]> git.sesse.net Git - mlt/blobdiff - src/modules/avformat/producer_avformat.c
refactor avformat producer_open
[mlt] / src / modules / avformat / producer_avformat.c
index 550b6e4f0ea119cbb5e1654283a5e289bff9e680..c593d210642ab81a8e82c669e7fd92d7132b19e2 100644 (file)
@@ -129,7 +129,8 @@ struct producer_avformat_s
 typedef struct producer_avformat_s *producer_avformat;
 
 // Forward references.
-static int producer_open( producer_avformat self, mlt_profile profile, char *file );
+static int list_components( char* file );
+static int producer_open( producer_avformat self, mlt_profile profile, const char *URL );
 static int producer_get_frame( mlt_producer producer, mlt_frame_ptr frame, int index );
 static void producer_avformat_close( producer_avformat );
 static void producer_close( mlt_producer parent );
@@ -147,45 +148,17 @@ static int video_codec_init( producer_avformat self, int index, mlt_properties p
 
 mlt_producer producer_avformat_init( mlt_profile profile, const char *service, char *file )
 {
-       int skip = 0;
+       if ( list_components( file ) )
+               return NULL;
 
-       // Report information about available demuxers and codecs as YAML Tiny
-       if ( file && strstr( file, "f-list" ) )
-       {
-               fprintf( stderr, "---\nformats:\n" );
-               AVInputFormat *format = NULL;
-               while ( ( format = av_iformat_next( format ) ) )
-                       fprintf( stderr, "  - %s\n", format->name );
-               fprintf( stderr, "...\n" );
-               skip = 1;
-       }
-       if ( file && strstr( file, "acodec-list" ) )
-       {
-               fprintf( stderr, "---\naudio_codecs:\n" );
-               AVCodec *codec = NULL;
-               while ( ( codec = av_codec_next( codec ) ) )
-                       if ( codec->decode && codec->type == CODEC_TYPE_AUDIO )
-                               fprintf( stderr, "  - %s\n", codec->name );
-               fprintf( stderr, "...\n" );
-               skip = 1;
-       }
-       if ( file && strstr( file, "vcodec-list" ) )
-       {
-               fprintf( stderr, "---\nvideo_codecs:\n" );
-               AVCodec *codec = NULL;
-               while ( ( codec = av_codec_next( codec ) ) )
-                       if ( codec->decode && codec->type == CODEC_TYPE_VIDEO )
-                               fprintf( stderr, "  - %s\n", codec->name );
-               fprintf( stderr, "...\n" );
-               skip = 1;
-       }
+       mlt_producer producer = NULL;
 
        // Check that we have a non-NULL argument
-       if ( !skip && file )
+       if ( file )
        {
                // Construct the producer
-               mlt_producer producer = calloc( 1, sizeof( struct mlt_producer_s ) );
                producer_avformat self = calloc( 1, sizeof( struct producer_avformat_s ) );
+               producer = calloc( 1, sizeof( struct mlt_producer_s ) );
 
                // Initialise it
                if ( mlt_producer_init( producer, self ) == 0 )
@@ -203,7 +176,7 @@ mlt_producer producer_avformat_init( mlt_profile profile, const char *service, c
 
                        // Register our get_frame implementation
                        producer->get_frame = producer_get_frame;
-                       
+
                        if ( strcmp( service, "avformat-novalidate" ) )
                        {
                                // Open the file
@@ -227,38 +200,76 @@ mlt_producer producer_avformat_init( mlt_profile profile, const char *service, c
                                                av_close_input_file( self->video_format );
                                        self->video_format = NULL;
                                        avformat_unlock();
-       
+
                                        // Default the user-selectable indices from the auto-detected indices
                                        mlt_properties_set_int( properties, "audio_index",  self->audio_index );
                                        mlt_properties_set_int( properties, "video_index",  self->video_index );
-                                       
-#ifdef VDPAU
-                                       mlt_service_cache_set_size( MLT_PRODUCER_SERVICE(producer), "producer_avformat", 5 );
-#endif
-                                       mlt_service_cache_put( MLT_PRODUCER_SERVICE(producer), "producer_avformat", self, 0, (mlt_destructor) producer_avformat_close );
                                }
                        }
-                       else
+                       if ( producer )
                        {
 #ifdef VDPAU
                                mlt_service_cache_set_size( MLT_PRODUCER_SERVICE(producer), "producer_avformat", 5 );
 #endif
                                mlt_service_cache_put( MLT_PRODUCER_SERVICE(producer), "producer_avformat", self, 0, (mlt_destructor) producer_avformat_close );
                        }
-                       return producer;
                }
        }
-       return NULL;
+       return producer;
+}
+
+int list_components( char* file )
+{
+       int skip = 0;
+
+       // Report information about available demuxers and codecs as YAML Tiny
+       if ( file && strstr( file, "f-list" ) )
+       {
+               fprintf( stderr, "---\nformats:\n" );
+               AVInputFormat *format = NULL;
+               while ( ( format = av_iformat_next( format ) ) )
+                       fprintf( stderr, "  - %s\n", format->name );
+               fprintf( stderr, "...\n" );
+               skip = 1;
+       }
+       if ( file && strstr( file, "acodec-list" ) )
+       {
+               fprintf( stderr, "---\naudio_codecs:\n" );
+               AVCodec *codec = NULL;
+               while ( ( codec = av_codec_next( codec ) ) )
+                       if ( codec->decode && codec->type == CODEC_TYPE_AUDIO )
+                               fprintf( stderr, "  - %s\n", codec->name );
+               fprintf( stderr, "...\n" );
+               skip = 1;
+       }
+       if ( file && strstr( file, "vcodec-list" ) )
+       {
+               fprintf( stderr, "---\nvideo_codecs:\n" );
+               AVCodec *codec = NULL;
+               while ( ( codec = av_codec_next( codec ) ) )
+                       if ( codec->decode && codec->type == CODEC_TYPE_VIDEO )
+                               fprintf( stderr, "  - %s\n", codec->name );
+               fprintf( stderr, "...\n" );
+               skip = 1;
+       }
+
+       return skip;
 }
 
 /** Find the default streams.
 */
 
-static mlt_properties find_default_streams( mlt_properties meta_media, AVFormatContext *context, int *audio_index, int *video_index )
+static mlt_properties find_default_streams( producer_avformat self )
 {
        int i;
        char key[200];
        AVMetadataTag *tag = NULL;
+       AVFormatContext *context = self->video_format;
+       mlt_properties meta_media = MLT_PRODUCER_PROPERTIES( self->parent );
+
+       // Default to the first audio and video streams found
+       self->audio_index = -1;
+       self->video_index = -1;
 
        mlt_properties_set_int( meta_media, "meta.media.nb_streams", context->nb_streams );
 
@@ -279,8 +290,9 @@ static mlt_properties find_default_streams( mlt_properties meta_media, AVFormatC
                switch( codec_context->codec_type )
                {
                        case CODEC_TYPE_VIDEO:
-                               if ( *video_index < 0 )
-                                       *video_index = i;
+                               // Use first video stream
+                               if ( self->video_index < 0 )
+                                       self->video_index = i;
                                mlt_properties_set( meta_media, key, "video" );
                                snprintf( key, sizeof(key), "meta.media.%d.stream.frame_rate", i );
 #if LIBAVFORMAT_VERSION_INT >= ((52<<16)+(42<<8)+0)
@@ -325,8 +337,9 @@ static mlt_properties find_default_streams( mlt_properties meta_media, AVFormatC
 #endif
                                break;
                        case CODEC_TYPE_AUDIO:
-                               if ( *audio_index < 0 )
-                                       *audio_index = i;
+                               // Use first audio stream
+                               if ( self->audio_index < 0 )
+                                       self->audio_index = i;
                                mlt_properties_set( meta_media, key, "audio" );
 #if LIBAVCODEC_VERSION_MAJOR > 52
                                snprintf( key, sizeof(key), "meta.media.%d.codec.sample_fmt", i );
@@ -528,249 +541,262 @@ static double get_aspect_ratio( mlt_properties properties, AVStream *stream, AVC
        return aspect_ratio;
 }
 
-/** Open the file.
-*/
-
-static int producer_open( producer_avformat self, mlt_profile profile, char *file )
+static char* parse_url( mlt_profile profile, const char* URL, AVInputFormat **format, AVFormatParameters **parameters )
 {
-       // Return an error code (0 == no error)
-       int error = 0;
+       if ( !URL ) return NULL;
 
-       // Context for avformat
-       AVFormatContext *context = NULL;
-
-       // Get the properties
-       mlt_properties properties = MLT_PRODUCER_PROPERTIES( self->parent );
-
-       // We will treat everything with the producer fps
-       double fps = mlt_profile_fps( profile );
-
-       // Lock the service
-       pthread_mutex_init( &self->audio_mutex, NULL );
-       pthread_mutex_init( &self->video_mutex, NULL );
-       pthread_mutex_lock( &self->audio_mutex );
-       pthread_mutex_lock( &self->video_mutex );
-
-       // If "MRL", then create AVInputFormat
-       AVInputFormat *format = NULL;
-       AVFormatParameters *params = NULL;
-       char *standard = NULL;
-       char *mrl = strchr( file, ':' );
-
-       // AV option (0 = both, 1 = video, 2 = audio)
-       int av = 0;
+       char *result = NULL;
+       char *protocol = strdup( URL );
+       char *url = strchr( protocol, ':' );
 
        // Only if there is not a protocol specification that avformat can handle
 #if LIBAVFORMAT_VERSION_MAJOR > 52
-       if ( mrl && !avio_check( file, 0 ) )
+       if ( url && avio_check( URL, 0 ) < 0 )
 #else
-       if ( mrl && !url_exist( file ) )
+       if ( url && !url_exist( URL ) )
 #endif
        {
-               // 'file' becomes format abbreviation
-               mrl[0] = 0;
+               // Truncate protocol string
+               url[0] = 0;
 
                // Lookup the format
-               format = av_find_input_format( file );
+               *format = av_find_input_format( protocol );
 
                // Eat the format designator
-               file = ++mrl;
+               result = ++url;
 
-               if ( format )
+               if ( *format )
                {
                        // Allocate params
-                       params = calloc( sizeof( AVFormatParameters ), 1 );
+                       AVFormatParameters *params = *parameters = calloc( 1, sizeof( AVFormatParameters ) );
 
-                       // These are required by video4linux (defaults)
-                       params->width = 640;
-                       params->height = 480;
-                       params->time_base= (AVRational){1,25};
+                       // These are required by video4linux2 (defaults)
+                       params->width = profile->width;
+                       params->height = profile->height;
+                       params->time_base= (AVRational){ profile->frame_rate_den, profile->frame_rate_num };
                        params->channels = 2;
                        params->sample_rate = 48000;
-               }
 
-               // Parse out params
-               mrl = strchr( file, '?' );
-               while ( mrl )
-               {
-                       mrl[0] = 0;
-                       char *name = strdup( ++mrl );
-                       char *value = strchr( name, ':' );
-                       if ( value )
+                       // Parse out params
+                       url = strchr( url, '?' );
+                       while ( url )
                        {
-                               value[0] = 0;
-                               value++;
-                               char *t = strchr( value, '&' );
-                               if ( t )
-                                       t[0] = 0;
-                               if ( !strcmp( name, "frame_rate" ) )
-                                       params->time_base.den = atoi( value );
-                               else if ( !strcmp( name, "frame_rate_base" ) )
-                                       params->time_base.num = atoi( value );
-                               else if ( !strcmp( name, "sample_rate" ) )
-                                       params->sample_rate = atoi( value );
-                               else if ( !strcmp( name, "channel" ) )
-                                       params->channel = atoi( value );
-                               else if ( !strcmp( name, "channels" ) )
-                                       params->channels = atoi( value );
+                               url[0] = 0;
+                               char *name = strdup( ++url );
+                               char *value = strchr( name, ':' );
+                               if ( value )
+                               {
+                                       value[0] = 0;
+                                       value++;
+                                       char *t = strchr( value, '&' );
+                                       if ( t )
+                                               t[0] = 0;
+                                       if ( !strcmp( name, "frame_rate" ) )
+                                               params->time_base.den = atoi( value );
+                                       else if ( !strcmp( name, "frame_rate_base" ) )
+                                               params->time_base.num = atoi( value );
+                                       else if ( !strcmp( name, "sample_rate" ) )
+                                               params->sample_rate = atoi( value );
+                                       else if ( !strcmp( name, "channel" ) )
+                                               params->channel = atoi( value );
+                                       else if ( !strcmp( name, "channels" ) )
+                                               params->channels = atoi( value );
 #if (LIBAVUTIL_VERSION_INT > ((50<<16)+(7<<8)+0))
-                               else if ( !strcmp( name, "pix_fmt" ) )
-                                       params->pix_fmt = av_get_pix_fmt( value );
+                                       else if ( !strcmp( name, "pix_fmt" ) )
+                                               params->pix_fmt = av_get_pix_fmt( value );
 #endif
-                               else if ( !strcmp( name, "width" ) )
-                                       params->width = atoi( value );
-                               else if ( !strcmp( name, "height" ) )
-                                       params->height = atoi( value );
-                               else if ( !strcmp( name, "standard" ) )
-                               {
-                                       standard = strdup( value );
-                                       params->standard = standard;
+                                       else if ( !strcmp( name, "width" ) )
+                                               params->width = atoi( value );
+                                       else if ( !strcmp( name, "height" ) )
+                                               params->height = atoi( value );
+                                       else if ( !strcmp( name, "standard" ) )
+                                               params->standard = strdup( value );
                                }
-                               else if ( !strcmp( name, "av" ) )
-                                       av = atoi( value );
+                               free( name );
+                               url = strchr( url, '&' );
                        }
-                       free( name );
-                       mrl = strchr( mrl, '&' );
                }
        }
+       free( protocol );
+       return result ? strdup( result ) : strdup( URL );
+}
 
-       // Now attempt to open the file
-       error = av_open_input_file( &context, file, format, 0, params ) < 0;
-
-       // Cleanup AVFormatParameters
-       free( standard );
-       free( params );
+static int get_basic_info( producer_avformat self, mlt_profile profile, const char *filename )
+{
+       int error = 0;
 
-       // If successful, then try to get additional info
-       if ( !error )
-       {
-               // Get the stream info
-               error = av_find_stream_info( context ) < 0;
+       // Get the properties
+       mlt_properties properties = MLT_PRODUCER_PROPERTIES( self->parent );
 
-               // Continue if no error
-               if ( !error )
-               {
-                       // We will default to the first audio and video streams found
-                       int audio_index = -1;
-                       int video_index = -1;
+       AVFormatContext *format = self->video_format;
 
-                       // Find default audio and video streams
-                       find_default_streams( properties, context, &audio_index, &video_index );
+       // We will treat everything with the producer fps.
+       // TODO: make this more flexible.
+       double fps = mlt_profile_fps( profile );
 
-                       // Now set properties where we can (use default unknowns if required)
-                       if ( context->duration != AV_NOPTS_VALUE )
-                       {
-                               // This isn't going to be accurate for all formats
-                               // Workaround some clips whose estimated duration cause problems:
-                               // http://www.kdenlive.org/mantis/view.php?id=2003
-                               int adjust = -3;
-                               if ( mlt_properties_get( properties, "adjust_length" ) )
-                                       adjust = mlt_properties_get_int( properties, "adjust_length" );
-                               mlt_position frames = ( mlt_position )( ( ( double )context->duration / ( double )AV_TIME_BASE ) * fps + adjust );
-                               if  ( mlt_properties_get_position( properties, "force_length" ) > 0 )
-                                       frames = mlt_properties_get_position( properties, "force_length" );
-                               mlt_properties_set_position( properties, "out", frames - 1 );
-                               mlt_properties_set_position( properties, "length", frames );
-                       }
+       // Get the duration
+       if ( !mlt_properties_get_int( properties, "_length_computed" ) )
+       {
+               // The _length_computed flag prevents overwriting explicity set length/out/eof properties
+               // when producer_open is called after initial call when restoring or reseting the producer.
+               if ( format->duration != AV_NOPTS_VALUE )
+               {
+                       // This isn't going to be accurate for all formats
+                       mlt_position frames = ( mlt_position )( ( ( double )format->duration / ( double )AV_TIME_BASE ) * fps );
+                       mlt_properties_set_position( properties, "out", frames - 1 );
+                       mlt_properties_set_position( properties, "length", frames );
+                       mlt_properties_set_int( properties, "_length_computed", 1 );
+               }
+               else
+               {
+                       // Set live sources to run forever
+                       mlt_properties_set_position( properties, "length", INT_MAX );
+                       mlt_properties_set_position( properties, "out", INT_MAX - 1 );
+                       mlt_properties_set( properties, "eof", "loop" );
+                       mlt_properties_set_int( properties, "_length_computed", 1 );
+               }
+       }
 
-                       if ( context->start_time != AV_NOPTS_VALUE )
-                               self->start_time = context->start_time;
+       if ( format->start_time != AV_NOPTS_VALUE )
+               self->start_time = format->start_time;
 
-                       // Check if we're seekable
-                       // avdevices are typically AVFMT_NOFILE and not seekable
-                       self->seekable = !format || !( format->flags & AVFMT_NOFILE );
-                       if ( context->pb )
-                       {
-                               // protocols can indicate if they support seeking
+       // Check if we're seekable
+       // avdevices are typically AVFMT_NOFILE and not seekable
+       self->seekable = !format->iformat || !( format->iformat->flags & AVFMT_NOFILE );
+       if ( format->pb )
+       {
+               // protocols can indicate if they support seeking
 #if LIBAVFORMAT_VERSION_MAJOR > 52
-                               self->seekable = context->pb->seekable;
+               self->seekable = context->pb->seekable;
 #else
-                               URLContext *uc = url_fileno( context->pb );
-                               if ( uc )
-                                       self->seekable = !uc->is_streamed;
+               URLContext *uc = url_fileno( format->pb );
+               if ( uc )
+                       self->seekable = !uc->is_streamed;
 #endif
-                       }
-                       if ( self->seekable )
-                       {
-                               self->seekable = av_seek_frame( context, -1, self->start_time, AVSEEK_FLAG_BACKWARD ) >= 0;
-                               mlt_properties_set_int( properties, "seekable", self->seekable );
-                               self->dummy_context = context;
-                               av_open_input_file( &context, file, NULL, 0, NULL );
-                               av_find_stream_info( context );
-                       }
+       }
+       if ( self->seekable )
+       {
+               // Do a more rigourous test of seekable on a disposable context
+               self->seekable = av_seek_frame( format, -1, self->start_time, AVSEEK_FLAG_BACKWARD ) >= 0;
+               mlt_properties_set_int( properties, "seekable", self->seekable );
+               self->dummy_context = format;
+               av_open_input_file( &self->video_format, filename, NULL, 0, NULL );
+               format = self->video_format;
+               av_find_stream_info( format );
+       }
 
-                       // Store selected audio and video indexes on properties
-                       self->audio_index = audio_index;
-                       self->video_index = video_index;
-                       self->first_pts = -1;
-                       self->last_position = POSITION_INITIAL;
+       // Fetch the width, height and aspect ratio
+       if ( self->video_index != -1 )
+       {
+               AVCodecContext *codec_context = format->streams[ self->video_index ]->codec;
+               mlt_properties_set_int( properties, "width", codec_context->width );
+               mlt_properties_set_int( properties, "height", codec_context->height );
 
-                       // Fetch the width, height and aspect ratio
-                       if ( video_index != -1 )
+               if ( codec_context->codec_id == CODEC_ID_DVVIDEO )
+               {
+                       // Fetch the first frame of DV so we can read it directly
+                       AVPacket pkt;
+                       int ret = 0;
+                       while ( ret >= 0 )
                        {
-                               AVCodecContext *codec_context = context->streams[ video_index ]->codec;
-                               mlt_properties_set_int( properties, "width", codec_context->width );
-                               mlt_properties_set_int( properties, "height", codec_context->height );
-
-                               if ( codec_context->codec_id == CODEC_ID_DVVIDEO )
-                               {
-                                       // Fetch the first frame of DV so we can read it directly
-                                       AVPacket pkt;
-                                       int ret = 0;
-                                       while ( ret >= 0 )
-                                       {
-                                               ret = av_read_frame( context, &pkt );
-                                               if ( ret >= 0 && pkt.stream_index == video_index && pkt.size > 0 )
-                                               {
-                                                       get_aspect_ratio( properties, context->streams[ video_index ], codec_context, &pkt );
-                                                       break;
-                                               }
-                                       }
-                               }
-                               else
+                               ret = av_read_frame( format, &pkt );
+                               if ( ret >= 0 && pkt.stream_index == self->video_index && pkt.size > 0 )
                                {
-                                       get_aspect_ratio( properties, context->streams[ video_index ], codec_context, NULL );
+                                       get_aspect_ratio( properties, format->streams[ self->video_index ], codec_context, &pkt );
+                                       break;
                                }
+                       }
+               }
+               else
+               {
+                       get_aspect_ratio( properties, format->streams[ self->video_index ], codec_context, NULL );
+               }
+
 #ifdef SWSCALE
-                               struct SwsContext *context = sws_getContext( codec_context->width, codec_context->height, codec_context->pix_fmt,
-                                       codec_context->width, codec_context->height, PIX_FMT_YUYV422, SWS_BILINEAR, NULL, NULL, NULL);
-                               if ( context )
-                                       sws_freeContext( context );
-                               else
-                                       error = 1;
+               // Verify that we can convert this to YUV 4:2:2
+               // TODO: we can now also return RGB and RGBA and quite possibly more in the future.
+               struct SwsContext *context = sws_getContext( codec_context->width, codec_context->height, codec_context->pix_fmt,
+                       codec_context->width, codec_context->height, PIX_FMT_YUYV422, SWS_BILINEAR, NULL, NULL, NULL);
+               if ( context )
+                       sws_freeContext( context );
+               else
+                       error = 1;
 #endif
-                       }
+       }
+       return error;
+}
 
-                       // We're going to cheat here - for a/v files, we will have two contexts (reasoning will be clear later)
-                       if ( av == 0 && audio_index != -1 && video_index != -1 )
-                       {
-                               // We'll use the open one as our video_format
-                               self->video_format = context;
+/** Open the file.
+*/
 
-                               // And open again for our audio context
-                               av_open_input_file( &context, file, NULL, 0, NULL );
-                               av_find_stream_info( context );
+static int producer_open( producer_avformat self, mlt_profile profile, const char *URL )
+{
+       // Return an error code (0 == no error)
+       int error = 0;
 
-                               // Audio context
-                               self->audio_format = context;
-                       }
-                       else if ( av != 2 && video_index != -1 )
+       // Lock the service
+       pthread_mutex_init( &self->audio_mutex, NULL );
+       pthread_mutex_init( &self->video_mutex, NULL );
+       pthread_mutex_lock( &self->audio_mutex );
+       pthread_mutex_lock( &self->video_mutex );
+
+       // Parse URL
+       AVInputFormat *format = NULL;
+       AVFormatParameters *params = NULL;
+       char *filename = parse_url( profile, URL, &format, &params );
+
+       // Now attempt to open the file
+       error = av_open_input_file( &self->video_format, filename, format, 0, params ) < 0;
+
+       // Cleanup AVFormatParameters
+       if ( params )
+       {
+               if ( params->standard )
+                       free( (void*) params->standard );
+               free( params );
+       }
+
+       // If successful, then try to get additional info
+       if ( !error )
+       {
+               // Get the stream info
+               error = av_find_stream_info( self->video_format ) < 0;
+
+               // Continue if no error
+               if ( !error )
+               {
+                       // Find default audio and video streams
+                       find_default_streams( self );
+                       error = get_basic_info( self, profile, filename );
+
+                       // Initialize position info
+                       self->first_pts = -1;
+                       self->last_position = POSITION_INITIAL;
+
+                       // We're going to cheat here - for seekable A/V files, we will have separate contexts
+                       // to support independent seeking of audio from video.
+                       // TODO: Is this really necessary?
+                       if ( self->audio_index != -1 && self->video_index != -1 )
                        {
-                               // We only have a video context
-                               self->video_format = context;
+                               // And open again for our audio context
+                               av_open_input_file( &self->audio_format, filename, NULL, 0, NULL );
+                               av_find_stream_info( self->audio_format );
                        }
-                       else if ( audio_index != -1 )
+                       else if ( self->audio_index != -1 )
                        {
                                // We only have an audio context
-                               self->audio_format = context;
+                               self->audio_format = self->video_format;
+                               self->video_format = NULL;
                        }
-                       else
+                       else if ( self->video_index == -1 )
                        {
                                // Something has gone wrong
                                error = -1;
                        }
                }
        }
+       if ( filename )
+               free( filename );
 
        // Unlock the service
        pthread_mutex_unlock( &self->audio_mutex );
@@ -2207,11 +2233,15 @@ static int producer_get_audio( mlt_frame frame, void **buffer, mlt_audio_format
                        if ( self->audio_used[ index ] > 0 )
                        {
                                uint8_t *src = self->audio_buffer[ index ];
-                               *samples = self->audio_used[ index ] < *samples ? self->audio_used[ index ] : *samples;
-                               size = *samples * *channels * sizeof_sample;
-                               memcpy( *buffer, src, size );
-                               self->audio_used[ index ] -= *samples;
-                               memmove( src, src + size, self->audio_used[ index ] * *channels * sizeof_sample );
+                               // copy samples from audio_buffer
+                               size = self->audio_used[ index ] < *samples ? self->audio_used[ index ] : *samples;
+                               memcpy( *buffer, src, size * *channels * sizeof_sample );
+                               // supply the remaining requested samples as silence
+                               if ( *samples > self->audio_used[ index ] )
+                                       memset( *buffer + size * *channels * sizeof_sample, 0, ( *samples - self->audio_used[ index ] ) * *channels * sizeof_sample );
+                               // reposition the samples within audio_buffer
+                               self->audio_used[ index ] -= size;
+                               memmove( src, src + size * *channels * sizeof_sample, self->audio_used[ index ] * *channels * sizeof_sample );
                        }
                        else
                        {
@@ -2351,8 +2381,8 @@ static void producer_set_up_audio( producer_avformat self, mlt_frame frame )
        // Get the codec(s)
        if ( context && index == INT_MAX )
        {
-               mlt_properties_set_int( frame_properties, "frequency", self->max_frequency );
-               mlt_properties_set_int( frame_properties, "channels", self->total_channels );
+               mlt_properties_set_int( frame_properties, "audio_frequency", self->max_frequency );
+               mlt_properties_set_int( frame_properties, "audio_channels", self->total_channels );
                for ( index = 0; index < context->nb_streams; index++ )
                {
                        if ( context->streams[ index ]->codec->codec_type == CODEC_TYPE_AUDIO )
@@ -2464,6 +2494,9 @@ static void producer_avformat_close( producer_avformat self )
 
 static void producer_close( mlt_producer parent )
 {
+       // Remove this instance from the cache
+       mlt_service_cache_purge( MLT_PRODUCER_SERVICE(parent) );
+
        // Close the parent
        parent->close = NULL;
        mlt_producer_close( parent );