Logo Search packages:      
Sourcecode: libjorbis-java version File versions  Download package

DecodeExample.java

/* -*-mode:java; c-basic-offset:2; indent-tabs-mode:nil -*- */
/* JOrbis
 * Copyright (C) 2000 ymnk, JCraft,Inc.
 *  
 * Written by: 2000 ymnk<ymnk@jcraft.com>
 *   
 * Many thanks to 
 *   Monty <monty@xiph.org> and 
 *   The XIPHOPHORUS Company http://www.xiph.org/ .
 * JOrbis has been based on their awesome works, Vorbis codec.
 *   
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public License
 * as published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
   
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Library General Public License for more details.
 * 
 * You should have received a copy of the GNU Library General Public
 * License along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

package com.jcraft.jorbis;

import com.jcraft.jogg.*;

// Takes a vorbis bitstream from stdin and writes raw stereo PCM to
// stdout.  Decodes simple and chained OggVorbis files from beginning
// to end.  Vorbisfile.a is somewhat more complex than the code below.

class DecodeExample{
  static int convsize=4096*2;
  static byte[] convbuffer=new byte[convsize]; // take 8k out of the data segment, not the stack

  public static void main(String[] arg){
    java.io.InputStream input=System.in;
    if(arg.length>0){
      try{
        input=new java.io.FileInputStream(arg[0]);
      }
      catch(Exception e){
        System.err.println(e);
      }
    }

    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

    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){
        System.err.println(e);
        System.exit(-1);
      }
      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
        System.err.println("Input does not appear to be an Ogg bitstream.");
        System.exit(1);
      }

      // 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
        System.err.println("Error reading first page of Ogg bitstream data.");
        System.exit(1);
      }

      if(os.packetout(op)!=1){
        // no page? must not be vorbis
        System.err.println("Error reading initial header packet.");
        System.exit(1);
      }

      if(vi.synthesis_headerin(vc, op)<0){
        // error case; not a vorbis header
        System.err
            .println("This Ogg bitstream does not contain Vorbis audio data.");
        System.exit(1);
      }

      // 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.
                System.err.println("Corrupt secondary header.  Exiting.");
                System.exit(1);
              }
              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){
          System.err.println(e);
          System.exit(1);
        }
        if(bytes==0&&i<2){
          System.err.println("End of file before finding all Vorbis headers!");
          System.exit(1);
        }
        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<ptr.length; j++){
          if(ptr[j]==null)
            break;
          System.err.println(new String(ptr[j], 0, ptr[j].length-1));
        }
        System.err.println("\nBitstream is "+vi.channels+" channel, "+vi.rate
            +"Hz");
        System.err.println("Encoded by: "
            +new String(vc.vendor, 0, vc.vendor.length-1)+"\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
            System.err
                .println("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];
                  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.);
                      //                  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;
                      }
                      if(val<-32768){
                        val=-32768;
                      }
                      if(val<0)
                        val=val|0x8000;
                      convbuffer[ptr]=(byte)(val);
                      convbuffer[ptr+1]=(byte)(val>>>8);
                      ptr+=2*(vi.channels);
                    }
                  }

                  System.out.write(convbuffer, 0, 2*vi.channels*bout);

                  // tell libvorbis how
                  // many samples we
                  // actually consumed
                  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){
            System.err.println(e);
            System.exit(1);
          }
          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();
    System.err.println("Done.");
  }
}

Generated by  Doxygen 1.6.0   Back to index