more complete next/prev clip behaviour
[melted] / mlt / src / framework / mlt_multitrack.c
index d3496de..9db2aad 100644 (file)
@@ -60,6 +60,7 @@ mlt_multitrack mlt_multitrack_init( )
                        mlt_properties properties = mlt_multitrack_properties( this );
                        producer->get_frame = producer_get_frame;
                        mlt_properties_set_data( properties, "multitrack", this, 0, NULL, NULL );
+                       mlt_properties_set( properties, "log_id", "multitrack" );
                }
                else
                {
@@ -121,7 +122,7 @@ void mlt_multitrack_refresh( mlt_multitrack this )
                if ( producer != NULL )
                {
                        // Determine the longest length
-                       length = mlt_producer_get_length( producer ) > length ? mlt_producer_get_length( producer ) : length;
+                       length = mlt_producer_get_playtime( producer ) > length ? mlt_producer_get_playtime( producer ) : length;
                        
                        // Handle fps
                        if ( fps == 0 )
@@ -147,6 +148,9 @@ void mlt_multitrack_refresh( mlt_multitrack this )
 }
 
 /** Connect a producer to a given track.
+
+       Note that any producer can be connected here, but see special case treatment
+       of playlist in clip point determination below.
 */
 
 int mlt_multitrack_connect( mlt_multitrack this, mlt_producer producer, int track )
@@ -180,6 +184,75 @@ int mlt_multitrack_connect( mlt_multitrack this, mlt_producer producer, int trac
        return result;
 }
 
+/** Determine the clip point.
+
+       Special case here: a 'producer' has no concept of multiple clips - only the 
+       playlist and multitrack producers have clip functionality. Further to that a 
+       multitrack determines clip information from any connected tracks that happen 
+       to be playlists.
+
+       Additionally, it must locate clips in the correct order, for example, consider
+       the following track arrangement:
+
+       playlist1 |0.0     |b0.0      |0.1          |0.1         |0.2           |
+       playlist2 |b1.0  |1.0           |b1.1     |1.1             |
+
+       Note - b clips represent blanks. They are also reported as clip positions.
+
+       When extracting clip positions from these playlists, we should get a sequence of:
+
+       0.0, 1.0, b0.0, 0.1, b1.1, 1.1, 0.1, 0.2, [out of playlist2], [out of playlist1]
+*/
+
+mlt_timecode mlt_multitrack_clip( mlt_multitrack this, mlt_whence whence, int index )
+{
+       int first = 1;
+       mlt_timecode position = 0;
+       int i = 0;
+
+       // Loop through each of the tracks
+       for ( i = 0; i < this->count; i ++ )
+       {
+               // Get the producer for this track
+               mlt_producer producer = this->list[ i ];
+
+               // If it's assigned...
+               if ( producer != NULL )
+               {
+                       // Get the properties of this producer
+                       mlt_properties properties = mlt_producer_properties( producer );
+
+                       // Determine if it's a playlist
+                       mlt_playlist playlist = mlt_properties_get_data( properties, "playlist", NULL );
+
+                       // We only consider playlists
+                       if ( playlist != NULL )
+                       {
+                               // Locate the smallest timecode
+                               if ( first )
+                               {
+                                       // First position found
+                                       position = mlt_playlist_clip( playlist, whence, index );
+       
+                                       // We're no longer first
+                                       first = 0;
+                               }
+                               else
+                               {
+                                       // Obtain the clip position in this playlist
+                                       mlt_timecode position2 = mlt_playlist_clip( playlist, whence, index );
+
+                                       // If this position is prior to the first, then use it
+                                       if ( position2 < position )
+                                               position = position2;
+                               }
+                       }
+               }
+       }
+
+       return position;
+}
+
 /** Get frame method.
 
        Special case here: The multitrack must be used in a conjunction with a downstream
@@ -236,15 +309,18 @@ static int producer_get_frame( mlt_producer parent, mlt_frame_ptr frame, int ind
                // Generate a test frame
                *frame = mlt_frame_init( );
 
-               // Let tractor know if we've reached the end
-               mlt_properties_set_int( mlt_frame_properties( *frame ), "last_track", index >= this->count );
-
                // Update timecode on the frame we're creating
                mlt_frame_set_timecode( *frame, mlt_producer_position( parent ) );
 
                // Move on to the next frame
                if ( index >= this->count )
+               {
+                       // Let tractor know if we've reached the end
+                       mlt_properties_set_int( mlt_frame_properties( *frame ), "last_track", 1 );
+
+                       // Move to the next frame
                        mlt_producer_prepare_next( parent );
+               }
 
                // Refresh our stats
                mlt_multitrack_refresh( this );
@@ -253,56 +329,6 @@ static int producer_get_frame( mlt_producer parent, mlt_frame_ptr frame, int ind
        return 0;
 }
 
-/** Determine the clip point.
-*/
-
-mlt_timecode mlt_multitrack_clip( mlt_multitrack this, mlt_whence whence, int index )
-{
-       int first = 1;
-       mlt_timecode position = 0;
-       int i = 0;
-
-       for ( i = 0; i < this->count; i ++ )
-       {
-               // Get the producer
-               mlt_producer producer = this->list[ i ];
-
-               if ( producer != NULL )
-               {
-                       // Get the properties of this producer
-                       mlt_properties properties = mlt_producer_properties( producer );
-
-                       // Determine if it's a playlist
-                       mlt_playlist playlist = mlt_properties_get_data( properties, "playlist", NULL );
-
-                       // We only consider playlists
-                       if ( playlist != NULL )
-                       {
-                               // Locate the smallest timecode
-                               if ( first )
-                               {
-                                       // First position found
-                                       position = mlt_playlist_clip( playlist, whence, index );
-       
-                                       // We're no longer first
-                                       first = 0;
-                               }
-                               else
-                               {
-                                       // Obtain the clip position in this playlist
-                                       mlt_timecode position2 = mlt_playlist_clip( playlist, whence, index );
-
-                                       // If this position is prior to the first, then use it
-                                       if ( position2 < position )
-                                               position = position2;
-                               }
-                       }
-               }
-       }
-
-       return position;
-}
-
 /** Close this instance.
 */