synthesis_headerin() публичный Метод

public synthesis_headerin ( Comment vc, Packet op ) : int
vc Comment
op csogg.Packet
Результат int
		// uses the local ogg_stream storage in vf; this is important for
		// non-streaming input sources
        public int fetch_headers(Info vi, Comment vc, int[] serialno, Page og_ptr, VorbisFileInstance instance)
		{
			//System.err.println("fetch_headers");
			Page og=new Page();
			Packet op=new Packet();
			int ret;

			if(og_ptr==null)
			{
                ret = get_next_page(og, CHUNKSIZE, instance);
				if(ret==OV_EREAD)return OV_EREAD;
				if(ret<0) return OV_ENOTVORBIS;
				og_ptr=og;
			}
  
			if(serialno!=null)serialno[0]=og_ptr.serialno();

			instance.os.init(og_ptr.serialno());
  
			// extract the initial header from the first page and verify that the
			// Ogg bitstream is in fact Vorbis data
  
			vi.init();
			vc.init();
  
			int i=0;
			while(i<3)
			{
                instance.os.pagein(og_ptr);
				while(i<3)
				{
                    int result = instance.os.packetout(op);
					if(result==0)break;
					if(result==-1)
					{
						Console.Error.WriteLine("Corrupt header in logical bitstream.");
						//goto bail_header;
						vi.clear();
						vc.clear();
                        instance.os.clear();
						return -1;
					}
					if(vi.synthesis_headerin(vc, op)!=0)
					{
						Console.Error.WriteLine("Illegal header in logical bitstream.");
						//goto bail_header;
						vi.clear();
						vc.clear();
                        instance.os.clear();
						return -1;
					}
					i++;
				}
				if(i<3)
					if(get_next_page(og_ptr, 1, instance)<0)
					{
						Console.Error.WriteLine("Missing header in logical bitstream.");
						//goto bail_header;
						vi.clear();
						vc.clear();
                        instance.os.clear();
						return -1;
					}
			}
			return 0; 
		}
Пример #2
0
        /// <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);
            }
        }
Пример #3
0
        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;
        }
Пример #4
0
		// uses the local ogg_stream storage in vf; this is important for
		// non-streaming input sources
		int fetch_headers(Info vi, Comment vc, int[] serialno, Page og_ptr)
		{
			//System.err.println("fetch_headers");
			Page og=new Page();
			Packet op=new Packet();
			int ret;

			if(og_ptr==null)
			{
				ret=get_next_page(og, CHUNKSIZE);
				if(ret==OV_EREAD)return OV_EREAD;
				if(ret<0) return OV_ENOTVORBIS;
				og_ptr=og;
			}
  
			if(serialno!=null)serialno[0]=og_ptr.serialno();

			os.init(og_ptr.serialno());
  
			// extract the initial header from the first page and verify that the
			// Ogg bitstream is in fact Vorbis data
  
			vi.init();
			vc.init();
  
			int i=0;
			while(i<3)
			{
				os.pagein(og_ptr);
				while(i<3)
				{
					int result=os.packetout(op);
					if(result==0)break;
					if(result==-1)
					{
						Console.Error.WriteLine("Corrupt header in logical bitstream.");
						//goto bail_header;
						vi.clear();
						vc.clear();
						os.clear();
						return -1;
					}
					if(vi.synthesis_headerin(vc, op)!=0)
					{
						Console.Error.WriteLine("Illegal header in logical bitstream.");
						//goto bail_header;
						vi.clear();
						vc.clear();
						os.clear();
						return -1;
					}
					i++;
				}
				if(i<3)
					if(get_next_page(og_ptr, 1)<0)
					{
						Console.Error.WriteLine("Missing header in logical bitstream.");
						//goto bail_header;
						vi.clear();
						vc.clear();
						os.clear();
						return -1;
					}
			}
			return 0; 
		}
Пример #5
0
        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;
        }
Пример #6
0
        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);
        }