MAJOR fix for any situation where an audio track is playing more channels than it has output ports. this needs pounding on to make it doesn't break other odd cases. triggered by a report about playing an 8-chn AIFF file via the auditioner

git-svn-id: svn://localhost/ardour2/branches/2.0-ongoing@4285 d708f5d6-7413-0410-9779-e7cbd77b26cf

1 files changed, 58 insertions, 7 deletions

diff --git a/libs/ardour/audio_track.cc b/libs/ardour/audio_track.cc
index 595471e7b5..ca74176a16 100644
--- a/libs/ardour/audio_track.cc
+++ b/libs/ardour/audio_track.cc
@@ -606,18 +606,69 @@ AudioTrack::roll (nframes_t nframes, nframes_t start_frame, nframes_t end_frame,
 		/* copy the diskstream data to all output buffers */
 		
 		vector<Sample*>& bufs = _session.get_passthru_buffers ();
+		vector<Sample*>::size_type blimit = bufs.size();
 		uint32_t limit = n_process_buffers ();
 		
 		uint32_t n;
 		uint32_t i;
 
+		if (limit > blimit) {
 
-		for (i = 0, n = 1; i < limit; ++i, ++n) {
-			memcpy (bufs[i], b, sizeof (Sample) * nframes); 
-			if (n < diskstream->n_channels()) {
-				tmpb = diskstream->playback_buffer(n);
-				if (tmpb!=0) {
-					b = tmpb;
+			/* example case: auditioner configured for stereo output,
+			   but loaded with an 8 channel file. there are only
+			   2 passthrough buffers, but n_process_buffers() will
+			   return 8.
+			   
+			   arbitrary decision: map all channels in the diskstream
+			   to the outputs available.
+			*/
+
+			float scaling = limit/blimit;
+
+			for (i = 0, n = 1; i < blimit; ++i, ++n) {
+
+				/* first time through just copy a channel into 
+				   the output buffer.
+				*/
+				
+				for (nframes_t xx = 0; xx < nframes; ++xx) {
+					bufs[i][xx] = b[xx] * scaling;
+				}
+
+				if (n < diskstream->n_channels()) {
+					tmpb = diskstream->playback_buffer(n);
+					if (tmpb!=0) {
+						b = tmpb;
+					}
+				}
+			}
+
+			for (;i < limit; ++i, ++n) {
+				
+				/* for all remaining channels, sum with existing
+				   data in the output buffers 
+				*/
+				
+				_session.mix_buffers_with_gain (bufs[i%blimit], b, nframes, scaling);
+
+				if (n < diskstream->n_channels()) {
+					tmpb = diskstream->playback_buffer(n);
+					if (tmpb!=0) {
+						b = tmpb;
+					}
+				}
+				
+			}
+
+		} else {
+		
+			for (i = 0, n = 1; i < limit; ++i, ++n) {
+				memcpy (bufs[i], b, sizeof (Sample) * nframes); 
+				if (n < diskstream->n_channels()) {
+					tmpb = diskstream->playback_buffer(n);
+					if (tmpb!=0) {
+						b = tmpb;
+					}
 				}
 			}
 		}
@@ -632,7 +683,7 @@ AudioTrack::roll (nframes_t nframes, nframes_t start_frame, nframes_t end_frame,
 			}
 		}
 
-		process_output_buffers (bufs, limit, start_frame, end_frame, nframes, offset, (!_session.get_record_enabled() || !Config->get_do_not_record_plugins()), declick, (_meter_point != MeterInput));
+		process_output_buffers (bufs, blimit, start_frame, end_frame, nframes, offset, (!_session.get_record_enabled() || !Config->get_do_not_record_plugins()), declick, (_meter_point != MeterInput));
 		
 	} else {
 		/* problem with the diskstream; just be quiet for a bit */