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00022 #include "libavutil/crc.h"
00023 #include "libavcodec/ac3_parser.h"
00024 #include "avformat.h"
00025 #include "rawdec.h"
00026
00027 static int ac3_eac3_probe(AVProbeData *p, enum CodecID expected_codec_id)
00028 {
00029 int max_frames, first_frames = 0, frames;
00030 uint8_t *buf, *buf2, *end;
00031 AC3HeaderInfo hdr;
00032 GetBitContext gbc;
00033 enum CodecID codec_id = CODEC_ID_AC3;
00034
00035 max_frames = 0;
00036 buf = p->buf;
00037 end = buf + p->buf_size;
00038
00039 for(; buf < end; buf++) {
00040 buf2 = buf;
00041
00042 for(frames = 0; buf2 < end; frames++) {
00043 init_get_bits(&gbc, buf2, 54);
00044 if(avpriv_ac3_parse_header(&gbc, &hdr) < 0)
00045 break;
00046 if(buf2 + hdr.frame_size > end ||
00047 av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, buf2 + 2, hdr.frame_size - 2))
00048 break;
00049 if (hdr.bitstream_id > 10)
00050 codec_id = CODEC_ID_EAC3;
00051 buf2 += hdr.frame_size;
00052 }
00053 max_frames = FFMAX(max_frames, frames);
00054 if(buf == p->buf)
00055 first_frames = frames;
00056 }
00057 if(codec_id != expected_codec_id) return 0;
00058
00059
00060 if (first_frames>=4) return AVPROBE_SCORE_MAX/2+1;
00061 else if(max_frames>500)return AVPROBE_SCORE_MAX/2;
00062 else if(max_frames>=4) return AVPROBE_SCORE_MAX/4;
00063 else if(max_frames>=1) return 1;
00064 else return 0;
00065 }
00066
00067 #if CONFIG_AC3_DEMUXER
00068 static int ac3_probe(AVProbeData *p)
00069 {
00070 return ac3_eac3_probe(p, CODEC_ID_AC3);
00071 }
00072
00073 AVInputFormat ff_ac3_demuxer = {
00074 .name = "ac3",
00075 .long_name = NULL_IF_CONFIG_SMALL("raw AC-3"),
00076 .read_probe = ac3_probe,
00077 .read_header = ff_raw_audio_read_header,
00078 .read_packet = ff_raw_read_partial_packet,
00079 .flags= AVFMT_GENERIC_INDEX,
00080 .extensions = "ac3",
00081 .value = CODEC_ID_AC3,
00082 };
00083 #endif
00084
00085 #if CONFIG_EAC3_DEMUXER
00086 static int eac3_probe(AVProbeData *p)
00087 {
00088 return ac3_eac3_probe(p, CODEC_ID_EAC3);
00089 }
00090
00091 AVInputFormat ff_eac3_demuxer = {
00092 .name = "eac3",
00093 .long_name = NULL_IF_CONFIG_SMALL("raw E-AC-3"),
00094 .read_probe = eac3_probe,
00095 .read_header = ff_raw_audio_read_header,
00096 .read_packet = ff_raw_read_partial_packet,
00097 .flags= AVFMT_GENERIC_INDEX,
00098 .extensions = "eac3",
00099 .value = CODEC_ID_EAC3,
00100 };
00101 #endif