rmenc: write correct bytes per minute

improves playback of ac3 in RealPlayer
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/rmenc.c

@@ -217,8 +217,8 @@ static int rv10_write_header(AVFormatContext *ctx,
                 coded_frame_size--;
             avio_wb32(s, coded_frame_size); /* frame length */
             avio_wb32(s, 0x51540); /* unknown */
-            avio_wb32(s, 0x249f0); /* unknown */
-            avio_wb32(s, 0x249f0); /* unknown */
+            avio_wb32(s, stream->enc->bit_rate / 8 * 60); /* bytes per minute */
+            avio_wb32(s, stream->enc->bit_rate / 8 * 60); /* bytes per minute */
             avio_wb16(s, 0x01);
             /* frame length : seems to be very important */
             avio_wb16(s, coded_frame_size);

tests/ref/lavf/rm

-85ef42a1fdeffaf083d14b633bbd697f *./tests/data/lavf/lavf.rm
+a3a875be9c528a2a4534a5a31230fdae *./tests/data/lavf/lavf.rm
 346424 ./tests/data/lavf/lavf.rm