/// <summary>
/// Constructs a stream that will accept PCM audio input, and automatically encode it to Opus and packetize it using Ogg,
/// writing the output pages to an underlying stream (usually a file stream).
/// You are allowed to change the encoding parameters mid-stream using the properties of the OpusEncoder; the only thing you
/// cannot change is the sample rate and num# of channels.
/// </summary>
/// <param name="encoder">An opus encoder to use for output</param>
/// <param name="outputStream">A base stream to accept the encoded ogg file output</param>
/// <param name="fileTags">(optional) A set of tags to include in the encoded file</param>
/// <param name="inputSampleRate">The actual real sample rate of your input data (NOT the encoder's sample rate).
/// The opus encoder usually requires 48Khz input, but most MP3s and such will give you 44.1Khz. To get the
/// sample rates to line up properly in this case, set the encoder to 48000 and pass inputSampleRate = 44100,
/// and the write stream will perform resampling for you automatically (Note that resampling will slow down
/// the encoding).</param>
public OpusOggWriteStream(OpusEncoder encoder, Stream outputStream, OpusTags fileTags = null, int inputSampleRate = 0, int logicalStreamId = 0)
{
_encoder = encoder;
if (_encoder.UseDTX)
{
throw new ArgumentException("DTX is not currently supported in Ogg streams");
}
_inputSampleRate = inputSampleRate;
if (_inputSampleRate == 0)
{
_inputSampleRate = _encoder.SampleRate;
}
if (logicalStreamId == 0)
{
logicalStreamId = new Random().Next();
}
_logicalStreamId = logicalStreamId;
_encoderSampleRate = encoder.SampleRate;
_inputChannels = encoder.NumChannels;
_outputStream = outputStream;
_opusFrameIndex = 0;
_granulePosition = 0;
_opusFrameSamples = (int)((long)_encoderSampleRate * FRAME_SIZE_MS / 1000);
_opusFrame = new short[_opusFrameSamples * _inputChannels];
_crc = new Crc();
_resampler = SpeexResampler.Create(_inputChannels, _inputSampleRate, _encoderSampleRate, 5);
BeginNewPage();
WriteOpusHeadPage();
WriteOpusTagsPage(fileTags);
}
/// <summary>
/// Looks for the next opus data packet in the Ogg stream and queues it up.
/// If the end of stream has been reached, this does nothing.
/// </summary>
private void QueueNextPacket()
{
if (_endOfStream)
{
return;
}
DataPacket packet = _packetProvider.GetNextPacket();
if (packet == null || packet.IsEndOfStream)
{
_endOfStream = true;
_nextDataPacket = null;
return;
}
byte[] buf = new byte[packet.Length];
packet.Read(buf, 0, packet.Length);
packet.Done();
if (buf.Length > 8 && "OpusHead".Equals(Encoding.UTF8.GetString(buf, 0, 8)))
{
_header = OpusHeader.ParsePacket(buf, buf.Length);
QueueNextPacket();
}
else if (buf.Length > 8 && "OpusTags".Equals(Encoding.UTF8.GetString(buf, 0, 8)))
{
_tags = OpusTags.ParsePacket(buf, buf.Length);
QueueNextPacket();
}
else
{
_nextDataPacket = buf;
}
}
internal static OpusTags ParsePacket(byte[] packet, int packetLength)
{
if (packetLength < 8)
{
return(null);
}
if (!"OpusTags".Equals(Encoding.UTF8.GetString(packet, 0, 8)))
{
return(null);
}
OpusTags returnVal = new OpusTags();
int cursor = 8;
int nextFieldLength = BitConverter.ToInt32(packet, cursor);
cursor += 4;
if (nextFieldLength > 0)
{
returnVal._comment = Encoding.UTF8.GetString(packet, cursor, nextFieldLength);
cursor += nextFieldLength;
}
int numTags = BitConverter.ToInt32(packet, cursor);
cursor += 4;
for (int c = 0; c < numTags; c++)
{
nextFieldLength = BitConverter.ToInt32(packet, cursor);
cursor += 4;
if (nextFieldLength > 0)
{
string tag = Encoding.UTF8.GetString(packet, cursor, nextFieldLength);
cursor += nextFieldLength;
int eq = tag.IndexOf('=');
if (eq > 0)
{
string key = tag.Substring(0, eq);
string val = tag.Substring(eq + 1);
returnVal._fields[key] = val;
}
}
}
return(returnVal);
}
/// <summary>
/// Looks for the next opus data packet in the Ogg stream and queues it up.
/// If the end of stream has been reached, this does nothing.
/// </summary>
private void QueueNextPacket()
{
if (_endOfStream)
{
return;
}
DataPacket packet = _packetProvider.GetNextPacket();
if (packet == null)
{
_endOfStream = true;
_nextDataPacket = null;
return;
}
PageGranulePosition = packet.PageGranulePosition;
PagePosition = packet.PageSequenceNumber;
byte[] buf = new byte[packet.Length];
packet.Read(buf, 0, packet.Length);
packet.Done();
if (buf.Length > 8 && "OpusHead".Equals(Encoding.UTF8.GetString(buf, 0, 8)))
{
QueueNextPacket();
}
else if (buf.Length > 8 && "OpusTags".Equals(Encoding.UTF8.GetString(buf, 0, 8)))
{
Tags = OpusTags.ParsePacket(buf, buf.Length);
QueueNextPacket();
}
else
{
_nextDataPacket = buf;
}
}
/// <summary>
/// Writes an Ogg page for the OpusTags, given an input tag set
/// </summary>
/// <param name="tags"></param>
private void WriteOpusTagsPage(OpusTags tags = null)
{
if (tags == null)
{
tags = new OpusTags();
}
if (string.IsNullOrEmpty(tags.Comment))
{
tags.Comment = CodecHelpers.GetVersionString();
}
if (_payloadIndex != 0)
{
throw new InvalidOperationException("Must begin writing OpusTags on a new page!");
}
// BUGBUG: Very long tags can overflow the page and corrupt the stream
_payloadIndex += WriteValueToByteBuffer("OpusTags", _currentPayload, _payloadIndex);
// write comment
int stringLength = WriteValueToByteBuffer(tags.Comment, _currentPayload, _payloadIndex + 4);
_payloadIndex += WriteValueToByteBuffer(stringLength, _currentPayload, _payloadIndex);
_payloadIndex += stringLength;
// capture the location of the tag count field to fill in later
int numTagsIndex = _payloadIndex;
_payloadIndex += 4;
// write each tag. skipping empty or invalid ones
int tagsWritten = 0;
foreach (var kvp in tags.Fields)
{
if (string.IsNullOrEmpty(kvp.Key) || string.IsNullOrEmpty(kvp.Value))
{
continue;
}
string tag = kvp.Key + "=" + kvp.Value;
stringLength = WriteValueToByteBuffer(tag, _currentPayload, _payloadIndex + 4);
_payloadIndex += WriteValueToByteBuffer(stringLength, _currentPayload, _payloadIndex);
_payloadIndex += stringLength;
tagsWritten++;
}
// Write actual tag count
WriteValueToByteBuffer(tagsWritten, _currentPayload, numTagsIndex);
// Write segment data, ensuring we can handle tags longer than 255 bytes
int tagsSegmentSize = _payloadIndex;
while (tagsSegmentSize >= 255)
{
_currentHeader[_headerIndex++] = 255;
_lacingTableCount++;
tagsSegmentSize -= 255;
}
_currentHeader[_headerIndex++] = (byte)tagsSegmentSize;
_lacingTableCount++;
FinalizePage();
}
/// <summary>
/// Constructs a stream that will accept PCM audio input, and automatically encode it to Opus and packetize it using Ogg,
/// writing the output pages to an underlying stream (usually a file stream).
/// You are allowed to change the encoding parameters mid-stream using the properties of the OpusEncoder; the only thing you
/// cannot change is the sample rate and num# of channels.
/// </summary>
/// <param name="outputStream">A base stream to accept the encoded ogg file output</param>
/// <param name="sampleRate"></param>
/// <param name="channelCount"></param>
/// <param name="preSkip"></param>
/// <param name="sampleCount"></param>
/// <param name="fileTags">(optional) A set of tags to include in the encoded file</param>
/// <param name="inputSampleRate">The actual real sample rate of your input data (NOT the encoder's sample rate).
/// The opus encoder usually requires 48Khz input, but most MP3s and such will give you 44.1Khz. To get the
/// sample rates to line up properly in this case, set the encoder to 48000 and pass inputSampleRate = 44100,
/// and the write stream will perform resampling for you automatically (Note that resampling will slow down
/// the encoding).</param>
public OpusOggWriteStream(Stream outputStream, int sampleRate, int channelCount, int preSkip, int sampleCount = -1, OpusTags fileTags = null, int inputSampleRate = 0)
{
_inputSampleRate = inputSampleRate;
if (_inputSampleRate == 0)
{
_inputSampleRate = sampleRate;
}
_logicalStreamId = new Random().Next();
_encoderSampleRate = sampleRate;
_inputChannels = channelCount;
_outputStream = outputStream;
//_opusFrameIndex = 0;
_granulePosition = 0;
_opusFrameSamples = (int)((long)_encoderSampleRate * FRAME_SIZE_MS / 1000);
_opusFrame = new short[_opusFrameSamples * _inputChannels];
_crc = new Crc();
_resampler = SpeexResampler.Create(_inputChannels, _inputSampleRate, _encoderSampleRate, 5);
_preSkipSamples = preSkip;
_sampleCount = sampleCount == -1 ? int.MaxValue : preSkip + sampleCount;
BeginNewPage();
WriteOpusHeadPage();
WriteOpusTagsPage(fileTags);
}
