diff --git a/libavformat/movenc.c b/libavformat/movenc.c
index f08aa7e..3e3ac24 100644
--- a/libavformat/movenc.c
+++ b/libavformat/movenc.c
@@ -1109,7 +1109,11 @@ static int mov_write_video_tag(AVIOContext *pb, MOVTrack *track)
     avio_w8(pb, strlen(compressor_name));
     avio_write(pb, compressor_name, 31);
 
-    if (track->mode == MODE_MOV && track->enc->bits_per_coded_sample)
+    if (track->mode == MODE_MOV &&
+        track->enc->codec_id == AV_CODEC_ID_RAWVIDEO &&
+        track->enc->pix_fmt == PIX_FMT_GRAY8)
+        avio_wb16(pb, 0x28);
+    else if (track->mode == MODE_MOV && track->enc->bits_per_coded_sample)
         avio_wb16(pb, track->enc->bits_per_coded_sample);
     else
         avio_wb16(pb, 0x18); /* Reserved */