mpegenc: limit the maximum muxrate

It is written to the file as a 22-bit value.

CC: libav-stable@libav.org

libavformat/mpegenc.c

@@ -1162,7 +1162,7 @@ static int mpeg_mux_end(AVFormatContext *ctx)
 #define OFFSET(x) offsetof(MpegMuxContext, x)
 #define E AV_OPT_FLAG_ENCODING_PARAM
 static const AVOption options[] = {
-    { "muxrate", NULL,                                          OFFSET(mux_rate), AV_OPT_TYPE_INT, { .i64 =      0 }, 0, INT_MAX, E },
+    { "muxrate", NULL,                                          OFFSET(mux_rate), AV_OPT_TYPE_INT, { .i64 =      0 }, 0, (1 << 22) - 1, E },
     { "preload", "Initial demux-decode delay in microseconds.", OFFSET(preload),  AV_OPT_TYPE_INT, { .i64 = 500000 }, 0, INT_MAX, E },
     { NULL },
 };