Index: libmpdemux/demux_mov.c
===================================================================
--- libmpdemux/demux_mov.c	(revision 18891)
+++ libmpdemux/demux_mov.c	(working copy)
@@ -267,10 +267,21 @@
 		// skip!
 		el->frames=0; continue;
 	    }
-	    // find start sample
+	    // find start sample. If track has keyframes, choose the nearest
+	    // (earlier) keyframe. Otherwise, just choose the nearest sample.
+	    if(trak->keyframes_size) {
+                unsigned int kfi;
+                for(kfi=0;kfi<trak->keyframes_size-1;kfi++){
+                    if(trak->samples[trak->keyframes[kfi+1]].pts > pts){
+                        sample = trak->keyframes[kfi];
+                        break;
+                    }
+	        }
+	    } else {
 	    for(;sample<trak->samples_size;sample++){
 		if(pts<=trak->samples[sample].pts) break;
 	    }
+	    }
 	    el->start_sample=sample;
 	    el->pts_offset=((long long)e_pts*(long long)trak->timescale)/(long long)timescale-trak->samples[sample].pts;
 	    pts+=((long long)el->dur*(long long)trak->timescale)/(long long)timescale;