56 /* vorbis_dsp_state buffers the current vorbis audio

    57    analysis/synthesis state.  The DSP state belongs to a specific

    58    logical bitstream ****************************************************/

    59 typedef struct vorbis_dsp_state{

    60   int analysisp;

    61   vorbis_info *vi;

    62 

    63   ogg_int32_t **pcm;

    64   ogg_int32_t **pcmret;

    65   int      pcm_storage;

    66   int      pcm_current;

    67   int      pcm_returned;

    68 

    69   int  preextrapolate;

    70   int  eofflag;

    71 

    72   long lW;

    73   long W;

    74   long nW;

    75   long centerW;

    76 

    77   ogg_int64_t granulepos;

    78   ogg_int64_t sequence;

    79 

    80   void       *backend_state;

    81 } vorbis_dsp_state;

    82 

    83 typedef struct vorbis_block{

    84   /* necessary stream state for linking to the framing abstraction */

    85   ogg_int32_t  **pcm;       /* this is a pointer into local storage */ 

    86   oggpack_buffer opb;

    87   

    88   long  lW;

    89   long  W;

    90   long  nW;

    91   int   pcmend;

    92   int   mode;

    93 

    94   int         eofflag;

    95   ogg_int64_t granulepos;

    96   ogg_int64_t sequence;

    97   vorbis_dsp_state *vd; /* For read-only access of configuration */

    98 

    99   /* local storage to avoid remallocing; it's up to the mapping to

   100      structure it */

   101   void               *localstore;

   102   long                localtop;

   103   long                localalloc;

   104   long                totaluse;

   105   struct alloc_chain *reap;

   106 

   107 } vorbis_block;

   108 

   109 /* vorbis_block is a single block of data to be processed as part of

   110 the analysis/synthesis stream; it belongs to a specific logical

   111 bitstream, but is independant from other vorbis_blocks belonging to

   112 that logical bitstream. *************************************************/

   113 

   114 struct alloc_chain{

   115   void *ptr;

   116   struct alloc_chain *next;

   117 };

   118 

   119 /* vorbis_info contains all the setup information specific to the

   120    specific compression/decompression mode in progress (eg,

   121    psychoacoustic settings, channel setup, options, codebook

   122    etc). vorbis_info and substructures are in backends.h.

   123 *********************************************************************/

   124 

   125 /* the comments are not part of vorbis_info so that vorbis_info can be

   126    static storage */

   128   /* unlimited user comment fields.  libvorbis writes 'libvorbis'

   129      whatever vendor is set to in encode */

   137 

   138 /* libvorbis encodes in two abstraction layers; first we perform DSP

   139    and produce a packet (see docs/analysis.txt).  The packet is then

   140    coded into a framed OggSquish bitstream by the second layer (see

   141    docs/framing.txt).  Decode is the reverse process; we sync/frame

   142    the bitstream and extract individual packets, then decode the

   143    packet back into PCM audio.

   144 

   145    The extra framing/packetizing is used in streaming formats, such as

   146    files.  Over the net (such as with UDP), the framing and

   147    packetization aren't necessary as they're provided by the transport

   148    and the streaming layer is not used */

   162 

   163 extern int      vorbis_block_init(vorbis_dsp_state *v, vorbis_block *vb);

   164 extern int      vorbis_block_clear(vorbis_block *vb);

   165 extern void     vorbis_dsp_clear(vorbis_dsp_state *v);

   166 

   167 /* Vorbis PRIMITIVES: synthesis layer *******************************/

   168 extern int      vorbis_synthesis_headerin(vorbis_info *vi,vorbis_comment *vc,

   169 					  ogg_packet *op);

   170 

   171 extern int      vorbis_synthesis_init(vorbis_dsp_state *v,vorbis_info *vi);

   172 extern int      vorbis_synthesis_restart(vorbis_dsp_state *v);

   173 extern int      vorbis_synthesis(vorbis_block *vb,ogg_packet *op,int decodep);

   174 extern int      vorbis_synthesis_blockin(vorbis_dsp_state *v,vorbis_block *vb);

   175 extern int      vorbis_synthesis_pcmout(vorbis_dsp_state *v,ogg_int32_t ***pcm);

   176 extern int      vorbis_synthesis_read(vorbis_dsp_state *v,int samples);

   177 extern long     vorbis_packet_blocksize(vorbis_info *vi,ogg_packet *op);