1 /*****************************************************************************
2 * mpeg_audio.c: parse MPEG audio sync info and packetize the stream
3 *****************************************************************************
4 * Copyright (C) 2001-2003 the VideoLAN team
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
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.
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.
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 *****************************************************************************/
27 /*****************************************************************************
29 *****************************************************************************/
34 #include <vlc_common.h>
35 #include <vlc_plugin.h>
36 #include <vlc_codec.h>
39 #include <vlc_block_helper.h>
41 /*****************************************************************************
42 * decoder_sys_t : decoder descriptor
43 *****************************************************************************/
54 block_bytestream_t bytestream;
60 unsigned int i_current_layer;
64 int i_frame_size, i_free_frame_size;
65 unsigned int i_channels_conf, i_channels;
66 unsigned int i_rate, i_max_frame_size, i_frame_length;
67 unsigned int i_layer, i_bit_rate;
82 /* This isn't the place to put mad-specific stuff. However, it makes the
83 * mad plug-in's life much easier if we put 8 extra bytes at the end of the
84 * buffer, because that way it doesn't have to copy the aout_buffer_t to a
85 * bigger buffer. This has no implication on other plug-ins, and we only
86 * lose 8 bytes per frame. --Meuuh */
87 #define MAD_BUFFER_GUARD 8
88 #define MPGA_HEADER_SIZE 4
90 /****************************************************************************
92 ****************************************************************************/
93 static int OpenDecoder ( vlc_object_t * );
94 static int OpenPacketizer( vlc_object_t * );
95 static void CloseDecoder ( vlc_object_t * );
96 static void *DecodeBlock ( decoder_t *, block_t ** );
98 static uint8_t *GetOutBuffer ( decoder_t *, void ** );
99 static aout_buffer_t *GetAoutBuffer( decoder_t * );
100 static block_t *GetSoutBuffer( decoder_t * );
102 static int SyncInfo( uint32_t i_header, unsigned int * pi_channels,
103 unsigned int * pi_channels_conf,
104 unsigned int * pi_sample_rate, unsigned int * pi_bit_rate,
105 unsigned int * pi_frame_length,
106 unsigned int * pi_max_frame_size,
107 unsigned int * pi_layer );
109 /*****************************************************************************
111 *****************************************************************************/
113 set_description( N_("MPEG audio layer I/II/III decoder") )
114 set_category( CAT_INPUT )
115 set_subcategory( SUBCAT_INPUT_ACODEC )
116 #if defined(UNDER_CE)
117 set_capability( "decoder", 5 )
119 set_capability( "decoder", 100 )
121 set_callbacks( OpenDecoder, CloseDecoder )
124 set_description( N_("MPEG audio layer I/II/III packetizer") )
125 set_capability( "packetizer", 10 )
126 set_callbacks( OpenPacketizer, CloseDecoder )
129 /*****************************************************************************
130 * Open: probe the decoder and return score
131 *****************************************************************************/
132 static int Open( vlc_object_t *p_this )
134 decoder_t *p_dec = (decoder_t*)p_this;
135 decoder_sys_t *p_sys;
137 if( p_dec->fmt_in.i_codec != VLC_CODEC_MPGA )
142 /* Allocate the memory needed to store the decoder's structure */
143 if( ( p_dec->p_sys = p_sys =
144 (decoder_sys_t *)malloc(sizeof(decoder_sys_t)) ) == NULL )
148 p_sys->b_packetizer = false;
149 p_sys->i_state = STATE_NOSYNC;
150 date_Set( &p_sys->end_date, 0 );
151 p_sys->bytestream = block_BytestreamInit();
152 p_sys->i_pts = VLC_TS_INVALID;
153 p_sys->b_discontinuity = false;
155 /* Set output properties */
156 p_dec->fmt_out.i_cat = AUDIO_ES;
157 p_dec->fmt_out.i_codec = VLC_CODEC_MPGA;
158 p_dec->fmt_out.audio.i_rate = 0; /* So end_date gets initialized */
161 p_dec->pf_decode_audio = (aout_buffer_t *(*)(decoder_t *, block_t **))
163 p_dec->pf_packetize = (block_t *(*)(decoder_t *, block_t **))
166 /* Start with the minimum size for a free bitrate frame */
167 p_sys->i_free_frame_size = MPGA_HEADER_SIZE;
172 static int OpenDecoder( vlc_object_t *p_this )
174 /* HACK: Don't use this codec if we don't have an mpga audio filter */
175 if( !module_exists( "mpgatofixed32" ) )
178 return Open( p_this );
181 static int OpenPacketizer( vlc_object_t *p_this )
183 decoder_t *p_dec = (decoder_t*)p_this;
185 int i_ret = Open( p_this );
187 if( i_ret == VLC_SUCCESS ) p_dec->p_sys->b_packetizer = true;
192 /****************************************************************************
193 * DecodeBlock: the whole thing
194 ****************************************************************************
195 * This function is called just after the thread is launched.
196 ****************************************************************************/
197 static void *DecodeBlock( decoder_t *p_dec, block_t **pp_block )
199 decoder_sys_t *p_sys = p_dec->p_sys;
200 uint8_t p_header[MAD_BUFFER_GUARD];
205 if( !pp_block || !*pp_block ) return NULL;
207 if( (*pp_block)->i_flags&(BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) )
209 if( (*pp_block)->i_flags&BLOCK_FLAG_CORRUPTED )
211 p_sys->i_state = STATE_NOSYNC;
212 block_BytestreamEmpty( &p_sys->bytestream );
214 date_Set( &p_sys->end_date, 0 );
215 block_Release( *pp_block );
216 p_sys->b_discontinuity = true;
220 if( !date_Get( &p_sys->end_date ) && (*pp_block)->i_pts <= VLC_TS_INVALID )
222 /* We've just started the stream, wait for the first PTS. */
223 msg_Dbg( p_dec, "waiting for PTS" );
224 block_Release( *pp_block );
228 block_BytestreamPush( &p_sys->bytestream, *pp_block );
232 switch( p_sys->i_state )
236 while( block_PeekBytes( &p_sys->bytestream, p_header, 2 )
239 /* Look for sync word - should be 0xffe */
240 if( p_header[0] == 0xff && (p_header[1] & 0xe0) == 0xe0 )
242 p_sys->i_state = STATE_SYNC;
245 block_SkipByte( &p_sys->bytestream );
247 if( p_sys->i_state != STATE_SYNC )
249 block_BytestreamFlush( &p_sys->bytestream );
256 /* New frame, set the Presentation Time Stamp */
257 p_sys->i_pts = p_sys->bytestream.p_block->i_pts;
258 if( p_sys->i_pts > VLC_TS_INVALID &&
259 p_sys->i_pts != date_Get( &p_sys->end_date ) )
261 date_Set( &p_sys->end_date, p_sys->i_pts );
263 p_sys->i_state = STATE_HEADER;
266 /* Get MPGA frame header (MPGA_HEADER_SIZE bytes) */
267 if( block_PeekBytes( &p_sys->bytestream, p_header,
268 MPGA_HEADER_SIZE ) != VLC_SUCCESS )
274 /* Build frame header */
275 i_header = (p_header[0]<<24)|(p_header[1]<<16)|(p_header[2]<<8)
278 /* Check if frame is valid and get frame info */
279 p_sys->i_frame_size = SyncInfo( i_header,
281 &p_sys->i_channels_conf,
284 &p_sys->i_frame_length,
285 &p_sys->i_max_frame_size,
288 p_dec->fmt_in.i_profile = p_sys->i_layer;
290 if( p_sys->i_frame_size == -1 )
292 msg_Dbg( p_dec, "emulated startcode" );
293 block_SkipByte( &p_sys->bytestream );
294 p_sys->i_state = STATE_NOSYNC;
295 p_sys->b_discontinuity = true;
299 if( p_sys->i_bit_rate == 0 )
301 /* Free bitrate, but 99% emulated startcode :( */
302 if( p_dec->p_sys->i_free_frame_size == MPGA_HEADER_SIZE )
304 msg_Dbg( p_dec, "free bitrate mode");
306 /* The -1 below is to account for the frame padding */
307 p_sys->i_frame_size = p_sys->i_free_frame_size - 1;
310 p_sys->i_state = STATE_NEXT_SYNC;
312 case STATE_NEXT_SYNC:
313 /* TODO: If p_block == NULL, flush the buffer without checking the
316 /* Check if next expected frame contains the sync word */
317 if( block_PeekOffsetBytes( &p_sys->bytestream,
318 p_sys->i_frame_size, p_header,
319 MAD_BUFFER_GUARD ) != VLC_SUCCESS )
325 if( p_header[0] == 0xff && (p_header[1] & 0xe0) == 0xe0 )
327 /* Startcode is fine, let's try the header as an extra check */
328 int i_next_frame_size;
329 unsigned int i_next_channels, i_next_channels_conf;
330 unsigned int i_next_rate, i_next_bit_rate;
331 unsigned int i_next_frame_length, i_next_max_frame_size;
332 unsigned int i_next_layer;
334 /* Build frame header */
335 i_header = (p_header[0]<<24)|(p_header[1]<<16)|(p_header[2]<<8)
338 i_next_frame_size = SyncInfo( i_header,
340 &i_next_channels_conf,
343 &i_next_frame_length,
344 &i_next_max_frame_size,
347 /* Free bitrate only */
348 if( p_sys->i_bit_rate == 0 && i_next_frame_size == -1 )
350 if( (unsigned int)p_sys->i_frame_size >
351 p_sys->i_max_frame_size )
353 msg_Dbg( p_dec, "frame too big %d > %d "
354 "(emulated startcode ?)", p_sys->i_frame_size,
355 p_sys->i_max_frame_size );
356 block_SkipByte( &p_sys->bytestream );
357 p_sys->i_state = STATE_NOSYNC;
358 p_sys->i_free_frame_size = MPGA_HEADER_SIZE;
362 p_sys->i_frame_size++;
366 if( i_next_frame_size == -1 )
368 msg_Dbg( p_dec, "emulated startcode on next frame" );
369 block_SkipByte( &p_sys->bytestream );
370 p_sys->i_state = STATE_NOSYNC;
371 p_sys->b_discontinuity = true;
375 /* Check info is in sync with previous one */
376 if( i_next_channels_conf != p_sys->i_channels_conf ||
377 i_next_rate != p_sys->i_rate ||
378 i_next_layer != p_sys->i_layer ||
379 i_next_frame_length != p_sys->i_frame_length )
381 /* Free bitrate only */
382 if( p_sys->i_bit_rate == 0 )
384 p_sys->i_frame_size++;
388 msg_Dbg( p_dec, "parameters changed unexpectedly "
389 "(emulated startcode ?)" );
390 block_SkipByte( &p_sys->bytestream );
391 p_sys->i_state = STATE_NOSYNC;
395 /* Free bitrate only */
396 if( p_sys->i_bit_rate == 0 )
398 if( i_next_bit_rate != 0 )
400 p_sys->i_frame_size++;
408 /* Free bitrate only */
409 if( p_sys->i_bit_rate == 0 )
411 if( (unsigned int)p_sys->i_frame_size >
412 p_sys->i_max_frame_size )
414 msg_Dbg( p_dec, "frame too big %d > %d "
415 "(emulated startcode ?)", p_sys->i_frame_size,
416 p_sys->i_max_frame_size );
417 block_SkipByte( &p_sys->bytestream );
418 p_sys->i_state = STATE_NOSYNC;
419 p_sys->i_free_frame_size = MPGA_HEADER_SIZE;
423 p_sys->i_frame_size++;
427 msg_Dbg( p_dec, "emulated startcode "
428 "(no startcode on following frame)" );
429 p_sys->i_state = STATE_NOSYNC;
430 block_SkipByte( &p_sys->bytestream );
434 p_sys->i_state = STATE_SEND_DATA;
438 /* Make sure we have enough data.
439 * (Not useful if we went through NEXT_SYNC) */
440 if( block_WaitBytes( &p_sys->bytestream,
441 p_sys->i_frame_size ) != VLC_SUCCESS )
446 p_sys->i_state = STATE_SEND_DATA;
448 case STATE_SEND_DATA:
449 if( !(p_buf = GetOutBuffer( p_dec, &p_out_buffer )) )
451 //p_dec->b_error = true;
455 /* Free bitrate only */
456 if( p_sys->i_bit_rate == 0 )
458 p_sys->i_free_frame_size = p_sys->i_frame_size;
461 /* Copy the whole frame into the buffer. When we reach this point
462 * we already know we have enough data available. */
463 block_GetBytes( &p_sys->bytestream, p_buf, p_sys->i_frame_size );
465 /* Get beginning of next frame for libmad */
466 if( !p_sys->b_packetizer )
468 memcpy( p_buf + p_sys->i_frame_size,
469 p_header, MAD_BUFFER_GUARD );
472 p_sys->i_state = STATE_NOSYNC;
474 /* Make sure we don't reuse the same pts twice */
475 if( p_sys->i_pts == p_sys->bytestream.p_block->i_pts )
476 p_sys->i_pts = p_sys->bytestream.p_block->i_pts = VLC_TS_INVALID;
478 /* So p_block doesn't get re-added several times */
479 *pp_block = block_BytestreamPop( &p_sys->bytestream );
488 /*****************************************************************************
490 *****************************************************************************/
491 static uint8_t *GetOutBuffer( decoder_t *p_dec, void **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 aout_buffer_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 aout_buffer_t *GetAoutBuffer( decoder_t *p_dec )
538 decoder_sys_t *p_sys = p_dec->p_sys;
539 aout_buffer_t *p_buf;
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->i_buffer = 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_New( p_dec, 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, b_crc;
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 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;