internal AudioBufferList(IntPtr ptr)
{
#if MONOMAC
// Because it's .net 2.0 based
throw new NotImplementedException ();
#else
//
// Decodes
//
// struct AudioBufferList
// {
// UInt32 mNumberBuffers;
// AudioBuffer mBuffers[1]; // this is a variable length array of mNumberBuffers elements
// }
int count = Marshal.ReadInt32 (ptr, 0);
ptr += sizeof (int);
Buffers = new AudioBuffer [count];
for (int i = 0; i < count; ++i) {
Buffers [i] = (AudioBuffer) Marshal.PtrToStructure (ptr, typeof (AudioBuffer));
ptr += Marshal.SizeOf (typeof (AudioBuffer));
}
#endif
}
internal unsafe AudioBufferList(IntPtr _ptr)
{
byte *ptr = (byte *) _ptr;
//
// Decodes
//
// struct AudioBufferList
// {
// UInt32 mNumberBuffers;
// AudioBuffer mBuffers[1]; // this is a variable length array of mNumberBuffers elements
// }
int count = Marshal.ReadInt32 ((IntPtr) ptr, 0);
ptr += sizeof (int);
Buffers = new AudioBuffer [count];
for (int i = 0; i < count; ++i) {
Buffers [i] = (AudioBuffer) Marshal.PtrToStructure ((IntPtr) ptr, typeof (AudioBuffer));
ptr += Marshal.SizeOf (typeof (AudioBuffer));
}
}
public MutableAudioBufferList(int nubuffers, int bufferSize)
{
bufferCount = nubuffers;
buffers = new AudioBuffer[bufferCount];
for (int i = 0; i < bufferCount; i++) {
buffers[i].NumberChannels = 1;
buffers[i].DataByteSize = bufferSize;
buffers[i].Data = Marshal.AllocHGlobal((int)bufferSize);
}
}
public AudioBufferList(int bufferSize)
{
Buffers = new AudioBuffer [bufferSize];
}
public AudioBufferList(int bufferSize)
{
Buffers = new AudioBuffer [bufferSize];
}
public static bool Convert(string input, string output, AudioFormatType targetFormat, AudioFileType containerType, Microsoft.Xna.Framework.Content.Pipeline.Audio.ConversionQuality quality) {
CFUrl source = CFUrl.FromFile (input);
CFUrl dest = CFUrl.FromFile (output);
var dstFormat = new AudioStreamBasicDescription ();
var sourceFile = AudioFile.Open (source, AudioFilePermission.Read);
AudioFormatType outputFormat = targetFormat;
// get the source data format
var srcFormat = (AudioStreamBasicDescription)sourceFile.DataFormat;
var outputSampleRate = 0;
switch (quality)
{
case Microsoft.Xna.Framework.Content.Pipeline.Audio.ConversionQuality.Low:
outputSampleRate = (int)Math.Max (8000, srcFormat.SampleRate / 2);
break;
default:
outputSampleRate = (int)Math.Max (8000, srcFormat.SampleRate);
break;
}
dstFormat.SampleRate = (outputSampleRate == 0 ? srcFormat.SampleRate : outputSampleRate); // set sample rate
if (outputFormat == AudioFormatType.LinearPCM) {
// if the output format is PC create a 16-bit int PCM file format description as an example
dstFormat.Format = outputFormat;
dstFormat.ChannelsPerFrame = srcFormat.ChannelsPerFrame;
dstFormat.BitsPerChannel = 16;
dstFormat.BytesPerPacket = dstFormat.BytesPerFrame = 2 * dstFormat.ChannelsPerFrame;
dstFormat.FramesPerPacket = 1;
dstFormat.FormatFlags = AudioFormatFlags.LinearPCMIsPacked | AudioFormatFlags.LinearPCMIsSignedInteger;
} else {
// compressed format - need to set at least format, sample rate and channel fields for kAudioFormatProperty_FormatInfo
dstFormat.Format = outputFormat;
dstFormat.ChannelsPerFrame = (outputFormat == AudioFormatType.iLBC ? 1 : srcFormat.ChannelsPerFrame); // for iLBC num channels must be 1
// use AudioFormat API to fill out the rest of the description
var fie = AudioStreamBasicDescription.GetFormatInfo (ref dstFormat);
if (fie != AudioFormatError.None) {
return false;
}
}
var converter = AudioConverter.Create (srcFormat, dstFormat);
converter.InputData += HandleInputData;
// if the source has a cookie, get it and set it on the Audio Converter
ReadCookie (sourceFile, converter);
// get the actual formats back from the Audio Converter
srcFormat = converter.CurrentInputStreamDescription;
dstFormat = converter.CurrentOutputStreamDescription;
// if encoding to AAC set the bitrate to 192k which is a nice value for this demo
// kAudioConverterEncodeBitRate is a UInt32 value containing the number of bits per second to aim for when encoding data
if (dstFormat.Format == AudioFormatType.MPEG4AAC) {
uint outputBitRate = 192000; // 192k
// ignore errors as setting may be invalid depending on format specifics such as samplerate
try {
converter.EncodeBitRate = outputBitRate;
} catch {
}
// get it back and print it out
outputBitRate = converter.EncodeBitRate;
}
// create the destination file
var destinationFile = AudioFile.Create (dest, containerType, dstFormat, AudioFileFlags.EraseFlags);
// set up source buffers and data proc info struct
afio = new AudioFileIO (32768);
afio.SourceFile = sourceFile;
afio.SrcFormat = srcFormat;
if (srcFormat.BytesPerPacket == 0) {
// if the source format is VBR, we need to get the maximum packet size
// use kAudioFilePropertyPacketSizeUpperBound which returns the theoretical maximum packet size
// in the file (without actually scanning the whole file to find the largest packet,
// as may happen with kAudioFilePropertyMaximumPacketSize)
afio.SrcSizePerPacket = sourceFile.PacketSizeUpperBound;
// how many packets can we read for our buffer size?
afio.NumPacketsPerRead = afio.SrcBufferSize / afio.SrcSizePerPacket;
// allocate memory for the PacketDescription structures describing the layout of each packet
afio.PacketDescriptions = new AudioStreamPacketDescription [afio.NumPacketsPerRead];
} else {
// CBR source format
afio.SrcSizePerPacket = srcFormat.BytesPerPacket;
afio.NumPacketsPerRead = afio.SrcBufferSize / afio.SrcSizePerPacket;
// allocate memory for the PacketDescription structures describing the layout of each packet
afio.PacketDescriptions = new AudioStreamPacketDescription [afio.NumPacketsPerRead];
}
// set up output buffers
int outputSizePerPacket = dstFormat.BytesPerPacket; // this will be non-zero if the format is CBR
const int theOutputBufSize = 32768;
var outputBuffer = Marshal.AllocHGlobal (theOutputBufSize);
AudioStreamPacketDescription[] outputPacketDescriptions = null;
if (outputSizePerPacket == 0) {
// if the destination format is VBR, we need to get max size per packet from the converter
outputSizePerPacket = (int)converter.MaximumOutputPacketSize;
}
// allocate memory for the PacketDescription structures describing the layout of each packet
outputPacketDescriptions = new AudioStreamPacketDescription [theOutputBufSize / outputSizePerPacket];
int numOutputPackets = theOutputBufSize / outputSizePerPacket;
// if the destination format has a cookie, get it and set it on the output file
WriteCookie (converter, destinationFile);
// write destination channel layout
if (srcFormat.ChannelsPerFrame > 2) {
WriteDestinationChannelLayout (converter, sourceFile, destinationFile);
}
long totalOutputFrames = 0; // used for debugging
long outputFilePos = 0;
AudioBuffers fillBufList = new AudioBuffers (1);
bool error = false;
// loop to convert data
while (true) {
// set up output buffer list
fillBufList [0] = new AudioBuffer () {
NumberChannels = dstFormat.ChannelsPerFrame,
DataByteSize = theOutputBufSize,
Data = outputBuffer
};
// convert data
int ioOutputDataPackets = numOutputPackets;
var fe = converter.FillComplexBuffer (ref ioOutputDataPackets, fillBufList, outputPacketDescriptions);
// if interrupted in the process of the conversion call, we must handle the error appropriately
if (fe != AudioConverterError.None) {
error = true;
break;
}
if (ioOutputDataPackets == 0) {
// this is the EOF conditon
break;
}
// write to output file
var inNumBytes = fillBufList [0].DataByteSize;
var we = destinationFile.WritePackets (false, inNumBytes, outputPacketDescriptions, outputFilePos, ref ioOutputDataPackets, outputBuffer);
if (we != 0) {
error = true;
break;
}
// advance output file packet position
outputFilePos += ioOutputDataPackets;
if (dstFormat.FramesPerPacket != 0) {
// the format has constant frames per packet
totalOutputFrames += (ioOutputDataPackets * dstFormat.FramesPerPacket);
} else {
// variable frames per packet require doing this for each packet (adding up the number of sample frames of data in each packet)
for (var i = 0; i < ioOutputDataPackets; ++i)
totalOutputFrames += outputPacketDescriptions [i].VariableFramesInPacket;
}
}
Marshal.FreeHGlobal (outputBuffer);
if (!error) {
// write out any of the leading and trailing frames for compressed formats only
if (dstFormat.BitsPerChannel == 0) {
// our output frame count should jive with
WritePacketTableInfo (converter, destinationFile);
}
// write the cookie again - sometimes codecs will update cookies at the end of a conversion
WriteCookie (converter, destinationFile);
}
converter.Dispose ();
destinationFile.Dispose ();
sourceFile.Dispose ();
return true;
}
