Support H264 from QNAP Systems.

libavformat/riff.c

@@ -36,6 +36,7 @@ const AVCodecTag ff_codec_bmp_tags[] = {
     { CODEC_ID_H264,         MKTAG('a', 'v', 'c', '1') },
     { CODEC_ID_H264,         MKTAG('D', 'A', 'V', 'C') },
     { CODEC_ID_H264,         MKTAG('V', 'S', 'S', 'H') },
+    { CODEC_ID_H264,         MKTAG('Q', '2', '6', '4') }, /* QNAP surveillance system */
     { CODEC_ID_H263,         MKTAG('H', '2', '6', '3') },
     { CODEC_ID_H263,         MKTAG('X', '2', '6', '3') },
     { CODEC_ID_H263,         MKTAG('T', '2', '6', '3') },