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 void avformat_lock( );
  37 void avformat_unlock( );
  38
  39 // Forward references.
  40 static int producer_open( mlt_producer this, char *file );
  41 static int producer_get_frame( mlt_producer this, mlt_frame_ptr frame, int index );
  42
  43 /** Constructor for libavformat.
  44 */
  45
  46 mlt_producer producer_avformat_init( char *file )
  47 {
  48         mlt_producer this = NULL;
  49
  50         // Check that we have a non-NULL argument
  51         if ( file != NULL )
  52         {
  53                 // Construct the producer
  54                 this = calloc( 1, sizeof( struct mlt_producer_s ) );
  55
  56                 // Initialise it
  57                 if ( mlt_producer_init( this, NULL ) == 0 )
  58                 {
  59                         // Get the properties
  60                         mlt_properties properties = mlt_producer_properties( this );
  61
  62                         // Set the resource property (required for all producers)
  63                         mlt_properties_set( properties, "resource", file );
  64
  65                         // TEST: audio sync tweaking
  66                         mlt_properties_set_double( properties, "discrepancy", 1 );
  67
  68                         // Register our get_frame implementation
  69                         this->get_frame = producer_get_frame;
  70
  71                         // Open the file
  72                         if ( producer_open( this, file ) != 0 )
  73                         {
  74                                 // Clean up
  75                                 mlt_producer_close( this );
  76                                 this = NULL;
  77                         }
  78                 }
  79         }
  80
  81         return this;
  82 }
  83
  84 /** Find the default streams.
  85 */
  86
  87 static void find_default_streams( AVFormatContext *context, int *audio_index, int *video_index )
  88 {
  89         int i;
  90
  91         // Allow for multiple audio and video streams in the file and select first of each (if available)
  92         for( i = 0; i < context->nb_streams; i++ )
  93         {
  94                 // Get the codec context
  95                 AVCodecContext *codec_context = &context->streams[ i ]->codec;
  96
  97                 // Determine the type and obtain the first index of each type
  98                 switch( codec_context->codec_type )
  99                 {
 100                         case CODEC_TYPE_VIDEO:
 101                                 if ( *video_index < 0 )
 102                                         *video_index = i;
 103                                 break;
 104                         case CODEC_TYPE_AUDIO:
 105                                 if ( *audio_index < 0 )
 106                                         *audio_index = i;
 107                                 break;
 108                         default:
 109                                 break;
 110                 }
 111         }
 112 }
 113
 114 /** Producer file destructor.
 115 */
 116
 117 static void producer_file_close( void *context )
 118 {
 119         if ( context != NULL )
 120         {
 121                 // Lock the mutex now
 122                 avformat_lock( );
 123
 124                 // Close the file
 125                 av_close_input_file( context );
 126
 127                 // Unlock the mutex now
 128                 avformat_unlock( );
 129         }
 130 }
 131
 132 /** Producer file destructor.
 133 */
 134
 135 static void producer_codec_close( void *codec )
 136 {
 137         if ( codec != NULL )
 138         {
 139                 // Lock the mutex now
 140                 avformat_lock( );
 141
 142                 // Close the file
 143                 avcodec_close( codec );
 144
 145                 // Unlock the mutex now
 146                 avformat_unlock( );
 147         }
 148 }
 149
 150 /** Open the file.
 151 */
 152
 153 static int producer_open( mlt_producer this, char *file )
 154 {
 155         // Return an error code (0 == no error)
 156         int error = 0;
 157
 158         // Context for avformat
 159         AVFormatContext *context = NULL;
 160
 161         // Get the properties
 162         mlt_properties properties = mlt_producer_properties( this );
 163
 164         // We will treat everything with the producer fps
 165         double fps = mlt_properties_get_double( properties, "fps" );
 166
 167         // Lock the mutex now
 168         avformat_lock( );
 169
 170         // If "MRL", then create AVInputFormat
 171         AVInputFormat *format = NULL;
 172         AVFormatParameters *params = NULL;
 173         char *standard = NULL;
 174         char *mrl = strchr( file, ':' );
 175
 176         // Only if there is not a protocol specification that avformat can handle
 177         if ( mrl && !url_exist( file ) )
 178         {
 179                 // 'file' becomes format abbreviation
 180                 mrl[0] = 0;
 181
 182                 // Lookup the format
 183                 format = av_find_input_format( file );
 184
 185                 // Eat the format designator
 186                 file = ++mrl;
 187
 188                 if ( format )
 189                 {
 190                         // Allocate params
 191                         params = calloc( sizeof( AVFormatParameters ), 1 );
 192
 193                         // These are required by video4linux (defaults)
 194                         params->width = 640;
 195                         params->height = 480;
 196                         params->frame_rate = 25;
 197                         params->frame_rate_base = 1;
 198                         params->device = file;
 199                         params->channels = 2;
 200                         params->sample_rate = 48000;
 201                 }
 202
 203                 // Parse out params
 204                 mrl = strchr( file, '?' );
 205                 while ( mrl )
 206                 {
 207                         mrl[0] = 0;
 208                         char *name = strdup( ++mrl );
 209                         char *value = strchr( name, ':' );
 210                         if ( value )
 211                         {
 212                                 value[0] = 0;
 213                                 value++;
 214                                 char *t = strchr( value, '&' );
 215                                 if ( t )
 216                                         t[0] = 0;
 217                                 if ( !strcmp( name, "frame_rate" ) )
 218                                         params->frame_rate = atoi( value );
 219                                 else if ( !strcmp( name, "frame_rate_base" ) )
 220                                         params->frame_rate_base = atoi( value );
 221                                 else if ( !strcmp( name, "sample_rate" ) )
 222                                         params->sample_rate = atoi( value );
 223                                 else if ( !strcmp( name, "channels" ) )
 224                                         params->channels = atoi( value );
 225                                 else if ( !strcmp( name, "width" ) )
 226                                         params->width = atoi( value );
 227                                 else if ( !strcmp( name, "height" ) )
 228                                         params->height = atoi( value );
 229                                 else if ( !strcmp( name, "standard" ) )
 230                                 {
 231                                         standard = strdup( value );
 232                                         params->standard = standard;
 233                                 }
 234                         }
 235                         free( name );
 236                         mrl = strchr( mrl, '&' );
 237                 }
 238         }
 239
 240         // Now attempt to open the file
 241         error = av_open_input_file( &context, file, format, 0, params );
 242         error = error < 0;
 243
 244         // Cleanup AVFormatParameters
 245         free( standard );
 246         free( params );
 247
 248         // If successful, then try to get additional info
 249         if ( error == 0 )
 250         {
 251                 // Get the stream info
 252                 error = av_find_stream_info( context ) < 0;
 253
 254                 // Continue if no error
 255                 if ( error == 0 )
 256                 {
 257                         // We will default to the first audio and video streams found
 258                         int audio_index = -1;
 259                         int video_index = -1;
 260
 261                         // Now set properties where we can (use default unknowns if required)
 262                         if ( context->duration != AV_NOPTS_VALUE )
 263                         {
 264                                 // This isn't going to be accurate for all formats
 265                                 mlt_position frames = ( mlt_position )( ( ( double )context->duration / ( double )AV_TIME_BASE ) * fps );
 266                                 mlt_properties_set_position( properties, "out", frames - 2 );
 267                                 mlt_properties_set_position( properties, "length", frames - 1 );
 268                         }
 269
 270                         // Find default audio and video streams
 271                         find_default_streams( context, &audio_index, &video_index );
 272
 273                         // Store selected audio and video indexes on properties
 274                         mlt_properties_set_int( properties, "audio_index", audio_index );
 275                         mlt_properties_set_int( properties, "video_index", video_index );
 276
 277                         // We're going to cheat here - for a/v files, we will have two contexts (reasoning will be clear later)
 278                         if ( audio_index != -1 && video_index != -1 )
 279                         {
 280                                 // We'll use the open one as our video_context
 281                                 mlt_properties_set_data( properties, "video_context", context, 0, producer_file_close, NULL );
 282
 283                                 // And open again for our audio context
 284                                 av_open_input_file( &context, file, NULL, 0, NULL );
 285                                 av_find_stream_info( context );
 286
 287                                 // Audio context
 288                                 mlt_properties_set_data( properties, "audio_context", context, 0, producer_file_close, NULL );
 289                         }
 290                         else if ( video_index != -1 )
 291                         {
 292                                 // We only have a video context
 293                                 mlt_properties_set_data( properties, "video_context", context, 0, producer_file_close, NULL );
 294                         }
 295                         else if ( audio_index != -1 )
 296                         {
 297                                 // We only have an audio context
 298                                 mlt_properties_set_data( properties, "audio_context", context, 0, producer_file_close, NULL );
 299                         }
 300                         else
 301                         {
 302                                 // Something has gone wrong
 303                                 error = -1;
 304                         }
 305                 }
 306         }
 307
 308         // Unlock the mutex now
 309         avformat_unlock( );
 310
 311         return error;
 312 }
 313
 314 /** Convert a frame position to a time code.
 315 */
 316
 317 static double producer_time_of_frame( mlt_producer this, mlt_position position )
 318 {
 319         // Get the properties
 320         mlt_properties properties = mlt_producer_properties( this );
 321
 322         // Obtain the fps
 323         double fps = mlt_properties_get_double( properties, "fps" );
 324
 325         // Do the calc
 326         return ( double )position / fps;
 327 }
 328
 329 /** Get an image from a frame.
 330 */
 331
 332 static int producer_get_image( mlt_frame frame, uint8_t **buffer, mlt_image_format *format, int *width, int *height, int writable )
 333 {
 334         // Get the properties from the frame
 335         mlt_properties frame_properties = mlt_frame_properties( frame );
 336
 337         // Obtain the frame number of this frame
 338         mlt_position position = mlt_properties_get_position( frame_properties, "avformat_position" );
 339
 340         // Get the producer
 341         mlt_producer this = mlt_properties_get_data( frame_properties, "avformat_producer", NULL );
 342
 343         // Get the producer properties
 344         mlt_properties properties = mlt_producer_properties( this );
 345
 346         // Fetch the video_context
 347         AVFormatContext *context = mlt_properties_get_data( properties, "video_context", NULL );
 348
 349         // Get the video_index
 350         int index = mlt_properties_get_int( properties, "video_index" );
 351
 352         // Obtain the expected frame numer
 353         mlt_position expected = mlt_properties_get_position( properties, "video_expected" );
 354
 355         // Calculate the real time code
 356         double real_timecode = producer_time_of_frame( this, position );
 357
 358         // Get the video stream
 359         AVStream *stream = context->streams[ index ];
 360
 361         // Get codec context
 362         AVCodecContext *codec_context = &stream->codec;
 363
 364         // Packet
 365         AVPacket pkt;
 366
 367         // Get the conversion frame
 368         AVPicture *output = mlt_properties_get_data( properties, "video_output_frame", NULL );
 369
 370         // Special case pause handling flag
 371         int paused = 0;
 372
 373         // Special case ffwd handling
 374         int ignore = 0;
 375
 376         // Current time calcs
 377         double current_time = mlt_properties_get_double( properties, "current_time" );
 378
 379         // We may want to use the source fps if available
 380         double source_fps = mlt_properties_get_double( properties, "source_fps" );
 381
 382         // Set the result arguments that we know here (only *buffer is now required)
 383         *format = mlt_image_yuv422;
 384         *width = codec_context->width;
 385         *height = codec_context->height;
 386
 387         // Set this on the frame properties
 388         mlt_properties_set_int( frame_properties, "width", *width );
 389         mlt_properties_set_int( frame_properties, "height", *height );
 390
 391         // Lock the mutex now
 392         avformat_lock( );
 393
 394         // Construct an AVFrame for YUV422 conversion
 395         if ( output == NULL )
 396         {
 397                 int size = avpicture_get_size( PIX_FMT_YUV422, *width, *height + 1 );
 398                 uint8_t *buf = mlt_pool_alloc( size );
 399                 output = mlt_pool_alloc( sizeof( AVPicture ) );
 400                 avpicture_fill( output, buf, PIX_FMT_YUV422, *width, *height );
 401                 mlt_properties_set_data( properties, "video_output_frame", output, 0, ( mlt_destructor )mlt_pool_release, NULL );
 402                 mlt_properties_set_data( properties, "video_output_buffer", buf, 0, ( mlt_destructor )mlt_pool_release, NULL );
 403         }
 404
 405         // Seek if necessary
 406         if ( position != expected )
 407         {
 408                 if ( position + 1 == expected )
 409                 {
 410                         // We're paused - use last image
 411                         paused = 1;
 412                 }
 413                 else if ( position > expected && ( position - expected ) < 250 )
 414                 {
 415                         // Fast forward - seeking is inefficient for small distances - just ignore following frames
 416                         ignore = position - expected;
 417                 }
 418                 else
 419                 {
 420                         // Set to the real timecode
 421                         av_seek_frame( context, -1, real_timecode * 1000000.0 );
 422
 423                         // Remove the cached info relating to the previous position
 424                         mlt_properties_set_double( properties, "current_time", real_timecode );
 425                         mlt_properties_set_data( properties, "current_image", NULL, 0, NULL, NULL );
 426                 }
 427         }
 428
 429         // Duplicate the last image if necessary
 430         if ( mlt_properties_get_data( properties, "current_image", NULL ) != NULL &&
 431                  ( paused || mlt_properties_get_double( properties, "current_time" ) >= real_timecode ) )
 432         {
 433                 // Get current image and size
 434                 int size = 0;
 435                 uint8_t *image = mlt_properties_get_data( properties, "current_image", &size );
 436
 437                 // Duplicate it
 438                 *buffer = mlt_pool_alloc( size );
 439                 memcpy( *buffer, image, size );
 440
 441                 // Set this on the frame properties
 442                 mlt_properties_set_data( frame_properties, "image", *buffer, size, ( mlt_destructor )mlt_pool_release, NULL );
 443         }
 444         else
 445         {
 446                 int ret = 0;
 447                 int got_picture = 0;
 448                 AVFrame frame;
 449
 450                 memset( &pkt, 0, sizeof( pkt ) );
 451                 memset( &frame, 0, sizeof( frame ) );
 452
 453                 while( ret >= 0 && !got_picture )
 454                 {
 455                         // Read a packet
 456                         ret = av_read_frame( context, &pkt );
 457
 458                         // We only deal with video from the selected video_index
 459                         if ( ret >= 0 && pkt.stream_index == index && pkt.size > 0 )
 460                         {
 461                                 // Decode the image
 462                                 ret = avcodec_decode_video( codec_context, &frame, &got_picture, pkt.data, pkt.size );
 463
 464                                 if ( got_picture )
 465                                 {
 466                                         if ( pkt.pts != AV_NOPTS_VALUE && pkt.pts != 0  )
 467                                                 current_time = ( double )pkt.pts / 1000000.0;
 468                                         else
 469                                                 current_time = real_timecode;
 470
 471                                         // Handle ignore
 472                                         if ( ( int )( current_time * 100 ) < ( int )( real_timecode * 100 ) - 7 )
 473                                         {
 474                                                 ignore = 0;
 475                                                 got_picture = 0;
 476                                         }
 477                                         else if ( current_time >= real_timecode )
 478                                         {
 479                                                 //current_time = real_timecode;
 480                                                 ignore = 0;
 481                                         }
 482                                         else if ( ignore -- )
 483                                         {
 484                                                 got_picture = 0;
 485                                         }
 486                                 }
 487                         }
 488
 489                         // We're finished with this packet regardless
 490                         av_free_packet( &pkt );
 491                 }
 492
 493                 // Now handle the picture if we have one
 494                 if ( got_picture )
 495                 {
 496                         // Get current image and size
 497                         int size = 0;
 498                         uint8_t *image = mlt_properties_get_data( properties, "current_image", &size );
 499
 500                         if ( image == NULL || size != *width * *height * 2 )
 501                         {
 502                                 size = *width * ( *height + 1 ) * 2;
 503                                 image = mlt_pool_alloc( size );
 504                                 mlt_properties_set_data( properties, "current_image", image, size, ( mlt_destructor )mlt_pool_release, NULL );
 505                         }
 506
 507                         *buffer = mlt_pool_alloc( size );
 508
 509                         // EXPERIMENTAL IMAGE NORMALISATIONS
 510                         if ( codec_context->pix_fmt == PIX_FMT_YUV420P )
 511                         {
 512                                 register int i, j;
 513                                 register int half = *width >> 1;
 514                                 register uint8_t *Y = ( ( AVPicture * )&frame )->data[ 0 ];
 515                                 register uint8_t *U = ( ( AVPicture * )&frame )->data[ 1 ];
 516                                 register uint8_t *V = ( ( AVPicture * )&frame )->data[ 2 ];
 517                                 register uint8_t *d = *buffer;
 518                                 register uint8_t *y, *u, *v;
 519
 520                                 i = *height >> 1;
 521                                 while ( i -- )
 522                                 {
 523                                         y = Y;
 524                                         u = U;
 525                                         v = V;
 526                                         j = half;
 527                                         while ( j -- )
 528                                         {
 529                                                 *d ++ = *y ++;
 530                                                 *d ++ = *u ++;
 531                                                 *d ++ = *y ++;
 532                                                 *d ++ = *v ++;
 533                                         }
 534
 535                                         Y += ( ( AVPicture * )&frame )->linesize[ 0 ];
 536                                         y = Y;
 537                                         u = U;
 538                                         v = V;
 539                                         j = half;
 540                                         while ( j -- )
 541                                         {
 542                                                 *d ++ = *y ++;
 543                                                 *d ++ = *u ++;
 544                                                 *d ++ = *y ++;
 545                                                 *d ++ = *v ++;
 546                                         }
 547
 548                                         Y += ( ( AVPicture * )&frame )->linesize[ 0 ];
 549                                         U += ( ( AVPicture * )&frame )->linesize[ 1 ];
 550                                         V += ( ( AVPicture * )&frame )->linesize[ 2 ];
 551                                 }
 552                         }
 553                         else
 554                         {
 555                                 img_convert( output, PIX_FMT_YUV422, (AVPicture *)&frame, codec_context->pix_fmt, *width, *height );
 556                                 memcpy( *buffer, output->data[ 0 ], size );
 557                         }
 558
 559                         memcpy( image, *buffer, size );
 560                         mlt_properties_set_data( frame_properties, "image", *buffer, size, ( mlt_destructor )mlt_pool_release, NULL );
 561
 562                         if ( current_time == 0 && source_fps != 0 )
 563                         {
 564                                 double fps = mlt_properties_get_double( properties, "fps" );
 565                                 current_time = ceil( source_fps * ( double )position / fps ) * ( 1 / source_fps );
 566                                 mlt_properties_set_double( properties, "current_time", current_time );
 567                         }
 568                         else
 569                         {
 570                                 mlt_properties_set_double( properties, "current_time", current_time );
 571                         }
 572                 }
 573         }
 574
 575         // Regardless of speed, we expect to get the next frame (cos we ain't too bright)
 576         mlt_properties_set_position( properties, "video_expected", position + 1 );
 577
 578         // Unlock the mutex now
 579         avformat_unlock( );
 580
 581         return 0;
 582 }
 583
 584 /** Set up video handling.
 585 */
 586
 587 static void producer_set_up_video( mlt_producer this, mlt_frame frame )
 588 {
 589         // Get the properties
 590         mlt_properties properties = mlt_producer_properties( this );
 591
 592         // Fetch the video_context
 593         AVFormatContext *context = mlt_properties_get_data( properties, "video_context", NULL );
 594
 595         // Get the video_index
 596         int index = mlt_properties_get_int( properties, "video_index" );
 597
 598         // Get the frame properties
 599         mlt_properties frame_properties = mlt_frame_properties( frame );
 600
 601         // Lock the mutex now
 602         avformat_lock( );
 603
 604         if ( context != NULL && index != -1 )
 605         {
 606                 // Get the video stream
 607                 AVStream *stream = context->streams[ index ];
 608
 609                 // Get codec context
 610                 AVCodecContext *codec_context = &stream->codec;
 611
 612                 // Get the codec
 613                 AVCodec *codec = mlt_properties_get_data( properties, "video_codec", NULL );
 614
 615                 // Initialise the codec if necessary
 616                 if ( codec == NULL )
 617                 {
 618                         // Find the codec
 619                         codec = avcodec_find_decoder( codec_context->codec_id );
 620
 621                         // If we don't have a codec and we can't initialise it, we can't do much more...
 622                         if ( codec != NULL && avcodec_open( codec_context, codec ) >= 0 )
 623                         {
 624                                 // Now store the codec with its destructor
 625                                 mlt_properties_set_data( properties, "video_codec", codec_context, 0, producer_codec_close, NULL );
 626                         }
 627                         else
 628                         {
 629                                 // Remember that we can't use this later
 630                                 mlt_properties_set_int( properties, "video_index", -1 );
 631                         }
 632                 }
 633
 634                 // No codec, no show...
 635                 if ( codec != NULL )
 636                 {
 637                         double aspect_ratio = 1;
 638                         double source_fps = 0;
 639
 640                         // Set aspect ratio
 641                         if ( codec_context->sample_aspect_ratio.num > 0 )
 642                                 aspect_ratio = av_q2d( codec_context->sample_aspect_ratio );
 643
 644                         mlt_properties_set_double( properties, "aspect_ratio", aspect_ratio );
 645                         //fprintf( stderr, "AVFORMAT: sample aspect %f %dx%d\n", av_q2d( codec_context->sample_aspect_ratio ), codec_context->width, codec_context->height );
 646
 647                         // Determine the fps
 648                         source_fps = ( double )codec_context->frame_rate / ( codec_context->frame_rate_base == 0 ? 1 : codec_context->frame_rate_base );
 649
 650                         // We'll use fps if it's available
 651                         if ( source_fps > 0 && source_fps < 30 )
 652                                 mlt_properties_set_double( properties, "source_fps", source_fps );
 653
 654                         // Set the width and height
 655                         mlt_properties_set_int( frame_properties, "width", codec_context->width );
 656                         mlt_properties_set_int( frame_properties, "height", codec_context->height );
 657
 658                         mlt_frame_push_get_image( frame, producer_get_image );
 659                         mlt_properties_set_data( frame_properties, "avformat_producer", this, 0, NULL, NULL );
 660                 }
 661                 else
 662                 {
 663                         mlt_properties_set_int( frame_properties, "test_image", 1 );
 664                 }
 665         }
 666         else
 667         {
 668                 mlt_properties_set_int( frame_properties, "test_image", 1 );
 669         }
 670
 671         // Unlock the mutex now
 672         avformat_unlock( );
 673 }
 674
 675 /** Get the audio from a frame.
 676 */
 677
 678 static int producer_get_audio( mlt_frame frame, int16_t **buffer, mlt_audio_format *format, int *frequency, int *channels, int *samples )
 679 {
 680         // Get the properties from the frame
 681         mlt_properties frame_properties = mlt_frame_properties( frame );
 682
 683         // Obtain the frame number of this frame
 684         mlt_position position = mlt_properties_get_position( frame_properties, "avformat_position" );
 685
 686         // Get the producer
 687         mlt_producer this = mlt_properties_get_data( frame_properties, "avformat_producer", NULL );
 688
 689         // Get the producer properties
 690         mlt_properties properties = mlt_producer_properties( this );
 691
 692         // Fetch the audio_context
 693         AVFormatContext *context = mlt_properties_get_data( properties, "audio_context", NULL );
 694
 695         // Get the audio_index
 696         int index = mlt_properties_get_int( properties, "audio_index" );
 697
 698         // Obtain the expected frame numer
 699         mlt_position expected = mlt_properties_get_position( properties, "audio_expected" );
 700
 701         // Obtain the resample context if it exists (not always needed)
 702         ReSampleContext *resample = mlt_properties_get_data( properties, "audio_resample", NULL );
 703
 704         // Obtain the audio buffer
 705         int16_t *audio_buffer = mlt_properties_get_data( properties, "audio_buffer", NULL );
 706
 707         // Get amount of audio used
 708         int audio_used =  mlt_properties_get_int( properties, "audio_used" );
 709
 710         // Calculate the real time code
 711         double real_timecode = producer_time_of_frame( this, position );
 712
 713         // Get the audio stream
 714         AVStream *stream = context->streams[ index ];
 715
 716         // Get codec context
 717         AVCodecContext *codec_context = &stream->codec;
 718
 719         // Packet
 720         AVPacket pkt;
 721
 722         // Number of frames to ignore (for ffwd)
 723         int ignore = 0;
 724
 725         // Flag for paused (silence)
 726         int paused = 0;
 727         int locked = 0;
 728
 729         // Lock the mutex now
 730         avformat_lock( );
 731
 732         // Check for resample and create if necessary
 733         if ( resample == NULL && codec_context->channels <= 2 )
 734         {
 735                 // Create the resampler
 736                 resample = audio_resample_init( *channels, codec_context->channels, *frequency, codec_context->sample_rate );
 737
 738                 // And store it on properties
 739                 mlt_properties_set_data( properties, "audio_resample", resample, 0, ( mlt_destructor )audio_resample_close, NULL );
 740         }
 741         else if ( resample == NULL )
 742         {
 743                 *channels = codec_context->channels;
 744                 *frequency = codec_context->sample_rate;
 745         }
 746
 747         // Check for audio buffer and create if necessary
 748         if ( audio_buffer == NULL )
 749         {
 750                 // Allocate the audio buffer
 751                 audio_buffer = mlt_pool_alloc( AVCODEC_MAX_AUDIO_FRAME_SIZE * sizeof( int16_t ) );
 752
 753                 // And store it on properties for reuse
 754                 mlt_properties_set_data( properties, "audio_buffer", audio_buffer, 0, ( mlt_destructor )mlt_pool_release, NULL );
 755         }
 756
 757         // Seek if necessary
 758         if ( position != expected )
 759         {
 760                 if ( position + 1 == expected )
 761                 {
 762                         // We're paused - silence required
 763                         paused = 1;
 764                 }
 765                 else if ( position > expected && ( position - expected ) < 250 )
 766                 {
 767                         // Fast forward - seeking is inefficient for small distances - just ignore following frames
 768                         ignore = position - expected;
 769                 }
 770                 else
 771                 {
 772                         // Set to the real timecode
 773                         av_seek_frame( context, -1, real_timecode * 1000000.0 );
 774
 775                         // Clear the usage in the audio buffer
 776                         audio_used = 0;
 777
 778                         locked = 1;
 779                 }
 780         }
 781
 782         // Get the audio if required
 783         if ( !paused )
 784         {
 785                 int ret = 0;
 786                 int got_audio = 0;
 787                 int16_t *temp = mlt_pool_alloc( sizeof( int16_t ) * AVCODEC_MAX_AUDIO_FRAME_SIZE );
 788
 789                 memset( &pkt, 0, sizeof( pkt ) );
 790
 791                 while( ret >= 0 && !got_audio )
 792                 {
 793                         // Check if the buffer already contains the samples required
 794                         if ( audio_used >= *samples && ignore == 0 )
 795                         {
 796                                 got_audio = 1;
 797                                 break;
 798                         }
 799
 800                         // Read a packet
 801                         ret = av_read_frame( context, &pkt );
 802
 803                 int len = pkt.size;
 804                 uint8_t *ptr = pkt.data;
 805                         int data_size;
 806
 807                         // We only deal with audio from the selected audio_index
 808                         while ( ptr != NULL && ret >= 0 && pkt.stream_index == index && len > 0 )
 809                         {
 810                                 // Decode the audio
 811                                 ret = avcodec_decode_audio( codec_context, temp, &data_size, ptr, len );
 812
 813                                 if ( ret < 0 )
 814                                 {
 815                                         ret = 0;
 816                                         break;
 817                                 }
 818
 819                                 len -= ret;
 820                                 ptr += ret;
 821
 822                                 if ( data_size > 0 )
 823                                 {
 824                                         if ( resample != NULL )
 825                                         {
 826                                                 audio_used += audio_resample( resample, &audio_buffer[ audio_used * *channels ], temp, data_size / ( codec_context->channels * sizeof( int16_t ) ) );
 827                                         }
 828                                         else
 829                                         {
 830                                                 memcpy( &audio_buffer[ audio_used * *channels ], temp, data_size );
 831                                                 audio_used += data_size / ( codec_context->channels * sizeof( int16_t ) );
 832                                         }
 833
 834                                         // Handle ignore
 835                                         while ( ignore && audio_used > *samples )
 836                                         {
 837                                                 ignore --;
 838                                                 audio_used -= *samples;
 839                                                 memmove( audio_buffer, &audio_buffer[ *samples * *channels ], audio_used * sizeof( int16_t ) );
 840                                         }
 841                                 }
 842
 843                                 // If we're behind, ignore this packet
 844                                 float current_pts = (float)pkt.pts / 1000000.0;
 845                                 double discrepancy = mlt_properties_get_double( properties, "discrepancy" );
 846                                 if ( current_pts != 0 && real_timecode != 0 )
 847                                 {
 848                                         if ( discrepancy != 1 )
 849                                                 discrepancy = ( discrepancy + ( real_timecode / current_pts ) ) / 2;
 850                                         else
 851                                                 discrepancy = real_timecode / current_pts;
 852                                         if ( discrepancy > 0.9 && discrepancy < 1.1 )
 853                                                 discrepancy = 1.0;
 854                                         else
 855                                                 discrepancy = floor( discrepancy + 0.5 );
 856
 857                                         if ( discrepancy == 0 )
 858                                                 discrepancy = 1.0;
 859
 860                                         mlt_properties_set_double( properties, "discrepancy", discrepancy );
 861                                 }
 862
 863                                 if ( !ignore && discrepancy * current_pts <= ( real_timecode - 0.02 ) )
 864                                         ignore = 1;
 865                         }
 866
 867                         // We're finished with this packet regardless
 868                         av_free_packet( &pkt );
 869                 }
 870
 871                 *buffer = mlt_pool_alloc( *samples * *channels * sizeof( int16_t ) );
 872                 mlt_properties_set_data( frame_properties, "audio", *buffer, 0, ( mlt_destructor )mlt_pool_release, NULL );
 873
 874                 // Now handle the audio if we have enough
 875                 if ( audio_used >= *samples )
 876                 {
 877                         memcpy( *buffer, audio_buffer, *samples * *channels * sizeof( int16_t ) );
 878                         audio_used -= *samples;
 879                         memmove( audio_buffer, &audio_buffer[ *samples * *channels ], audio_used * *channels * sizeof( int16_t ) );
 880                 }
 881                 else
 882                 {
 883                         memset( *buffer, 0, *samples * *channels * sizeof( int16_t ) );
 884                 }
 885
 886                 // Store the number of audio samples still available
 887                 mlt_properties_set_int( properties, "audio_used", audio_used );
 888
 889                 // Release the temporary audio
 890                 mlt_pool_release( temp );
 891         }
 892         else
 893         {
 894                 // Get silence and don't touch the context
 895                 frame->get_audio = NULL;
 896                 mlt_frame_get_audio( frame, buffer, format, frequency, channels, samples );
 897         }
 898
 899         // Regardless of speed, we expect to get the next frame (cos we ain't too bright)
 900         mlt_properties_set_position( properties, "audio_expected", position + 1 );
 901
 902         // Unlock the mutex now
 903         avformat_unlock( );
 904
 905         return 0;
 906 }
 907
 908 /** Set up audio handling.
 909 */
 910
 911 static void producer_set_up_audio( mlt_producer this, mlt_frame frame )
 912 {
 913         // Get the properties
 914         mlt_properties properties = mlt_producer_properties( this );
 915
 916         // Fetch the audio_context
 917         AVFormatContext *context = mlt_properties_get_data( properties, "audio_context", NULL );
 918
 919         // Get the audio_index
 920         int index = mlt_properties_get_int( properties, "audio_index" );
 921
 922         // Lock the mutex now
 923         avformat_lock( );
 924
 925         // Deal with audio context
 926         if ( context != NULL && index != -1 )
 927         {
 928                 // Get the frame properties
 929                 mlt_properties frame_properties = mlt_frame_properties( frame );
 930
 931                 // Get the audio stream
 932                 AVStream *stream = context->streams[ index ];
 933
 934                 // Get codec context
 935                 AVCodecContext *codec_context = &stream->codec;
 936
 937                 // Get the codec
 938                 AVCodec *codec = mlt_properties_get_data( properties, "audio_codec", NULL );
 939
 940                 // Initialise the codec if necessary
 941                 if ( codec == NULL )
 942                 {
 943                         // Find the codec
 944                         codec = avcodec_find_decoder( codec_context->codec_id );
 945
 946                         // If we don't have a codec and we can't initialise it, we can't do much more...
 947                         if ( codec != NULL && avcodec_open( codec_context, codec ) >= 0 )
 948                         {
 949                                 // Now store the codec with its destructor
 950                                 mlt_properties_set_data( properties, "audio_codec", codec_context, 0, producer_codec_close, NULL );
 951
 952                         }
 953                         else
 954                         {
 955                                 // Remember that we can't use this later
 956                                 mlt_properties_set_int( properties, "audio_index", -1 );
 957                         }
 958                 }
 959
 960                 // No codec, no show...
 961                 if ( codec != NULL )
 962                 {
 963                         frame->get_audio = producer_get_audio;
 964                         mlt_properties_set_data( frame_properties, "avformat_producer", this, 0, NULL, NULL );
 965                 }
 966         }
 967
 968         // Unlock the mutex now
 969         avformat_unlock( );
 970 }
 971
 972 /** Our get frame implementation.
 973 */
 974
 975 static int producer_get_frame( mlt_producer this, mlt_frame_ptr frame, int index )
 976 {
 977         // Create an empty frame
 978         *frame = mlt_frame_init( );
 979
 980         // Update timecode on the frame we're creating
 981         mlt_frame_set_position( *frame, mlt_producer_position( this ) );
 982
 983         // Set the position of this producer
 984         mlt_properties_set_position( mlt_frame_properties( *frame ), "avformat_position", mlt_producer_get_in( this ) + mlt_producer_position( this ) );
 985
 986         // Set up the video
 987         producer_set_up_video( this, *frame );
 988
 989         // Set up the audio
 990         producer_set_up_audio( this, *frame );
 991
 992         // Set the aspect_ratio
 993         mlt_properties_set_double( mlt_frame_properties( *frame ), "aspect_ratio", mlt_properties_get_double( mlt_producer_properties( this ), "aspect_ratio" ) );
 994
 995         // Calculate the next timecode
 996         mlt_producer_prepare_next( this );
 997
 998         return 0;
 999 }