static void mp3_parse_info_tag(AVFormatContext *s, AVStream *st, MPADecodeHeader *c, uint32_t spf) { #define LAST_BITS(k, n) ((k) & ((1 << (n)) - 1)) #define MIDDLE_BITS(k, m, n) LAST_BITS((k) >> (m), ((n) - (m))) uint16_t crc; uint32_t v; char version[10]; uint32_t peak = 0; int32_t r_gain = INT32_MIN, a_gain = INT32_MIN; MP3DecContext *mp3 = s->priv_data; static const int64_t xing_offtbl[2][2] = {{32, 17}, {17,9}}; uint64_t fsize = avio_size(s->pb); /* Check for Xing / Info tag */ avio_skip(s->pb, xing_offtbl[c->lsf == 1][c->nb_channels == 1]); v = avio_rb32(s->pb); mp3->is_cbr = v == MKBETAG('I', 'n', 'f', 'o'); if (v != MKBETAG('X', 'i', 'n', 'g') && !mp3->is_cbr) return; v = avio_rb32(s->pb); if (v & XING_FLAG_FRAMES) mp3->frames = avio_rb32(s->pb); if (v & XING_FLAG_SIZE) mp3->header_filesize = avio_rb32(s->pb); if (fsize && mp3->header_filesize) { uint64_t min, delta; min = FFMIN(fsize, mp3->header_filesize); delta = FFMAX(fsize, mp3->header_filesize) - min; if (fsize > mp3->header_filesize && delta > min >> 4) { mp3->frames = 0; } else if (delta > min >> 4) { av_log(s, AV_LOG_WARNING, "filesize and duration do not match (growing file?)\n"); } } if (v & XING_FLAG_TOC) read_xing_toc(s, mp3->header_filesize, av_rescale_q(mp3->frames, (AVRational){spf, c->sample_rate}, st->time_base)); /* VBR quality */ if(v & 8) avio_skip(s->pb, 4); /* Encoder short version string */ memset(version, 0, sizeof(version)); avio_read(s->pb, version, 9); /* Info Tag revision + VBR method */ avio_r8(s->pb); /* Lowpass filter value */ avio_r8(s->pb); /* ReplayGain peak */ v = avio_rb32(s->pb); peak = av_rescale(v, 100000, 1 << 23); /* Radio ReplayGain */ v = avio_rb16(s->pb); if (MIDDLE_BITS(v, 13, 15) == 1) { r_gain = MIDDLE_BITS(v, 0, 8) * 10000; if (v & (1 << 9)) r_gain *= -1; } /* Audiophile ReplayGain */ v = avio_rb16(s->pb); if (MIDDLE_BITS(v, 13, 15) == 2) { a_gain = MIDDLE_BITS(v, 0, 8) * 10000; if (v & (1 << 9)) a_gain *= -1; } /* Encoding flags + ATH Type */ avio_r8(s->pb); /* if ABR {specified bitrate} else {minimal bitrate} */ avio_r8(s->pb); /* Encoder delays */ v= avio_rb24(s->pb); if(AV_RB32(version) == MKBETAG('L', 'A', 'M', 'E') || AV_RB32(version) == MKBETAG('L', 'a', 'v', 'f')) { mp3->start_pad = v>>12; mp3-> end_pad = v&4095; st->skip_samples = mp3->start_pad + 528 + 1; if (mp3->frames) st->end_discard_sample = -mp3->end_pad + 528 + 1 + mp3->frames * (int64_t)spf; if (!st->start_time) st->start_time = av_rescale_q(st->skip_samples, (AVRational){1, c->sample_rate}, st->time_base); av_log(s, AV_LOG_DEBUG, "pad %d %d\n", mp3->start_pad, mp3-> end_pad); } /* Misc */ avio_r8(s->pb); /* MP3 gain */ avio_r8(s->pb); /* Preset and surround info */ avio_rb16(s->pb); /* Music length */ avio_rb32(s->pb); /* Music CRC */ avio_rb16(s->pb); /* Info Tag CRC */ crc = ffio_get_checksum(s->pb); v = avio_rb16(s->pb); if (v == crc) { ff_replaygain_export_raw(st, r_gain, peak, a_gain, 0); av_dict_set(&st->metadata, "encoder", version, 0); } }
static void mp3_parse_info_tag(AVFormatContext *s, AVStream *st, MPADecodeHeader *c, uint32_t spf) { #define LAST_BITS(k, n) ((k) & ((1 << (n)) - 1)) #define MIDDLE_BITS(k, m, n) LAST_BITS((k) >> (m), ((n) - (m))) uint16_t crc; uint32_t v; char version[10]; uint32_t peak = 0; int32_t r_gain = INT32_MIN, a_gain = INT32_MIN; MP3DecContext *mp3 = s->priv_data; static const int64_t xing_offtbl[2][2] = {{32, 17}, {17,9}}; uint64_t fsize = avio_size(s->pb);   avio_skip(s->pb, xing_offtbl[c->lsf == 1][c->nb_channels == 1]); v = avio_rb32(s->pb); mp3->is_cbr = v == MKBETAG('I', 'n', 'f', 'o'); if (v != MKBETAG('X', 'i', 'n', 'g') && !mp3->is_cbr) return; v = avio_rb32(s->pb); if (v & XING_FLAG_FRAMES) mp3->frames = avio_rb32(s->pb); if (v & XING_FLAG_SIZE) mp3->header_filesize = avio_rb32(s->pb); if (fsize && mp3->header_filesize) { uint64_t min, delta; min = FFMIN(fsize, mp3->header_filesize); delta = FFMAX(fsize, mp3->header_filesize) - min; if (fsize > mp3->header_filesize && delta > min >> 4) { mp3->frames = 0; } else if (delta > min >> 4) { av_log(s, AV_LOG_WARNING, "filesize and duration do not match (growing file?)\n"); } } if (v & XING_FLAG_TOC) read_xing_toc(s, mp3->header_filesize, av_rescale_q(mp3->frames, (AVRational){spf, c->sample_rate}, st->time_base));   if(v & 8) avio_skip(s->pb, 4);   memset(version, 0, sizeof(version)); avio_read(s->pb, version, 9);   avio_r8(s->pb);   avio_r8(s->pb);   v = avio_rb32(s->pb); peak = av_rescale(v, 100000, 1 << 23);   v = avio_rb16(s->pb); if (MIDDLE_BITS(v, 13, 15) == 1) { r_gain = MIDDLE_BITS(v, 0, 8) * 10000; if (v & (1 << 9)) r_gain *= -1; }   v = avio_rb16(s->pb); if (MIDDLE_BITS(v, 13, 15) == 2) { a_gain = MIDDLE_BITS(v, 0, 8) * 10000; if (v & (1 << 9)) a_gain *= -1; }   avio_r8(s->pb);   avio_r8(s->pb);   v= avio_rb24(s->pb); if(AV_RB32(version) == MKBETAG('L', 'A', 'M', 'E') || AV_RB32(version) == MKBETAG('L', 'a', 'v', 'f')) { mp3->start_pad = v>>12; mp3-> end_pad = v&4095; st->skip_samples = mp3->start_pad + 528 + 1; if (mp3->frames) st->end_discard_sample = -mp3->end_pad + 528 + 1 + mp3->frames * (int64_t)spf; if (!st->start_time) st->start_time = av_rescale_q(st->skip_samples, (AVRational){1, c->sample_rate}, st->time_base); av_log(s, AV_LOG_DEBUG, "pad %d %d\n", mp3->start_pad, mp3-> end_pad); }   avio_r8(s->pb);   avio_r8(s->pb);   avio_rb16(s->pb);   avio_rb32(s->pb);   avio_rb16(s->pb);   crc = ffio_get_checksum(s->pb); v = avio_rb16(s->pb); if (v == crc) { ff_replaygain_export_raw(st, r_gain, peak, a_gain, 0); av_dict_set(&st->metadata, "encoder", version, 0); } }