1 /*****************************************************************************
2 * mpeg_audio.c: parse MPEG audio sync info and packetize the stream
3 *****************************************************************************
4 * Copyright (C) 2001-2003 VLC authors and VideoLAN
7 * Authors: Laurent Aimar <fenrir@via.ecp.fr>
8 * Eric Petit <titer@videolan.org>
9 * Christophe Massiot <massiot@via.ecp.fr>
10 * Gildas Bazin <gbazin@videolan.org>
12 * This program is free software; you can redistribute it and/or modify it
13 * under the terms of the GNU Lesser General Public License as published by
14 * the Free Software Foundation; either version 2.1 of the License, or
15 * (at your option) any later version.
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 Lesser General Public License for more details.
22 * You should have received a copy of the GNU Lesser General Public License
23 * along with this program; if not, write to the Free Software Foundation,
24 * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
25 *****************************************************************************/
27 /*****************************************************************************
29 *****************************************************************************/
34 #include <vlc_common.h>
35 #include <vlc_plugin.h>
36 #include <vlc_codec.h>
38 #include <vlc_modules.h>
41 #include <vlc_block_helper.h>
43 #include "../packetizer/packetizer_helper.h"
45 /*****************************************************************************
46 * decoder_sys_t : decoder descriptor
47 *****************************************************************************/
58 block_bytestream_t bytestream;
64 unsigned int i_current_layer;
68 int i_frame_size, i_free_frame_size;
69 unsigned int i_channels_conf, i_channels;
70 unsigned int i_rate, i_max_frame_size, i_frame_length;
71 unsigned int i_layer, i_bit_rate;
76 /* This isn't the place to put mad-specific stuff. However, it makes the
77 * mad plug-in's life much easier if we put 8 extra bytes at the end of the
78 * buffer, because that way it doesn't have to copy the block_t to a bigger
79 * buffer. This has no implication on other plug-ins, and we only lose 8 bytes
80 * per frame. --Meuuh */
81 #define MAD_BUFFER_GUARD 8
82 #define MPGA_HEADER_SIZE 4
84 /****************************************************************************
86 ****************************************************************************/
87 static int OpenDecoder ( vlc_object_t * );
88 static int OpenPacketizer( vlc_object_t * );
89 static void CloseDecoder ( vlc_object_t * );
90 static block_t *DecodeBlock ( decoder_t *, block_t ** );
92 static uint8_t *GetOutBuffer ( decoder_t *, block_t ** );
93 static block_t *GetAoutBuffer( decoder_t * );
94 static block_t *GetSoutBuffer( decoder_t * );
96 static int SyncInfo( uint32_t i_header, unsigned int * pi_channels,
97 unsigned int * pi_channels_conf,
98 unsigned int * pi_sample_rate, unsigned int * pi_bit_rate,
99 unsigned int * pi_frame_length,
100 unsigned int * pi_max_frame_size,
101 unsigned int * pi_layer );
103 /*****************************************************************************
105 *****************************************************************************/
107 set_description( N_("MPEG audio layer I/II/III decoder") )
108 set_category( CAT_INPUT )
109 set_subcategory( SUBCAT_INPUT_ACODEC )
110 set_capability( "decoder", 100 )
111 set_callbacks( OpenDecoder, CloseDecoder )
114 set_description( N_("MPEG audio layer I/II/III packetizer") )
115 set_capability( "packetizer", 10 )
116 set_callbacks( OpenPacketizer, CloseDecoder )
119 /*****************************************************************************
120 * Open: probe the decoder and return score
121 *****************************************************************************/
122 static int Open( vlc_object_t *p_this )
124 decoder_t *p_dec = (decoder_t*)p_this;
125 decoder_sys_t *p_sys;
127 if(( p_dec->fmt_in.i_codec != VLC_CODEC_MPGA ) &&
128 ( p_dec->fmt_in.i_codec != VLC_CODEC_MP3 ) )
133 /* Allocate the memory needed to store the decoder's structure */
134 if( ( p_dec->p_sys = p_sys =
135 (decoder_sys_t *)malloc(sizeof(decoder_sys_t)) ) == NULL )
139 p_sys->b_packetizer = false;
140 p_sys->i_state = STATE_NOSYNC;
141 date_Set( &p_sys->end_date, 0 );
142 block_BytestreamInit( &p_sys->bytestream );
143 p_sys->i_pts = VLC_TS_INVALID;
144 p_sys->b_discontinuity = false;
146 /* Set output properties */
147 p_dec->fmt_out.i_cat = AUDIO_ES;
148 p_dec->fmt_out.i_codec = VLC_CODEC_MPGA;
149 p_dec->fmt_out.audio.i_rate = 0; /* So end_date gets initialized */
152 p_dec->pf_decode_audio = DecodeBlock;
153 p_dec->pf_packetize = DecodeBlock;
155 /* Start with the minimum size for a free bitrate frame */
156 p_sys->i_free_frame_size = MPGA_HEADER_SIZE;
161 static int OpenDecoder( vlc_object_t *p_this )
163 /* HACK: Don't use this codec if we don't have an mpga audio filter */
164 if( !module_exists( "mpgatofixed32" ) )
167 return Open( p_this );
170 static int OpenPacketizer( vlc_object_t *p_this )
172 decoder_t *p_dec = (decoder_t*)p_this;
174 int i_ret = Open( p_this );
176 if( i_ret == VLC_SUCCESS ) p_dec->p_sys->b_packetizer = true;
181 /****************************************************************************
182 * DecodeBlock: the whole thing
183 ****************************************************************************
184 * This function is called just after the thread is launched.
185 ****************************************************************************/
186 static block_t *DecodeBlock( decoder_t *p_dec, block_t **pp_block )
188 decoder_sys_t *p_sys = p_dec->p_sys;
189 uint8_t p_header[MAD_BUFFER_GUARD];
192 block_t *p_out_buffer;
194 block_t *p_block = pp_block ? *pp_block : NULL;
197 if( p_block->i_flags&(BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) )
199 if( p_block->i_flags&BLOCK_FLAG_CORRUPTED )
201 p_sys->i_state = STATE_NOSYNC;
202 block_BytestreamEmpty( &p_sys->bytestream );
204 date_Set( &p_sys->end_date, 0 );
205 block_Release( p_block );
206 p_sys->b_discontinuity = true;
210 if( !date_Get( &p_sys->end_date ) && p_block->i_pts <= VLC_TS_INVALID )
212 /* We've just started the stream, wait for the first PTS. */
213 msg_Dbg( p_dec, "waiting for PTS" );
214 block_Release( p_block );
218 block_BytestreamPush( &p_sys->bytestream, p_block );
220 p_sys->i_state = STATE_SEND_DATA; /* return all the data we have left */
224 switch( p_sys->i_state )
228 while( block_PeekBytes( &p_sys->bytestream, p_header, 2 )
231 /* Look for sync word - should be 0xffe */
232 if( p_header[0] == 0xff && (p_header[1] & 0xe0) == 0xe0 )
234 p_sys->i_state = STATE_SYNC;
237 block_SkipByte( &p_sys->bytestream );
239 if( p_sys->i_state != STATE_SYNC )
241 block_BytestreamFlush( &p_sys->bytestream );
248 /* New frame, set the Presentation Time Stamp */
249 p_sys->i_pts = p_sys->bytestream.p_block->i_pts;
250 if( p_sys->i_pts > VLC_TS_INVALID &&
251 p_sys->i_pts != date_Get( &p_sys->end_date ) )
253 date_Set( &p_sys->end_date, p_sys->i_pts );
255 p_sys->i_state = STATE_HEADER;
258 /* Get MPGA frame header (MPGA_HEADER_SIZE bytes) */
259 if( block_PeekBytes( &p_sys->bytestream, p_header,
260 MPGA_HEADER_SIZE ) != VLC_SUCCESS )
266 /* Build frame header */
267 i_header = (p_header[0]<<24)|(p_header[1]<<16)|(p_header[2]<<8)
270 /* Check if frame is valid and get frame info */
271 p_sys->i_frame_size = SyncInfo( i_header,
273 &p_sys->i_channels_conf,
276 &p_sys->i_frame_length,
277 &p_sys->i_max_frame_size,
280 p_dec->fmt_in.i_profile = p_sys->i_layer;
282 if( p_sys->i_frame_size == -1 )
284 msg_Dbg( p_dec, "emulated startcode" );
285 block_SkipByte( &p_sys->bytestream );
286 p_sys->i_state = STATE_NOSYNC;
287 p_sys->b_discontinuity = true;
291 if( p_sys->i_bit_rate == 0 )
293 /* Free bitrate, but 99% emulated startcode :( */
294 if( p_dec->p_sys->i_free_frame_size == MPGA_HEADER_SIZE )
296 msg_Dbg( p_dec, "free bitrate mode");
298 /* The -1 below is to account for the frame padding */
299 p_sys->i_frame_size = p_sys->i_free_frame_size - 1;
302 p_sys->i_state = STATE_NEXT_SYNC;
304 case STATE_NEXT_SYNC:
305 /* TODO: If p_block == NULL, flush the buffer without checking the
308 /* Check if next expected frame contains the sync word */
309 if( block_PeekOffsetBytes( &p_sys->bytestream,
310 p_sys->i_frame_size, p_header,
311 MAD_BUFFER_GUARD ) != VLC_SUCCESS )
317 if( p_header[0] == 0xff && (p_header[1] & 0xe0) == 0xe0 )
319 /* Startcode is fine, let's try the header as an extra check */
320 int i_next_frame_size;
321 unsigned int i_next_channels, i_next_channels_conf;
322 unsigned int i_next_rate, i_next_bit_rate;
323 unsigned int i_next_frame_length, i_next_max_frame_size;
324 unsigned int i_next_layer;
326 /* Build frame header */
327 i_header = (p_header[0]<<24)|(p_header[1]<<16)|(p_header[2]<<8)
330 i_next_frame_size = SyncInfo( i_header,
332 &i_next_channels_conf,
335 &i_next_frame_length,
336 &i_next_max_frame_size,
339 /* Free bitrate only */
340 if( p_sys->i_bit_rate == 0 && i_next_frame_size == -1 )
342 if( (unsigned int)p_sys->i_frame_size >
343 p_sys->i_max_frame_size )
345 msg_Dbg( p_dec, "frame too big %d > %d "
346 "(emulated startcode ?)", p_sys->i_frame_size,
347 p_sys->i_max_frame_size );
348 block_SkipByte( &p_sys->bytestream );
349 p_sys->i_state = STATE_NOSYNC;
350 p_sys->i_free_frame_size = MPGA_HEADER_SIZE;
354 p_sys->i_frame_size++;
358 if( i_next_frame_size == -1 )
360 msg_Dbg( p_dec, "emulated startcode on next frame" );
361 block_SkipByte( &p_sys->bytestream );
362 p_sys->i_state = STATE_NOSYNC;
363 p_sys->b_discontinuity = true;
367 /* Check info is in sync with previous one */
368 if( i_next_channels_conf != p_sys->i_channels_conf ||
369 i_next_rate != p_sys->i_rate ||
370 i_next_layer != p_sys->i_layer ||
371 i_next_frame_length != p_sys->i_frame_length )
373 /* Free bitrate only */
374 if( p_sys->i_bit_rate == 0 )
376 p_sys->i_frame_size++;
380 msg_Dbg( p_dec, "parameters changed unexpectedly "
381 "(emulated startcode ?)" );
382 block_SkipByte( &p_sys->bytestream );
383 p_sys->i_state = STATE_NOSYNC;
387 /* Free bitrate only */
388 if( p_sys->i_bit_rate == 0 )
390 if( i_next_bit_rate != 0 )
392 p_sys->i_frame_size++;
400 /* Free bitrate only */
401 if( p_sys->i_bit_rate == 0 )
403 if( (unsigned int)p_sys->i_frame_size >
404 p_sys->i_max_frame_size )
406 msg_Dbg( p_dec, "frame too big %d > %d "
407 "(emulated startcode ?)", p_sys->i_frame_size,
408 p_sys->i_max_frame_size );
409 block_SkipByte( &p_sys->bytestream );
410 p_sys->i_state = STATE_NOSYNC;
411 p_sys->i_free_frame_size = MPGA_HEADER_SIZE;
415 p_sys->i_frame_size++;
419 msg_Dbg( p_dec, "emulated startcode "
420 "(no startcode on following frame)" );
421 p_sys->i_state = STATE_NOSYNC;
422 block_SkipByte( &p_sys->bytestream );
426 p_sys->i_state = STATE_SEND_DATA;
430 /* Make sure we have enough data.
431 * (Not useful if we went through NEXT_SYNC) */
432 if( block_WaitBytes( &p_sys->bytestream,
433 p_sys->i_frame_size ) != VLC_SUCCESS )
438 p_sys->i_state = STATE_SEND_DATA;
440 case STATE_SEND_DATA:
441 if( !(p_buf = GetOutBuffer( p_dec, &p_out_buffer )) )
443 //p_dec->b_error = true;
447 /* Free bitrate only */
448 if( p_sys->i_bit_rate == 0 )
450 p_sys->i_free_frame_size = p_sys->i_frame_size;
453 /* Copy the whole frame into the buffer. */
454 if (block_GetBytes( &p_sys->bytestream,
455 p_buf, __MIN( (unsigned)p_sys->i_frame_size, p_out_buffer->i_buffer ) )) {
456 block_Release(p_out_buffer);
460 /* Get beginning of next frame for libmad */
461 if( !p_sys->b_packetizer )
463 assert( p_out_buffer->i_buffer >= (unsigned)p_sys->i_frame_size + MAD_BUFFER_GUARD );
464 memcpy( p_buf + p_sys->i_frame_size,
465 p_header, MAD_BUFFER_GUARD );
468 p_sys->i_state = STATE_NOSYNC;
470 /* Make sure we don't reuse the same pts twice */
471 if( p_sys->i_pts == p_sys->bytestream.p_block->i_pts )
472 p_sys->i_pts = p_sys->bytestream.p_block->i_pts = VLC_TS_INVALID;
474 /* So p_block doesn't get re-added several times */
475 p_block = block_BytestreamPop( &p_sys->bytestream );
479 block_Release(p_block);
488 /*****************************************************************************
490 *****************************************************************************/
491 static uint8_t *GetOutBuffer( decoder_t *p_dec, block_t **pp_out_buffer )
493 decoder_sys_t *p_sys = p_dec->p_sys;
496 if( p_dec->fmt_out.audio.i_rate != p_sys->i_rate )
498 msg_Dbg( p_dec, "MPGA channels:%d samplerate:%d bitrate:%d",
499 p_sys->i_channels, p_sys->i_rate, p_sys->i_bit_rate );
501 date_Init( &p_sys->end_date, p_sys->i_rate, 1 );
502 date_Set( &p_sys->end_date, p_sys->i_pts );
505 p_dec->fmt_out.audio.i_rate = p_sys->i_rate;
506 p_dec->fmt_out.audio.i_channels = p_sys->i_channels;
507 p_dec->fmt_out.audio.i_frame_length = p_sys->i_frame_length;
508 p_dec->fmt_out.audio.i_bytes_per_frame =
509 p_sys->i_max_frame_size + MAD_BUFFER_GUARD;
511 p_dec->fmt_out.audio.i_original_channels = p_sys->i_channels_conf;
512 p_dec->fmt_out.audio.i_physical_channels =
513 p_sys->i_channels_conf & AOUT_CHAN_PHYSMASK;
515 p_dec->fmt_out.i_bitrate = p_sys->i_bit_rate * 1000;
517 if( p_sys->b_packetizer )
519 block_t *p_sout_buffer = GetSoutBuffer( p_dec );
520 p_buf = p_sout_buffer ? p_sout_buffer->p_buffer : NULL;
521 *pp_out_buffer = p_sout_buffer;
525 block_t *p_aout_buffer = GetAoutBuffer( p_dec );
526 p_buf = p_aout_buffer ? p_aout_buffer->p_buffer : NULL;
527 *pp_out_buffer = p_aout_buffer;
533 /*****************************************************************************
535 *****************************************************************************/
536 static block_t *GetAoutBuffer( decoder_t *p_dec )
538 decoder_sys_t *p_sys = p_dec->p_sys;
541 p_buf = decoder_NewAudioBuffer( p_dec, p_sys->i_frame_length );
542 if( p_buf == NULL ) return NULL;
544 p_buf->i_pts = date_Get( &p_sys->end_date );
545 p_buf->i_length = date_Increment( &p_sys->end_date, p_sys->i_frame_length )
547 if( p_sys->b_discontinuity )
548 p_buf->i_flags |= BLOCK_FLAG_DISCONTINUITY;
549 p_sys->b_discontinuity = false;
551 /* Hack for libmad filter */
552 p_buf = block_Realloc( p_buf, 0, p_sys->i_frame_size + MAD_BUFFER_GUARD );
557 /*****************************************************************************
559 *****************************************************************************/
560 static block_t *GetSoutBuffer( decoder_t *p_dec )
562 decoder_sys_t *p_sys = p_dec->p_sys;
565 p_block = block_Alloc( p_sys->i_frame_size );
566 if( p_block == NULL ) return NULL;
568 p_block->i_pts = p_block->i_dts = date_Get( &p_sys->end_date );
571 date_Increment( &p_sys->end_date, p_sys->i_frame_length ) - p_block->i_pts;
576 /*****************************************************************************
577 * CloseDecoder: clean up the decoder
578 *****************************************************************************/
579 static void CloseDecoder( vlc_object_t *p_this )
581 decoder_t *p_dec = (decoder_t *)p_this;
582 decoder_sys_t *p_sys = p_dec->p_sys;
584 block_BytestreamRelease( &p_sys->bytestream );
589 /*****************************************************************************
590 * SyncInfo: parse MPEG audio sync info
591 *****************************************************************************/
592 static int SyncInfo( uint32_t i_header, unsigned int * pi_channels,
593 unsigned int * pi_channels_conf,
594 unsigned int * pi_sample_rate, unsigned int * pi_bit_rate,
595 unsigned int * pi_frame_length,
596 unsigned int * pi_max_frame_size, unsigned int * pi_layer)
598 static const int ppi_bitrate[2][3][16] =
602 { 0, 32, 64, 96, 128, 160, 192, 224, 256, 288, 320, 352, 384,
605 { 0, 32, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256,
608 { 0, 32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224,
614 { 0, 32, 48, 56, 64, 80, 96, 112, 128, 144, 160, 176, 192,
617 { 0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128,
620 { 0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128,
625 static const int ppi_samplerate[2][4] = /* version 1 then 2 */
627 { 44100, 48000, 32000, 0 },
628 { 22050, 24000, 16000, 0 }
631 int i_version, i_mode, i_emphasis;
632 bool b_padding, b_mpeg_2_5;
633 int i_frame_size = 0;
634 int i_bitrate_index, i_samplerate_index;
637 b_mpeg_2_5 = 1 - ((i_header & 0x100000) >> 20);
638 i_version = 1 - ((i_header & 0x80000) >> 19);
639 *pi_layer = 4 - ((i_header & 0x60000) >> 17);
640 //bool b_crc = !((i_header >> 16) & 0x01);
641 i_bitrate_index = (i_header & 0xf000) >> 12;
642 i_samplerate_index = (i_header & 0xc00) >> 10;
643 b_padding = (i_header & 0x200) >> 9;
645 i_mode = (i_header & 0xc0) >> 6;
646 /* Modeext, copyright & original */
647 i_emphasis = i_header & 0x3;
649 if( *pi_layer != 4 &&
650 i_bitrate_index < 0x0f &&
651 i_samplerate_index != 0x03 &&
657 case 1: /* joint stereo */
659 *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT;
661 case 2: /* dual-mono */
663 *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
664 | AOUT_CHAN_DUALMONO;
668 *pi_channels_conf = AOUT_CHAN_CENTER;
671 *pi_bit_rate = ppi_bitrate[i_version][*pi_layer-1][i_bitrate_index];
672 i_max_bit_rate = ppi_bitrate[i_version][*pi_layer-1][14];
673 *pi_sample_rate = ppi_samplerate[i_version][i_samplerate_index];
677 *pi_sample_rate >>= 1;
683 i_frame_size = ( 12000 * *pi_bit_rate / *pi_sample_rate +
685 *pi_max_frame_size = ( 12000 * i_max_bit_rate /
686 *pi_sample_rate + 1 ) * 4;
687 *pi_frame_length = 384;
691 i_frame_size = 144000 * *pi_bit_rate / *pi_sample_rate + b_padding;
692 *pi_max_frame_size = 144000 * i_max_bit_rate / *pi_sample_rate + 1;
693 *pi_frame_length = 1152;
697 i_frame_size = ( i_version ? 72000 : 144000 ) *
698 *pi_bit_rate / *pi_sample_rate + b_padding;
699 *pi_max_frame_size = ( i_version ? 72000 : 144000 ) *
700 i_max_bit_rate / *pi_sample_rate + 1;
701 *pi_frame_length = i_version ? 576 : 1152;
708 /* Free bitrate mode can support higher bitrates */
709 if( !*pi_bit_rate ) *pi_max_frame_size *= 2;