godot/thirdparty/libvorbis/block.c

/********************************************************************
 *                                                                  *
 * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE.   *
 * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *
 * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
 * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *
 *                                                                  *
 * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2015             *
 * by the Xiph.Org Foundation https://xiph.org/                     *
 *                                                                  *
 ********************************************************************

 function: PCM data vector blocking, windowing and dis/reassembly

 Handle windowing, overlap-add, etc of the PCM vectors.  This is made
 more amusing by Vorbis' current two allowed block sizes.

 ********************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ogg/ogg.h>
#include "vorbis/codec.h"
#include "codec_internal.h"

#include "window.h"
#include "mdct.h"
#include "lpc.h"
#include "registry.h"
#include "misc.h"

/* pcm accumulator examples (not exhaustive):

 <-------------- lW ---------------->
                   <--------------- W ---------------->
:            .....|.....       _______________         |
:        .'''     |     '''_---      |       |\        |
:.....'''         |_____--- '''......|       | \_______|
:.................|__________________|_______|__|______|
                  |<------ Sl ------>|      > Sr <     |endW
                  |beginSl           |endSl  |  |endSr
                  |beginW            |endlW  |beginSr


                      |< lW >|
                   <--------------- W ---------------->
                  |   |  ..  ______________            |
                  |   | '  `/        |     ---_        |
                  |___.'___/`.       |         ---_____|
                  |_______|__|_______|_________________|
                  |      >|Sl|<      |<------ Sr ----->|endW
                  |       |  |endSl  |beginSr          |endSr
                  |beginW |  |endlW
                  mult[0] |beginSl                     mult[n]

 <-------------- lW ----------------->
                          |<--W-->|
:            ..............  ___  |   |
:        .'''             |`/   \ |   |
:.....'''                 |/`....\|...|
:.........................|___|___|___|
                          |Sl |Sr |endW
                          |   |   |endSr
                          |   |beginSr
                          |   |endSl
                          |beginSl
                          |beginW
*/

/* block abstraction setup *********************************************/

#ifndef WORD_ALIGN
#define WORD_ALIGN …
#endif

int vorbis_block_init(vorbis_dsp_state *v, vorbis_block *vb){ … }

void *_vorbis_block_alloc(vorbis_block *vb,long bytes){ … }

/* reap the chain, pull the ripcord */
void _vorbis_block_ripcord(vorbis_block *vb){ … }

int vorbis_block_clear(vorbis_block *vb){ … }

/* Analysis side code, but directly related to blocking.  Thus it's
   here and not in analysis.c (which is for analysis transforms only).
   The init is here because some of it is shared */

static int _vds_shared_init(vorbis_dsp_state *v,vorbis_info *vi,int encp){ … }

/* arbitrary settings and spec-mandated numbers get filled in here */
int vorbis_analysis_init(vorbis_dsp_state *v,vorbis_info *vi){ … }

void vorbis_dsp_clear(vorbis_dsp_state *v){ … }

float **vorbis_analysis_buffer(vorbis_dsp_state *v, int vals){ … }

static void _preextrapolate_helper(vorbis_dsp_state *v){ … }


/* call with val<=0 to set eof */

int vorbis_analysis_wrote(vorbis_dsp_state *v, int vals){ … }

/* do the deltas, envelope shaping, pre-echo and determine the size of
   the next block on which to continue analysis */
int vorbis_analysis_blockout(vorbis_dsp_state *v,vorbis_block *vb){ … }

int vorbis_synthesis_restart(vorbis_dsp_state *v){ … }

int vorbis_synthesis_init(vorbis_dsp_state *v,vorbis_info *vi){ … }

/* Unlike in analysis, the window is only partially applied for each
   block.  The time domain envelope is not yet handled at the point of
   calling (as it relies on the previous block). */

int vorbis_synthesis_blockin(vorbis_dsp_state *v,vorbis_block *vb){ … }

/* pcm==NULL indicates we just want the pending samples, no more */
int vorbis_synthesis_pcmout(vorbis_dsp_state *v,float ***pcm){ … }

int vorbis_synthesis_read(vorbis_dsp_state *v,int n){ … }

/* intended for use with a specific vorbisfile feature; we want access
   to the [usually synthetic/postextrapolated] buffer and lapping at
   the end of a decode cycle, specifically, a half-short-block worth.
   This funtion works like pcmout above, except it will also expose
   this implicit buffer data not normally decoded. */
int vorbis_synthesis_lapout(vorbis_dsp_state *v,float ***pcm){ … }

const float *vorbis_window(vorbis_dsp_state *v,int W){ … }