.000 kHz, 4 Bit, Mono

  FormatTag: DviAdpcm, Support Flags: Codec
  WaveFormat: DviAdpcm 8000Hz Channels: 1 Bits: 4 Block Align: 256, AverageBytesPerSecond: 4055 (32.4 kbps), Extra Size: 2
  Extra Bytes:
  F9 01

===========================================
Which is exactly the format of my stream.

How can I make this conversion to work?

Thank you,
Joe.

↧

New Post: Ima Adpcm to PCM

February 17, 2013, 5:15 pm

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≪ Previous: New Post: Adpcm to WAV

Hi,

I am trying to convert an Ima Adpcm stream into a PCM stream.
My latest attempt looks as follows:

            var bytes = File.ReadAllBytes(@"c:\temp\bytes.bin");
            using (var stream = new MemoryStream(bytes))
            {
                RawSourceWaveStream rawStream = new RawSourceWaveStream(stream, new ImaAdpcmWaveFormat(8000, 1, 4));
                WaveFormatConversionStream convertStream = new WaveFormatConversionStream(new WaveFormat(8000, 16, 1), rawStream);
                var buffer = new byte[640];
                convertStream.Read(buffer, 0, buffer.Length);
            }

This implementations has two problems:

The WaveFormatConversionStream is trying to create an AcmStream internally and its Ctor throws a DivisionByZero exception because the ImaAdpcm BlockAlign value is zero.
If I fix that, I get "AcmNotPossible calling acmStreamOpen" from the acmStreamOpen call.

When I enumerate the codec on my machine I see this:

Long Name: Microsoft IMA ADPCM CODEC
Short Name: Microsoft IMA ADPCM
Driver ID: 5370400
FormatTags:
 ===========================================
   Format 0: 8.000 kHz, 4 Bit, Mono
      FormatTag: DviAdpcm, Support Flags: Codec
      WaveFormat: DviAdpcm 8000Hz Channels: 1 Bits: 4 Block Align: 256, AverageBytesPerSecond: 4055 (32.4 kbps), Extra Size: 2
      Extra Bytes:
      F9 01 
   ===========================================

I tried setting the BlockAlign to be 256 and the AvgBPS to 4055 (because the default ImaAdpcm set them to zero) and I still get the same error.

How can I convert my stream into PCM?

Thank you,
Joe.