1 /*****************************************************************************
2 * mpeg4audio.c: parse and packetize an MPEG 4 audio stream
3 *****************************************************************************
4 * Copyright (C) 2001, 2002 VideoLAN
5 * $Id: mpeg4audio.c,v 1.17 2004/02/25 18:43:24 gbazin Exp $
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., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
23 *****************************************************************************/
25 /*****************************************************************************
27 *****************************************************************************/
28 #include <stdlib.h> /* malloc(), free() */
29 #include <string.h> /* strdup() */
33 #include <vlc/decoder.h>
34 #include <vlc/input.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;
71 int i_frame_size, i_raw_blocks;
72 unsigned int i_channels;
73 unsigned int i_rate, i_frame_length, i_header_size;
86 static int i_sample_rates[] =
88 96000, 88200, 64000, 48000, 44100, 32000, 24000, 22050,
89 16000, 12000, 11025, 8000, 7350, 0, 0, 0
92 #define ADTS_HEADER_SIZE 9
94 /****************************************************************************
96 ****************************************************************************/
97 static int OpenPacketizer( vlc_object_t * );
98 static void ClosePacketizer( vlc_object_t * );
100 static block_t *PacketizeBlock ( decoder_t *, block_t ** );
101 static block_t *ADTSPacketizeBlock( decoder_t *, block_t ** );
103 static uint8_t *GetOutBuffer ( decoder_t *, void ** );
105 static int ADTSSyncInfo( decoder_t *, const byte_t * p_buf,
106 unsigned int * pi_channels,
107 unsigned int * pi_sample_rate,
108 unsigned int * pi_frame_length,
109 unsigned int * pi_header_size,
110 unsigned int * pi_raw_blocks );
112 /*****************************************************************************
114 *****************************************************************************/
116 set_description( _("MPEG4 audio packetizer") );
117 set_capability( "packetizer", 50 );
118 set_callbacks( OpenPacketizer, ClosePacketizer );
121 /*****************************************************************************
122 * OpenPacketizer: probe the packetizer and return score
123 *****************************************************************************/
124 static int OpenPacketizer( vlc_object_t *p_this )
126 decoder_t *p_dec = (decoder_t*)p_this;
127 decoder_sys_t *p_sys;
129 if( p_dec->fmt_in.i_codec != VLC_FOURCC( 'm', 'p', '4', 'a' ) )
134 /* Allocate the memory needed to store the decoder's structure */
135 if( ( p_dec->p_sys = p_sys =
136 (decoder_sys_t *)malloc(sizeof(decoder_sys_t)) ) == NULL )
138 msg_Err( p_dec, "out of memory" );
143 p_sys->i_state = STATE_NOSYNC;
144 aout_DateSet( &p_sys->end_date, 0 );
145 p_sys->bytestream = block_BytestreamInit( p_dec );
147 /* Set output properties */
148 p_dec->fmt_out.i_cat = AUDIO_ES;
149 p_dec->fmt_out.i_codec = VLC_FOURCC('m','p','4','a');
152 p_dec->pf_packetize = PacketizeBlock;
154 msg_Info( p_dec, "running MPEG4 audio packetizer" );
156 if( p_dec->fmt_in.i_extra > 0 )
158 uint8_t *p_config = (uint8_t*)p_dec->fmt_in.p_extra;
161 i_index = ( ( p_config[0] << 1 ) | ( p_config[1] >> 7 ) ) & 0x0f;
162 if( i_index != 0x0f )
164 p_dec->fmt_out.audio.i_rate = i_sample_rates[i_index];
165 p_dec->fmt_out.audio.i_frame_length =
166 (( p_config[1] >> 2 ) & 0x01) ? 960 : 1024;
170 p_dec->fmt_out.audio.i_rate = ( ( p_config[1] & 0x7f ) << 17 ) |
171 ( p_config[2] << 9 ) | ( p_config[3] << 1 ) |
172 ( p_config[4] >> 7 );
173 p_dec->fmt_out.audio.i_frame_length =
174 (( p_config[4] >> 2 ) & 0x01) ? 960 : 1024;
177 msg_Dbg( p_dec, "AAC %dHz %d samples/frame",
178 p_dec->fmt_out.audio.i_rate,
179 p_dec->fmt_out.audio.i_frame_length );
181 aout_DateInit( &p_sys->end_date, p_dec->fmt_out.audio.i_rate );
183 p_dec->fmt_out.audio.i_channels = p_dec->fmt_in.audio.i_channels;
184 p_dec->fmt_out.i_extra = p_dec->fmt_in.i_extra;
185 p_dec->fmt_out.p_extra = malloc( p_dec->fmt_in.i_extra );
186 memcpy( p_dec->fmt_out.p_extra, p_dec->fmt_in.p_extra,
187 p_dec->fmt_in.i_extra );
191 msg_Dbg( p_dec, "no decoder specific info, must be an ADTS stream" );
193 /* We will try to create a AAC Config from adts */
194 p_dec->fmt_out.i_extra = 0;
195 p_dec->fmt_out.p_extra = NULL;
196 p_dec->pf_packetize = ADTSPacketizeBlock;
202 /****************************************************************************
203 * PacketizeBlock: the whole thing
204 ****************************************************************************
205 * This function must be fed with complete frames.
206 ****************************************************************************/
207 static block_t *PacketizeBlock( decoder_t *p_dec, block_t **pp_block )
209 decoder_sys_t *p_sys = p_dec->p_sys;
212 if( !pp_block || !*pp_block ) return NULL;
215 *pp_block = NULL; /* Don't reuse this block */
217 if( !aout_DateGet( &p_sys->end_date ) && !p_block->i_pts )
219 /* We've just started the stream, wait for the first PTS. */
220 block_Release( p_block );
223 else if( p_block->i_pts != 0 &&
224 p_block->i_pts != aout_DateGet( &p_sys->end_date ) )
226 aout_DateSet( &p_sys->end_date, p_block->i_pts );
229 p_block->i_pts = p_block->i_dts = aout_DateGet( &p_sys->end_date );
231 p_block->i_length = aout_DateIncrement( &p_sys->end_date,
232 p_dec->fmt_out.audio.i_frame_length ) - p_block->i_pts;
237 /****************************************************************************
238 * DTSPacketizeBlock: the whole thing
239 ****************************************************************************/
240 static block_t *ADTSPacketizeBlock( decoder_t *p_dec, block_t **pp_block )
242 decoder_sys_t *p_sys = p_dec->p_sys;
243 uint8_t p_header[ADTS_HEADER_SIZE];
247 if( !pp_block || !*pp_block ) return NULL;
249 if( !aout_DateGet( &p_sys->end_date ) && !(*pp_block)->i_pts )
251 /* We've just started the stream, wait for the first PTS. */
252 block_Release( *pp_block );
256 if( (*pp_block)->i_flags&BLOCK_FLAG_DISCONTINUITY )
258 p_sys->i_state = STATE_NOSYNC;
261 block_BytestreamPush( &p_sys->bytestream, *pp_block );
265 switch( p_sys->i_state )
269 while( block_PeekBytes( &p_sys->bytestream, p_header, 2 )
272 /* Look for sync word - should be 0xfff + 2 layer bits */
273 if( p_header[0] == 0xff && (p_header[1] & 0xf6) == 0xf0 )
275 p_sys->i_state = STATE_SYNC;
278 block_SkipByte( &p_sys->bytestream );
280 if( p_sys->i_state != STATE_SYNC )
282 block_BytestreamFlush( &p_sys->bytestream );
289 /* New frame, set the Presentation Time Stamp */
290 p_sys->i_pts = p_sys->bytestream.p_block->i_pts;
291 if( p_sys->i_pts != 0 &&
292 p_sys->i_pts != aout_DateGet( &p_sys->end_date ) )
294 aout_DateSet( &p_sys->end_date, p_sys->i_pts );
296 p_sys->i_state = STATE_HEADER;
300 /* Get ADTS frame header (ADTS_HEADER_SIZE bytes) */
301 if( block_PeekBytes( &p_sys->bytestream, p_header,
302 ADTS_HEADER_SIZE ) != VLC_SUCCESS )
308 /* Check if frame is valid and get frame info */
309 p_sys->i_frame_size = ADTSSyncInfo( p_dec, p_header,
312 &p_sys->i_frame_length,
313 &p_sys->i_header_size,
314 &p_sys->i_raw_blocks );
315 if( p_sys->i_frame_size <= 0 )
317 msg_Dbg( p_dec, "emulated sync word" );
318 block_SkipByte( &p_sys->bytestream );
319 p_sys->i_state = STATE_NOSYNC;
323 p_sys->i_state = STATE_NEXT_SYNC;
325 case STATE_NEXT_SYNC:
326 /* TODO: If p_block == NULL, flush the buffer without checking the
329 /* Check if next expected frame contains the sync word */
330 if( block_PeekOffsetBytes( &p_sys->bytestream, p_sys->i_frame_size
331 + p_sys->i_header_size, p_header, 2 )
338 if( p_header[0] != 0xff || (p_header[1] & 0xf6) != 0xf0 )
340 msg_Dbg( p_dec, "emulated sync word "
341 "(no sync on following frame)" );
342 p_sys->i_state = STATE_NOSYNC;
343 block_SkipByte( &p_sys->bytestream );
347 p_sys->i_state = STATE_SEND_DATA;
351 /* Make sure we have enough data.
352 * (Not useful if we went through NEXT_SYNC) */
353 if( block_WaitBytes( &p_sys->bytestream, p_sys->i_frame_size +
354 p_sys->i_header_size) != VLC_SUCCESS )
359 p_sys->i_state = STATE_SEND_DATA;
361 case STATE_SEND_DATA:
362 if( !(p_buf = GetOutBuffer( p_dec, &p_out_buffer )) )
364 //p_dec->b_error = VLC_TRUE;
368 /* When we reach this point we already know we have enough
371 /* Skip the ADTS header */
372 block_SkipBytes( &p_sys->bytestream, p_sys->i_header_size );
374 /* Copy the whole frame into the buffer */
375 block_GetBytes( &p_sys->bytestream, p_buf, p_sys->i_frame_size );
377 /* Make sure we don't reuse the same pts twice */
378 if( p_sys->i_pts == p_sys->bytestream.p_block->i_pts )
379 p_sys->i_pts = p_sys->bytestream.p_block->i_pts = 0;
381 /* So p_block doesn't get re-added several times */
382 *pp_block = block_BytestreamPop( &p_sys->bytestream );
384 p_sys->i_state = STATE_NOSYNC;
393 /*****************************************************************************
395 *****************************************************************************/
396 static uint8_t *GetOutBuffer( decoder_t *p_dec, void **pp_out_buffer )
398 decoder_sys_t *p_sys = p_dec->p_sys;
401 if( p_dec->fmt_out.audio.i_rate != p_sys->i_rate )
403 msg_Info( p_dec, "AAC channels: %d samplerate: %d",
404 p_sys->i_channels, p_sys->i_rate );
406 aout_DateInit( &p_sys->end_date, p_sys->i_rate );
407 aout_DateSet( &p_sys->end_date, p_sys->i_pts );
410 p_dec->fmt_out.audio.i_rate = p_sys->i_rate;
411 p_dec->fmt_out.audio.i_channels = p_sys->i_channels;
412 p_dec->fmt_out.audio.i_bytes_per_frame = p_sys->i_frame_size;
413 p_dec->fmt_out.audio.i_frame_length = p_sys->i_frame_length;
416 p_dec->fmt_out.audio.i_original_channels = p_sys->i_channels_conf;
417 p_dec->fmt_out.audio.i_physical_channels =
418 p_sys->i_channels_conf & AOUT_CHAN_PHYSMASK;
421 p_block = block_New( p_dec, p_sys->i_frame_size );
422 if( p_block == NULL ) return NULL;
424 p_block->i_pts = p_block->i_dts = aout_DateGet( &p_sys->end_date );
426 p_block->i_length = aout_DateIncrement( &p_sys->end_date,
427 p_sys->i_frame_length ) - p_block->i_pts;
429 *pp_out_buffer = p_block;
430 return p_block->p_buffer;
433 /*****************************************************************************
434 * ClosePacketizer: clean up the packetizer
435 *****************************************************************************/
436 static void ClosePacketizer( vlc_object_t *p_this )
438 decoder_t *p_dec = (decoder_t *)p_this;
439 decoder_sys_t *p_sys = p_dec->p_sys;
441 block_BytestreamRelease( &p_sys->bytestream );
443 free( p_dec->p_sys );
446 /*****************************************************************************
447 * ADTSSyncInfo: parse MPEG 4 audio ADTS sync info
448 *****************************************************************************/
449 static int ADTSSyncInfo( decoder_t * p_dec, const byte_t * p_buf,
450 unsigned int * pi_channels,
451 unsigned int * pi_sample_rate,
452 unsigned int * pi_frame_length,
453 unsigned int * pi_header_size,
454 unsigned int * pi_raw_blocks_in_frame )
456 int i_id, i_profile, i_sample_rate_idx, i_frame_size;
459 /* Fixed header between frames */
460 i_id = ( (p_buf[1] >> 3) & 0x01 ) ? 2 : 4;
461 b_crc = !(p_buf[1] & 0x01);
462 i_profile = p_buf[2] >> 6;
463 i_sample_rate_idx = (p_buf[2] >> 2) & 0x0f;
464 *pi_sample_rate = i_sample_rates[i_sample_rate_idx];
465 *pi_channels = ((p_buf[2] & 0x01) << 2) | ((p_buf[3] >> 6) & 0x03);
467 /* Variable header */
468 i_frame_size = ((p_buf[3] & 0x03) << 11) | (p_buf[4] << 3) |
469 ((p_buf[5] >> 5) & 0x7);
470 *pi_raw_blocks_in_frame = (p_buf[6] & 0x02) + 1;
472 if( !*pi_sample_rate || !*pi_channels || !i_frame_size )
478 *pi_frame_length = 1024;
480 /* Build the decoder specific info header */
481 if( !p_dec->fmt_out.i_extra )
483 p_dec->fmt_out.i_extra = 2;
484 p_dec->fmt_out.p_extra = malloc( 2 );
485 ((uint8_t *)p_dec->fmt_out.p_extra)[0] =
486 (i_profile + 1) << 3 | (i_sample_rate_idx >> 1);
487 ((uint8_t *)p_dec->fmt_out.p_extra)[1] =
488 ((i_sample_rate_idx & 0x01) << 7) | (*pi_channels <<3);
491 /* ADTS header length */
492 *pi_header_size = b_crc ? 9 : 7;
494 return i_frame_size - *pi_header_size;