+static int mov_write_ac3_tag(ByteIOContext *pb, MOVTrack *track)
+{
+ GetBitContext gbc;
+ PutBitContext pbc;
+ uint8_t buf[3];
+ int fscod, bsid, bsmod, acmod, lfeon, frmsizecod;
+
+ if (track->vosLen < 7)
+ return -1;
+
+ put_be32(pb, 11);
+ put_tag(pb, "dac3");
+
+ init_get_bits(&gbc, track->vosData+4, track->vosLen-4);
+ fscod = get_bits(&gbc, 2);
+ frmsizecod = get_bits(&gbc, 6);
+ bsid = get_bits(&gbc, 5);
+ bsmod = get_bits(&gbc, 3);
+ acmod = get_bits(&gbc, 3);
+ if (acmod == 2) {
+ skip_bits(&gbc, 2); // dsurmod
+ } else {
+ if ((acmod & 1) && acmod != 1)
+ skip_bits(&gbc, 2); // cmixlev
+ if (acmod & 4)
+ skip_bits(&gbc, 2); // surmixlev
+ }
+ lfeon = get_bits1(&gbc);
+
+ init_put_bits(&pbc, buf, sizeof(buf));
+ put_bits(&pbc, 2, fscod);
+ put_bits(&pbc, 5, bsid);
+ put_bits(&pbc, 3, bsmod);
+ put_bits(&pbc, 3, acmod);
+ put_bits(&pbc, 1, lfeon);
+ put_bits(&pbc, 5, frmsizecod>>1); // bit_rate_code
+ put_bits(&pbc, 5, 0); // reserved
+
+ flush_put_bits(&pbc);
+ put_buffer(pb, buf, sizeof(buf));
+
+ return 11;
+}
+