/// <summary>
/// Decodes a stream of Ogg Vorbis data into wav file format.
/// </summary>
/// <returns>
/// A MemoryStream with the entire decoded stream.
/// </returns>
/// <param name='input'>
/// Ogg Vorbis data to be decoded
/// </param>
/// <param name='output'>
/// <para>Stream to write wav data.</para>
/// <para>If writeWavHeader is true then this stream must be seekable.</para>
/// </param>
/// <param name='writeWavHeader'>
/// Write wav header in the beginning of the returned stream.
/// </param>
public static void DecodeStream(Stream input, Stream output, bool writeWavHeader)
{
int convsize = 4096 * 2;
byte[] convbuffer = new byte[convsize]; // take 8k out of the data segment, not the stack
long start = output.Position;
DebugWriter s_err = new DebugWriter();
if (writeWavHeader && !output.CanSeek)
throw new ArgumentException("To write wav header, the output stream must be seekable.", "output");
if (writeWavHeader)
output.Seek(HEADER_SIZE, SeekOrigin.Current); // reserve place for WAV header
SyncState oy = new SyncState(); // sync and verify incoming physical bitstream
StreamState os = new StreamState(); // take physical pages, weld into a logical stream of packets
Page og = new Page(); // one Ogg bitstream page. Vorbis packets are inside
Packet op = new Packet(); // one raw packet of data for decode
Info vi = new Info(); // struct that stores all the static vorbis bitstream settings
Comment vc = new Comment(); // struct that stores all the bitstream user comments
DspState vd = new DspState(); // central working state for the packet->PCM decoder
Block vb = new Block(vd); // local working space for packet->PCM decode
int bytes = 0;
// Decode setup
oy.init(); // Now we can read pages
// we repeat if the bitstream is chained
while (true)
{
int eos = 0;
// grab some data at the head of the stream. We want the first page
// (which is guaranteed to be small and only contain the Vorbis
// stream initial header) We need the first page to get the stream
// serialno.
// submit a 4k block to libvorbis' Ogg layer
int index = oy.buffer(4096);
bytes = input.Read(oy.data, index, 4096);
oy.wrote(bytes);
// Get the first page.
if (oy.pageout(og) != 1)
{
// have we simply run out of data? If so, we're done.
if (bytes < 4096)
break;
// error case. Must not be Vorbis data
s_err.WriteLine("Input does not appear to be an Ogg bitstream.");
}
// Get the serial number and set up the rest of decode.
// serialno first; use it to set up a logical stream
os.init(og.serialno());
// extract the initial header from the first page and verify that the
// Ogg bitstream is in fact Vorbis data
// I handle the initial header first instead of just having the code
// read all three Vorbis headers at once because reading the initial
// header is an easy way to identify a Vorbis bitstream and it's
// useful to see that functionality seperated out.
vi.init();
vc.init();
if (os.pagein(og) < 0)
{
// error; stream version mismatch perhaps
s_err.WriteLine("Error reading first page of Ogg bitstream data.");
}
if (os.packetout(op) != 1)
{
// no page? must not be vorbis
s_err.WriteLine("Error reading initial header packet.");
}
if (vi.synthesis_headerin(vc, op) < 0)
{
// error case; not a vorbis header
s_err.WriteLine("This Ogg bitstream does not contain Vorbis audio data.");
}
// At this point, we're sure we're Vorbis. We've set up the logical
// (Ogg) bitstream decoder. Get the comment and codebook headers and
// set up the Vorbis decoder
// The next two packets in order are the comment and codebook headers.
// They're likely large and may span multiple pages. Thus we reead
// and submit data until we get our two pacakets, watching that no
// pages are missing. If a page is missing, error out; losing a
// header page is the only place where missing data is fatal. */
int i = 0;
while (i < 2)
{
while (i < 2)
{
int result = oy.pageout(og);
if (result == 0)
break; // Need more data
// Don't complain about missing or corrupt data yet. We'll
// catch it at the packet output phase
if (result == 1)
{
os.pagein(og); // we can ignore any errors here
// as they'll also become apparent
// at packetout
while (i < 2)
{
result = os.packetout(op);
if (result == 0)
break;
if (result == -1)
{
// Uh oh; data at some point was corrupted or missing!
// We can't tolerate that in a header. Die.
s_err.WriteLine("Corrupt secondary header. Exiting.");
}
vi.synthesis_headerin(vc, op);
i++;
}
}
}
// no harm in not checking before adding more
index = oy.buffer(4096);
bytes = input.Read(oy.data, index, 4096);
if (bytes == 0 && i < 2)
{
s_err.WriteLine("End of file before finding all Vorbis headers!");
}
oy.wrote(bytes);
}
// Throw the comments plus a few lines about the bitstream we're
// decoding
{
byte[][] ptr = vc.user_comments;
for (int j = 0; j < vc.user_comments.Length; j++)
{
if (ptr [j] == null)
break;
s_err.WriteLine(vc.getComment(j));
}
s_err.WriteLine("\nBitstream is " + vi.channels + " channel, " + vi.rate + "Hz");
s_err.WriteLine("Encoded by: " + vc.getVendor() + "\n");
}
convsize = 4096 / vi.channels;
// OK, got and parsed all three headers. Initialize the Vorbis
// packet->PCM decoder.
vd.synthesis_init(vi); // central decode state
vb.init(vd); // local state for most of the decode
// so multiple block decodes can
// proceed in parallel. We could init
// multiple vorbis_block structures
// for vd here
float[][][] _pcm = new float[1][][];
int[] _index = new int[vi.channels];
// The rest is just a straight decode loop until end of stream
while (eos == 0)
{
while (eos == 0)
{
int result = oy.pageout(og);
if (result == 0)
break; // need more data
if (result == -1)
{
// missing or corrupt data at this page position
s_err.WriteLine("Corrupt or missing data in bitstream; continuing...");
} else
{
os.pagein(og); // can safely ignore errors at
// this point
while (true)
{
result = os.packetout(op);
if (result == 0)
break; // need more data
if (result == -1)
{ // missing or corrupt data at this page position
// no reason to complain; already complained above
} else
{
// we have a packet. Decode it
int samples;
if (vb.synthesis(op) == 0)
{ // test for success!
vd.synthesis_blockin(vb);
}
// **pcm is a multichannel float vector. In stereo, for
// example, pcm[0] is left, and pcm[1] is right. samples is
// the size of each channel. Convert the float values
// (-1.<=range<=1.) to whatever PCM format and write it out
while ((samples = vd.synthesis_pcmout(_pcm, _index)) > 0)
{
float[][] pcm = _pcm [0];
bool clipflag = false;
int bout = (samples < convsize ? samples : convsize);
// convert floats to 16 bit signed ints (host order) and
// interleave
for (i = 0; i < vi.channels; i++)
{
int ptr = i * 2;
//int ptr=i;
int mono = _index [i];
for (int j = 0; j < bout; j++)
{
int val = (int)(pcm [i] [mono + j] * 32767.0);
// short val=(short)(pcm[i][mono+j]*32767.);
// int val=(int)Math.round(pcm[i][mono+j]*32767.);
// might as well guard against clipping
if (val > 32767)
{
val = 32767;
clipflag = true;
}
if (val < -32768)
{
val = -32768;
clipflag = true;
}
if (val < 0)
val = val | 0x8000;
convbuffer [ptr] = (byte)(val);
convbuffer [ptr + 1] = (byte)((uint)val >> 8);
ptr += 2 * (vi.channels);
}
}
if (clipflag)
{
//s_err.WriteLine("Clipping in frame "+vd.sequence);
}
output.Write(convbuffer, 0, 2 * vi.channels * bout);
vd.synthesis_read(bout); // tell libvorbis how
// many samples we
// actually consumed
}
}
}
if (og.eos() != 0)
eos = 1;
}
}
if (eos == 0)
{
index = oy.buffer(4096);
bytes = input.Read(oy.data, index, 4096);
oy.wrote(bytes);
if (bytes == 0)
eos = 1;
}
}
// clean up this logical bitstream; before exit we see if we're
// followed by another [chained]
os.clear();
// ogg_page and ogg_packet structs always point to storage in
// libvorbis. They're never freed or manipulated directly
vb.clear();
vd.clear();
vi.clear(); // must be called last
}
// OK, clean up the framer
oy.clear();
s_err.WriteLine("Done.");
if (writeWavHeader)
{
long end = output.Position;
int length = (int)(end - (start + HEADER_SIZE));
output.Seek(start, SeekOrigin.Begin);
WriteHeader(output, length, vi.rate, (ushort)16, (ushort)vi.channels);
output.Seek(end, SeekOrigin.Begin);
}
}
public AudioSample OggToWav(Stream ogg, float volume, float pitch)
{
AudioSample sample = new AudioSample();
TextWriter s_err = new StringWriter();
Stream input = null;
MemoryStream output = null;
input = ogg;
output = new MemoryStream();
SyncState oy = new SyncState();
StreamState os = new StreamState();
Page og = new Page();
Packet op = new Packet();
Info vi = new Info();
Comment vc = new Comment();
DspState vd = new DspState();
Block vb = new Block(vd);
byte[] buffer;
int bytes = 0;
oy.init();
while (true)
{
int eos = 0;
int index = oy.buffer(4096);
buffer = oy.data;
try
{
bytes = input.Read(buffer, index, 4096);
}
catch (Exception e)
{
s_err.WriteLine(e);
}
oy.wrote(bytes);
if (oy.pageout(og) != 1)
{
if (bytes < 4096) break;
s_err.WriteLine("Input does not appear to be an Ogg bitstream.");
}
os.init(og.serialno());
vi.init();
vc.init();
if (os.pagein(og) < 0)
{
s_err.WriteLine("Error reading first page of Ogg bitstream data.");
}
if (os.packetout(op) != 1)
{
s_err.WriteLine("Error reading initial header packet.");
}
if (vi.synthesis_headerin(vc, op) < 0)
{
s_err.WriteLine("This Ogg bitstream does not contain Vorbis audio data.");
}
int i = 0;
while (i < 2)
{
while (i < 2)
{
int result = oy.pageout(og);
if (result == 0) break;
if (result == 1)
{
os.pagein(og);
while (i < 2)
{
result = os.packetout(op);
if (result == 0) break;
vi.synthesis_headerin(vc, op);
i++;
}
}
}
index = oy.buffer(4096);
buffer = oy.data;
try
{
bytes = input.Read(buffer, index, 4096);
}
catch (Exception e)
{
s_err.WriteLine(e);
}
oy.wrote(bytes);
}
sample.Channels = vi.channels;
sample.Rate = (int)((float)vi.rate * pitch);
convsize = 4096 / vi.channels;
vd.synthesis_init(vi);
vb.init(vd);
float[][][] _pcm = new float[1][][];
int[] _index = new int[vi.channels];
while (eos == 0)
{
while (eos == 0)
{
int result = oy.pageout(og);
if (result == 0) break;
if (result != -1)
{
os.pagein(og);
while (true)
{
result = os.packetout(op);
if (result == 0) break;
if (result != -1)
{
int samples;
if (vb.synthesis(op) == 0)
{
vd.synthesis_blockin(vb);
}
while ((samples = vd.synthesis_pcmout(_pcm, _index)) > 0)
{
float[][] pcm = _pcm[0];
int bout = (samples < convsize ? samples : convsize);
for (i = 0; i < vi.channels; i++)
{
int ptr = i * 2;
int mono = _index[i];
for (int j = 0; j < bout; j++)
{
int val = (int)(pcm[i][mono + j] * 32767.0);
if (val > 32767)
{
val = 32767;
}
if (val < -32768)
{
val = -32768;
}
val = (int)((float)val * volume);
if (val < 0) val = val | 0x8000;
convbuffer[ptr] = (byte)(val);
convbuffer[ptr + 1] = (byte)((uint)val >> 8);
ptr += 2 * (vi.channels);
}
}
output.Write(convbuffer, 0, 2 * vi.channels * bout);
vd.synthesis_read(bout);
}
}
}
if (og.eos() != 0) eos = 1;
}
}
if (eos == 0)
{
index = oy.buffer(4096);
buffer = oy.data;
try
{
bytes = input.Read(buffer, index, 4096);
}
catch (Exception e)
{
s_err.WriteLine(e);
}
oy.wrote(bytes);
if (bytes == 0) eos = 1;
}
}
os.clear();
vb.clear();
vd.clear();
vi.clear();
break;
}
oy.clear();
input.Close();
sample.Pcm = output.ToArray();
return sample;
}
Stream DecodeStream( Stream input, bool skipWavHeader )
{
int convsize = 4096 * 2;
byte [] convbuffer = new byte [ convsize ];
Stream output = new MemoryStream ();
if ( !skipWavHeader )
output.Seek ( HEADER_SIZE, SeekOrigin.Begin );
SyncState oy = new SyncState ();
StreamState os = new StreamState ();
Page og = new Page ();
Packet op = new Packet ();
Info vi = new Info ();
Comment vc = new Comment ();
DspState vd = new DspState ();
Block vb = new Block ( vd );
byte [] buffer;
int bytes = 0;
oy.init ();
while ( true )
{
int eos = 0;
int index = oy.buffer ( 4096 );
buffer = oy.data;
bytes = input.Read ( buffer, index, 4096 );
oy.wrote ( bytes );
if ( oy.pageout ( og ) != 1 )
{
if ( bytes < 4096 ) break;
throw new Exception ( "Input does not appear to be an Ogg bitstream." );
}
os.init ( og.serialno () );
vi.init ();
vc.init ();
if ( os.pagein ( og ) < 0 )
{
throw new Exception ( "Error reading first page of Ogg bitstream data." );
}
if ( os.packetout ( op ) != 1 )
{
throw new Exception ( "Error reading initial header packet." );
}
if ( vi.synthesis_headerin ( vc, op ) < 0 )
{
throw new Exception ( "This Ogg bitstream does not contain Vorbis audio data." );
}
int i = 0;
while ( i < 2 )
{
while ( i < 2 )
{
int result = oy.pageout ( og );
if ( result == 0 ) break;
if ( result == 1 )
{
os.pagein ( og );
while ( i < 2 )
{
result = os.packetout ( op );
if ( result == 0 ) break;
if ( result == -1 )
{
throw new Exception ( "Corrupt secondary header. Exiting." );
}
vi.synthesis_headerin ( vc, op );
i++;
}
}
}
index = oy.buffer ( 4096 );
buffer = oy.data;
bytes = input.Read ( buffer, index, 4096 );
if ( bytes == 0 && i < 2 )
{
throw new Exception ( "End of file before finding all Vorbis headers!" );
}
oy.wrote ( bytes );
}
{
byte [] [] ptr = vc.user_comments;
for ( int j = 0; j < vc.user_comments.Length; j++ )
{
if ( ptr [ j ] == null ) break;
}
}
convsize = 4096 / vi.channels;
vd.synthesis_init ( vi );
vb.init ( vd );
float [] [] [] _pcm = new float [ 1 ] [][];
int [] _index = new int [ vi.channels ];
while ( eos == 0 )
{
while ( eos == 0 )
{
int result = oy.pageout ( og );
if ( result == 0 ) break;
if ( result == -1 )
throw new Exception ( "Corrupt or missing data in bitstream; continuing..." );
else
{
os.pagein ( og );
while ( true )
{
result = os.packetout ( op );
if ( result == 0 ) break;
if ( result == -1 )
{
}
else
{
int samples;
if ( vb.synthesis ( op ) == 0 )
{
vd.synthesis_blockin ( vb );
}
while ( ( samples = vd.synthesis_pcmout ( _pcm, _index ) ) > 0 )
{
float [] [] pcm = _pcm [ 0 ];
bool clipflag = false;
int bout = ( samples < convsize ? samples : convsize );
for ( i = 0; i < vi.channels; i++ )
{
int ptr = i * 2;
int mono = _index [ i ];
for ( int j = 0; j < bout; j++ )
{
int val = ( int ) ( pcm [ i ] [ mono + j ] * 32767.0 );
if ( val > 32767 )
{
val = 32767;
clipflag = true;
}
if ( val < -32768 )
{
val = -32768;
clipflag = true;
}
if ( val < 0 ) val = val | 0x8000;
convbuffer [ ptr ] = ( byte ) ( val );
convbuffer [ ptr + 1 ] = ( byte ) ( ( uint ) val >> 8 );
ptr += 2 * ( vi.channels );
}
}
if ( clipflag )
{
}
output.Write ( convbuffer, 0, 2 * vi.channels * bout );
vd.synthesis_read ( bout );
}
}
}
if ( og.eos () != 0 ) eos = 1;
}
}
if ( eos == 0 )
{
index = oy.buffer ( 4096 );
buffer = oy.data;
bytes = input.Read ( buffer, index, 4096 );
oy.wrote ( bytes );
if ( bytes == 0 ) eos = 1;
}
}
os.clear ();
vb.clear ();
vd.clear ();
vi.clear ();
}
oy.clear ();
output.Seek ( 0, SeekOrigin.Begin );
if ( !skipWavHeader )
{
WriteHeader ( output, ( int ) ( output.Length - HEADER_SIZE ), vi.rate, ( ushort ) 16, ( ushort ) vi.channels );
output.Seek ( 0, SeekOrigin.Begin );
}
return output;
}
// fetch and process a packet. Handles the case where we're at a
// bitstream boundary and dumps the decoding machine. If the decoding
// machine is unloaded, it loads it. It also keeps pcm_offset up to
// date (seek and read both use this. seek uses a special hack with
// readp).
//
// return: -1) hole in the data (lost packet)
// 0) need more date (only if readp==0)/eof
// 1) got a packet
int process_packet(int readp)
{
Page og=new Page();
// handle one packet. Try to fetch it from current stream state
// extract packets from page
while(true)
{
// process a packet if we can. If the machine isn't loaded,
// neither is a page
if(decode_ready)
{
Packet op=new Packet();
int result=os.packetout(op);
long granulepos;
// if(result==-1)return(-1); // hole in the data. For now, swallow
// and go. We'll need to add a real
// error code in a bit.
if(result>0)
{
// got a packet. process it
granulepos=op.granulepos;
if(vb.synthesis(op)==0)
{ // lazy check for lazy
// header handling. The
// header packets aren't
// audio, so if/when we
// submit them,
// vorbis_synthesis will
// reject them
// suck in the synthesis data and track bitrate
{
int oldsamples=vd.synthesis_pcmout(null, null);
vd.synthesis_blockin(vb);
samptrack+=vd.synthesis_pcmout(null, null)-oldsamples;
bittrack+=op.bytes*8;
}
// update the pcm offset.
if(granulepos!=-1 && op.e_o_s==0)
{
int link=(skable?current_link:0);
int samples;
// this packet has a pcm_offset on it (the last packet
// completed on a page carries the offset) After processing
// (above), we know the pcm position of the *last* sample
// ready to be returned. Find the offset of the *first*
//
// As an aside, this trick is inaccurate if we begin
// reading anew right at the last page; the end-of-stream
// granulepos declares the last frame in the stream, and the
// last packet of the last page may be a partial frame.
// So, we need a previous granulepos from an in-sequence page
// to have a reference point. Thus the !op.e_o_s clause above
samples=vd.synthesis_pcmout(null, null);
granulepos-=samples;
for(int i=0;i<link;i++)
{
granulepos+=pcmlengths[i];
}
pcm_offset=granulepos;
}
return(1);
}
}
}
if(readp==0)return(0);
if(get_next_page(og,-1)<0)return(0); // eof. leave unitialized
// bitrate tracking; add the header's bytes here, the body bytes
// are done by packet above
bittrack+=og.header_len*8;
// has our decoding just traversed a bitstream boundary?
if(decode_ready)
{
if(current_serialno!=og.serialno())
{
decode_clear();
}
}
// Do we need to load a new machine before submitting the page?
// This is different in the seekable and non-seekable cases.
//
// In the seekable case, we already have all the header
// information loaded and cached; we just initialize the machine
// with it and continue on our merry way.
//
// In the non-seekable (streaming) case, we'll only be at a
// boundary if we just left the previous logical bitstream and
// we're now nominally at the header of the next bitstream
if(!decode_ready)
{
int i;
if(skable)
{
current_serialno=og.serialno();
// match the serialno to bitstream section. We use this rather than
// offset positions to avoid problems near logical bitstream
// boundaries
for(i=0;i<links;i++)
{
if(serialnos[i]==current_serialno)break;
}
if(i==links)return(-1); // sign of a bogus stream. error out,
// leave machine uninitialized
current_link=i;
os.init(current_serialno);
os.reset();
}
else
{
// we're streaming
// fetch the three header packets, build the info struct
int[] foo = new int[1];
int ret=fetch_headers(vi[0], vc[0], foo, og);
current_serialno=foo[0];
if(ret!=0)return ret;
current_link++;
i=0;
}
make_decode_ready();
}
os.pagein(og);
}
}
static MemoryStream DecodeStream(Stream input, bool skipWavHeader, out Info vi)
{
int convsize = 4096 * 2;
byte[] convbuffer = new byte[convsize]; // take 8k out of the data segment, not the stack
TextWriter s_err = new DebugWriter();
var output = new MemoryStream();
if (!skipWavHeader)
{
output.Seek(HEADER_SIZE, SeekOrigin.Begin); // reserve place for WAV header
}
SyncState oy = new SyncState(); // sync and verify incoming physical bitstream
StreamState os = new StreamState(); // take physical pages, weld into a logical stream of packets
Page og = new Page(); // one Ogg bitstream page. Vorbis packets are inside
Packet op = new Packet(); // one raw packet of data for decode
vi = new Info(); // struct that stores all the static vorbis bitstream settings
Comment vc = new Comment(); // struct that stores all the bitstream user comments
DspState vd = new DspState(); // central working state for the packet->PCM decoder
Block vb = new Block(vd); // local working space for packet->PCM decode
byte[] buffer;
int bytes = 0;
// Decode setup
oy.init(); // Now we can read pages
while (true)
{ // we repeat if the bitstream is chained
int eos = 0;
// grab some data at the head of the stream. We want the first page
// (which is guaranteed to be small and only contain the Vorbis
// stream initial header) We need the first page to get the stream
// serialno.
// submit a 4k block to libvorbis' Ogg layer
int index = oy.buffer(4096);
buffer = oy.data;
try
{
bytes = input.Read(buffer, index, 4096);
}
catch (Exception e)
{
s_err.WriteLine(e);
}
oy.wrote(bytes);
// Get the first page.
if (oy.pageout(og) != 1)
{
// have we simply run out of data? If so, we're done.
if (bytes < 4096)
{
break;
}
// error case. Must not be Vorbis data
s_err.WriteLine("Input does not appear to be an Ogg bitstream.");
}
// Get the serial number and set up the rest of decode.
// serialno first; use it to set up a logical stream
os.init(og.serialno());
// extract the initial header from the first page and verify that the
// Ogg bitstream is in fact Vorbis data
// I handle the initial header first instead of just having the code
// read all three Vorbis headers at once because reading the initial
// header is an easy way to identify a Vorbis bitstream and it's
// useful to see that functionality seperated out.
vi.init();
vc.init();
if (os.pagein(og) < 0)
{
// error; stream version mismatch perhaps
s_err.WriteLine("Error reading first page of Ogg bitstream data.");
}
if (os.packetout(op) != 1)
{
// no page? must not be vorbis
s_err.WriteLine("Error reading initial header packet.");
}
if (vi.synthesis_headerin(vc, op) < 0)
{
// error case; not a vorbis header
s_err.WriteLine("This Ogg bitstream does not contain Vorbis audio data.");
}
// At this point, we're sure we're Vorbis. We've set up the logical
// (Ogg) bitstream decoder. Get the comment and codebook headers and
// set up the Vorbis decoder
// The next two packets in order are the comment and codebook headers.
// They're likely large and may span multiple pages. Thus we reead
// and submit data until we get our two pacakets, watching that no
// pages are missing. If a page is missing, error out; losing a
// header page is the only place where missing data is fatal. */
int i = 0;
while (i < 2)
{
while (i < 2)
{
int result = oy.pageout(og);
if (result == 0)
{
break; // Need more data
}
// Don't complain about missing or corrupt data yet. We'll
// catch it at the packet output phase
if (result == 1)
{
os.pagein(og); // we can ignore any errors here
// as they'll also become apparent
// at packetout
while (i < 2)
{
result = os.packetout(op);
if (result == 0)
{
break;
}
if (result == -1)
{
// Uh oh; data at some point was corrupted or missing!
// We can't tolerate that in a header. Die.
s_err.WriteLine("Corrupt secondary header. Exiting.");
}
vi.synthesis_headerin(vc, op);
i++;
}
}
}
// no harm in not checking before adding more
index = oy.buffer(4096);
buffer = oy.data;
try
{
bytes = input.Read(buffer, index, 4096);
}
catch (Exception e)
{
s_err.WriteLine(e);
}
if (bytes == 0 && i < 2)
{
s_err.WriteLine("End of file before finding all Vorbis headers!");
}
oy.wrote(bytes);
}
// Throw the comments plus a few lines about the bitstream we're
// decoding
{
byte[][] ptr = vc.user_comments;
for (int j = 0; j < vc.user_comments.Length; j++)
{
if (ptr[j] == null)
{
break;
}
s_err.WriteLine(vc.getComment(j));
}
s_err.WriteLine("\nBitstream is " + vi.channels + " channel, " + vi.rate + "Hz");
s_err.WriteLine("Encoded by: " + vc.getVendor() + "\n");
}
convsize = 4096 / vi.channels;
// OK, got and parsed all three headers. Initialize the Vorbis
// packet->PCM decoder.
vd.synthesis_init(vi); // central decode state
vb.init(vd); // local state for most of the decode
// so multiple block decodes can
// proceed in parallel. We could init
// multiple vorbis_block structures
// for vd here
float[][][] _pcm = new float[1][][];
int[] _index = new int[vi.channels];
// The rest is just a straight decode loop until end of stream
while (eos == 0)
{
while (eos == 0)
{
int result = oy.pageout(og);
if (result == 0)
{
break; // need more data
}
if (result == -1)
{ // missing or corrupt data at this page position
s_err.WriteLine("Corrupt or missing data in bitstream; continuing...");
}
else
{
os.pagein(og); // can safely ignore errors at
// this point
while (true)
{
result = os.packetout(op);
if (result == 0)
{
break; // need more data
}
if (result == -1)
{ // missing or corrupt data at this page position
// no reason to complain; already complained above
}
else
{
// we have a packet. Decode it
int samples;
if (vb.synthesis(op) == 0)
{ // test for success!
vd.synthesis_blockin(vb);
}
// **pcm is a multichannel float vector. In stereo, for
// example, pcm[0] is left, and pcm[1] is right. samples is
// the size of each channel. Convert the float values
// (-1.<=range<=1.) to whatever PCM format and write it out
while ((samples = vd.synthesis_pcmout(_pcm, _index)) > 0)
{
float[][] pcm = _pcm[0];
bool clipflag = false;
int bout = (samples < convsize ? samples : convsize);
// convert floats to 16 bit signed ints (host order) and
// interleave
for (i = 0; i < vi.channels; i++)
{
int ptr = i * 2;
//int ptr=i;
int mono = _index[i];
for (int j = 0; j < bout; j++)
{
int val = (int)(pcm[i][mono + j] * 32767.0);
// short val=(short)(pcm[i][mono+j]*32767.);
// int val=(int)Math.round(pcm[i][mono+j]*32767.);
// might as well guard against clipping
if (val > 32767)
{
val = 32767;
clipflag = true;
}
if (val < -32768)
{
val = -32768;
clipflag = true;
}
if (val < 0)
{
val = val | 0x8000;
}
convbuffer[ptr] = (byte)(val);
convbuffer[ptr + 1] = (byte)((uint)val >> 8);
ptr += 2 * (vi.channels);
}
}
if (clipflag)
{
//s_err.WriteLine("Clipping in frame "+vd.sequence);
}
output.Write(convbuffer, 0, 2 * vi.channels * bout);
vd.synthesis_read(bout); // tell libvorbis how
// many samples we
// actually consumed
}
}
}
if (og.eos() != 0)
{
eos = 1;
}
}
}
if (eos == 0)
{
index = oy.buffer(4096);
buffer = oy.data;
try
{
bytes = input.Read(buffer, index, 4096);
}
catch (Exception e)
{
s_err.WriteLine(e);
}
oy.wrote(bytes);
if (bytes == 0)
{
eos = 1;
}
}
}
// clean up this logical bitstream; before exit we see if we're
// followed by another [chained]
os.clear();
// ogg_page and ogg_packet structs always point to storage in
// libvorbis. They're never freed or manipulated directly
vb.clear();
vd.clear();
vi.clear(); // must be called last
}
// OK, clean up the framer
oy.clear();
s_err.WriteLine("Done.");
output.Seek(0, SeekOrigin.Begin);
if (!skipWavHeader)
{
WriteHeader(output, (int)(output.Length - HEADER_SIZE), vi.rate, (ushort)16, (ushort)vi.channels);
output.Seek(0, SeekOrigin.Begin);
}
return(output);
}