static int h264_probe(AVProbeData *p) { uint32_t code = -1; int sps = 0, pps = 0, idr = 0, res = 0, sli = 0; int i; for (i = 0; i < p->buf_size; i++) { code = (code << 8) + p->buf[i]; if ((code & 0xffffff00) == 0x100) { int ref_idc = (code >> 5) & 3; int type = code & 0x1F; static const int8_t ref_zero[] = { 2, 0, 0, 0, 0, -1, 1, -1, -1, 1, 1, 1, 1, -1, 2, 2, 2, 2, 2, 0, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2 }; if (code & 0x80) // forbidden_bit return 0; if (ref_zero[type] == 1 && ref_idc) return 0; if (ref_zero[type] == -1 && !ref_idc) return 0; if (ref_zero[type] == 2) { if (!(code == 0x100 && !p->buf[i + 1] && !p->buf[i + 2])) res++; } switch (type) { case 1: sli++; break; case 5: idr++; break; case 7: if (p->buf[i + 2] & 0x03) return 0; sps++; break; case 8: pps++; break; } } } ff_tlog(NULL, "sps:%d pps:%d idr:%d sli:%d res:%d\n", sps, pps, idr, sli, res); if (sps && pps && (idr || sli > 3) && res < (sps + pps + idr)) return AVPROBE_SCORE_EXTENSION + 1; // 1 more than .mpg return 0; }