centralize buffer silent-flag

fixes possible x-talk 1 in, >= 2 out tracks:

Previously, only the first route-buffer of the input buffers
were marked as non-silent in Route::process_output_buffers().
Other buffers in the set (e.g. post-panner) would
contain audio but not marked as non-silent.

1 files changed, 16 insertions, 2 deletions

diff --git a/libs/ardour/audio_buffer.cc b/libs/ardour/audio_buffer.cc
index a36ad81c2a..b4e2a55ac2 100644
--- a/libs/ardour/audio_buffer.cc
+++ b/libs/ardour/audio_buffer.cc
@@ -76,12 +76,26 @@ AudioBuffer::resize (size_t size)
 }
 
 bool
-AudioBuffer::check_silence (pframes_t nframes, pframes_t& n) const
+AudioBuffer::check_silence (pframes_t nframes, bool wholebuffer, pframes_t& n) const
 {
-	for (n = 0; n < _size && n < nframes; ++n) {
+	for (n = 0; (wholebuffer || n < _size) &&  n < nframes; ++n) {
 		if (_data[n] != Sample (0)) {
 			return false;
 		}
 	}
 	return true;
 }
+
+void
+AudioBuffer::silence (framecnt_t len, framecnt_t offset) {
+	pframes_t n = 0;
+	if (!_silent) {
+		assert(_capacity > 0);
+		assert(offset + len <= _capacity);
+		memset(_data + offset, 0, sizeof (Sample) * len);
+		if (len == _capacity) {
+			_silent = true;
+		}
+	}
+	_written = true;
+}