1 /*****************************************************************************
2 * mpeg4audio.c: parse and packetize an MPEG 4 audio stream
3 *****************************************************************************
4 * Copyright (C) 2001, 2002, 2006 the VideoLAN team
7 * Authors: Laurent Aimar <fenrir@via.ecp.fr>
8 * Gildas Bazin <gbazin@netcourrier.com>
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
23 *****************************************************************************/
25 /*****************************************************************************
27 *****************************************************************************/
28 #include <stdlib.h> /* malloc(), free() */
29 #include <string.h> /* strdup() */
33 #include <vlc_codec.h>
34 #include <vlc_block.h>
36 #include <vlc_codecs.h>
38 #include "vlc_block_helper.h"
42 * AudioObjectType 5 bits
43 * samplingFrequencyIndex 4 bits
44 * if (samplingFrequencyIndex == 0xF)
45 * samplingFrequency 24 bits
46 * channelConfiguration 4 bits
48 * FrameLengthFlag 1 bit 1024 or 960
49 * DependsOnCoreCoder 1 bit (always 0)
50 * ExtensionFlag 1 bit (always 0)
53 /*****************************************************************************
54 * decoder_sys_t : decoder descriptor
55 *****************************************************************************/
63 block_bytestream_t bytestream;
68 audio_date_t end_date;
72 unsigned int i_raw_blocks;
73 unsigned int i_channels;
74 unsigned int i_rate, i_frame_length, i_header_size;
87 static int i_sample_rates[] =
89 96000, 88200, 64000, 48000, 44100, 32000, 24000, 22050,
90 16000, 12000, 11025, 8000, 7350, 0, 0, 0
93 #define ADTS_HEADER_SIZE 9
95 /****************************************************************************
97 ****************************************************************************/
98 static int OpenPacketizer( vlc_object_t * );
99 static void ClosePacketizer( vlc_object_t * );
101 static block_t *PacketizeBlock ( decoder_t *, block_t ** );
102 static block_t *ADTSPacketizeBlock( decoder_t *, block_t ** );
104 static uint8_t *GetOutBuffer ( decoder_t *, void ** );
106 static int ADTSSyncInfo( decoder_t *, const byte_t * p_buf,
107 unsigned int * pi_channels,
108 unsigned int * pi_sample_rate,
109 unsigned int * pi_frame_length,
110 unsigned int * pi_header_size,
111 unsigned int * pi_raw_blocks );
113 /*****************************************************************************
115 *****************************************************************************/
117 set_category( CAT_SOUT );
118 set_subcategory( SUBCAT_SOUT_PACKETIZER );
119 set_description( _("MPEG4 audio packetizer") );
120 set_capability( "packetizer", 50 );
121 set_callbacks( OpenPacketizer, ClosePacketizer );
124 /*****************************************************************************
125 * OpenPacketizer: probe the packetizer and return score
126 *****************************************************************************/
127 static int OpenPacketizer( vlc_object_t *p_this )
129 decoder_t *p_dec = (decoder_t*)p_this;
130 decoder_sys_t *p_sys;
132 if( p_dec->fmt_in.i_codec != VLC_FOURCC( 'm', 'p', '4', 'a' ) )
137 /* Allocate the memory needed to store the decoder's structure */
138 if( ( p_dec->p_sys = p_sys =
139 (decoder_sys_t *)malloc(sizeof(decoder_sys_t)) ) == NULL )
141 msg_Err( p_dec, "out of memory" );
146 p_sys->i_state = STATE_NOSYNC;
147 aout_DateSet( &p_sys->end_date, 0 );
148 p_sys->bytestream = block_BytestreamInit( p_dec );
150 /* Set output properties */
151 p_dec->fmt_out.i_cat = AUDIO_ES;
152 p_dec->fmt_out.i_codec = VLC_FOURCC('m','p','4','a');
155 p_dec->pf_packetize = PacketizeBlock;
157 msg_Dbg( p_dec, "running MPEG4 audio packetizer" );
159 if( p_dec->fmt_in.i_extra > 0 )
161 uint8_t *p_config = (uint8_t*)p_dec->fmt_in.p_extra;
164 i_index = ( ( p_config[0] << 1 ) | ( p_config[1] >> 7 ) ) & 0x0f;
165 if( i_index != 0x0f )
167 p_dec->fmt_out.audio.i_rate = i_sample_rates[i_index];
168 p_dec->fmt_out.audio.i_frame_length =
169 (( p_config[1] >> 2 ) & 0x01) ? 960 : 1024;
173 p_dec->fmt_out.audio.i_rate = ( ( p_config[1] & 0x7f ) << 17 ) |
174 ( p_config[2] << 9 ) | ( p_config[3] << 1 ) |
175 ( p_config[4] >> 7 );
176 p_dec->fmt_out.audio.i_frame_length =
177 (( p_config[4] >> 2 ) & 0x01) ? 960 : 1024;
180 msg_Dbg( p_dec, "AAC %dHz %d samples/frame",
181 p_dec->fmt_out.audio.i_rate,
182 p_dec->fmt_out.audio.i_frame_length );
184 aout_DateInit( &p_sys->end_date, p_dec->fmt_out.audio.i_rate );
186 p_dec->fmt_out.audio.i_channels = p_dec->fmt_in.audio.i_channels;
187 p_dec->fmt_out.i_extra = p_dec->fmt_in.i_extra;
188 p_dec->fmt_out.p_extra = malloc( p_dec->fmt_in.i_extra );
189 memcpy( p_dec->fmt_out.p_extra, p_dec->fmt_in.p_extra,
190 p_dec->fmt_in.i_extra );
194 msg_Dbg( p_dec, "no decoder specific info, must be an ADTS stream" );
196 /* We will try to create a AAC Config from adts */
197 p_dec->fmt_out.i_extra = 0;
198 p_dec->fmt_out.p_extra = NULL;
199 p_dec->pf_packetize = ADTSPacketizeBlock;
205 /****************************************************************************
206 * PacketizeBlock: the whole thing
207 ****************************************************************************
208 * This function must be fed with complete frames.
209 ****************************************************************************/
210 static block_t *PacketizeBlock( decoder_t *p_dec, block_t **pp_block )
212 decoder_sys_t *p_sys = p_dec->p_sys;
215 if( !pp_block || !*pp_block ) return NULL;
218 *pp_block = NULL; /* Don't reuse this block */
220 if( !aout_DateGet( &p_sys->end_date ) && !p_block->i_pts )
222 /* We've just started the stream, wait for the first PTS. */
223 block_Release( p_block );
226 else if( p_block->i_pts != 0 &&
227 p_block->i_pts != aout_DateGet( &p_sys->end_date ) )
229 aout_DateSet( &p_sys->end_date, p_block->i_pts );
232 p_block->i_pts = p_block->i_dts = aout_DateGet( &p_sys->end_date );
234 p_block->i_length = aout_DateIncrement( &p_sys->end_date,
235 p_dec->fmt_out.audio.i_frame_length ) - p_block->i_pts;
240 /****************************************************************************
241 * DTSPacketizeBlock: the whole thing
242 ****************************************************************************/
243 static block_t *ADTSPacketizeBlock( decoder_t *p_dec, block_t **pp_block )
245 decoder_sys_t *p_sys = p_dec->p_sys;
246 uint8_t p_header[ADTS_HEADER_SIZE];
250 if( !pp_block || !*pp_block ) return NULL;
252 if( !aout_DateGet( &p_sys->end_date ) && !(*pp_block)->i_pts )
254 /* We've just started the stream, wait for the first PTS. */
255 block_Release( *pp_block );
259 if( (*pp_block)->i_flags&BLOCK_FLAG_DISCONTINUITY )
261 p_sys->i_state = STATE_NOSYNC;
264 block_BytestreamPush( &p_sys->bytestream, *pp_block );
268 switch( p_sys->i_state )
272 while( block_PeekBytes( &p_sys->bytestream, p_header, 2 )
275 /* Look for sync word - should be 0xfff + 2 layer bits */
276 if( p_header[0] == 0xff && (p_header[1] & 0xf6) == 0xf0 )
278 p_sys->i_state = STATE_SYNC;
281 block_SkipByte( &p_sys->bytestream );
283 if( p_sys->i_state != STATE_SYNC )
285 block_BytestreamFlush( &p_sys->bytestream );
292 /* New frame, set the Presentation Time Stamp */
293 p_sys->i_pts = p_sys->bytestream.p_block->i_pts;
294 if( p_sys->i_pts != 0 &&
295 p_sys->i_pts != aout_DateGet( &p_sys->end_date ) )
297 aout_DateSet( &p_sys->end_date, p_sys->i_pts );
299 p_sys->i_state = STATE_HEADER;
303 /* Get ADTS frame header (ADTS_HEADER_SIZE bytes) */
304 if( block_PeekBytes( &p_sys->bytestream, p_header,
305 ADTS_HEADER_SIZE ) != VLC_SUCCESS )
311 /* Check if frame is valid and get frame info */
312 p_sys->i_frame_size = ADTSSyncInfo( p_dec, p_header,
315 &p_sys->i_frame_length,
316 &p_sys->i_header_size,
317 &p_sys->i_raw_blocks );
318 if( p_sys->i_frame_size <= 0 )
320 msg_Dbg( p_dec, "emulated sync word" );
321 block_SkipByte( &p_sys->bytestream );
322 p_sys->i_state = STATE_NOSYNC;
326 p_sys->i_state = STATE_NEXT_SYNC;
328 case STATE_NEXT_SYNC:
329 /* TODO: If p_block == NULL, flush the buffer without checking the
332 /* Check if next expected frame contains the sync word */
333 if( block_PeekOffsetBytes( &p_sys->bytestream, p_sys->i_frame_size
334 + p_sys->i_header_size, p_header, 2 )
341 if( p_header[0] != 0xff || (p_header[1] & 0xf6) != 0xf0 )
343 msg_Dbg( p_dec, "emulated sync word "
344 "(no sync on following frame)" );
345 p_sys->i_state = STATE_NOSYNC;
346 block_SkipByte( &p_sys->bytestream );
350 p_sys->i_state = STATE_SEND_DATA;
354 /* Make sure we have enough data.
355 * (Not useful if we went through NEXT_SYNC) */
356 if( block_WaitBytes( &p_sys->bytestream, p_sys->i_frame_size +
357 p_sys->i_header_size) != VLC_SUCCESS )
362 p_sys->i_state = STATE_SEND_DATA;
364 case STATE_SEND_DATA:
365 if( !(p_buf = GetOutBuffer( p_dec, &p_out_buffer )) )
367 //p_dec->b_error = VLC_TRUE;
371 /* When we reach this point we already know we have enough
374 /* Skip the ADTS header */
375 block_SkipBytes( &p_sys->bytestream, p_sys->i_header_size );
377 /* Copy the whole frame into the buffer */
378 block_GetBytes( &p_sys->bytestream, p_buf, p_sys->i_frame_size );
380 /* Make sure we don't reuse the same pts twice */
381 if( p_sys->i_pts == p_sys->bytestream.p_block->i_pts )
382 p_sys->i_pts = p_sys->bytestream.p_block->i_pts = 0;
384 /* So p_block doesn't get re-added several times */
385 *pp_block = block_BytestreamPop( &p_sys->bytestream );
387 p_sys->i_state = STATE_NOSYNC;
396 /*****************************************************************************
398 *****************************************************************************/
399 static uint8_t *GetOutBuffer( decoder_t *p_dec, void **pp_out_buffer )
401 decoder_sys_t *p_sys = p_dec->p_sys;
404 if( p_dec->fmt_out.audio.i_rate != p_sys->i_rate )
406 msg_Info( p_dec, "AAC channels: %d samplerate: %d",
407 p_sys->i_channels, p_sys->i_rate );
409 aout_DateInit( &p_sys->end_date, p_sys->i_rate );
410 aout_DateSet( &p_sys->end_date, p_sys->i_pts );
413 p_dec->fmt_out.audio.i_rate = p_sys->i_rate;
414 p_dec->fmt_out.audio.i_channels = p_sys->i_channels;
415 p_dec->fmt_out.audio.i_bytes_per_frame = p_sys->i_frame_size;
416 p_dec->fmt_out.audio.i_frame_length = p_sys->i_frame_length;
419 p_dec->fmt_out.audio.i_original_channels = p_sys->i_channels_conf;
420 p_dec->fmt_out.audio.i_physical_channels =
421 p_sys->i_channels_conf & AOUT_CHAN_PHYSMASK;
424 p_block = block_New( p_dec, p_sys->i_frame_size );
425 if( p_block == NULL ) return NULL;
427 p_block->i_pts = p_block->i_dts = aout_DateGet( &p_sys->end_date );
429 p_block->i_length = aout_DateIncrement( &p_sys->end_date,
430 p_sys->i_frame_length ) - p_block->i_pts;
432 *pp_out_buffer = p_block;
433 return p_block->p_buffer;
436 /*****************************************************************************
437 * ClosePacketizer: clean up the packetizer
438 *****************************************************************************/
439 static void ClosePacketizer( vlc_object_t *p_this )
441 decoder_t *p_dec = (decoder_t *)p_this;
442 decoder_sys_t *p_sys = p_dec->p_sys;
444 block_BytestreamRelease( &p_sys->bytestream );
446 free( p_dec->p_sys );
449 /*****************************************************************************
450 * ADTSSyncInfo: parse MPEG 4 audio ADTS sync info
451 *****************************************************************************/
452 static int ADTSSyncInfo( decoder_t * p_dec, const byte_t * p_buf,
453 unsigned int * pi_channels,
454 unsigned int * pi_sample_rate,
455 unsigned int * pi_frame_length,
456 unsigned int * pi_header_size,
457 unsigned int * pi_raw_blocks_in_frame )
459 int i_id, i_profile, i_sample_rate_idx, i_frame_size;
462 /* Fixed header between frames */
463 i_id = ( (p_buf[1] >> 3) & 0x01 ) ? 2 : 4;
464 b_crc = !(p_buf[1] & 0x01);
465 i_profile = p_buf[2] >> 6;
466 i_sample_rate_idx = (p_buf[2] >> 2) & 0x0f;
467 *pi_sample_rate = i_sample_rates[i_sample_rate_idx];
468 *pi_channels = ((p_buf[2] & 0x01) << 2) | ((p_buf[3] >> 6) & 0x03);
470 /* Variable header */
471 i_frame_size = ((p_buf[3] & 0x03) << 11) | (p_buf[4] << 3) |
472 ((p_buf[5] >> 5) & 0x7);
473 *pi_raw_blocks_in_frame = (p_buf[6] & 0x02) + 1;
475 if( !*pi_sample_rate || !*pi_channels || !i_frame_size )
481 *pi_frame_length = 1024;
483 /* Build the decoder specific info header */
484 if( !p_dec->fmt_out.i_extra )
486 p_dec->fmt_out.i_extra = 2;
487 p_dec->fmt_out.p_extra = malloc( 2 );
488 ((uint8_t *)p_dec->fmt_out.p_extra)[0] =
489 (i_profile + 1) << 3 | (i_sample_rate_idx >> 1);
490 ((uint8_t *)p_dec->fmt_out.p_extra)[1] =
491 ((i_sample_rate_idx & 0x01) << 7) | (*pi_channels <<3);
494 /* ADTS header length */
495 *pi_header_size = b_crc ? 9 : 7;
497 return i_frame_size - *pi_header_size;