git.sesse.net Git - vlc/blob - modules/codec/lpcm.c

   1 /*****************************************************************************
   2  * lpcm.c: lpcm decoder/packetizer module
   3  *****************************************************************************
   4  * Copyright (C) 1999-2005 the VideoLAN team
   5  * $Id$
   6  *
   7  * Authors: Samuel Hocevar <sam@zoy.org>
   8  *          Henri Fallon <henri@videolan.org>
   9  *          Christophe Massiot <massiot@via.ecp.fr>
  10  *          Gildas Bazin <gbazin@videolan.org>
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  25  *****************************************************************************/
  26
  27 /*****************************************************************************
  28  * Preamble
  29  *****************************************************************************/
  30 #ifdef HAVE_CONFIG_H
  31 # include "config.h"
  32 #endif
  33
  34 #include <vlc/vlc.h>
  35 #include <vlc_plugin.h>
  36 #include <vlc_codec.h>
  37 #include <vlc_aout.h>
  38
  39 /*****************************************************************************
  40  * decoder_sys_t : lpcm decoder descriptor
  41  *****************************************************************************/
  42 struct decoder_sys_t
  43 {
  44     /* Module mode */
  45     bool b_packetizer;
  46
  47     /*
  48      * Output properties
  49      */
  50     audio_date_t end_date;
  51
  52 };
  53
  54 /*
  55  * LPCM header :
  56  * - PES header
  57  * - private stream ID (16 bits) == 0xA0 -> not in the bitstream
  58  *
  59  * - frame number (8 bits)
  60  * - unknown (16 bits) == 0x0003 ?
  61  * - unknown (4 bits)
  62  * - current frame (4 bits)
  63  * - unknown (2 bits)
  64  * - frequency (2 bits) 0 == 48 kHz, 1 == 32 kHz, 2 == ?, 3 == ?
  65  * - unknown (1 bit)
  66  * - number of channels - 1 (3 bits) 1 == 2 channels
  67  * - start code (8 bits) == 0x80
  68  */
  69
  70 #define LPCM_HEADER_LEN 6
  71
  72 /*****************************************************************************
  73  * Local prototypes
  74  *****************************************************************************/
  75 static int  OpenDecoder   ( vlc_object_t * );
  76 static int  OpenPacketizer( vlc_object_t * );
  77 static void CloseDecoder  ( vlc_object_t * );
  78
  79 static void *DecodeFrame  ( decoder_t *, block_t ** );
  80
  81 /*****************************************************************************
  82  * Module descriptor
  83  *****************************************************************************/
  84 vlc_module_begin();
  85
  86     set_category( CAT_INPUT );
  87     set_subcategory( SUBCAT_INPUT_ACODEC );
  88     set_description( _("Linear PCM audio decoder") );
  89     set_capability( "decoder", 100 );
  90     set_callbacks( OpenDecoder, CloseDecoder );
  91
  92     add_submodule();
  93     set_description( _("Linear PCM audio packetizer") );
  94     set_capability( "packetizer", 100 );
  95     set_callbacks( OpenPacketizer, CloseDecoder );
  96
  97 vlc_module_end();
  98
  99 /*****************************************************************************
 100  * OpenDecoder: probe the decoder and return score
 101  *****************************************************************************/
 102 static int OpenDecoder( vlc_object_t *p_this )
 103 {
 104     decoder_t *p_dec = (decoder_t*)p_this;
 105     decoder_sys_t *p_sys;
 106
 107     if( p_dec->fmt_in.i_codec != VLC_FOURCC('l','p','c','m')
 108          && p_dec->fmt_in.i_codec != VLC_FOURCC('l','p','c','b') )
 109     {
 110         return VLC_EGENERIC;
 111     }
 112
 113     /* Allocate the memory needed to store the decoder's structure */
 114     if( ( p_dec->p_sys = p_sys =
 115           (decoder_sys_t *)malloc(sizeof(decoder_sys_t)) ) == NULL )
 116     {
 117         msg_Err( p_dec, "out of memory" );
 118         return VLC_EGENERIC;
 119     }
 120
 121     /* Misc init */
 122     p_sys->b_packetizer = false;
 123     aout_DateSet( &p_sys->end_date, 0 );
 124
 125     /* Set output properties */
 126     p_dec->fmt_out.i_cat = AUDIO_ES;
 127
 128     if( p_dec->fmt_out.audio.i_bitspersample == 24 )
 129     {
 130         p_dec->fmt_out.i_codec = VLC_FOURCC('s','2','4','b');
 131     }
 132     else
 133     {
 134         p_dec->fmt_out.i_codec = VLC_FOURCC('s','1','6','b');
 135         p_dec->fmt_out.audio.i_bitspersample = 16;
 136     }
 137
 138     /* Set callback */
 139     p_dec->pf_decode_audio = (aout_buffer_t *(*)(decoder_t *, block_t **))
 140         DecodeFrame;
 141     p_dec->pf_packetize    = (block_t *(*)(decoder_t *, block_t **))
 142         DecodeFrame;
 143
 144     return VLC_SUCCESS;
 145 }
 146
 147 static int OpenPacketizer( vlc_object_t *p_this )
 148 {
 149     decoder_t *p_dec = (decoder_t*)p_this;
 150
 151     int i_ret = OpenDecoder( p_this );
 152
 153     if( i_ret != VLC_SUCCESS ) return i_ret;
 154
 155     p_dec->p_sys->b_packetizer = true;
 156
 157     p_dec->fmt_out.i_codec = VLC_FOURCC('l','p','c','m');
 158
 159     return i_ret;
 160 }
 161
 162 /*****************************************************************************
 163  * DecodeFrame: decodes an lpcm frame.
 164  ****************************************************************************
 165  * Beware, this function must be fed with complete frames (PES packet).
 166  *****************************************************************************/
 167 static void *DecodeFrame( decoder_t *p_dec, block_t **pp_block )
 168 {
 169     decoder_sys_t *p_sys = p_dec->p_sys;
 170     block_t       *p_block;
 171     unsigned int  i_rate = 0, i_original_channels = 0, i_channels = 0;
 172     int           i_frame_length, i_bitspersample;
 173     uint8_t       i_header;
 174
 175     if( !pp_block || !*pp_block ) return NULL;
 176
 177     p_block = *pp_block;
 178     *pp_block = NULL; /* So the packet doesn't get re-sent */
 179
 180     /* Date management */
 181     if( p_block->i_pts > 0 &&
 182         p_block->i_pts != aout_DateGet( &p_sys->end_date ) )
 183     {
 184         aout_DateSet( &p_sys->end_date, p_block->i_pts );
 185     }
 186
 187     if( !aout_DateGet( &p_sys->end_date ) )
 188     {
 189         /* We've just started the stream, wait for the first PTS. */
 190         block_Release( p_block );
 191         return NULL;
 192     }
 193
 194     if( p_block->i_buffer <= LPCM_HEADER_LEN )
 195     {
 196         msg_Err(p_dec, "frame is too short");
 197         block_Release( p_block );
 198         return NULL;
 199     }
 200
 201     i_header = p_block->p_buffer[4];
 202     switch ( (i_header >> 4) & 0x3 )
 203     {
 204     case 0:
 205         i_rate = 48000;
 206         break;
 207     case 1:
 208         i_rate = 96000;
 209         break;
 210     case 2:
 211         i_rate = 44100;
 212         break;
 213     case 3:
 214         i_rate = 32000;
 215         break;
 216     }
 217
 218     i_channels = (i_header & 0x7);
 219     switch ( i_channels )
 220     {
 221     case 0:
 222         i_original_channels = AOUT_CHAN_CENTER;
 223         break;
 224     case 1:
 225         i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT;
 226         break;
 227     case 2:
 228         /* This is unsure. */
 229         i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_LFE;
 230         break;
 231     case 3:
 232         i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 233                                | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT;
 234         break;
 235     case 4:
 236         /* This is unsure. */
 237         i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 238                                | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT
 239                                | AOUT_CHAN_LFE;
 240         break;
 241     case 5:
 242         i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 243                                | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT
 244                                | AOUT_CHAN_CENTER | AOUT_CHAN_LFE;
 245         break;
 246     case 6:
 247         i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 248                                | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT
 249                                | AOUT_CHAN_CENTER | AOUT_CHAN_MIDDLELEFT
 250                                | AOUT_CHAN_MIDDLERIGHT;
 251         break;
 252     case 7:
 253         i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 254                                | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT
 255                                | AOUT_CHAN_CENTER | AOUT_CHAN_MIDDLELEFT
 256                                | AOUT_CHAN_MIDDLERIGHT | AOUT_CHAN_LFE;
 257         break;
 258     }
 259
 260     switch ( (i_header >> 6) & 0x3 )
 261     {
 262     case 2:
 263         p_dec->fmt_out.i_codec = VLC_FOURCC('s','2','4','b');
 264         p_dec->fmt_out.audio.i_bitspersample = 24;
 265         i_bitspersample = 24;
 266         break;
 267     case 1:
 268         p_dec->fmt_out.i_codec = VLC_FOURCC('s','2','4','b');
 269         p_dec->fmt_out.audio.i_bitspersample = 24;
 270         i_bitspersample = 20;
 271         break;
 272     case 0:
 273     default:
 274         p_dec->fmt_out.i_codec = VLC_FOURCC('s','1','6','b');
 275         p_dec->fmt_out.audio.i_bitspersample = 16;
 276         i_bitspersample = 16;
 277         break;
 278     }
 279
 280     /* Check frame sync and drop it. */
 281     if( p_block->p_buffer[5] != 0x80 )
 282     {
 283         msg_Warn( p_dec, "no frame sync" );
 284         block_Release( p_block );
 285         return NULL;
 286     }
 287
 288     /* Set output properties */
 289     if( p_dec->fmt_out.audio.i_rate != i_rate )
 290     {
 291         aout_DateInit( &p_sys->end_date, i_rate );
 292         aout_DateSet( &p_sys->end_date, p_block->i_pts );
 293     }
 294     p_dec->fmt_out.audio.i_rate = i_rate;
 295     p_dec->fmt_out.audio.i_channels = i_channels + 1;
 296     p_dec->fmt_out.audio.i_original_channels = i_original_channels;
 297     p_dec->fmt_out.audio.i_physical_channels
 298         = i_original_channels & AOUT_CHAN_PHYSMASK;
 299
 300     i_frame_length = (p_block->i_buffer - LPCM_HEADER_LEN) /
 301         p_dec->fmt_out.audio.i_channels * 8 / i_bitspersample;
 302
 303     if( p_sys->b_packetizer )
 304     {
 305         p_dec->fmt_out.i_codec = VLC_FOURCC('l','p','c','m');
 306         p_block->i_pts = p_block->i_dts = aout_DateGet( &p_sys->end_date );
 307         p_block->i_length =
 308             aout_DateIncrement( &p_sys->end_date, i_frame_length ) -
 309             p_block->i_pts;
 310
 311         /* Just pass on the incoming frame */
 312         return p_block;
 313     }
 314     else
 315     {
 316         aout_buffer_t *p_aout_buffer;
 317         p_aout_buffer = p_dec->pf_aout_buffer_new( p_dec, i_frame_length );
 318         if( p_aout_buffer == NULL ) return NULL;
 319
 320         p_aout_buffer->start_date = aout_DateGet( &p_sys->end_date );
 321         p_aout_buffer->end_date =
 322             aout_DateIncrement( &p_sys->end_date, i_frame_length );
 323
 324         p_block->p_buffer += LPCM_HEADER_LEN;
 325         p_block->i_buffer -= LPCM_HEADER_LEN;
 326
 327         /* 20/24 bits LPCM use special packing */
 328         if( i_bitspersample == 24 )
 329         {
 330             uint8_t *p_out = p_aout_buffer->p_buffer;
 331
 332             while( p_block->i_buffer / 12 )
 333             {
 334                 /* Sample 1 */
 335                 p_out[0] = p_block->p_buffer[0];
 336                 p_out[1] = p_block->p_buffer[1];
 337                 p_out[2] = p_block->p_buffer[8];
 338                 /* Sample 2 */
 339                 p_out[3] = p_block->p_buffer[2];
 340                 p_out[4] = p_block->p_buffer[3];
 341                 p_out[5] = p_block->p_buffer[9];
 342                 /* Sample 3 */
 343                 p_out[6] = p_block->p_buffer[4];
 344                 p_out[7] = p_block->p_buffer[5];
 345                 p_out[8] = p_block->p_buffer[10];
 346                 /* Sample 4 */
 347                 p_out[9] = p_block->p_buffer[6];
 348                 p_out[10] = p_block->p_buffer[7];
 349                 p_out[11] = p_block->p_buffer[11];
 350
 351                 p_block->i_buffer -= 12;
 352                 p_block->p_buffer += 12;
 353                 p_out += 12;
 354             }
 355         }
 356         else if( i_bitspersample == 20 )
 357         {
 358             uint8_t *p_out = p_aout_buffer->p_buffer;
 359
 360             while( p_block->i_buffer / 10 )
 361             {
 362                 /* Sample 1 */
 363                 p_out[0] = p_block->p_buffer[0];
 364                 p_out[1] = p_block->p_buffer[1];
 365                 p_out[2] = p_block->p_buffer[8] & 0xF0;
 366                 /* Sample 2 */
 367                 p_out[3] = p_block->p_buffer[2];
 368                 p_out[4] = p_block->p_buffer[3];
 369                 p_out[5] = p_block->p_buffer[8] << 4;
 370                 /* Sample 3 */
 371                 p_out[6] = p_block->p_buffer[4];
 372                 p_out[7] = p_block->p_buffer[5];
 373                 p_out[8] = p_block->p_buffer[9] & 0xF0;
 374                 /* Sample 4 */
 375                 p_out[9] = p_block->p_buffer[6];
 376                 p_out[10] = p_block->p_buffer[7];
 377                 p_out[11] = p_block->p_buffer[9] << 4;
 378
 379                 p_block->i_buffer -= 10;
 380                 p_block->p_buffer += 10;
 381                 p_out += 12;
 382             }
 383         }
 384         else
 385         {
 386             memcpy( p_aout_buffer->p_buffer,
 387                     p_block->p_buffer, p_block->i_buffer );
 388         }
 389
 390         block_Release( p_block );
 391         return p_aout_buffer;
 392     }
 393 }
 394
 395 /*****************************************************************************
 396  * CloseDecoder : lpcm decoder destruction
 397  *****************************************************************************/
 398 static void CloseDecoder( vlc_object_t *p_this )
 399 {
 400     decoder_t *p_dec = (decoder_t*)p_this;
 401     free( p_dec->p_sys );
 402 }