Fix assertion failure when processors return fewer channels than the DCP has.

[dcpomatic.git] / src / lib / mid_side_decoder.cc

diff --git a/src/lib/mid_side_decoder.cc b/src/lib/mid_side_decoder.cc
index 842d5c8ee56d066b49a2e631cfa73cabd7eb5d88..4f619ad572f347309e21e5354c8dba1b57e70ad8 100644 (file)
--- a/src/lib/mid_side_decoder.cc
+++ b/src/lib/mid_side_decoder.cc
@@ -59,16 +59,27 @@ MidSideDecoder::clone (int) const
 }
 
 shared_ptr<AudioBuffers>
-MidSideDecoder::run (shared_ptr<const AudioBuffers> in)
+MidSideDecoder::run (shared_ptr<const AudioBuffers> in, int channels)
 {
-       shared_ptr<AudioBuffers> out (new AudioBuffers (3, in->frames ()));
+       int const N = min (channels, 3);
+       shared_ptr<AudioBuffers> out (new AudioBuffers (channels, in->frames ()));
        for (int i = 0; i < in->frames(); ++i) {
                float const left = in->data()[0][i];
                float const right = in->data()[1][i];
                float const mid = (left + right) / 2;
-               out->data()[0][i] = left - mid;
-               out->data()[1][i] = right - mid;
-               out->data()[2][i] = mid;
+               if (N > 0) {
+                       out->data()[0][i] = left - mid;
+               }
+               if (N > 1) {
+                       out->data()[1][i] = right - mid;
+               }
+               if (N > 2) {
+                       out->data()[2][i] = mid;
+               }
+       }
+
+       for (int i = N; i < channels; ++i) {
+               out->make_silent (i);
        }
 
        return out;