git.sesse.net Git - mlt/blob - src/modules/avformat/producer_avformat.c

   1 /*
   2  * producer_avformat.c -- avformat producer
   3  * Copyright (C) 2003-2004 Ushodaya Enterprises Limited
   4  * Author: Charles Yates <charles.yates@pandora.be>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software Foundation,
  18  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  19  */
  20
  21 // Local header files
  22 #include "producer_avformat.h"
  23
  24 // MLT Header files
  25 #include <framework/mlt_frame.h>
  26
  27 // ffmpeg Header files
  28 #include <ffmpeg/avformat.h>
  29
  30 // System header files
  31 #include <stdlib.h>
  32 #include <string.h>
  33 #include <pthread.h>
  34 #include <math.h>
  35
  36 // Forward references.
  37 static int producer_open( mlt_producer this, char *file );
  38 static int producer_get_frame( mlt_producer this, mlt_frame_ptr frame, int index );
  39
  40 // A static flag used to determine if avformat has been initialised
  41 static int avformat_initialised = 0;
  42 static pthread_mutex_t avformat_mutex;
  43
  44 void *av_malloc( unsigned int size )
  45 {
  46         return mlt_pool_alloc( size );
  47 }
  48
  49 void *av_realloc( void *ptr, unsigned int size )
  50 {
  51         return mlt_pool_realloc( ptr, size );
  52 }
  53
  54 void av_free( void *ptr )
  55 {
  56         return mlt_pool_release( ptr );
  57 }
  58
  59 /** Constructor for libavformat.
  60 */
  61
  62 mlt_producer producer_avformat_init( char *file )
  63 {
  64         mlt_producer this = NULL;
  65
  66         // Check that we have a non-NULL argument
  67         if ( file != NULL )
  68         {
  69                 // Construct the producer
  70                 this = calloc( 1, sizeof( struct mlt_producer_s ) );
  71
  72                 // Initialise it
  73                 if ( mlt_producer_init( this, NULL ) == 0 )
  74                 {
  75                         // Get the properties
  76                         mlt_properties properties = mlt_producer_properties( this );
  77
  78                         // Set the resource property (required for all producers)
  79                         mlt_properties_set( properties, "resource", file );
  80
  81                         // TEST: audio sync tweaking
  82                         mlt_properties_set_double( properties, "discrepancy", 1 );
  83
  84                         // Register our get_frame implementation
  85                         this->get_frame = producer_get_frame;
  86
  87                         // Initialise avformat if necessary
  88                         if ( avformat_initialised == 0 )
  89                         {
  90                                 avformat_initialised = 1;
  91                                 pthread_mutex_init( &avformat_mutex, NULL );
  92                                 av_register_all( );
  93                         }
  94
  95                         // Open the file
  96                         if ( producer_open( this, file ) != 0 )
  97                         {
  98                                 // Clean up
  99                                 mlt_producer_close( this );
 100                                 this = NULL;
 101                         }
 102                 }
 103         }
 104
 105         return this;
 106 }
 107
 108 /** Find the default streams.
 109 */
 110
 111 static void find_default_streams( AVFormatContext *context, int *audio_index, int *video_index )
 112 {
 113         int i;
 114
 115         // Allow for multiple audio and video streams in the file and select first of each (if available)
 116         for( i = 0; i < context->nb_streams; i++ )
 117         {
 118                 // Get the codec context
 119                 AVCodecContext *codec_context = &context->streams[ i ]->codec;
 120
 121                 // Determine the type and obtain the first index of each type
 122                 switch( codec_context->codec_type )
 123                 {
 124                         case CODEC_TYPE_VIDEO:
 125                                 if ( *video_index < 0 )
 126                                         *video_index = i;
 127                                 break;
 128                         case CODEC_TYPE_AUDIO:
 129                                 if ( *audio_index < 0 )
 130                                         *audio_index = i;
 131                                 break;
 132                         default:
 133                                 break;
 134                 }
 135         }
 136 }
 137
 138 /** Producer file destructor.
 139 */
 140
 141 static void producer_file_close( void *context )
 142 {
 143         if ( context != NULL )
 144         {
 145                 // Lock the mutex now
 146                 pthread_mutex_lock( &avformat_mutex );
 147
 148                 // Close the file
 149                 av_close_input_file( context );
 150
 151                 // Unlock the mutex now
 152                 pthread_mutex_unlock( &avformat_mutex );
 153         }
 154 }
 155
 156 /** Producer file destructor.
 157 */
 158
 159 static void producer_codec_close( void *codec )
 160 {
 161         if ( codec != NULL )
 162         {
 163                 // Lock the mutex now
 164                 pthread_mutex_lock( &avformat_mutex );
 165
 166                 // Close the file
 167                 avcodec_close( codec );
 168
 169                 // Unlock the mutex now
 170                 pthread_mutex_unlock( &avformat_mutex );
 171         }
 172 }
 173
 174 /** Open the file.
 175 */
 176
 177 static int producer_open( mlt_producer this, char *file )
 178 {
 179         // Return an error code (0 == no error)
 180         int error = 0;
 181
 182         // Context for avformat
 183         AVFormatContext *context = NULL;
 184
 185         // Get the properties
 186         mlt_properties properties = mlt_producer_properties( this );
 187
 188         // We will treat everything with the producer fps
 189         double fps = mlt_properties_get_double( properties, "fps" );
 190
 191         // Lock the mutex now
 192         pthread_mutex_lock( &avformat_mutex );
 193
 194         // Now attempt to open the file
 195         error = av_open_input_file( &context, file, NULL, 0, NULL );
 196         error = error < 0;
 197
 198         // If successful, then try to get additional info
 199         if ( error == 0 )
 200         {
 201                 // Get the stream info
 202                 error = av_find_stream_info( context ) < 0;
 203
 204                 // Continue if no error
 205                 if ( error == 0 )
 206                 {
 207                         // We will default to the first audio and video streams found
 208                         int audio_index = -1;
 209                         int video_index = -1;
 210
 211                         // Now set properties where we can (use default unknowns if required)
 212                         if ( context->duration != AV_NOPTS_VALUE )
 213                         {
 214                                 // This isn't going to be accurate for all formats
 215                                 mlt_position frames = ( mlt_position )( ( ( double )context->duration / ( double )AV_TIME_BASE ) * fps );
 216                                 mlt_properties_set_position( properties, "out", frames - 2 );
 217                                 mlt_properties_set_position( properties, "length", frames - 1 );
 218                         }
 219
 220                         // Find default audio and video streams
 221                         find_default_streams( context, &audio_index, &video_index );
 222
 223                         // Store selected audio and video indexes on properties
 224                         mlt_properties_set_int( properties, "audio_index", audio_index );
 225                         mlt_properties_set_int( properties, "video_index", video_index );
 226
 227                         // We're going to cheat here - for a/v files, we will have two contexts (reasoning will be clear later)
 228                         if ( audio_index != -1 && video_index != -1 )
 229                         {
 230                                 // We'll use the open one as our video_context
 231                                 mlt_properties_set_data( properties, "video_context", context, 0, producer_file_close, NULL );
 232
 233                                 // And open again for our audio context
 234                                 av_open_input_file( &context, file, NULL, 0, NULL );
 235                                 av_find_stream_info( context );
 236
 237                                 // Audio context
 238                                 mlt_properties_set_data( properties, "audio_context", context, 0, producer_file_close, NULL );
 239                         }
 240                         else if ( video_index != -1 )
 241                         {
 242                                 // We only have a video context
 243                                 mlt_properties_set_data( properties, "video_context", context, 0, producer_file_close, NULL );
 244                         }
 245                         else if ( audio_index != -1 )
 246                         {
 247                                 // We only have an audio context
 248                                 mlt_properties_set_data( properties, "audio_context", context, 0, producer_file_close, NULL );
 249                         }
 250                         else
 251                         {
 252                                 // Something has gone wrong
 253                                 error = -1;
 254                         }
 255                 }
 256         }
 257
 258         // Unlock the mutex now
 259         pthread_mutex_unlock( &avformat_mutex );
 260
 261         return error;
 262 }
 263
 264 /** Convert a frame position to a time code.
 265 */
 266
 267 static double producer_time_of_frame( mlt_producer this, mlt_position position )
 268 {
 269         // Get the properties
 270         mlt_properties properties = mlt_producer_properties( this );
 271
 272         // Obtain the fps
 273         double fps = mlt_properties_get_double( properties, "fps" );
 274
 275         // Do the calc
 276         return ( double )position / fps;
 277 }
 278
 279 /** Get an image from a frame.
 280 */
 281
 282 static int producer_get_image( mlt_frame frame, uint8_t **buffer, mlt_image_format *format, int *width, int *height, int writable )
 283 {
 284         // Get the properties from the frame
 285         mlt_properties frame_properties = mlt_frame_properties( frame );
 286
 287         // Obtain the frame number of this frame
 288         mlt_position position = mlt_properties_get_position( frame_properties, "avformat_position" );
 289
 290         // Get the producer
 291         mlt_producer this = mlt_properties_get_data( frame_properties, "avformat_producer", NULL );
 292
 293         // Get the producer properties
 294         mlt_properties properties = mlt_producer_properties( this );
 295
 296         // Fetch the video_context
 297         AVFormatContext *context = mlt_properties_get_data( properties, "video_context", NULL );
 298
 299         // Get the video_index
 300         int index = mlt_properties_get_int( properties, "video_index" );
 301
 302         // Obtain the expected frame numer
 303         mlt_position expected = mlt_properties_get_position( properties, "video_expected" );
 304
 305         // Calculate the real time code
 306         double real_timecode = producer_time_of_frame( this, position );
 307
 308         // Get the video stream
 309         AVStream *stream = context->streams[ index ];
 310
 311         // Get codec context
 312         AVCodecContext *codec_context = &stream->codec;
 313
 314         // Packet
 315         AVPacket pkt;
 316
 317         // Get the conversion frame
 318         AVPicture *output = mlt_properties_get_data( properties, "video_output_frame", NULL );
 319
 320         // Special case pause handling flag
 321         int paused = 0;
 322
 323         // Special case ffwd handling
 324         int ignore = 0;
 325
 326         // Current time calcs
 327         double current_time = mlt_properties_get_double( properties, "current_time" );
 328
 329         // We may want to use the source fps if available
 330         double source_fps = mlt_properties_get_double( properties, "source_fps" );
 331
 332         // Set the result arguments that we know here (only *buffer is now required)
 333         *format = mlt_image_yuv422;
 334         *width = codec_context->width;
 335         *height = codec_context->height;
 336
 337         // Set this on the frame properties
 338         mlt_properties_set_int( frame_properties, "width", *width );
 339         mlt_properties_set_int( frame_properties, "height", *height );
 340
 341         // Lock the mutex now
 342         pthread_mutex_lock( &avformat_mutex );
 343
 344         // Construct an AVFrame for YUV422 conversion
 345         if ( output == NULL )
 346         {
 347                 int size = avpicture_get_size( PIX_FMT_YUV422, *width, *height );
 348                 size += *width * 2;
 349                 uint8_t *buf = mlt_pool_alloc( size );
 350                 output = mlt_pool_alloc( sizeof( AVPicture ) );
 351                 //memset( output, 0, sizeof( AVPicture ) );
 352                 avpicture_fill( output, buf, PIX_FMT_YUV422, *width, *height );
 353                 mlt_properties_set_data( properties, "video_output_frame", output, 0, ( mlt_destructor )mlt_pool_release, NULL );
 354                 mlt_properties_set_data( properties, "video_output_buffer", buf, 0, ( mlt_destructor )mlt_pool_release, NULL );
 355         }
 356
 357         // Seek if necessary
 358         if ( position != expected )
 359         {
 360                 if ( position + 1 == expected )
 361                 {
 362                         // We're paused - use last image
 363                         paused = 1;
 364                 }
 365                 else if ( position > expected && ( position - expected ) < 250 )
 366                 {
 367                         // Fast forward - seeking is inefficient for small distances - just ignore following frames
 368                         ignore = position - expected;
 369                 }
 370                 else
 371                 {
 372                         // Set to the real timecode
 373                         av_seek_frame( context, -1, real_timecode * 1000000.0 );
 374
 375                         // Remove the cached info relating to the previous position
 376                         mlt_properties_set_double( properties, "current_time", real_timecode );
 377                         mlt_properties_set_data( properties, "current_image", NULL, 0, NULL, NULL );
 378                 }
 379         }
 380
 381         // Duplicate the last image if necessary
 382         if ( mlt_properties_get_data( properties, "current_image", NULL ) != NULL &&
 383                  ( paused || mlt_properties_get_double( properties, "current_time" ) >= real_timecode ) )
 384         {
 385                 // Get current image and size
 386                 int size = 0;
 387                 uint8_t *image = mlt_properties_get_data( properties, "current_image", &size );
 388
 389                 // Duplicate it
 390                 *buffer = mlt_pool_alloc( size );
 391                 memcpy( *buffer, image, size );
 392
 393                 // Set this on the frame properties
 394                 mlt_properties_set_data( frame_properties, "image", *buffer, size, ( mlt_destructor )mlt_pool_release, NULL );
 395         }
 396         else
 397         {
 398                 int ret = 0;
 399                 int got_picture = 0;
 400                 AVFrame frame;
 401
 402                 memset( &pkt, 0, sizeof( pkt ) );
 403                 memset( &frame, 0, sizeof( frame ) );
 404
 405                 while( ret >= 0 && !got_picture )
 406                 {
 407                         // Read a packet
 408                         ret = av_read_frame( context, &pkt );
 409
 410                         // We only deal with video from the selected video_index
 411                         if ( ret >= 0 && pkt.stream_index == index && pkt.size > 0 )
 412                         {
 413                                 // Decode the image
 414                                 ret = avcodec_decode_video( codec_context, &frame, &got_picture, pkt.data, pkt.size );
 415
 416                                 if ( got_picture )
 417                                 {
 418                                         if ( pkt.pts != AV_NOPTS_VALUE && pkt.pts != 0  )
 419                                                 current_time = ( double )pkt.pts / 1000000.0;
 420                                         else
 421                                                 current_time = real_timecode;
 422
 423                                         // Handle ignore
 424                                         if ( current_time < real_timecode )
 425                                         {
 426                                                 ignore = 0;
 427                                                 got_picture = 0;
 428                                         }
 429                                         else if ( current_time >= real_timecode )
 430                                         {
 431                                                 //current_time = real_timecode;
 432                                                 ignore = 0;
 433                                         }
 434                                         else if ( ignore -- )
 435                                         {
 436                                                 got_picture = 0;
 437                                         }
 438                                 }
 439                         }
 440
 441                         // We're finished with this packet regardless
 442                         av_free_packet( &pkt );
 443                 }
 444
 445                 // Now handle the picture if we have one
 446                 if ( got_picture )
 447                 {
 448                         // Get current image and size
 449                         int size = 0;
 450                         uint8_t *image = mlt_properties_get_data( properties, "current_image", &size );
 451
 452                         if ( image == NULL || size != *width * *height * 2 )
 453                         {
 454                                 size = *width * ( *height + 1 ) * 2;
 455                                 image = mlt_pool_alloc( size );
 456                                 mlt_properties_set_data( properties, "current_image", image, size, ( mlt_destructor )mlt_pool_release, NULL );
 457                         }
 458
 459                         *buffer = mlt_pool_alloc( size );
 460
 461                         // EXPERIMENTAL IMAGE NORMALISATIONS
 462                         if ( codec_context->pix_fmt == PIX_FMT_YUV420P )
 463                         {
 464                                 register int i, j;
 465                                 register int half = *width >> 1;
 466                                 register uint8_t *Y = ( ( AVPicture * )&frame )->data[ 0 ];
 467                                 register uint8_t *U = ( ( AVPicture * )&frame )->data[ 1 ];
 468                                 register uint8_t *V = ( ( AVPicture * )&frame )->data[ 2 ];
 469                                 register uint8_t *d = *buffer;
 470                                 register uint8_t *y, *u, *v;
 471
 472                                 i = *height >> 1;
 473                                 while ( i -- )
 474                                 {
 475                                         y = Y;
 476                                         u = U;
 477                                         v = V;
 478                                         j = half;
 479                                         while ( j -- )
 480                                         {
 481                                                 *d ++ = *y ++;
 482                                                 *d ++ = *u ++;
 483                                                 *d ++ = *y ++;
 484                                                 *d ++ = *v ++;
 485                                         }
 486
 487                                         Y += ( ( AVPicture * )&frame )->linesize[ 0 ];
 488                                         y = Y;
 489                                         u = U;
 490                                         v = V;
 491                                         j = half;
 492                                         while ( j -- )
 493                                         {
 494                                                 *d ++ = *y ++;
 495                                                 *d ++ = *u ++;
 496                                                 *d ++ = *y ++;
 497                                                 *d ++ = *v ++;
 498                                         }
 499
 500                                         Y += ( ( AVPicture * )&frame )->linesize[ 0 ];
 501                                         U += ( ( AVPicture * )&frame )->linesize[ 1 ];
 502                                         V += ( ( AVPicture * )&frame )->linesize[ 2 ];
 503                                 }
 504                         }
 505                         else
 506                         {
 507                                 img_convert( output, PIX_FMT_YUV422, (AVPicture *)&frame, codec_context->pix_fmt, *width, *height );
 508                                 memcpy( *buffer, output->data[ 0 ], size );
 509                         }
 510
 511                         memcpy( image, *buffer, size );
 512                         mlt_properties_set_data( frame_properties, "image", *buffer, size, ( mlt_destructor )mlt_pool_release, NULL );
 513
 514                         if ( current_time == 0 && source_fps != 0 )
 515                         {
 516                                 double fps = mlt_properties_get_double( properties, "fps" );
 517                                 current_time = ceil( source_fps * ( double )position / fps ) * ( 1 / source_fps );
 518                                 mlt_properties_set_double( properties, "current_time", current_time );
 519                         }
 520                         else
 521                         {
 522                                 mlt_properties_set_double( properties, "current_time", current_time );
 523                         }
 524                 }
 525         }
 526
 527         // Regardless of speed, we expect to get the next frame (cos we ain't too bright)
 528         mlt_properties_set_position( properties, "video_expected", position + 1 );
 529
 530         // Unlock the mutex now
 531         pthread_mutex_unlock( &avformat_mutex );
 532
 533         return 0;
 534 }
 535
 536 /** Set up video handling.
 537 */
 538
 539 static void producer_set_up_video( mlt_producer this, mlt_frame frame )
 540 {
 541         // Get the properties
 542         mlt_properties properties = mlt_producer_properties( this );
 543
 544         // Fetch the video_context
 545         AVFormatContext *context = mlt_properties_get_data( properties, "video_context", NULL );
 546
 547         // Get the video_index
 548         int index = mlt_properties_get_int( properties, "video_index" );
 549
 550         // Get the frame properties
 551         mlt_properties frame_properties = mlt_frame_properties( frame );
 552
 553         // Lock the mutex now
 554         pthread_mutex_lock( &avformat_mutex );
 555
 556         if ( context != NULL && index != -1 )
 557         {
 558                 // Get the video stream
 559                 AVStream *stream = context->streams[ index ];
 560
 561                 // Get codec context
 562                 AVCodecContext *codec_context = &stream->codec;
 563
 564                 // Get the codec
 565                 AVCodec *codec = mlt_properties_get_data( properties, "video_codec", NULL );
 566
 567                 // Initialise the codec if necessary
 568                 if ( codec == NULL )
 569                 {
 570                         // Find the codec
 571                         codec = avcodec_find_decoder( codec_context->codec_id );
 572
 573                         // If we don't have a codec and we can't initialise it, we can't do much more...
 574                         if ( codec != NULL && avcodec_open( codec_context, codec ) >= 0 )
 575                         {
 576                                 // Now store the codec with its destructor
 577                                 mlt_properties_set_data( properties, "video_codec", codec_context, 0, producer_codec_close, NULL );
 578                         }
 579                         else
 580                         {
 581                                 // Remember that we can't use this later
 582                                 mlt_properties_set_int( properties, "video_index", -1 );
 583                         }
 584                 }
 585
 586                 // No codec, no show...
 587                 if ( codec != NULL )
 588                 {
 589                         double aspect_ratio = 1;
 590                         double source_fps = 0;
 591
 592                         // Set aspect ratio
 593                         if ( codec_context->sample_aspect_ratio.num > 0 )
 594                                 aspect_ratio = av_q2d( codec_context->sample_aspect_ratio );
 595
 596                         mlt_properties_set_double( properties, "aspect_ratio", aspect_ratio );
 597                         //fprintf( stderr, "AVFORMAT: sample aspect %f %dx%d\n", av_q2d( codec_context->sample_aspect_ratio ), codec_context->width, codec_context->height );
 598
 599                         // Determine the fps
 600                         source_fps = ( double )codec_context->frame_rate / codec_context->frame_rate_base;
 601
 602                         // We'll use fps if it's available
 603                         if ( source_fps > 0 && source_fps < 30 )
 604                                 mlt_properties_set_double( properties, "source_fps", source_fps );
 605
 606                         // Set the width and height
 607                         mlt_properties_set_int( frame_properties, "width", codec_context->width );
 608                         mlt_properties_set_int( frame_properties, "height", codec_context->height );
 609
 610                         mlt_frame_push_get_image( frame, producer_get_image );
 611                         mlt_properties_set_data( frame_properties, "avformat_producer", this, 0, NULL, NULL );
 612                 }
 613                 else
 614                 {
 615                         mlt_properties_set_int( frame_properties, "test_image", 1 );
 616                 }
 617         }
 618         else
 619         {
 620                 mlt_properties_set_int( frame_properties, "test_image", 1 );
 621         }
 622
 623         // Unlock the mutex now
 624         pthread_mutex_unlock( &avformat_mutex );
 625 }
 626
 627 /** Get the audio from a frame.
 628 */
 629
 630 static int producer_get_audio( mlt_frame frame, int16_t **buffer, mlt_audio_format *format, int *frequency, int *channels, int *samples )
 631 {
 632         // Get the properties from the frame
 633         mlt_properties frame_properties = mlt_frame_properties( frame );
 634
 635         // Obtain the frame number of this frame
 636         mlt_position position = mlt_properties_get_position( frame_properties, "avformat_position" );
 637
 638         // Get the producer
 639         mlt_producer this = mlt_properties_get_data( frame_properties, "avformat_producer", NULL );
 640
 641         // Get the producer properties
 642         mlt_properties properties = mlt_producer_properties( this );
 643
 644         // Fetch the audio_context
 645         AVFormatContext *context = mlt_properties_get_data( properties, "audio_context", NULL );
 646
 647         // Get the audio_index
 648         int index = mlt_properties_get_int( properties, "audio_index" );
 649
 650         // Obtain the expected frame numer
 651         mlt_position expected = mlt_properties_get_position( properties, "audio_expected" );
 652
 653         // Obtain the resample context if it exists (not always needed)
 654         ReSampleContext *resample = mlt_properties_get_data( properties, "audio_resample", NULL );
 655
 656         // Obtain the audio buffer
 657         int16_t *audio_buffer = mlt_properties_get_data( properties, "audio_buffer", NULL );
 658
 659         // Get amount of audio used
 660         int audio_used =  mlt_properties_get_int( properties, "audio_used" );
 661
 662         // Calculate the real time code
 663         double real_timecode = producer_time_of_frame( this, position );
 664
 665         // Get the audio stream
 666         AVStream *stream = context->streams[ index ];
 667
 668         // Get codec context
 669         AVCodecContext *codec_context = &stream->codec;
 670
 671         // Packet
 672         AVPacket pkt;
 673
 674         // Number of frames to ignore (for ffwd)
 675         int ignore = 0;
 676
 677         // Flag for paused (silence)
 678         int paused = 0;
 679         int locked = 0;
 680
 681         // Lock the mutex now
 682         pthread_mutex_lock( &avformat_mutex );
 683
 684         // Check for resample and create if necessary
 685         if ( resample == NULL )
 686         {
 687                 // Create the resampler
 688                 resample = audio_resample_init( *channels, codec_context->channels, *frequency, codec_context->sample_rate );
 689
 690                 // And store it on properties
 691                 mlt_properties_set_data( properties, "audio_resample", resample, 0, ( mlt_destructor )audio_resample_close, NULL );
 692         }
 693
 694         // Check for audio buffer and create if necessary
 695         if ( audio_buffer == NULL )
 696         {
 697                 // Allocate the audio buffer
 698                 audio_buffer = mlt_pool_alloc( AVCODEC_MAX_AUDIO_FRAME_SIZE * sizeof( int16_t ) );
 699
 700                 // And store it on properties for reuse
 701                 mlt_properties_set_data( properties, "audio_buffer", audio_buffer, 0, ( mlt_destructor )mlt_pool_release, NULL );
 702         }
 703
 704         // Seek if necessary
 705         if ( position != expected )
 706         {
 707                 if ( position + 1 == expected )
 708                 {
 709                         // We're paused - silence required
 710                         paused = 1;
 711                 }
 712                 else if ( position > expected && ( position - expected ) < 250 )
 713                 {
 714                         // Fast forward - seeking is inefficient for small distances - just ignore following frames
 715                         ignore = position - expected;
 716                 }
 717                 else
 718                 {
 719                         // Set to the real timecode
 720                         av_seek_frame( context, -1, real_timecode * 1000000.0 );
 721
 722                         // Clear the usage in the audio buffer
 723                         audio_used = 0;
 724
 725                         locked = 1;
 726                 }
 727         }
 728
 729         // Get the audio if required
 730         if ( !paused )
 731         {
 732                 int ret = 0;
 733                 int got_audio = 0;
 734                 int16_t *temp = mlt_pool_alloc( sizeof( int16_t ) * AVCODEC_MAX_AUDIO_FRAME_SIZE );
 735
 736                 memset( &pkt, 0, sizeof( pkt ) );
 737
 738                 while( ret >= 0 && !got_audio )
 739                 {
 740                         // Check if the buffer already contains the samples required
 741                         if ( audio_used >= *samples && ignore == 0 )
 742                         {
 743                                 got_audio = 1;
 744                                 break;
 745                         }
 746
 747                         // Read a packet
 748                         ret = av_read_frame( context, &pkt );
 749
 750                 int len = pkt.size;
 751                 uint8_t *ptr = pkt.data;
 752                         int data_size;
 753
 754                         // We only deal with video from the selected video_index
 755                         while ( ptr != NULL && ret >= 0 && pkt.stream_index == index && len > 0 )
 756                         {
 757                                 // Decode the audio
 758                                 ret = avcodec_decode_audio( codec_context, temp, &data_size, ptr, len );
 759
 760                                 if ( ret < 0 )
 761                                 {
 762                                         ret = 0;
 763                                         break;
 764                                 }
 765
 766                                 len -= ret;
 767                                 ptr += ret;
 768
 769                                 if ( data_size > 0 )
 770                                 {
 771                                         int size_out = audio_resample( resample, &audio_buffer[ audio_used * *channels ], temp, data_size / ( codec_context->channels * sizeof( int16_t ) ) );
 772
 773                                         audio_used += size_out;
 774
 775                                         // Handle ignore
 776                                         while ( ignore && audio_used > *samples )
 777                                         {
 778                                                 ignore --;
 779                                                 audio_used -= *samples;
 780                                                 memmove( audio_buffer, &audio_buffer[ *samples * *channels ], audio_used * sizeof( int16_t ) );
 781                                         }
 782                                 }
 783
 784                                 // If we're behind, ignore this packet
 785                                 float current_pts = (float)pkt.pts / 1000000.0;
 786                                 double discrepancy = mlt_properties_get_double( properties, "discrepancy" );
 787                                 if ( current_pts != 0 && real_timecode != 0 )
 788                                 {
 789                                         if ( discrepancy != 1 )
 790                                                 discrepancy = ( discrepancy + ( real_timecode / current_pts ) ) / 2;
 791                                         else
 792                                                 discrepancy = real_timecode / current_pts;
 793                                         if ( discrepancy > 0.9 && discrepancy < 1.1 )
 794                                                 discrepancy = 1.0;
 795                                         else
 796                                                 discrepancy = floor( discrepancy + 0.5 );
 797
 798                                         if ( discrepancy == 0 )
 799                                                 discrepancy = 1.0;
 800
 801                                         mlt_properties_set_double( properties, "discrepancy", discrepancy );
 802                                 }
 803
 804                                 if ( !ignore && discrepancy * current_pts <= ( real_timecode - 0.02 ) )
 805                                         ignore = 1;
 806                         }
 807
 808                         // We're finished with this packet regardless
 809                         av_free_packet( &pkt );
 810                 }
 811
 812                 *buffer = mlt_pool_alloc( *samples * *channels * sizeof( int16_t ) );
 813                 mlt_properties_set_data( frame_properties, "audio", *buffer, 0, ( mlt_destructor )mlt_pool_release, NULL );
 814
 815                 // Now handle the audio if we have enough
 816                 if ( audio_used >= *samples )
 817                 {
 818                         memcpy( *buffer, audio_buffer, *samples * *channels * sizeof( int16_t ) );
 819                         audio_used -= *samples;
 820                         memmove( audio_buffer, &audio_buffer[ *samples * *channels ], audio_used * *channels * sizeof( int16_t ) );
 821                 }
 822                 else
 823                 {
 824                         memset( *buffer, 0, *samples * *channels * sizeof( int16_t ) );
 825                 }
 826
 827                 // Store the number of audio samples still available
 828                 mlt_properties_set_int( properties, "audio_used", audio_used );
 829
 830                 // Release the temporary audio
 831                 mlt_pool_release( temp );
 832         }
 833         else
 834         {
 835                 // Get silence and don't touch the context
 836                 frame->get_audio = NULL;
 837                 mlt_frame_get_audio( frame, buffer, format, frequency, channels, samples );
 838         }
 839
 840         // Regardless of speed, we expect to get the next frame (cos we ain't too bright)
 841         mlt_properties_set_position( properties, "audio_expected", position + 1 );
 842
 843         // Unlock the mutex now
 844         pthread_mutex_unlock( &avformat_mutex );
 845
 846         return 0;
 847 }
 848
 849 /** Set up audio handling.
 850 */
 851
 852 static void producer_set_up_audio( mlt_producer this, mlt_frame frame )
 853 {
 854         // Get the properties
 855         mlt_properties properties = mlt_producer_properties( this );
 856
 857         // Fetch the audio_context
 858         AVFormatContext *context = mlt_properties_get_data( properties, "audio_context", NULL );
 859
 860         // Get the audio_index
 861         int index = mlt_properties_get_int( properties, "audio_index" );
 862
 863         // Lock the mutex now
 864         pthread_mutex_lock( &avformat_mutex );
 865
 866         // Deal with audio context
 867         if ( context != NULL && index != -1 )
 868         {
 869                 // Get the frame properties
 870                 mlt_properties frame_properties = mlt_frame_properties( frame );
 871
 872                 // Get the audio stream
 873                 AVStream *stream = context->streams[ index ];
 874
 875                 // Get codec context
 876                 AVCodecContext *codec_context = &stream->codec;
 877
 878                 // Get the codec
 879                 AVCodec *codec = mlt_properties_get_data( properties, "audio_codec", NULL );
 880
 881                 // Initialise the codec if necessary
 882                 if ( codec == NULL )
 883                 {
 884                         // Find the codec
 885                         codec = avcodec_find_decoder( codec_context->codec_id );
 886
 887                         // If we don't have a codec and we can't initialise it, we can't do much more...
 888                         if ( codec != NULL && avcodec_open( codec_context, codec ) >= 0 )
 889                         {
 890                                 // Now store the codec with its destructor
 891                                 mlt_properties_set_data( properties, "audio_codec", codec_context, 0, producer_codec_close, NULL );
 892
 893                         }
 894                         else
 895                         {
 896                                 // Remember that we can't use this later
 897                                 mlt_properties_set_int( properties, "audio_index", -1 );
 898                         }
 899                 }
 900
 901                 // No codec, no show...
 902                 if ( codec != NULL )
 903                 {
 904                         frame->get_audio = producer_get_audio;
 905                         mlt_properties_set_data( frame_properties, "avformat_producer", this, 0, NULL, NULL );
 906                 }
 907         }
 908
 909         // Unlock the mutex now
 910         pthread_mutex_unlock( &avformat_mutex );
 911 }
 912
 913 /** Our get frame implementation.
 914 */
 915
 916 static int producer_get_frame( mlt_producer this, mlt_frame_ptr frame, int index )
 917 {
 918         // Create an empty frame
 919         *frame = mlt_frame_init( );
 920
 921         // Update timecode on the frame we're creating
 922         mlt_frame_set_position( *frame, mlt_producer_position( this ) );
 923
 924         // Set the position of this producer
 925         mlt_properties_set_position( mlt_frame_properties( *frame ), "avformat_position", mlt_producer_get_in( this ) + mlt_producer_position( this ) );
 926
 927         // Set up the video
 928         producer_set_up_video( this, *frame );
 929
 930         // Set up the audio
 931         producer_set_up_audio( this, *frame );
 932
 933         // Set the aspect_ratio
 934         mlt_properties_set_double( mlt_frame_properties( *frame ), "aspect_ratio", mlt_properties_get_double( mlt_producer_properties( this ), "aspect_ratio" ) );
 935
 936         // Calculate the next timecode
 937         mlt_producer_prepare_next( this );
 938
 939         return 0;
 940 }