From 974f36cfb552d91fde5e4eb69eb51609234769aa Mon Sep 17 00:00:00 2001
From: Paul Davis <paul@linuxaudiosystems.com>
Date: Thu, 4 Dec 2008 13:42:46 +0000
Subject: [PATCH] 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
---
 libs/ardour/audio_track.cc | 65 ++++++++++++++++++++++++++++++++++----
 1 file 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 */