modules/codec/opus.c

   1 /*****************************************************************************
   2  * opus.c: opus decoder/encoder module making use of libopus.
   3  *****************************************************************************
   4  * Copyright (C) 2003-2009, 2012 VLC authors and VideoLAN
   5  *
   6  * Authors: Gregory Maxwell <greg@xiph.org>
   7  * Based on speex.c by: Gildas Bazin <gbazin@videolan.org>
   8  *
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU Lesser General Public License as published by
  11  * the Free Software Foundation; either version 2.1 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  17  * GNU Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public License
  20  * along with this program; if not, write to the Free Software Foundation,
  21  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  22  *****************************************************************************/
  23
  24 /*****************************************************************************
  25  * Preamble
  26  *****************************************************************************/
  27 #ifdef HAVE_CONFIG_H
  28 # include "config.h"
  29 #endif
  30
  31 #include <vlc_common.h>
  32 #include <vlc_plugin.h>
  33 #include <vlc_input.h>
  34 #include <vlc_codec.h>
  35 #include <vlc_aout.h>
  36 #include "../demux/xiph.h"
  37
  38 #include <ogg/ogg.h>
  39 #include <opus.h>
  40 #include <opus_multistream.h>
  41
  42 #include "opus_header.h"
  43
  44 #ifndef OPUS_SET_GAIN
  45 #include <math.h>
  46 #endif
  47
  48 /*****************************************************************************
  49  * Module descriptor
  50  *****************************************************************************/
  51 static int  OpenDecoder   ( vlc_object_t * );
  52 static void CloseDecoder  ( vlc_object_t * );
  53 #ifdef ENABLE_SOUT
  54 static int  OpenEncoder   ( vlc_object_t * );
  55 static void CloseEncoder  ( vlc_object_t * );
  56 #endif
  57
  58 vlc_module_begin ()
  59     set_category( CAT_INPUT )
  60     set_subcategory( SUBCAT_INPUT_ACODEC )
  61
  62     set_description( N_("Opus audio decoder") )
  63     set_capability( "audio decoder", 100 )
  64     set_shortname( N_("Opus") )
  65     set_callbacks( OpenDecoder, CloseDecoder )
  66
  67 #ifdef ENABLE_SOUT
  68     add_submodule ()
  69     set_description( N_("Opus audio encoder") )
  70     set_capability( "encoder", 150 )
  71     set_shortname( N_("Opus") )
  72     set_callbacks( OpenEncoder, CloseEncoder )
  73 #endif
  74
  75 vlc_module_end ()
  76
  77 /*****************************************************************************
  78  * decoder_sys_t : opus decoder descriptor
  79  *****************************************************************************/
  80 struct decoder_sys_t
  81 {
  82     /*
  83      * Input properties
  84      */
  85     bool b_has_headers;
  86
  87     /*
  88      * Opus properties
  89      */
  90     OpusHeader header;
  91     OpusMSDecoder *p_st;
  92
  93     /*
  94      * Common properties
  95      */
  96     date_t end_date;
  97 };
  98
  99 static const int pi_channels_maps[9] =
 100 {
 101     0,
 102     AOUT_CHAN_CENTER,
 103     AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT,
 104     AOUT_CHAN_CENTER | AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT,
 105     AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_REARLEFT
 106      | AOUT_CHAN_REARRIGHT,
 107     AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
 108      | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT,
 109     AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
 110      | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT | AOUT_CHAN_LFE,
 111     AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
 112      | AOUT_CHAN_REARCENTER | AOUT_CHAN_MIDDLELEFT
 113      | AOUT_CHAN_MIDDLERIGHT | AOUT_CHAN_LFE,
 114     AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER | AOUT_CHAN_REARLEFT
 115      | AOUT_CHAN_REARRIGHT | AOUT_CHAN_MIDDLELEFT | AOUT_CHAN_MIDDLERIGHT
 116      | AOUT_CHAN_LFE,
 117 };
 118
 119 /*
 120 **  channel order as defined in http://www.xiph.org/vorbis/doc/Vorbis_I_spec.html#x1-800004.3.9
 121 */
 122
 123 /* recommended vorbis channel order for 8 channels */
 124 static const uint32_t pi_8channels_in[] =
 125 { AOUT_CHAN_LEFT, AOUT_CHAN_CENTER, AOUT_CHAN_RIGHT,
 126   AOUT_CHAN_MIDDLELEFT, AOUT_CHAN_MIDDLERIGHT,
 127   AOUT_CHAN_REARLEFT, AOUT_CHAN_REARRIGHT,AOUT_CHAN_LFE, 0 };
 128
 129 /* recommended vorbis channel order for 7 channels */
 130 static const uint32_t pi_7channels_in[] =
 131 { AOUT_CHAN_LEFT, AOUT_CHAN_CENTER, AOUT_CHAN_RIGHT,
 132   AOUT_CHAN_MIDDLELEFT, AOUT_CHAN_MIDDLERIGHT,
 133   AOUT_CHAN_REARCENTER, AOUT_CHAN_LFE, 0 };
 134
 135 /* recommended vorbis channel order for 6 channels */
 136 static const uint32_t pi_6channels_in[] =
 137 { AOUT_CHAN_LEFT, AOUT_CHAN_CENTER, AOUT_CHAN_RIGHT,
 138   AOUT_CHAN_REARLEFT, AOUT_CHAN_REARRIGHT, AOUT_CHAN_LFE, 0 };
 139
 140 /* recommended vorbis channel order for 5 channels */
 141 static const uint32_t pi_5channels_in[] =
 142 { AOUT_CHAN_LEFT, AOUT_CHAN_CENTER, AOUT_CHAN_RIGHT,
 143   AOUT_CHAN_REARLEFT, AOUT_CHAN_REARRIGHT, 0 };
 144
 145 /* recommended vorbis channel order for 4 channels */
 146 static const uint32_t pi_4channels_in[] =
 147 { AOUT_CHAN_LEFT, AOUT_CHAN_RIGHT, AOUT_CHAN_REARLEFT, AOUT_CHAN_REARRIGHT, 0 };
 148
 149 /* recommended vorbis channel order for 3 channels */
 150 static const uint32_t pi_3channels_in[] =
 151 { AOUT_CHAN_LEFT, AOUT_CHAN_CENTER, AOUT_CHAN_RIGHT, 0 };
 152
 153 /****************************************************************************
 154  * Local prototypes
 155  ****************************************************************************/
 156
 157 static block_t *Packetize ( decoder_t *, block_t ** );
 158 static int  DecodeAudio ( decoder_t *, block_t * );
 159 static void Flush( decoder_t * );
 160 static int  ProcessHeaders( decoder_t * );
 161 static int  ProcessInitialHeader ( decoder_t *, ogg_packet * );
 162 static block_t *ProcessPacket( decoder_t *, ogg_packet *, block_t * );
 163
 164 static block_t *DecodePacket( decoder_t *, ogg_packet *, int, int );
 165
 166 /*****************************************************************************
 167  * OpenDecoder: probe the decoder and return score
 168  *****************************************************************************/
 169 static int OpenDecoder( vlc_object_t *p_this )
 170 {
 171     decoder_t *p_dec = (decoder_t*)p_this;
 172     decoder_sys_t *p_sys;
 173
 174     if( p_dec->fmt_in.i_codec != VLC_CODEC_OPUS )
 175         return VLC_EGENERIC;
 176
 177     /* Allocate the memory needed to store the decoder's structure */
 178     if( ( p_dec->p_sys = p_sys = malloc(sizeof(decoder_sys_t)) ) == NULL )
 179         return VLC_ENOMEM;
 180     p_dec->p_sys->b_has_headers = false;
 181
 182     date_Set( &p_sys->end_date, 0 );
 183
 184     /* Set output properties */
 185     p_dec->fmt_out.i_codec = VLC_CODEC_FL32;
 186
 187     p_dec->pf_decode    = DecodeAudio;
 188     p_dec->pf_packetize = Packetize;
 189     p_dec->pf_flush     = Flush;
 190
 191     p_sys->p_st = NULL;
 192
 193     return VLC_SUCCESS;
 194 }
 195
 196 /****************************************************************************
 197  * DecodeBlock: the whole thing
 198  ****************************************************************************
 199  * This function must be fed with ogg packets.
 200  ****************************************************************************/
 201 static block_t *DecodeBlock( decoder_t *p_dec, block_t *p_block )
 202 {
 203     decoder_sys_t *p_sys = p_dec->p_sys;
 204     ogg_packet oggpacket;
 205
 206     /* Block to Ogg packet */
 207     oggpacket.packet = p_block->p_buffer;
 208     oggpacket.bytes = p_block->i_buffer;
 209
 210     oggpacket.granulepos = -1;
 211     oggpacket.b_o_s = 0;
 212     oggpacket.e_o_s = 0;
 213     oggpacket.packetno = 0;
 214
 215     /* Check for headers */
 216     if( !p_sys->b_has_headers )
 217     {
 218         if( ProcessHeaders( p_dec ) )
 219         {
 220             block_Release( p_block );
 221             return NULL;
 222         }
 223         p_sys->b_has_headers = true;
 224     }
 225
 226     return ProcessPacket( p_dec, &oggpacket, p_block );
 227 }
 228
 229 static int DecodeAudio( decoder_t *p_dec, block_t *p_block )
 230 {
 231     if( p_block == NULL ) /* No Drain */
 232         return VLCDEC_SUCCESS;
 233
 234     p_block = DecodeBlock( p_dec, p_block );
 235     if( p_block != NULL )
 236         decoder_QueueAudio( p_dec, p_block );
 237     return VLCDEC_SUCCESS;
 238 }
 239
 240 static block_t *Packetize( decoder_t *p_dec, block_t **pp_block )
 241 {
 242     if( pp_block == NULL ) /* No Drain */
 243         return NULL;
 244     block_t *p_block = *pp_block; *pp_block = NULL;
 245     if( p_block == NULL )
 246         return NULL;
 247     return DecodeBlock( p_dec, p_block );
 248 }
 249
 250 /*****************************************************************************
 251  * ProcessHeaders: process Opus headers.
 252  *****************************************************************************/
 253 static int ProcessHeaders( decoder_t *p_dec )
 254 {
 255     ogg_packet oggpacket;
 256
 257     unsigned pi_size[XIPH_MAX_HEADER_COUNT];
 258     void     *pp_data[XIPH_MAX_HEADER_COUNT];
 259     unsigned i_count;
 260
 261     int i_extra = p_dec->fmt_in.i_extra;
 262     uint8_t *p_extra = p_dec->fmt_in.p_extra;
 263
 264     /* If we have no header (e.g. from RTP), make one. */
 265     bool b_dummy_header = false;
 266     if( !i_extra ||
 267         (i_extra > 10 && memcmp( &p_extra[2], "OpusHead", 8 )) ) /* Borked muxers */
 268     {
 269         OpusHeader header;
 270         opus_prepare_header( p_dec->fmt_in.audio.i_channels,
 271                              p_dec->fmt_in.audio.i_rate, &header );
 272         if( opus_write_header( &p_extra, &i_extra, &header,
 273                                opus_get_version_string() ) )
 274             return VLC_ENOMEM;
 275         b_dummy_header = true;
 276     }
 277
 278     if( xiph_SplitHeaders( pi_size, pp_data, &i_count,
 279                            i_extra, p_extra ) )
 280     {
 281         if( b_dummy_header )
 282             free( p_extra );
 283         return VLC_EGENERIC;
 284     }
 285
 286     if( i_count < 2 )
 287     {
 288         if( b_dummy_header )
 289             free( p_extra );
 290         return VLC_EGENERIC;
 291     }
 292
 293     oggpacket.granulepos = -1;
 294     oggpacket.e_o_s = 0;
 295     oggpacket.packetno = 0;
 296
 297     /* Take care of the initial Opus header */
 298     oggpacket.b_o_s = 1; /* yes this actually is a b_o_s packet :) */
 299     oggpacket.bytes  = pi_size[0];
 300     oggpacket.packet = pp_data[0];
 301     int ret = ProcessInitialHeader( p_dec, &oggpacket );
 302
 303     if (ret != VLC_SUCCESS)
 304         msg_Err( p_dec, "initial Opus header is corrupted" );
 305
 306     if( b_dummy_header )
 307         free( p_extra );
 308
 309     return ret;
 310 }
 311
 312 /*****************************************************************************
 313  * ProcessInitialHeader: processes the inital Opus header packet.
 314  *****************************************************************************/
 315 static int ProcessInitialHeader( decoder_t *p_dec, ogg_packet *p_oggpacket )
 316 {
 317     int err;
 318     unsigned char new_stream_map[8];
 319     decoder_sys_t *p_sys = p_dec->p_sys;
 320
 321     OpusHeader *p_header = &p_sys->header;
 322
 323     if( !opus_header_parse((unsigned char *)p_oggpacket->packet,p_oggpacket->bytes,p_header) )
 324     {
 325         msg_Err( p_dec, "cannot read Opus header" );
 326         return VLC_EGENERIC;
 327     }
 328     msg_Dbg( p_dec, "Opus audio with %d channels", p_header->channels);
 329
 330     if((p_header->channels>2 && p_header->channel_mapping==0) ||
 331         p_header->channels>8 ||
 332         p_header->channel_mapping>1)
 333     {
 334         msg_Err( p_dec, "Unsupported channel mapping" );
 335         return VLC_EGENERIC;
 336     }
 337
 338     /* Setup the format */
 339     p_dec->fmt_out.audio.i_physical_channels =
 340         pi_channels_maps[p_header->channels];
 341     p_dec->fmt_out.audio.i_channels = p_header->channels;
 342     p_dec->fmt_out.audio.i_rate = 48000;
 343
 344     if( p_header->channels>2 )
 345     {
 346         static const uint32_t *pi_ch[6] = { pi_3channels_in, pi_4channels_in,
 347                                             pi_5channels_in, pi_6channels_in,
 348                                             pi_7channels_in, pi_8channels_in };
 349         uint8_t pi_chan_table[AOUT_CHAN_MAX];
 350
 351         aout_CheckChannelReorder( pi_ch[p_header->channels-3], NULL,
 352                                   p_dec->fmt_out.audio.i_physical_channels,
 353                                   pi_chan_table );
 354         for(int i=0;i<p_header->channels;i++)
 355             new_stream_map[pi_chan_table[i]]=p_header->stream_map[i];
 356     }
 357     /* Opus decoder init */
 358     p_sys->p_st = opus_multistream_decoder_create( 48000, p_header->channels,
 359                     p_header->nb_streams, p_header->nb_coupled,
 360                     p_header->channels>2?new_stream_map:p_header->stream_map,
 361                     &err );
 362     if( !p_sys->p_st || err!=OPUS_OK )
 363     {
 364         msg_Err( p_dec, "decoder initialization failed" );
 365         return VLC_EGENERIC;
 366     }
 367
 368 #ifdef OPUS_SET_GAIN
 369     if( opus_multistream_decoder_ctl( p_sys->p_st,OPUS_SET_GAIN(p_header->gain) ) != OPUS_OK )
 370     {
 371         msg_Err( p_dec, "OPUS_SET_GAIN failed" );
 372         opus_multistream_decoder_destroy( p_sys->p_st );
 373         return VLC_EGENERIC;
 374     }
 375 #endif
 376
 377     date_Init( &p_sys->end_date, 48000, 1 );
 378
 379     return VLC_SUCCESS;
 380 }
 381
 382 /*****************************************************************************
 383  * Flush:
 384  *****************************************************************************/
 385 static void Flush( decoder_t *p_dec )
 386 {
 387     decoder_sys_t *p_sys = p_dec->p_sys;
 388
 389     date_Set( &p_sys->end_date, 0 );
 390 }
 391
 392 /*****************************************************************************
 393  * ProcessPacket: processes a Opus packet.
 394  *****************************************************************************/
 395 static block_t *ProcessPacket( decoder_t *p_dec, ogg_packet *p_oggpacket,
 396                                block_t *p_block )
 397 {
 398     decoder_sys_t *p_sys = p_dec->p_sys;
 399
 400     if( p_block->i_flags & (BLOCK_FLAG_CORRUPTED|BLOCK_FLAG_DISCONTINUITY) )
 401     {
 402         Flush( p_dec );
 403         if( p_block->i_flags & BLOCK_FLAG_CORRUPTED )
 404         {
 405             block_Release( p_block );
 406             return NULL;
 407         }
 408     }
 409
 410     /* Date management */
 411     if( p_block->i_pts > VLC_TS_INVALID &&
 412         p_block->i_pts != date_Get( &p_sys->end_date ) )
 413     {
 414         date_Set( &p_sys->end_date, p_block->i_pts );
 415     }
 416
 417     if( !date_Get( &p_sys->end_date ) )
 418     {
 419         /* We've just started the stream, wait for the first PTS. */
 420         block_Release( p_block );
 421         return NULL;
 422     }
 423
 424     block_t *p_aout_buffer = DecodePacket( p_dec, p_oggpacket,
 425                                            p_block->i_nb_samples,
 426                                            (int)p_block->i_length );
 427
 428     block_Release( p_block );
 429     return p_aout_buffer;
 430 }
 431
 432 /*****************************************************************************
 433  * DecodePacket: decodes a Opus packet.
 434  *****************************************************************************/
 435 static block_t *DecodePacket( decoder_t *p_dec, ogg_packet *p_oggpacket,
 436                               int i_nb_samples, int i_end_trim )
 437 {
 438     decoder_sys_t *p_sys = p_dec->p_sys;
 439
 440     if( !p_oggpacket->bytes )
 441         return NULL;
 442
 443     int spp;
 444     spp=opus_packet_get_nb_frames(p_oggpacket->packet,p_oggpacket->bytes);
 445     if(spp>0)spp*=opus_packet_get_samples_per_frame(p_oggpacket->packet,48000);
 446     if(spp<120||spp>120*48)return NULL;
 447
 448     /* Since the information isn't always available at the demux level
 449      * use the packet's sample number */
 450     if(!i_nb_samples)
 451         i_nb_samples = spp;
 452
 453     if( decoder_UpdateAudioFormat( p_dec ) )
 454         return NULL;
 455     block_t *p_aout_buffer=decoder_NewAudioBuffer( p_dec, spp );
 456     if ( !p_aout_buffer )
 457     {
 458         msg_Err(p_dec, "Oops: No new buffer was returned!");
 459         return NULL;
 460     }
 461
 462     spp=opus_multistream_decode_float(p_sys->p_st, p_oggpacket->packet,
 463          p_oggpacket->bytes, (float *)p_aout_buffer->p_buffer, spp, 0);
 464     if( spp < 0 || i_nb_samples <= 0 || i_end_trim >= i_nb_samples)
 465     {
 466         block_Release(p_aout_buffer);
 467         if( spp < 0 )
 468             msg_Err( p_dec, "Error: corrupted stream?" );
 469         return NULL;
 470     }
 471
 472     p_aout_buffer->i_buffer = (i_nb_samples - i_end_trim) *
 473                               p_sys->header.channels * sizeof(float);
 474
 475     if( spp > i_nb_samples )
 476     {
 477         memmove(p_aout_buffer->p_buffer,
 478             p_aout_buffer->p_buffer
 479             + (spp - i_nb_samples)*p_sys->header.channels*sizeof(float),
 480             p_aout_buffer->i_buffer);
 481     }
 482     i_nb_samples -= i_end_trim;
 483
 484 #ifndef OPUS_SET_GAIN
 485     if(p_sys->header.gain!=0)
 486     {
 487         float gain = pow(10., p_sys->header.gain/5120.);
 488         float *buf =(float *)p_aout_buffer->p_buffer;
 489         for( int i = 0; i < i_nb_samples*p_sys->header.channels; i++)
 490             buf[i] *= gain;
 491     }
 492 #endif
 493     p_aout_buffer->i_nb_samples = i_nb_samples;
 494     p_aout_buffer->i_pts = date_Get( &p_sys->end_date );
 495     p_aout_buffer->i_length = date_Increment( &p_sys->end_date, i_nb_samples )
 496         - p_aout_buffer->i_pts;
 497     return p_aout_buffer;
 498 }
 499
 500 /*****************************************************************************
 501  * CloseDecoder: Opus decoder destruction
 502  *****************************************************************************/
 503 static void CloseDecoder( vlc_object_t *p_this )
 504 {
 505     decoder_t * p_dec = (decoder_t *)p_this;
 506     decoder_sys_t *p_sys = p_dec->p_sys;
 507
 508     if( p_sys->p_st ) opus_multistream_decoder_destroy(p_sys->p_st);
 509
 510     free( p_sys );
 511 }
 512
 513 #ifdef ENABLE_SOUT
 514
 515 /* only ever encode 20 ms at a time, going longer doesn't yield much compression
 516    gain, shorter does have a compression loss, and doesn't matter so much in
 517    Ogg, unless you really need low latency, which would also require muxing one
 518    packet per page. */
 519 static const unsigned OPUS_FRAME_SIZE = 960; /* 48000 * 20 / 1000 */
 520
 521 struct encoder_sys_t
 522 {
 523     OpusMSEncoder *enc;
 524     float *buffer;
 525     unsigned i_nb_samples;
 526     int i_samples_delay;
 527     block_t *padding;
 528     int nb_streams;
 529 };
 530
 531 static unsigned fill_buffer(encoder_t *enc, unsigned src_start, block_t *src,
 532                             unsigned samples)
 533 {
 534     encoder_sys_t *p_sys = enc->p_sys;
 535     const unsigned channels = enc->fmt_out.audio.i_channels;
 536     const float *src_buf = ((const float *) src->p_buffer) + src_start;
 537     float *dest_buf = p_sys->buffer + (p_sys->i_nb_samples * channels);
 538     const unsigned len = samples * channels;
 539
 540     memcpy(dest_buf, src_buf, len * sizeof(float));
 541
 542     p_sys->i_nb_samples += samples;
 543     src_start += len;
 544
 545     src->i_nb_samples -= samples;
 546     return src_start;
 547 }
 548
 549 static block_t *Encode(encoder_t *enc, block_t *buf)
 550 {
 551     encoder_sys_t *sys = enc->p_sys;
 552
 553     if (!buf)
 554         return NULL;
 555
 556     mtime_t i_pts = buf->i_pts -
 557                 (mtime_t) CLOCK_FREQ * (mtime_t) sys->i_samples_delay /
 558                 (mtime_t) enc->fmt_in.audio.i_rate;
 559
 560     sys->i_samples_delay += buf->i_nb_samples;
 561
 562     block_t *result = NULL;
 563     unsigned src_start = 0;
 564     unsigned padding_start = 0;
 565     /* The maximum Opus frame size is 1275 bytes + TOC sequence length. */
 566     const unsigned OPUS_MAX_ENCODED_BYTES = ((1275 + 3) * sys->nb_streams) - 2;
 567
 568     while (sys->i_nb_samples + buf->i_nb_samples >= OPUS_FRAME_SIZE)
 569     {
 570         block_t *out_block = block_Alloc(OPUS_MAX_ENCODED_BYTES);
 571
 572         /* add padding to beginning */
 573         if (sys->padding)
 574         {
 575             const size_t leftover_space = OPUS_FRAME_SIZE - sys->i_nb_samples;
 576             padding_start = fill_buffer(enc, padding_start, sys->padding,
 577                     __MIN(sys->padding->i_nb_samples, leftover_space));
 578             if (sys->padding->i_nb_samples <= 0)
 579             {
 580                 block_Release(sys->padding);
 581                 sys->padding = NULL;
 582             }
 583         }
 584
 585         /* padding may have been freed either before or inside previous
 586          * if-statement */
 587         if (!sys->padding)
 588         {
 589             const size_t leftover_space = OPUS_FRAME_SIZE - sys->i_nb_samples;
 590             src_start = fill_buffer(enc, src_start, buf,
 591                     __MIN(buf->i_nb_samples, leftover_space));
 592         }
 593
 594         opus_int32 bytes_encoded = opus_multistream_encode_float(sys->enc, sys->buffer,
 595                 OPUS_FRAME_SIZE, out_block->p_buffer, out_block->i_buffer);
 596
 597         if (bytes_encoded < 0)
 598         {
 599             block_Release(out_block);
 600         }
 601         else
 602         {
 603             out_block->i_length = (mtime_t) CLOCK_FREQ *
 604                 (mtime_t) OPUS_FRAME_SIZE / (mtime_t) enc->fmt_in.audio.i_rate;
 605
 606             out_block->i_dts = out_block->i_pts = i_pts;
 607
 608             sys->i_samples_delay -= OPUS_FRAME_SIZE;
 609
 610             i_pts += out_block->i_length;
 611
 612             sys->i_nb_samples = 0;
 613
 614             out_block->i_buffer = bytes_encoded;
 615             block_ChainAppend(&result, out_block);
 616         }
 617     }
 618
 619     /* put leftover samples at beginning of buffer */
 620     if (buf->i_nb_samples > 0)
 621         fill_buffer(enc, src_start, buf, buf->i_nb_samples);
 622
 623     return result;
 624 }
 625
 626 static int OpenEncoder(vlc_object_t *p_this)
 627 {
 628     encoder_t *enc = (encoder_t *)p_this;
 629
 630     if (enc->fmt_out.i_codec != VLC_CODEC_OPUS)
 631         return VLC_EGENERIC;
 632
 633     encoder_sys_t *sys = malloc(sizeof(*sys));
 634     if (!sys)
 635         return VLC_ENOMEM;
 636
 637     int status = VLC_SUCCESS;
 638     sys->buffer = NULL;
 639     sys->enc = NULL;
 640
 641     enc->pf_encode_audio = Encode;
 642     enc->fmt_in.i_codec = VLC_CODEC_FL32;
 643     enc->fmt_in.audio.i_rate = /* Only 48kHz */
 644     enc->fmt_out.audio.i_rate = 48000;
 645     enc->fmt_out.audio.i_channels = enc->fmt_in.audio.i_channels;
 646
 647     OpusHeader header;
 648
 649     opus_prepare_header(enc->fmt_out.audio.i_channels,
 650             enc->fmt_out.audio.i_rate, &header);
 651
 652     /* needed for max encoded size calculation */
 653     sys->nb_streams = header.nb_streams;
 654
 655     int err;
 656     sys->enc =
 657         opus_multistream_surround_encoder_create(enc->fmt_in.audio.i_rate,
 658                 enc->fmt_in.audio.i_channels, header.channel_mapping,
 659                 &header.nb_streams, &header.nb_coupled, header.stream_map,
 660                 OPUS_APPLICATION_AUDIO, &err);
 661
 662     if (err != OPUS_OK)
 663     {
 664         msg_Err(enc, "Could not create encoder: error %d", err);
 665         sys->enc = NULL;
 666         status = VLC_EGENERIC;
 667         goto error;
 668     }
 669
 670     /* TODO: vbr, fec */
 671
 672     if( enc->fmt_out.i_bitrate )
 673         opus_multistream_encoder_ctl(sys->enc, OPUS_SET_BITRATE( enc->fmt_out.i_bitrate ));
 674
 675     /* Buffer for incoming audio, since opus only accepts frame sizes that are
 676        multiples of 2.5ms */
 677     enc->p_sys = sys;
 678     sys->buffer = vlc_alloc(header.channels, sizeof(float) * OPUS_FRAME_SIZE);
 679     if (!sys->buffer) {
 680         status = VLC_ENOMEM;
 681         goto error;
 682     }
 683
 684     sys->i_nb_samples = 0;
 685
 686     sys->i_samples_delay = 0;
 687     int ret = opus_multistream_encoder_ctl(enc->p_sys->enc,
 688             OPUS_GET_LOOKAHEAD(&sys->i_samples_delay));
 689     if (ret != OPUS_OK)
 690         msg_Err(enc, "Unable to get number of lookahead samples: %s\n",
 691                 opus_strerror(ret));
 692
 693     header.preskip = sys->i_samples_delay;
 694
 695     /* Now that we have preskip, we can write the header to extradata */
 696     if (opus_write_header((uint8_t **) &enc->fmt_out.p_extra,
 697                           &enc->fmt_out.i_extra, &header, opus_get_version_string()))
 698     {
 699         msg_Err(enc, "Failed to write header.");
 700         status = VLC_ENOMEM;
 701         goto error;
 702     }
 703
 704     if (sys->i_samples_delay > 0)
 705     {
 706         const unsigned padding_samples = sys->i_samples_delay *
 707             enc->fmt_out.audio.i_channels;
 708         sys->padding = block_Alloc(padding_samples * sizeof(float));
 709         if (!sys->padding) {
 710             status = VLC_ENOMEM;
 711             goto error;
 712         }
 713         sys->padding->i_nb_samples = sys->i_samples_delay;
 714         float *pad_ptr = (float *) sys->padding->p_buffer;
 715         memset(pad_ptr, 0, padding_samples * sizeof(float));
 716     }
 717     else
 718     {
 719         sys->padding = NULL;
 720     }
 721
 722     return status;
 723
 724 error:
 725     if (sys->enc)
 726         opus_multistream_encoder_destroy(sys->enc);
 727     free(sys->buffer);
 728     free(sys);
 729     return status;
 730 }
 731
 732 static void CloseEncoder(vlc_object_t *p_this)
 733 {
 734     encoder_t *enc = (encoder_t *)p_this;
 735     encoder_sys_t *sys = enc->p_sys;
 736
 737     opus_multistream_encoder_destroy(sys->enc);
 738     if (sys->padding)
 739         block_Release(sys->padding);
 740     free(sys->buffer);
 741     free(sys);
 742 }
 743 #endif /* ENABLE_SOUT */