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 /** Constructor for libavformat.
  45 */
  46
  47 mlt_producer producer_avformat_init( char *file )
  48 {
  49         mlt_producer this = NULL;
  50
  51         // Check that we have a non-NULL argument
  52         if ( file != NULL )
  53         {
  54                 // Construct the producer
  55                 this = calloc( 1, sizeof( struct mlt_producer_s ) );
  56
  57                 // Initialise it
  58                 if ( mlt_producer_init( this, NULL ) == 0 )
  59                 {
  60                         // Get the properties
  61                         mlt_properties properties = mlt_producer_properties( this );
  62
  63                         // Set the resource property (required for all producers)
  64                         mlt_properties_set( properties, "resource", file );
  65
  66                         // TEST: audio sync tweaking
  67                         mlt_properties_set_double( properties, "discrepancy", 1 );
  68
  69                         // Register our get_frame implementation
  70                         this->get_frame = producer_get_frame;
  71
  72                         // Initialise avformat if necessary
  73                         if ( avformat_initialised == 0 )
  74                         {
  75                                 pthread_mutex_init( &avformat_mutex, NULL );
  76                                 avformat_initialised = 1;
  77                                 av_register_all( );
  78                         }
  79
  80                         // Open the file
  81                         if ( producer_open( this, file ) != 0 )
  82                         {
  83                                 // Clean up
  84                                 mlt_producer_close( this );
  85                                 this = NULL;
  86                         }
  87                 }
  88         }
  89
  90         return this;
  91 }
  92
  93 /** Find the default streams.
  94 */
  95
  96 static void find_default_streams( AVFormatContext *context, int *audio_index, int *video_index )
  97 {
  98         int i;
  99
 100         // Allow for multiple audio and video streams in the file and select first of each (if available)
 101         for( i = 0; i < context->nb_streams; i++ )
 102         {
 103                 // Get the codec context
 104                 AVCodecContext *codec_context = &context->streams[ i ]->codec;
 105
 106                 // Determine the type and obtain the first index of each type
 107                 switch( codec_context->codec_type )
 108                 {
 109                         case CODEC_TYPE_VIDEO:
 110                                 if ( *video_index < 0 )
 111                                         *video_index = i;
 112                                 break;
 113                         case CODEC_TYPE_AUDIO:
 114                                 if ( *audio_index < 0 )
 115                                         *audio_index = i;
 116                                 break;
 117                         default:
 118                                 break;
 119                 }
 120         }
 121 }
 122
 123 /** Producer file destructor.
 124 */
 125
 126 static void producer_file_close( void *context )
 127 {
 128         if ( context != NULL )
 129         {
 130                 // Lock the mutex now
 131                 pthread_mutex_lock( &avformat_mutex );
 132
 133                 // Close the file
 134                 av_close_input_file( context );
 135
 136                 // Unlock the mutex now
 137                 pthread_mutex_unlock( &avformat_mutex );
 138         }
 139 }
 140
 141 /** Producer file destructor.
 142 */
 143
 144 static void producer_codec_close( void *codec )
 145 {
 146         if ( codec != NULL )
 147         {
 148                 // Lock the mutex now
 149                 pthread_mutex_lock( &avformat_mutex );
 150
 151                 // Close the file
 152                 avcodec_close( codec );
 153
 154                 // Unlock the mutex now
 155                 pthread_mutex_unlock( &avformat_mutex );
 156         }
 157 }
 158
 159 /** Open the file.
 160 */
 161
 162 static int producer_open( mlt_producer this, char *file )
 163 {
 164         // Return an error code (0 == no error)
 165         int error = 0;
 166
 167         // Context for avformat
 168         AVFormatContext *context = NULL;
 169
 170         // Get the properties
 171         mlt_properties properties = mlt_producer_properties( this );
 172
 173         // We will treat everything with the producer fps
 174         double fps = mlt_properties_get_double( properties, "fps" );
 175
 176         // Lock the mutex now
 177         pthread_mutex_lock( &avformat_mutex );
 178
 179         // Now attempt to open the file
 180         error = av_open_input_file( &context, file, NULL, 0, NULL );
 181         error = error < 0;
 182
 183         // If successful, then try to get additional info
 184         if ( error == 0 )
 185         {
 186                 // Get the stream info
 187                 error = av_find_stream_info( context ) < 0;
 188
 189                 // Continue if no error
 190                 if ( error == 0 )
 191                 {
 192                         // We will default to the first audio and video streams found
 193                         int audio_index = -1;
 194                         int video_index = -1;
 195
 196                         // Now set properties where we can (use default unknowns if required)
 197                         if ( context->duration != AV_NOPTS_VALUE )
 198                         {
 199                                 // This isn't going to be accurate for all formats
 200                                 mlt_position frames = ( mlt_position )( ( ( double )context->duration / ( double )AV_TIME_BASE ) * fps );
 201                                 mlt_properties_set_position( properties, "out", frames - 2 );
 202                                 mlt_properties_set_position( properties, "length", frames - 1 );
 203                         }
 204
 205                         // Find default audio and video streams
 206                         find_default_streams( context, &audio_index, &video_index );
 207
 208                         // Store selected audio and video indexes on properties
 209                         mlt_properties_set_int( properties, "audio_index", audio_index );
 210                         mlt_properties_set_int( properties, "video_index", video_index );
 211
 212                         // We're going to cheat here - for a/v files, we will have two contexts (reasoning will be clear later)
 213                         if ( audio_index != -1 && video_index != -1 )
 214                         {
 215                                 // We'll use the open one as our video_context
 216                                 mlt_properties_set_data( properties, "video_context", context, 0, producer_file_close, NULL );
 217
 218                                 // And open again for our audio context
 219                                 av_open_input_file( &context, file, NULL, 0, NULL );
 220                                 av_find_stream_info( context );
 221
 222                                 // Audio context
 223                                 mlt_properties_set_data( properties, "audio_context", context, 0, producer_file_close, NULL );
 224                         }
 225                         else if ( video_index != -1 )
 226                         {
 227                                 // We only have a video context
 228                                 mlt_properties_set_data( properties, "video_context", context, 0, producer_file_close, NULL );
 229                         }
 230                         else if ( audio_index != -1 )
 231                         {
 232                                 // We only have an audio context
 233                                 mlt_properties_set_data( properties, "audio_context", context, 0, producer_file_close, NULL );
 234                         }
 235                         else
 236                         {
 237                                 // Something has gone wrong
 238                                 error = -1;
 239                         }
 240                 }
 241         }
 242
 243         // Unlock the mutex now
 244         pthread_mutex_unlock( &avformat_mutex );
 245
 246         return error;
 247 }
 248
 249 /** Convert a frame position to a time code.
 250 */
 251
 252 static double producer_time_of_frame( mlt_producer this, mlt_position position )
 253 {
 254         // Get the properties
 255         mlt_properties properties = mlt_producer_properties( this );
 256
 257         // Obtain the fps
 258         double fps = mlt_properties_get_double( properties, "fps" );
 259
 260         // Do the calc
 261         return ( double )position / fps;
 262 }
 263
 264 /** Get an image from a frame.
 265 */
 266
 267 static int producer_get_image( mlt_frame frame, uint8_t **buffer, mlt_image_format *format, int *width, int *height, int writable )
 268 {
 269         // Get the properties from the frame
 270         mlt_properties frame_properties = mlt_frame_properties( frame );
 271
 272         // Obtain the frame number of this frame
 273         mlt_position position = mlt_properties_get_position( frame_properties, "avformat_position" );
 274
 275         // Get the producer
 276         mlt_producer this = mlt_properties_get_data( frame_properties, "avformat_producer", NULL );
 277
 278         // Get the producer properties
 279         mlt_properties properties = mlt_producer_properties( this );
 280
 281         // Fetch the video_context
 282         AVFormatContext *context = mlt_properties_get_data( properties, "video_context", NULL );
 283
 284         // Get the video_index
 285         int index = mlt_properties_get_int( properties, "video_index" );
 286
 287         // Obtain the expected frame numer
 288         mlt_position expected = mlt_properties_get_position( properties, "video_expected" );
 289
 290         // Calculate the real time code
 291         double real_timecode = producer_time_of_frame( this, position );
 292
 293         // Get the video stream
 294         AVStream *stream = context->streams[ index ];
 295
 296         // Get codec context
 297         AVCodecContext *codec_context = &stream->codec;
 298
 299         // Packet
 300         AVPacket pkt;
 301
 302         // Get the conversion frame
 303         AVPicture *output = mlt_properties_get_data( properties, "video_output_frame", NULL );
 304
 305         // Special case pause handling flag
 306         int paused = 0;
 307
 308         // Special case ffwd handling
 309         int ignore = 0;
 310
 311         // Current time calcs
 312         double current_time = 0;
 313
 314         // We may want to use the source fps if available
 315         double source_fps = mlt_properties_get_double( properties, "source_fps" );
 316
 317         // Set the result arguments that we know here (only *buffer is now required)
 318         *format = mlt_image_yuv422;
 319         *width = codec_context->width;
 320         *height = codec_context->height;
 321
 322         // Set this on the frame properties
 323         mlt_properties_set_int( frame_properties, "width", *width );
 324         mlt_properties_set_int( frame_properties, "height", *height );
 325
 326         // Lock the mutex now
 327         pthread_mutex_lock( &avformat_mutex );
 328
 329         // Construct an AVFrame for YUV422 conversion
 330         if ( output == NULL )
 331         {
 332                 int size = avpicture_get_size( PIX_FMT_YUV422, *width, *height );
 333                 size += *width * 2;
 334                 uint8_t *buf = mlt_pool_alloc( size );
 335                 output = mlt_pool_alloc( sizeof( AVPicture ) );
 336                 //memset( output, 0, sizeof( AVPicture ) );
 337                 avpicture_fill( output, buf, PIX_FMT_YUV422, *width, *height );
 338                 mlt_properties_set_data( properties, "video_output_frame", output, 0, ( mlt_destructor )mlt_pool_release, NULL );
 339                 mlt_properties_set_data( properties, "video_output_buffer", buf, 0, ( mlt_destructor )mlt_pool_release, NULL );
 340         }
 341
 342         // Seek if necessary
 343         if ( position != expected )
 344         {
 345                 if ( position + 1 == expected )
 346                 {
 347                         // We're paused - use last image
 348                         paused = 1;
 349                 }
 350                 else if ( position > expected && ( position - expected ) < 250 )
 351                 {
 352                         // Fast forward - seeking is inefficient for small distances - just ignore following frames
 353                         ignore = position - expected;
 354                 }
 355                 else
 356                 {
 357                         // Set to the real timecode
 358                         av_seek_frame( context, -1, real_timecode * 1000000.0 );
 359
 360                         // Remove the cached info relating to the previous position
 361                         mlt_properties_set_double( properties, "current_time", 0 );
 362                         mlt_properties_set_data( properties, "current_image", NULL, 0, NULL, NULL );
 363                 }
 364         }
 365
 366         // Duplicate the last image if necessary
 367         if ( mlt_properties_get_data( properties, "current_image", NULL ) != NULL &&
 368                  ( paused || mlt_properties_get_double( properties, "current_time" ) >= real_timecode ) )
 369         {
 370                 // Get current image and size
 371                 int size = 0;
 372                 uint8_t *image = mlt_properties_get_data( properties, "current_image", &size );
 373
 374                 // Duplicate it
 375                 *buffer = mlt_pool_alloc( size );
 376                 memcpy( *buffer, image, size );
 377
 378                 // Set this on the frame properties
 379                 mlt_properties_set_data( frame_properties, "image", *buffer, size, ( mlt_destructor )mlt_pool_release, NULL );
 380         }
 381         else
 382         {
 383                 int ret = 0;
 384                 int got_picture = 0;
 385                 AVFrame frame;
 386
 387                 memset( &pkt, 0, sizeof( pkt ) );
 388                 memset( &frame, 0, sizeof( frame ) );
 389
 390                 while( ret >= 0 && !got_picture )
 391                 {
 392                         // Read a packet
 393                         ret = av_read_frame( context, &pkt );
 394
 395                         // We only deal with video from the selected video_index
 396                         if ( ret >= 0 && pkt.stream_index == index && pkt.size > 0 )
 397                         {
 398                                 current_time = ( double )pkt.pts / 1000000.0;
 399
 400                                 // Decode the image
 401                                 ret = avcodec_decode_video( codec_context, &frame, &got_picture, pkt.data, pkt.size );
 402
 403                                 if ( got_picture )
 404                                 {
 405                                         // Handle ignore
 406                                         if ( current_time < real_timecode )
 407                                         {
 408                                                 ignore = 0;
 409                                                 got_picture = 0;
 410                                         }
 411                                         else if ( current_time >= real_timecode )
 412                                         {
 413                                                 ignore = 0;
 414                                         }
 415                                         else if ( got_picture && ignore -- )
 416                                         {
 417                                                 got_picture = 0;
 418                                         }
 419                                 }
 420                         }
 421
 422                         // We're finished with this packet regardless
 423                         av_free_packet( &pkt );
 424                 }
 425
 426                 // Now handle the picture if we have one
 427                 if ( got_picture )
 428                 {
 429                         // Get current image and size
 430                         int size = 0;
 431                         uint8_t *image = mlt_properties_get_data( properties, "current_image", &size );
 432
 433                         if ( image == NULL || size != *width * *height * 2 )
 434                         {
 435                                 size = *width * ( *height + 1 ) * 2;
 436                                 image = mlt_pool_alloc( size );
 437                                 mlt_properties_set_data( properties, "current_image", image, size, ( mlt_destructor )mlt_pool_release, NULL );
 438                         }
 439
 440                         *buffer = mlt_pool_alloc( size );
 441
 442                         // EXPERIMENTAL IMAGE NORMALISATIONS
 443                         if ( codec_context->pix_fmt == PIX_FMT_YUV420P )
 444                         {
 445                                 register int i, j;
 446                                 register int half = *width >> 1;
 447                                 uint8_t *Y = ( ( AVPicture * )&frame )->data[ 0 ];
 448                                 uint8_t *U = ( ( AVPicture * )&frame )->data[ 1 ];
 449                                 uint8_t *V = ( ( AVPicture * )&frame )->data[ 2 ];
 450                                 register uint8_t *d = *buffer;
 451                                 register uint8_t *y, *u, *v;
 452
 453                                 i = *height >> 1;
 454                                 while ( i -- )
 455                                 {
 456                                         y = Y;
 457                                         u = U;
 458                                         v = V;
 459                                         j = half;
 460                                         while ( j -- )
 461                                         {
 462                                                 *d ++ = *y ++;
 463                                                 *d ++ = *u ++;
 464                                                 *d ++ = *y ++;
 465                                                 *d ++ = *v ++;
 466                                         }
 467
 468                                         Y += ( ( AVPicture * )&frame )->linesize[ 0 ];
 469                                         y = Y;
 470                                         u = U;
 471                                         v = V;
 472                                         j = half;
 473                                         while ( j -- )
 474                                         {
 475                                                 *d ++ = *y ++;
 476                                                 *d ++ = *u ++;
 477                                                 *d ++ = *y ++;
 478                                                 *d ++ = *v ++;
 479                                         }
 480
 481                                         Y += ( ( AVPicture * )&frame )->linesize[ 0 ];
 482                                         U += ( ( AVPicture * )&frame )->linesize[ 1 ];
 483                                         V += ( ( AVPicture * )&frame )->linesize[ 2 ];
 484                                 }
 485                         }
 486                         else
 487                         {
 488                                 img_convert( output, PIX_FMT_YUV422, (AVPicture *)&frame, codec_context->pix_fmt, *width, *height );
 489                                 memcpy( *buffer, output->data[ 0 ], size );
 490                         }
 491
 492                         memcpy( image, *buffer, size );
 493                         mlt_properties_set_data( frame_properties, "image", *buffer, size, ( mlt_destructor )mlt_pool_release, NULL );
 494
 495                         if ( current_time == 0 && source_fps != 0 )
 496                         {
 497                                 double fps = mlt_properties_get_double( properties, "fps" );
 498                                 current_time = ceil( source_fps * ( double )position / fps ) * ( 1 / source_fps );
 499                                 mlt_properties_set_double( properties, "current_time", current_time );
 500                         }
 501                         else
 502                         {
 503                                 mlt_properties_set_double( properties, "current_time", current_time );
 504                         }
 505                 }
 506         }
 507
 508         // Regardless of speed, we expect to get the next frame (cos we ain't too bright)
 509         mlt_properties_set_position( properties, "video_expected", position + 1 );
 510
 511         // Unlock the mutex now
 512         pthread_mutex_unlock( &avformat_mutex );
 513
 514         return 0;
 515 }
 516
 517 /** Set up video handling.
 518 */
 519
 520 static void producer_set_up_video( mlt_producer this, mlt_frame frame )
 521 {
 522         // Get the properties
 523         mlt_properties properties = mlt_producer_properties( this );
 524
 525         // Fetch the video_context
 526         AVFormatContext *context = mlt_properties_get_data( properties, "video_context", NULL );
 527
 528         // Get the video_index
 529         int index = mlt_properties_get_int( properties, "video_index" );
 530
 531         // Get the frame properties
 532         mlt_properties frame_properties = mlt_frame_properties( frame );
 533
 534         // Lock the mutex now
 535         pthread_mutex_lock( &avformat_mutex );
 536
 537         if ( context != NULL && index != -1 )
 538         {
 539                 // Get the video stream
 540                 AVStream *stream = context->streams[ index ];
 541
 542                 // Get codec context
 543                 AVCodecContext *codec_context = &stream->codec;
 544
 545                 // Get the codec
 546                 AVCodec *codec = mlt_properties_get_data( properties, "video_codec", NULL );
 547
 548                 // Initialise the codec if necessary
 549                 if ( codec == NULL )
 550                 {
 551                         // Find the codec
 552                         codec = avcodec_find_decoder( codec_context->codec_id );
 553
 554                         // If we don't have a codec and we can't initialise it, we can't do much more...
 555                         if ( codec != NULL && avcodec_open( codec_context, codec ) >= 0 )
 556                         {
 557                                 double aspect_ratio = 0;
 558                                 double source_fps = 0;
 559
 560                                 // Set aspect ratio
 561                                 if ( codec_context->sample_aspect_ratio.num == 0 )
 562                                         aspect_ratio = 0;
 563                                 else
 564                                         aspect_ratio = av_q2d( codec_context->sample_aspect_ratio ) * codec_context->width / codec_context->height;
 565
 566                                 // XXX: This assumes square pixels!
 567                         if (aspect_ratio <= 0.0)
 568                                         aspect_ratio = ( double )codec_context->width / ( double )codec_context->height;
 569
 570                                 mlt_properties_set_double( properties, "aspect_ratio", aspect_ratio );
 571                                 fprintf( stderr, "AVFORMAT: sample aspect %f computed display aspect %f\n", av_q2d( codec_context->sample_aspect_ratio ), aspect_ratio );
 572
 573                                 // Determine the fps
 574                                 source_fps = ( double )codec_context->frame_rate / codec_context->frame_rate_base;
 575
 576                                 // We'll use fps if it's available
 577                                 if ( source_fps > 0 && source_fps < 30 )
 578                                         mlt_properties_set_double( properties, "source_fps", source_fps );
 579
 580                                 // Now store the codec with its destructor
 581                                 mlt_properties_set_data( properties, "video_codec", codec_context, 0, producer_codec_close, NULL );
 582
 583                                 // Set to the real timecode
 584                                 av_seek_frame( context, -1, 0 );
 585                         }
 586                         else
 587                         {
 588                                 // Remember that we can't use this later
 589                                 mlt_properties_set_int( properties, "video_index", -1 );
 590                         }
 591                 }
 592
 593                 // No codec, no show...
 594                 if ( codec != NULL )
 595                 {
 596                         mlt_frame_push_get_image( frame, producer_get_image );
 597                         mlt_properties_set_data( frame_properties, "avformat_producer", this, 0, NULL, NULL );
 598                 }
 599                 else
 600                 {
 601                         mlt_properties_set_int( frame_properties, "test_image", 1 );
 602                 }
 603         }
 604         else
 605         {
 606                 mlt_properties_set_int( frame_properties, "test_image", 1 );
 607         }
 608
 609         // Unlock the mutex now
 610         pthread_mutex_unlock( &avformat_mutex );
 611 }
 612
 613 /** Get the audio from a frame.
 614 */
 615
 616 static int producer_get_audio( mlt_frame frame, int16_t **buffer, mlt_audio_format *format, int *frequency, int *channels, int *samples )
 617 {
 618         // Get the properties from the frame
 619         mlt_properties frame_properties = mlt_frame_properties( frame );
 620
 621         // Obtain the frame number of this frame
 622         mlt_position position = mlt_properties_get_position( frame_properties, "avformat_position" );
 623
 624         // Get the producer
 625         mlt_producer this = mlt_properties_get_data( frame_properties, "avformat_producer", NULL );
 626
 627         // Get the producer properties
 628         mlt_properties properties = mlt_producer_properties( this );
 629
 630         // Fetch the audio_context
 631         AVFormatContext *context = mlt_properties_get_data( properties, "audio_context", NULL );
 632
 633         // Get the audio_index
 634         int index = mlt_properties_get_int( properties, "audio_index" );
 635
 636         // Obtain the expected frame numer
 637         mlt_position expected = mlt_properties_get_position( properties, "audio_expected" );
 638
 639         // Obtain the resample context if it exists (not always needed)
 640         ReSampleContext *resample = mlt_properties_get_data( properties, "audio_resample", NULL );
 641
 642         // Obtain the audio buffer
 643         int16_t *audio_buffer = mlt_properties_get_data( properties, "audio_buffer", NULL );
 644
 645         // Get amount of audio used
 646         int audio_used =  mlt_properties_get_int( properties, "audio_used" );
 647
 648         // Calculate the real time code
 649         double real_timecode = producer_time_of_frame( this, position );
 650
 651         // Get the audio stream
 652         AVStream *stream = context->streams[ index ];
 653
 654         // Get codec context
 655         AVCodecContext *codec_context = &stream->codec;
 656
 657         // Packet
 658         AVPacket pkt;
 659
 660         // Number of frames to ignore (for ffwd)
 661         int ignore = 0;
 662
 663         // Flag for paused (silence)
 664         int paused = 0;
 665         int locked = 0;
 666
 667         // Lock the mutex now
 668         pthread_mutex_lock( &avformat_mutex );
 669
 670         // Check for resample and create if necessary
 671         if ( resample == NULL )
 672         {
 673                 // Create the resampler
 674                 resample = audio_resample_init( *channels, codec_context->channels, *frequency, codec_context->sample_rate );
 675
 676                 // And store it on properties
 677                 mlt_properties_set_data( properties, "audio_resample", resample, 0, ( mlt_destructor )audio_resample_close, NULL );
 678         }
 679
 680         // Check for audio buffer and create if necessary
 681         if ( audio_buffer == NULL )
 682         {
 683                 // Allocate the audio buffer
 684                 audio_buffer = mlt_pool_alloc( AVCODEC_MAX_AUDIO_FRAME_SIZE * sizeof( int16_t ) );
 685
 686                 // And store it on properties for reuse
 687                 mlt_properties_set_data( properties, "audio_buffer", audio_buffer, 0, ( mlt_destructor )mlt_pool_release, NULL );
 688         }
 689
 690         // Seek if necessary
 691         if ( position != expected )
 692         {
 693                 if ( position + 1 == expected )
 694                 {
 695                         // We're paused - silence required
 696                         paused = 1;
 697                 }
 698                 else if ( position > expected && ( position - expected ) < 250 )
 699                 {
 700                         // Fast forward - seeking is inefficient for small distances - just ignore following frames
 701                         ignore = position - expected;
 702                 }
 703                 else
 704                 {
 705                         // Set to the real timecode
 706                         av_seek_frame( context, -1, real_timecode * 1000000.0 );
 707
 708                         // Clear the usage in the audio buffer
 709                         audio_used = 0;
 710
 711                         locked = 1;
 712                 }
 713         }
 714
 715         // Get the audio if required
 716         if ( !paused )
 717         {
 718                 int ret = 0;
 719                 int got_audio = 0;
 720                 int16_t *temp = mlt_pool_alloc( sizeof( int16_t ) * AVCODEC_MAX_AUDIO_FRAME_SIZE );
 721
 722                 memset( &pkt, 0, sizeof( pkt ) );
 723
 724                 while( ret >= 0 && !got_audio )
 725                 {
 726                         // Check if the buffer already contains the samples required
 727                         if ( audio_used >= *samples && ignore == 0 )
 728                         {
 729                                 got_audio = 1;
 730                                 break;
 731                         }
 732
 733                         // Read a packet
 734                         ret = av_read_frame( context, &pkt );
 735
 736                 int len = pkt.size;
 737                 uint8_t *ptr = pkt.data;
 738                         int data_size;
 739
 740                         // We only deal with video from the selected video_index
 741                         while ( ptr != NULL && ret >= 0 && pkt.stream_index == index && len > 0 )
 742                         {
 743                                 // Decode the audio
 744                                 ret = avcodec_decode_audio( codec_context, temp, &data_size, ptr, len );
 745
 746                                 if ( ret < 0 )
 747                                 {
 748                                         ret = 0;
 749                                         break;
 750                                 }
 751
 752                                 len -= ret;
 753                                 ptr += ret;
 754
 755                                 if ( data_size > 0 )
 756                                 {
 757                                         int size_out = audio_resample( resample, &audio_buffer[ audio_used * *channels ], temp, data_size / ( codec_context->channels * sizeof( int16_t ) ) );
 758
 759                                         audio_used += size_out;
 760
 761                                         // Handle ignore
 762                                         while ( ignore && audio_used > *samples )
 763                                         {
 764                                                 ignore --;
 765                                                 audio_used -= *samples;
 766                                                 memmove( audio_buffer, &audio_buffer[ *samples * *channels ], audio_used * sizeof( int16_t ) );
 767                                         }
 768                                 }
 769
 770                                 // If we're behind, ignore this packet
 771                                 float current_pts = (float)pkt.pts / 1000000.0;
 772                                 double discrepancy = mlt_properties_get_double( properties, "discrepancy" );
 773                                 if ( current_pts != 0 && real_timecode != 0 )
 774                                 {
 775                                         if ( discrepancy != 1 )
 776                                                 discrepancy = ( discrepancy + ( real_timecode / current_pts ) ) / 2;
 777                                         else
 778                                                 discrepancy = real_timecode / current_pts;
 779                                         if ( discrepancy > 0.9 && discrepancy < 1.1 )
 780                                                 discrepancy = 1.0;
 781                                         else
 782                                                 discrepancy = floor( discrepancy + 0.5 );
 783
 784                                         if ( discrepancy == 0 )
 785                                                 discrepancy = 1.0;
 786
 787                                         mlt_properties_set_double( properties, "discrepancy", discrepancy );
 788                                 }
 789
 790                                 if ( discrepancy * current_pts <= ( real_timecode - 0.02 ) )
 791                                         ignore = 1;
 792                         }
 793
 794                         // We're finished with this packet regardless
 795                         av_free_packet( &pkt );
 796                 }
 797
 798                 *buffer = mlt_pool_alloc( *samples * *channels * sizeof( int16_t ) );
 799                 mlt_properties_set_data( frame_properties, "audio", *buffer, 0, ( mlt_destructor )mlt_pool_release, NULL );
 800
 801                 // Now handle the audio if we have enough
 802                 if ( audio_used >= *samples )
 803                 {
 804                         memcpy( *buffer, audio_buffer, *samples * *channels * sizeof( int16_t ) );
 805                         audio_used -= *samples;
 806                         memmove( audio_buffer, &audio_buffer[ *samples * *channels ], audio_used * *channels * sizeof( int16_t ) );
 807                 }
 808                 else
 809                 {
 810                         memset( *buffer, 0, *samples * *channels * sizeof( int16_t ) );
 811                 }
 812
 813                 // Store the number of audio samples still available
 814                 mlt_properties_set_int( properties, "audio_used", audio_used );
 815
 816                 // Release the temporary audio
 817                 mlt_pool_release( temp );
 818         }
 819         else
 820         {
 821                 // Get silence and don't touch the context
 822                 frame->get_audio = NULL;
 823                 mlt_frame_get_audio( frame, buffer, format, frequency, channels, samples );
 824         }
 825
 826         // Regardless of speed, we expect to get the next frame (cos we ain't too bright)
 827         mlt_properties_set_position( properties, "audio_expected", position + 1 );
 828
 829         // Unlock the mutex now
 830         pthread_mutex_unlock( &avformat_mutex );
 831
 832         return 0;
 833 }
 834
 835 /** Set up audio handling.
 836 */
 837
 838 static void producer_set_up_audio( mlt_producer this, mlt_frame frame )
 839 {
 840         // Get the properties
 841         mlt_properties properties = mlt_producer_properties( this );
 842
 843         // Fetch the audio_context
 844         AVFormatContext *context = mlt_properties_get_data( properties, "audio_context", NULL );
 845
 846         // Get the audio_index
 847         int index = mlt_properties_get_int( properties, "audio_index" );
 848
 849         // Lock the mutex now
 850         pthread_mutex_lock( &avformat_mutex );
 851
 852         // Deal with audio context
 853         if ( context != NULL && index != -1 )
 854         {
 855                 // Get the frame properties
 856                 mlt_properties frame_properties = mlt_frame_properties( frame );
 857
 858                 // Get the audio stream
 859                 AVStream *stream = context->streams[ index ];
 860
 861                 // Get codec context
 862                 AVCodecContext *codec_context = &stream->codec;
 863
 864                 // Get the codec
 865                 AVCodec *codec = mlt_properties_get_data( properties, "audio_codec", NULL );
 866
 867                 // Initialise the codec if necessary
 868                 if ( codec == NULL )
 869                 {
 870                         // Find the codec
 871                         codec = avcodec_find_decoder( codec_context->codec_id );
 872
 873                         // If we don't have a codec and we can't initialise it, we can't do much more...
 874                         if ( codec != NULL && avcodec_open( codec_context, codec ) >= 0 )
 875                         {
 876                                 // Now store the codec with its destructor
 877                                 mlt_properties_set_data( properties, "audio_codec", codec_context, 0, producer_codec_close, NULL );
 878
 879                         }
 880                         else
 881                         {
 882                                 // Remember that we can't use this later
 883                                 mlt_properties_set_int( properties, "audio_index", -1 );
 884                         }
 885                 }
 886
 887                 // No codec, no show...
 888                 if ( codec != NULL )
 889                 {
 890                         frame->get_audio = producer_get_audio;
 891                         mlt_properties_set_data( frame_properties, "avformat_producer", this, 0, NULL, NULL );
 892                 }
 893         }
 894
 895         // Unlock the mutex now
 896         pthread_mutex_unlock( &avformat_mutex );
 897 }
 898
 899 /** Our get frame implementation.
 900 */
 901
 902 static int producer_get_frame( mlt_producer this, mlt_frame_ptr frame, int index )
 903 {
 904         // Create an empty frame
 905         *frame = mlt_frame_init( );
 906
 907         // Update timecode on the frame we're creating
 908         mlt_frame_set_position( *frame, mlt_producer_position( this ) );
 909
 910         // Set the position of this producer
 911         mlt_properties_set_position( mlt_frame_properties( *frame ), "avformat_position", mlt_producer_get_in( this ) + mlt_producer_position( this ) );
 912
 913         // Set up the video
 914         producer_set_up_video( this, *frame );
 915
 916         // Set up the audio
 917         producer_set_up_audio( this, *frame );
 918
 919         // Set the aspect_ratio
 920         mlt_properties_set_double( mlt_frame_properties( *frame ), "aspect_ratio", mlt_properties_get_double( mlt_producer_properties( this ), "aspect_ratio" ) );
 921
 922         // Calculate the next timecode
 923         mlt_producer_prepare_next( this );
 924
 925         return 0;
 926 }