AIFF: add 'twos' FourCC for the mux/demuxer (big endian PCM audio)

Signed-off-by: Anton Khirnov <anton@khirnov.net>

libavformat/aiff.h

@@ -43,6 +43,7 @@ static const AVCodecTag ff_codec_aiff_tags[] = {
     { CODEC_ID_MACE6,        MKTAG('M','A','C','6') },
     { CODEC_ID_GSM,          MKTAG('G','S','M',' ') },
     { CODEC_ID_ADPCM_G726,   MKTAG('G','7','2','6') },
+    { CODEC_ID_PCM_S16BE,    MKTAG('t','w','o','s') },
     { CODEC_ID_PCM_S16LE,    MKTAG('s','o','w','t') },
     { CODEC_ID_ADPCM_IMA_QT, MKTAG('i','m','a','4') },
     { CODEC_ID_QDM2,         MKTAG('Q','D','M','2') },