Fix possible incorrect eye mapping with 3D-alternate sources.

diff --git a/src/lib/video_decoder.cc b/src/lib/video_decoder.cc
index cee4bcdc696d64fde8d4e69957c1355b517560d1..8d6f7e6c77651af66ebe4a46235274e47531f5d8 100644 (file)
--- a/src/lib/video_decoder.cc
+++ b/src/lib/video_decoder.cc
@@ -105,7 +105,7 @@ VideoDecoder::emit (shared_ptr<const Film> film, shared_ptr<const ImageProxy> im
 
                if (vft == VideoFrameType::THREE_D_ALTERNATE) {
                        frame = decoder_frame / 2;
-                       eyes = (decoder_frame % 1) ? Eyes::RIGHT : Eyes::LEFT;
+                       eyes = (decoder_frame % 2) ? Eyes::RIGHT : Eyes::LEFT;
                } else {
                        frame = decoder_frame;
                        if (vft == VideoFrameType::THREE_D) {