avformat/mov: fix typo in comments

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavformat/mov.c

@@ -1475,7 +1475,7 @@ static int mov_read_mvhd(MOVContext *c, AVIOContext *pb, MOVAtom atom)
     av_log(c->fc, AV_LOG_TRACE, "time scale = %i\n", c->time_scale);
 
     c->duration = (version == 1) ? avio_rb64(pb) : avio_rb32(pb); /* duration */
-    // set the AVCodecContext duration because the duration of individual tracks
+    // set the AVFormatContext duration because the duration of individual tracks
     // may be inaccurate
     if (c->time_scale > 0 && !c->trex_data)
         c->fc->duration = av_rescale(c->duration, AV_TIME_BASE, c->time_scale);