static int ac3_eac3_probe(AVProbeData *p, enum AVCodecID expected_codec_id) { int max_frames, first_frames = 0, frames; uint8_t *buf, *buf2, *end; AC3HeaderInfo hdr; GetBitContext gbc; enum AVCodecID codec_id = AV_CODEC_ID_AC3; max_frames = 0; buf = p->buf; end = buf + p->buf_size; for(; buf < end; buf++) { if(buf > p->buf && !(buf[0] == 0x0B && buf[1] == 0x77) && !(buf[0] == 0x77 && buf[1] == 0x0B) ) continue; buf2 = buf; for(frames = 0; buf2 < end; frames++) { uint8_t buf3[4096]; int i; if(!memcmp(buf2, "\x1\x10\0\0\0\0\0\0", 8)) buf2+=16; if (buf[0] == 0x77 && buf[1] == 0x0B) { for(i=0; i<8; i+=2) { buf3[i ] = buf[i+1]; buf3[i+1] = buf[i ]; } init_get_bits(&gbc, buf3, 54); }else init_get_bits(&gbc, buf2, 54); if(avpriv_ac3_parse_header(&gbc, &hdr) < 0) break; if(buf2 + hdr.frame_size > end) break; if (buf[0] == 0x77 && buf[1] == 0x0B) { av_assert0(hdr.frame_size <= sizeof(buf3)); for(; i<hdr.frame_size; i+=2) { buf3[i ] = buf[i+1]; buf3[i+1] = buf[i ]; } } if(av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, gbc.buffer + 2, hdr.frame_size - 2)) break; if (hdr.bitstream_id > 10) codec_id = AV_CODEC_ID_EAC3; buf2 += hdr.frame_size; } max_frames = FFMAX(max_frames, frames); if(buf == p->buf) first_frames = frames; } if(codec_id != expected_codec_id) return 0; // keep this in sync with mp3 probe, both need to avoid // issues with MPEG-files! if (first_frames>=4) return AVPROBE_SCORE_MAX/2+1; else if(max_frames>200)return AVPROBE_SCORE_MAX/2; else if(max_frames>=4) return AVPROBE_SCORE_MAX/4; else if(max_frames>=1) return 1; else return 0; }