movenc: Simplify code by using avio_wb24

Signed-off-by: Martin Storsjö <martin@martin.st>

libavformat/movenc.c

@@ -305,8 +305,7 @@ static int mov_write_esds_tag(AVIOContext *pb, MOVTrack *track) // Basic
     else
         avio_w8(pb, 0x11); // flags (= Visualstream)
 
-    avio_w8(pb,  track->enc->rc_buffer_size>>(3+16));      // Buffersize DB (24 bits)
-    avio_wb16(pb, (track->enc->rc_buffer_size>>3)&0xFFFF); // Buffersize DB
+    avio_wb24(pb, track->enc->rc_buffer_size >> 3); // Buffersize DB
 
     avio_wb32(pb, FFMAX(track->enc->bit_rate, track->enc->rc_max_rate)); // maxbitrate (FIXME should be max rate in any 1 sec window)
     if(track->enc->rc_max_rate != track->enc->rc_min_rate || track->enc->rc_min_rate==0)