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added filter_channelcopy.
[mlt] / 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 #if 0
45 void *av_malloc( unsigned int size )
46 {
47         return mlt_pool_alloc( size );
48 }
49
50 void *av_realloc( void *ptr, unsigned int size )
51 {
52         return mlt_pool_realloc( ptr, size );
53 }
54
55 void av_free( void *ptr )
56 {
57         return mlt_pool_release( ptr );
58 }
59 #endif
60
61 /** Constructor for libavformat.
62 */
63
64 mlt_producer producer_avformat_init( char *file )
65 {
66         mlt_producer this = NULL;
67
68         // Check that we have a non-NULL argument
69         if ( file != NULL )
70         {
71                 // Construct the producer
72                 this = calloc( 1, sizeof( struct mlt_producer_s ) );
73
74                 // Initialise it
75                 if ( mlt_producer_init( this, NULL ) == 0 )
76                 {
77                         // Get the properties
78                         mlt_properties properties = mlt_producer_properties( this );
79
80                         // Set the resource property (required for all producers)
81                         mlt_properties_set( properties, "resource", file );
82
83                         // TEST: audio sync tweaking
84                         mlt_properties_set_double( properties, "discrepancy", 1 );
85
86                         // Register our get_frame implementation
87                         this->get_frame = producer_get_frame;
88
89                         // Initialise avformat if necessary
90                         if ( avformat_initialised == 0 )
91                         {
92                                 avformat_initialised = 1;
93                                 pthread_mutex_init( &avformat_mutex, NULL );
94                                 av_register_all( );
95                         }
96
97                         // Open the file
98                         if ( producer_open( this, file ) != 0 )
99                         {
100                                 // Clean up
101                                 mlt_producer_close( this );
102                                 this = NULL;
103                         }
104                 }
105         }
106
107         return this;
108 }
109
110 /** Find the default streams.
111 */
112
113 static void find_default_streams( AVFormatContext *context, int *audio_index, int *video_index )
114 {
115         int i;
116
117         // Allow for multiple audio and video streams in the file and select first of each (if available)
118         for( i = 0; i < context->nb_streams; i++ ) 
119         {
120                 // Get the codec context
121                 AVCodecContext *codec_context = &context->streams[ i ]->codec;
122
123                 // Determine the type and obtain the first index of each type
124                 switch( codec_context->codec_type ) 
125                 {
126                         case CODEC_TYPE_VIDEO:
127                                 if ( *video_index < 0 )
128                                         *video_index = i;
129                                 break;
130                         case CODEC_TYPE_AUDIO:
131                                 if ( *audio_index < 0 )
132                                         *audio_index = i;
133                                 break;
134                         default:
135                                 break;
136                 }
137         }
138 }
139
140 /** Producer file destructor.
141 */
142
143 static void producer_file_close( void *context )
144 {
145         if ( context != NULL )
146         {
147                 // Lock the mutex now
148                 pthread_mutex_lock( &avformat_mutex );
149
150                 // Close the file
151                 av_close_input_file( context );
152
153                 // Unlock the mutex now
154                 pthread_mutex_unlock( &avformat_mutex );
155         }
156 }
157
158 /** Producer file destructor.
159 */
160
161 static void producer_codec_close( void *codec )
162 {
163         if ( codec != NULL )
164         {
165                 // Lock the mutex now
166                 pthread_mutex_lock( &avformat_mutex );
167
168                 // Close the file
169                 avcodec_close( codec );
170
171                 // Unlock the mutex now
172                 pthread_mutex_unlock( &avformat_mutex );
173         }
174 }
175
176 /** Open the file.
177 */
178
179 static int producer_open( mlt_producer this, char *file )
180 {
181         // Return an error code (0 == no error)
182         int error = 0;
183
184         // Context for avformat
185         AVFormatContext *context = NULL;
186
187         // Get the properties
188         mlt_properties properties = mlt_producer_properties( this );
189
190         // We will treat everything with the producer fps
191         double fps = mlt_properties_get_double( properties, "fps" );
192
193         // Lock the mutex now
194         pthread_mutex_lock( &avformat_mutex );
195         
196         // If "MRL", then create AVInputFormat
197         AVInputFormat *format = NULL;
198         AVFormatParameters *params = NULL;
199         char *standard = NULL;
200         char *mrl = strchr( file, ':' );
201         
202         // Only if there is not a protocol specification that avformat can handle
203         if ( mrl && !url_exist( file ) )
204         {
205                 // 'file' becomes format abbreviation
206                 mrl[0] = 0;
207         
208                 // Lookup the format
209                 format = av_find_input_format( file );
210                 
211                 // Eat the format designator
212                 file = ++mrl;
213                 
214                 if ( format )
215                 {
216                         // Allocate params
217                         params = calloc( sizeof( AVFormatParameters ), 1 );
218                         
219                         // These are required by video4linux (defaults)
220                         params->width = 640;
221                         params->height = 480;
222                         params->frame_rate = 25;
223                         params->frame_rate_base = 1;
224                         params->device = file;
225                         params->channels = 2;
226                         params->sample_rate = 48000;
227                 }
228                 
229                 // Parse out params
230                 mrl = strchr( file, '?' );
231                 while ( mrl )
232                 {
233                         mrl[0] = 0;
234                         char *name = strdup( ++mrl );
235                         char *value = strchr( name, '=' );
236                         if ( value )
237                         {
238                                 value[0] = 0;
239                                 value++;
240                                 char *t = strchr( value, '&' );
241                                 if ( t )
242                                         t[0] = 0;
243                                 if ( !strcmp( name, "frame_rate" ) )
244                                         params->frame_rate = atoi( value );
245                                 else if ( !strcmp( name, "frame_rate_base" ) )
246                                         params->frame_rate_base = atoi( value );
247                                 else if ( !strcmp( name, "sample_rate" ) )
248                                         params->sample_rate = atoi( value );
249                                 else if ( !strcmp( name, "channels" ) )
250                                         params->channels = atoi( value );
251                                 else if ( !strcmp( name, "width" ) )
252                                         params->width = atoi( value );
253                                 else if ( !strcmp( name, "height" ) )
254                                         params->height = atoi( value );
255                                 else if ( !strcmp( name, "standard" ) )
256                                 {
257                                         standard = strdup( value );
258                                         params->standard = standard;
259                                 }
260                         }
261                         free( name );
262                         mrl = strchr( mrl, '&' );
263                 }
264         }
265
266         // Now attempt to open the file
267         error = av_open_input_file( &context, file, format, 0, params );
268         error = error < 0;
269         
270         // Cleanup AVFormatParameters
271         free( standard );
272         free( params );
273
274         // If successful, then try to get additional info
275         if ( error == 0 )
276         {
277                 // Get the stream info
278                 error = av_find_stream_info( context ) < 0;
279
280                 // Continue if no error
281                 if ( error == 0 )
282                 {
283                         // We will default to the first audio and video streams found
284                         int audio_index = -1;
285                         int video_index = -1;
286
287                         // Now set properties where we can (use default unknowns if required)
288                         if ( context->duration != AV_NOPTS_VALUE ) 
289                         {
290                                 // This isn't going to be accurate for all formats
291                                 mlt_position frames = ( mlt_position )( ( ( double )context->duration / ( double )AV_TIME_BASE ) * fps );
292                                 mlt_properties_set_position( properties, "out", frames - 2 );
293                                 mlt_properties_set_position( properties, "length", frames - 1 );
294                         }
295
296                         // Find default audio and video streams
297                         find_default_streams( context, &audio_index, &video_index );
298
299                         // Store selected audio and video indexes on properties
300                         mlt_properties_set_int( properties, "audio_index", audio_index );
301                         mlt_properties_set_int( properties, "video_index", video_index );
302                         
303                         // We're going to cheat here - for a/v files, we will have two contexts (reasoning will be clear later)
304                         if ( audio_index != -1 && video_index != -1 )
305                         {
306                                 // We'll use the open one as our video_context
307                                 mlt_properties_set_data( properties, "video_context", context, 0, producer_file_close, NULL );
308
309                                 // And open again for our audio context
310                                 av_open_input_file( &context, file, NULL, 0, NULL );
311                                 av_find_stream_info( context );
312
313                                 // Audio context
314                                 mlt_properties_set_data( properties, "audio_context", context, 0, producer_file_close, NULL );
315                         }
316                         else if ( video_index != -1 )
317                         {
318                                 // We only have a video context
319                                 mlt_properties_set_data( properties, "video_context", context, 0, producer_file_close, NULL );
320                         }
321                         else if ( audio_index != -1 )
322                         {
323                                 // We only have an audio context
324                                 mlt_properties_set_data( properties, "audio_context", context, 0, producer_file_close, NULL );
325                         }
326                         else
327                         {
328                                 // Something has gone wrong
329                                 error = -1;
330                         }
331                 }
332         }
333
334         // Unlock the mutex now
335         pthread_mutex_unlock( &avformat_mutex );
336
337         return error;
338 }
339
340 /** Convert a frame position to a time code.
341 */
342
343 static double producer_time_of_frame( mlt_producer this, mlt_position position )
344 {
345         // Get the properties
346         mlt_properties properties = mlt_producer_properties( this );
347
348         // Obtain the fps
349         double fps = mlt_properties_get_double( properties, "fps" );
350
351         // Do the calc
352         return ( double )position / fps;
353 }
354
355 /** Get an image from a frame.
356 */
357
358 static int producer_get_image( mlt_frame frame, uint8_t **buffer, mlt_image_format *format, int *width, int *height, int writable )
359 {
360         // Get the properties from the frame
361         mlt_properties frame_properties = mlt_frame_properties( frame );
362
363         // Obtain the frame number of this frame
364         mlt_position position = mlt_properties_get_position( frame_properties, "avformat_position" );
365
366         // Get the producer 
367         mlt_producer this = mlt_properties_get_data( frame_properties, "avformat_producer", NULL );
368
369         // Get the producer properties
370         mlt_properties properties = mlt_producer_properties( this );
371
372         // Fetch the video_context
373         AVFormatContext *context = mlt_properties_get_data( properties, "video_context", NULL );
374
375         // Get the video_index
376         int index = mlt_properties_get_int( properties, "video_index" );
377
378         // Obtain the expected frame numer
379         mlt_position expected = mlt_properties_get_position( properties, "video_expected" );
380
381         // Calculate the real time code
382         double real_timecode = producer_time_of_frame( this, position ) + mlt_properties_get_double( properties, "_v_pts_offset" );
383
384         // Get the video stream
385         AVStream *stream = context->streams[ index ];
386
387         // Get codec context
388         AVCodecContext *codec_context = &stream->codec;
389
390         // Packet
391         AVPacket pkt;
392
393         // Get the conversion frame
394         AVPicture *output = mlt_properties_get_data( properties, "video_output_frame", NULL );
395
396         // Special case pause handling flag
397         int paused = 0;
398
399         // Special case ffwd handling
400         int ignore = 0;
401
402         // Current time calcs
403         double current_time = mlt_properties_get_double( properties, "current_time" );
404
405         // We may want to use the source fps if available
406         double source_fps = mlt_properties_get_double( properties, "source_fps" );
407
408         // Set the result arguments that we know here (only *buffer is now required)
409         *format = mlt_image_yuv422;
410         *width = codec_context->width;
411         *height = codec_context->height;
412
413         // Set this on the frame properties
414         mlt_properties_set_int( frame_properties, "width", *width );
415         mlt_properties_set_int( frame_properties, "height", *height );
416
417         // Lock the mutex now
418         pthread_mutex_lock( &avformat_mutex );
419
420         // Construct an AVFrame for YUV422 conversion
421         if ( output == NULL )
422         {
423                 int size = avpicture_get_size( PIX_FMT_YUV422, *width, *height );
424                 size += *width * 2;
425                 uint8_t *buf = mlt_pool_alloc( size );
426                 output = mlt_pool_alloc( sizeof( AVPicture ) );
427                 //memset( output, 0, sizeof( AVPicture ) );
428                 avpicture_fill( output, buf, PIX_FMT_YUV422, *width, *height );
429                 mlt_properties_set_data( properties, "video_output_frame", output, 0, ( mlt_destructor )mlt_pool_release, NULL );
430                 mlt_properties_set_data( properties, "video_output_buffer", buf, 0, ( mlt_destructor )mlt_pool_release, NULL );
431         }
432
433         // Seek if necessary
434         if ( position != expected )
435         {
436                 if ( position + 1 == expected )
437                 {
438                         // We're paused - use last image
439                         paused = 1;
440                 }
441                 else if ( position > expected && ( position - expected ) < 250 )
442                 {
443                         // Fast forward - seeking is inefficient for small distances - just ignore following frames
444                         ignore = position - expected;
445                 }
446                 else
447                 {
448                         // Set to the real timecode
449                         av_seek_frame( context, -1, real_timecode * 1000000.0 );
450         
451                         // Remove the cached info relating to the previous position
452                         mlt_properties_set_double( properties, "current_time", real_timecode );
453                         mlt_properties_set_data( properties, "current_image", NULL, 0, NULL, NULL );
454                 }
455         }
456         
457         // Duplicate the last image if necessary
458         if ( mlt_properties_get_data( properties, "current_image", NULL ) != NULL &&
459                  ( paused || mlt_properties_get_double( properties, "current_time" ) >= real_timecode ) )
460         {
461                 // Get current image and size
462                 int size = 0;
463                 uint8_t *image = mlt_properties_get_data( properties, "current_image", &size );
464
465                 // Duplicate it
466                 *buffer = mlt_pool_alloc( size );
467                 memcpy( *buffer, image, size );
468
469                 // Set this on the frame properties
470                 mlt_properties_set_data( frame_properties, "image", *buffer, size, ( mlt_destructor )mlt_pool_release, NULL );
471         }
472         else
473         {
474                 int ret = 0;
475                 int got_picture = 0;
476                 AVFrame frame;
477
478                 memset( &pkt, 0, sizeof( pkt ) );
479                 memset( &frame, 0, sizeof( frame ) );
480
481                 while( ret >= 0 && !got_picture )
482                 {
483                         // Read a packet
484                         ret = av_read_frame( context, &pkt );
485
486                         // We only deal with video from the selected video_index
487                         if ( ret >= 0 && pkt.stream_index == index && pkt.size > 0 )
488                         {
489                                 // Decode the image
490                                 ret = avcodec_decode_video( codec_context, &frame, &got_picture, pkt.data, pkt.size );
491
492                                 if ( got_picture )
493                                 {
494                                         if ( pkt.pts != AV_NOPTS_VALUE && pkt.pts != 0  )
495                                         {
496                                                 if ( current_time == 0 )
497                                                 {
498                                                         mlt_properties_set_double( properties, "_v_pts_offset", ( double )( pkt.pts / 1000000 ) );
499                                                         real_timecode += pkt.pts / 1000000;
500                                                 }
501                                                 current_time = ( double )pkt.pts / 1000000.0;
502                                         }
503                                         else
504                                                 current_time = real_timecode;
505
506                                         // Handle ignore
507                                         if ( current_time < real_timecode )
508                                         {
509                                                 ignore = 0;
510                                                 got_picture = 0;
511                                         }
512                                         else if ( current_time >= real_timecode )
513                                         {
514                                                 //current_time = real_timecode;
515                                                 ignore = 0;
516                                         }
517                                         else if ( ignore -- )
518                                         {
519                                                 got_picture = 0;
520                                         }
521                                 }
522                         }
523
524                         // We're finished with this packet regardless
525                         av_free_packet( &pkt );
526                 }
527
528                 // Now handle the picture if we have one
529                 if ( got_picture )
530                 {
531                         // Get current image and size
532                         int size = 0;
533                         uint8_t *image = mlt_properties_get_data( properties, "current_image", &size );
534
535                         if ( image == NULL || size != *width * *height * 2 )
536                         {
537                                 size = *width * ( *height + 1 ) * 2;
538                                 image = mlt_pool_alloc( size );
539                                 mlt_properties_set_data( properties, "current_image", image, size, ( mlt_destructor )mlt_pool_release, NULL );
540                         }
541
542                         *buffer = mlt_pool_alloc( size );
543
544                         // EXPERIMENTAL IMAGE NORMALISATIONS
545                         if ( codec_context->pix_fmt == PIX_FMT_YUV420P )
546                         {
547                                 register int i, j;
548                                 register int half = *width >> 1;
549                                 register uint8_t *Y = ( ( AVPicture * )&frame )->data[ 0 ];
550                                 register uint8_t *U = ( ( AVPicture * )&frame )->data[ 1 ];
551                                 register uint8_t *V = ( ( AVPicture * )&frame )->data[ 2 ];
552                                 register uint8_t *d = *buffer;
553                                 register uint8_t *y, *u, *v;
554
555                                 i = *height >> 1;
556                                 while ( i -- )
557                                 {
558                                         y = Y;
559                                         u = U;
560                                         v = V;
561                                         j = half;
562                                         while ( j -- )
563                                         {
564                                                 *d ++ = *y ++;
565                                                 *d ++ = *u ++;
566                                                 *d ++ = *y ++;
567                                                 *d ++ = *v ++;
568                                         }
569
570                                         Y += ( ( AVPicture * )&frame )->linesize[ 0 ];
571                                         y = Y;
572                                         u = U;
573                                         v = V;
574                                         j = half;
575                                         while ( j -- )
576                                         {
577                                                 *d ++ = *y ++;
578                                                 *d ++ = *u ++;
579                                                 *d ++ = *y ++;
580                                                 *d ++ = *v ++;
581                                         }
582
583                                         Y += ( ( AVPicture * )&frame )->linesize[ 0 ];
584                                         U += ( ( AVPicture * )&frame )->linesize[ 1 ];
585                                         V += ( ( AVPicture * )&frame )->linesize[ 2 ];
586                                 }
587                         }
588                         else
589                         {
590                                 img_convert( output, PIX_FMT_YUV422, (AVPicture *)&frame, codec_context->pix_fmt, *width, *height );
591                                 memcpy( *buffer, output->data[ 0 ], size );
592                         }
593
594                         memcpy( image, *buffer, size );
595                         mlt_properties_set_data( frame_properties, "image", *buffer, size, ( mlt_destructor )mlt_pool_release, NULL );
596
597                         if ( current_time == 0 && source_fps != 0 )
598                         {
599                                 double fps = mlt_properties_get_double( properties, "fps" );
600                                 current_time = ceil( source_fps * ( double )position / fps ) * ( 1 / source_fps );
601                                 mlt_properties_set_double( properties, "current_time", current_time );
602                         }
603                         else
604                         {
605                                 mlt_properties_set_double( properties, "current_time", current_time );
606                         }
607                 }
608         }
609
610         // Regardless of speed, we expect to get the next frame (cos we ain't too bright)
611         mlt_properties_set_position( properties, "video_expected", position + 1 );
612
613         // Unlock the mutex now
614         pthread_mutex_unlock( &avformat_mutex );
615
616         return 0;
617 }
618
619 /** Set up video handling.
620 */
621
622 static void producer_set_up_video( mlt_producer this, mlt_frame frame )
623 {
624         // Get the properties
625         mlt_properties properties = mlt_producer_properties( this );
626
627         // Fetch the video_context
628         AVFormatContext *context = mlt_properties_get_data( properties, "video_context", NULL );
629
630         // Get the video_index
631         int index = mlt_properties_get_int( properties, "video_index" );
632
633         // Get the frame properties
634         mlt_properties frame_properties = mlt_frame_properties( frame );
635
636         // Lock the mutex now
637         pthread_mutex_lock( &avformat_mutex );
638
639         if ( context != NULL && index != -1 )
640         {
641                 // Get the video stream
642                 AVStream *stream = context->streams[ index ];
643
644                 // Get codec context
645                 AVCodecContext *codec_context = &stream->codec;
646
647                 // Get the codec
648                 AVCodec *codec = mlt_properties_get_data( properties, "video_codec", NULL );
649
650                 // Initialise the codec if necessary
651                 if ( codec == NULL )
652                 {
653                         // Find the codec
654                         codec = avcodec_find_decoder( codec_context->codec_id );
655
656                         // If we don't have a codec and we can't initialise it, we can't do much more...
657                         if ( codec != NULL && avcodec_open( codec_context, codec ) >= 0 )
658                         {
659                                 // Now store the codec with its destructor
660                                 mlt_properties_set_data( properties, "video_codec", codec_context, 0, producer_codec_close, NULL );
661                         }
662                         else
663                         {
664                                 // Remember that we can't use this later
665                                 mlt_properties_set_int( properties, "video_index", -1 );
666                         }
667                 }
668
669                 // No codec, no show...
670                 if ( codec != NULL )
671                 {
672                         double aspect_ratio = 1;
673                         double source_fps = 0;
674
675                         // Set aspect ratio
676                         if ( codec_context->sample_aspect_ratio.num > 0 )
677                                 aspect_ratio = av_q2d( codec_context->sample_aspect_ratio );
678
679                         mlt_properties_set_double( properties, "aspect_ratio", aspect_ratio );
680                         //fprintf( stderr, "AVFORMAT: sample aspect %f %dx%d\n", av_q2d( codec_context->sample_aspect_ratio ), codec_context->width, codec_context->height );
681
682                         // Determine the fps
683                         source_fps = ( double )codec_context->frame_rate / ( codec_context->frame_rate_base == 0 ? 1 : codec_context->frame_rate_base );
684
685                         // We'll use fps if it's available
686                         if ( source_fps > 0 && source_fps < 30 )
687                                 mlt_properties_set_double( properties, "source_fps", source_fps );
688                         
689                         // Set the width and height
690                         mlt_properties_set_int( frame_properties, "width", codec_context->width );
691                         mlt_properties_set_int( frame_properties, "height", codec_context->height );
692
693                         mlt_frame_push_get_image( frame, producer_get_image );
694                         mlt_properties_set_data( frame_properties, "avformat_producer", this, 0, NULL, NULL );
695                 }
696                 else
697                 {
698                         mlt_properties_set_int( frame_properties, "test_image", 1 );
699                 }
700         }
701         else
702         {
703                 mlt_properties_set_int( frame_properties, "test_image", 1 );
704         }
705
706         // Unlock the mutex now
707         pthread_mutex_unlock( &avformat_mutex );
708 }
709
710 /** Get the audio from a frame.
711 */
712
713 static int producer_get_audio( mlt_frame frame, int16_t **buffer, mlt_audio_format *format, int *frequency, int *channels, int *samples )
714 {
715         // Get the properties from the frame
716         mlt_properties frame_properties = mlt_frame_properties( frame );
717
718         // Obtain the frame number of this frame
719         mlt_position position = mlt_properties_get_position( frame_properties, "avformat_position" );
720
721         // Get the producer 
722         mlt_producer this = mlt_properties_get_data( frame_properties, "avformat_producer", NULL );
723
724         // Get the producer properties
725         mlt_properties properties = mlt_producer_properties( this );
726
727         // Fetch the audio_context
728         AVFormatContext *context = mlt_properties_get_data( properties, "audio_context", NULL );
729
730         // Get the audio_index
731         int index = mlt_properties_get_int( properties, "audio_index" );
732
733         // Obtain the expected frame numer
734         mlt_position expected = mlt_properties_get_position( properties, "audio_expected" );
735
736         // Obtain the resample context if it exists (not always needed)
737         ReSampleContext *resample = mlt_properties_get_data( properties, "audio_resample", NULL );
738
739         // Obtain the audio buffer
740         int16_t *audio_buffer = mlt_properties_get_data( properties, "audio_buffer", NULL );
741
742         // Get amount of audio used
743         int audio_used =  mlt_properties_get_int( properties, "audio_used" );
744
745         // Calculate the real time code
746         double real_timecode = producer_time_of_frame( this, position );
747
748         // Get the audio stream
749         AVStream *stream = context->streams[ index ];
750
751         // Get codec context
752         AVCodecContext *codec_context = &stream->codec;
753
754         // Packet
755         AVPacket pkt;
756
757         // Number of frames to ignore (for ffwd)
758         int ignore = 0;
759
760         // Flag for paused (silence) 
761         int paused = 0;
762         int locked = 0;
763
764         // Lock the mutex now
765         pthread_mutex_lock( &avformat_mutex );
766
767         // Check for resample and create if necessary
768         if ( resample == NULL )
769         {
770                 // Create the resampler
771                 resample = audio_resample_init( *channels, codec_context->channels, *frequency, codec_context->sample_rate );
772
773                 // And store it on properties
774                 mlt_properties_set_data( properties, "audio_resample", resample, 0, ( mlt_destructor )audio_resample_close, NULL );
775         }
776
777         // Check for audio buffer and create if necessary
778         if ( audio_buffer == NULL )
779         {
780                 // Allocate the audio buffer
781                 audio_buffer = mlt_pool_alloc( AVCODEC_MAX_AUDIO_FRAME_SIZE * sizeof( int16_t ) );
782
783                 // And store it on properties for reuse
784                 mlt_properties_set_data( properties, "audio_buffer", audio_buffer, 0, ( mlt_destructor )mlt_pool_release, NULL );
785         }
786
787         // Seek if necessary
788         if ( position != expected )
789         {
790                 if ( position + 1 == expected )
791                 {
792                         // We're paused - silence required
793                         paused = 1;
794                 }
795                 else if ( position > expected && ( position - expected ) < 250 )
796                 {
797                         // Fast forward - seeking is inefficient for small distances - just ignore following frames
798                         ignore = position - expected;
799                 }
800                 else
801                 {
802                         // Set to the real timecode
803                         av_seek_frame( context, -1, real_timecode * 1000000.0 );
804
805                         // Clear the usage in the audio buffer
806                         audio_used = 0;
807
808                         locked = 1;
809                 }
810         }
811
812         // Get the audio if required
813         if ( !paused )
814         {
815                 int ret = 0;
816                 int got_audio = 0;
817                 int16_t *temp = mlt_pool_alloc( sizeof( int16_t ) * AVCODEC_MAX_AUDIO_FRAME_SIZE );
818
819                 memset( &pkt, 0, sizeof( pkt ) );
820
821                 while( ret >= 0 && !got_audio )
822                 {
823                         // Check if the buffer already contains the samples required
824                         if ( audio_used >= *samples && ignore == 0 )
825                         {
826                                 got_audio = 1;
827                                 break;
828                         }
829
830                         // Read a packet
831                         ret = av_read_frame( context, &pkt );
832
833                 int len = pkt.size;
834                 uint8_t *ptr = pkt.data;
835                         int data_size;
836
837                         // We only deal with video from the selected video_index
838                         while ( ptr != NULL && ret >= 0 && pkt.stream_index == index && len > 0 )
839                         {
840                                 // Decode the audio
841                                 ret = avcodec_decode_audio( codec_context, temp, &data_size, ptr, len );
842
843                                 if ( ret < 0 )
844                                 {
845                                         ret = 0;
846                                         break;
847                                 }
848
849                                 len -= ret;
850                                 ptr += ret;
851
852                                 if ( data_size > 0 )
853                                 {
854                                         int size_out = audio_resample( resample, &audio_buffer[ audio_used * *channels ], temp, data_size / ( codec_context->channels * sizeof( int16_t ) ) );
855
856                                         audio_used += size_out;
857
858                                         // Handle ignore
859                                         while ( ignore && audio_used > *samples )
860                                         {
861                                                 ignore --;
862                                                 audio_used -= *samples;
863                                                 memmove( audio_buffer, &audio_buffer[ *samples * *channels ], audio_used * sizeof( int16_t ) );
864                                         }
865                                 }
866
867                                 // If we're behind, ignore this packet
868                                 float current_pts = (float)pkt.pts / 1000000.0;
869                                 double discrepancy = mlt_properties_get_double( properties, "discrepancy" );
870                                 if ( current_pts != 0 && real_timecode != 0 )
871                                 {
872                                         if ( discrepancy != 1 )
873                                                 discrepancy = ( discrepancy + ( real_timecode / current_pts ) ) / 2;
874                                         else
875                                                 discrepancy = real_timecode / current_pts;
876                                         if ( discrepancy > 0.9 && discrepancy < 1.1 )
877                                                 discrepancy = 1.0;
878                                         else
879                                                 discrepancy = floor( discrepancy + 0.5 );
880
881                                         if ( discrepancy == 0 )
882                                                 discrepancy = 1.0;
883
884                                         mlt_properties_set_double( properties, "discrepancy", discrepancy );
885                                 }
886
887                                 if ( !ignore && discrepancy * current_pts <= ( real_timecode - 0.02 ) )
888                                         ignore = 1;
889                         }
890
891                         // We're finished with this packet regardless
892                         av_free_packet( &pkt );
893                 }
894
895                 *buffer = mlt_pool_alloc( *samples * *channels * sizeof( int16_t ) );
896                 mlt_properties_set_data( frame_properties, "audio", *buffer, 0, ( mlt_destructor )mlt_pool_release, NULL );
897
898                 // Now handle the audio if we have enough
899                 if ( audio_used >= *samples )
900                 {
901                         memcpy( *buffer, audio_buffer, *samples * *channels * sizeof( int16_t ) );
902                         audio_used -= *samples;
903                         memmove( audio_buffer, &audio_buffer[ *samples * *channels ], audio_used * *channels * sizeof( int16_t ) );
904                 }
905                 else
906                 {
907                         memset( *buffer, 0, *samples * *channels * sizeof( int16_t ) );
908                 }
909                 
910                 // Store the number of audio samples still available
911                 mlt_properties_set_int( properties, "audio_used", audio_used );
912
913                 // Release the temporary audio
914                 mlt_pool_release( temp );
915         }
916         else
917         {
918                 // Get silence and don't touch the context
919                 frame->get_audio = NULL;
920                 mlt_frame_get_audio( frame, buffer, format, frequency, channels, samples );
921         }
922
923         // Regardless of speed, we expect to get the next frame (cos we ain't too bright)
924         mlt_properties_set_position( properties, "audio_expected", position + 1 );
925
926         // Unlock the mutex now
927         pthread_mutex_unlock( &avformat_mutex );
928
929         return 0;
930 }
931
932 /** Set up audio handling.
933 */
934
935 static void producer_set_up_audio( mlt_producer this, mlt_frame frame )
936 {
937         // Get the properties
938         mlt_properties properties = mlt_producer_properties( this );
939
940         // Fetch the audio_context
941         AVFormatContext *context = mlt_properties_get_data( properties, "audio_context", NULL );
942
943         // Get the audio_index
944         int index = mlt_properties_get_int( properties, "audio_index" );
945
946         // Lock the mutex now
947         pthread_mutex_lock( &avformat_mutex );
948
949         // Deal with audio context
950         if ( context != NULL && index != -1 )
951         {
952                 // Get the frame properties
953                 mlt_properties frame_properties = mlt_frame_properties( frame );
954
955                 // Get the audio stream
956                 AVStream *stream = context->streams[ index ];
957
958                 // Get codec context
959                 AVCodecContext *codec_context = &stream->codec;
960
961                 // Get the codec
962                 AVCodec *codec = mlt_properties_get_data( properties, "audio_codec", NULL );
963
964                 // Initialise the codec if necessary
965                 if ( codec == NULL )
966                 {
967                         // Find the codec
968                         codec = avcodec_find_decoder( codec_context->codec_id );
969
970                         // If we don't have a codec and we can't initialise it, we can't do much more...
971                         if ( codec != NULL && avcodec_open( codec_context, codec ) >= 0 )
972                         {
973                                 // Now store the codec with its destructor
974                                 mlt_properties_set_data( properties, "audio_codec", codec_context, 0, producer_codec_close, NULL );
975
976                         }
977                         else
978                         {
979                                 // Remember that we can't use this later
980                                 mlt_properties_set_int( properties, "audio_index", -1 );
981                         }
982                 }
983
984                 // No codec, no show...
985                 if ( codec != NULL )
986                 {
987                         frame->get_audio = producer_get_audio;
988                         mlt_properties_set_data( frame_properties, "avformat_producer", this, 0, NULL, NULL );
989                 }
990         }
991
992         // Unlock the mutex now
993         pthread_mutex_unlock( &avformat_mutex );
994 }
995
996 /** Our get frame implementation.
997 */
998
999 static int producer_get_frame( mlt_producer this, mlt_frame_ptr frame, int index )
1000 {
1001         // Create an empty frame
1002         *frame = mlt_frame_init( );
1003
1004         // Update timecode on the frame we're creating
1005         mlt_frame_set_position( *frame, mlt_producer_position( this ) );
1006
1007         // Set the position of this producer
1008         mlt_properties_set_position( mlt_frame_properties( *frame ), "avformat_position", mlt_producer_get_in( this ) + mlt_producer_position( this ) );
1009
1010         // Set up the video
1011         producer_set_up_video( this, *frame );
1012
1013         // Set up the audio
1014         producer_set_up_audio( this, *frame );
1015
1016         // Set the aspect_ratio
1017         mlt_properties_set_double( mlt_frame_properties( *frame ), "aspect_ratio", mlt_properties_get_double( mlt_producer_properties( this ), "aspect_ratio" ) );
1018
1019         // Calculate the next timecode
1020         mlt_producer_prepare_next( this );
1021
1022         return 0;
1023 }