+static int gsm_probe(AVProbeData *p)
+{
+ int valid = 0, invalid = 0;
+ uint8_t *b = p->buf;
+ while (b < p->buf + p->buf_size - 32) {
+ if ((*b & 0xf0) == 0xd0) {
+ valid++;
+ } else {
+ invalid++;
+ }
+ b += 33;
+ }
+ if (valid >> 5 > invalid)
+ return AVPROBE_SCORE_EXTENSION + 1;
+ return 0;
+}
+