1/* 2 * Musepack SV8 demuxer 3 * Copyright (c) 2007 Konstantin Shishkov 4 * 5 * This file is part of FFmpeg. 6 * 7 * FFmpeg is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU Lesser General Public 9 * License as published by the Free Software Foundation; either 10 * version 2.1 of the License, or (at your option) any later version. 11 * 12 * FFmpeg is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * Lesser General Public License for more details. 16 * 17 * You should have received a copy of the GNU Lesser General Public 18 * License along with FFmpeg; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 20 */ 21 22#include "libavcodec/bitstream.h" 23#include "libavcodec/unary.h" 24#include "avformat.h" 25 26/// Two-byte MPC tag 27#define MKMPCTAG(a, b) (a | (b << 8)) 28 29#define TAG_MPCK MKTAG('M','P','C','K') 30 31/// Reserved MPC tags 32enum MPCPacketTags{ 33 TAG_STREAMHDR = MKMPCTAG('S','H'), 34 TAG_STREAMEND = MKMPCTAG('S','E'), 35 36 TAG_AUDIOPACKET = MKMPCTAG('A','P'), 37 38 TAG_SEEKTBLOFF = MKMPCTAG('S','O'), 39 TAG_SEEKTABLE = MKMPCTAG('S','T'), 40 41 TAG_REPLAYGAIN = MKMPCTAG('R','G'), 42 TAG_ENCINFO = MKMPCTAG('E','I'), 43}; 44 45static const int mpc8_rate[8] = { 44100, 48000, 37800, 32000, -1, -1, -1, -1 }; 46 47typedef struct { 48 int ver; 49 int frame; 50 int64_t header_pos; 51 int64_t samples; 52} MPCContext; 53 54static int mpc8_probe(AVProbeData *p) 55{ 56 if (AV_RL32(p->buf) == TAG_MPCK) 57 return AVPROBE_SCORE_MAX; 58 return 0; 59} 60 61static inline int64_t gb_get_v(GetBitContext *gb) 62{ 63 int64_t v = 0; 64 int bits = 0; 65 while(get_bits1(gb) && bits < 64-7){ 66 v <<= 7; 67 v |= get_bits(gb, 7); 68 bits += 7; 69 } 70 v <<= 7; 71 v |= get_bits(gb, 7); 72 73 return v; 74} 75 76static void mpc8_get_chunk_header(ByteIOContext *pb, int *tag, int64_t *size) 77{ 78 int64_t pos; 79 pos = url_ftell(pb); 80 *tag = get_le16(pb); 81 *size = ff_get_v(pb); 82 *size -= url_ftell(pb) - pos; 83} 84 85static void mpc8_parse_seektable(AVFormatContext *s, int64_t off) 86{ 87 MPCContext *c = s->priv_data; 88 int tag; 89 int64_t size, pos, ppos[2]; 90 uint8_t *buf; 91 int i, t, seekd; 92 GetBitContext gb; 93 94 url_fseek(s->pb, off, SEEK_SET); 95 mpc8_get_chunk_header(s->pb, &tag, &size); 96 if(tag != TAG_SEEKTABLE){ 97 av_log(s, AV_LOG_ERROR, "No seek table at given position\n"); 98 return; 99 } 100 if(!(buf = av_malloc(size))) 101 return; 102 get_buffer(s->pb, buf, size); 103 init_get_bits(&gb, buf, size * 8); 104 size = gb_get_v(&gb); 105 if(size > UINT_MAX/4 || size > c->samples/1152){ 106 av_log(s, AV_LOG_ERROR, "Seek table is too big\n"); 107 return; 108 } 109 seekd = get_bits(&gb, 4); 110 for(i = 0; i < 2; i++){ 111 pos = gb_get_v(&gb) + c->header_pos; 112 ppos[1 - i] = pos; 113 av_add_index_entry(s->streams[0], pos, i, 0, 0, AVINDEX_KEYFRAME); 114 } 115 for(; i < size; i++){ 116 t = get_unary(&gb, 1, 33) << 12; 117 t += get_bits(&gb, 12); 118 if(t & 1) 119 t = -(t & ~1); 120 pos = (t >> 1) + ppos[0]*2 - ppos[1]; 121 av_add_index_entry(s->streams[0], pos, i << seekd, 0, 0, AVINDEX_KEYFRAME); 122 ppos[1] = ppos[0]; 123 ppos[0] = pos; 124 } 125 av_free(buf); 126} 127 128static void mpc8_handle_chunk(AVFormatContext *s, int tag, int64_t chunk_pos, int64_t size) 129{ 130 ByteIOContext *pb = s->pb; 131 int64_t pos, off; 132 133 switch(tag){ 134 case TAG_SEEKTBLOFF: 135 pos = url_ftell(pb) + size; 136 off = ff_get_v(pb); 137 mpc8_parse_seektable(s, chunk_pos + off); 138 url_fseek(pb, pos, SEEK_SET); 139 break; 140 default: 141 url_fskip(pb, size); 142 } 143} 144 145static int mpc8_read_header(AVFormatContext *s, AVFormatParameters *ap) 146{ 147 MPCContext *c = s->priv_data; 148 ByteIOContext *pb = s->pb; 149 AVStream *st; 150 int tag = 0; 151 int64_t size, pos; 152 153 c->header_pos = url_ftell(pb); 154 if(get_le32(pb) != TAG_MPCK){ 155 av_log(s, AV_LOG_ERROR, "Not a Musepack8 file\n"); 156 return -1; 157 } 158 159 while(!url_feof(pb)){ 160 pos = url_ftell(pb); 161 mpc8_get_chunk_header(pb, &tag, &size); 162 if(tag == TAG_STREAMHDR) 163 break; 164 mpc8_handle_chunk(s, tag, pos, size); 165 } 166 if(tag != TAG_STREAMHDR){ 167 av_log(s, AV_LOG_ERROR, "Stream header not found\n"); 168 return -1; 169 } 170 pos = url_ftell(pb); 171 url_fskip(pb, 4); //CRC 172 c->ver = get_byte(pb); 173 if(c->ver != 8){ 174 av_log(s, AV_LOG_ERROR, "Unknown stream version %d\n", c->ver); 175 return -1; 176 } 177 c->samples = ff_get_v(pb); 178 ff_get_v(pb); //silence samples at the beginning 179 180 st = av_new_stream(s, 0); 181 if (!st) 182 return AVERROR(ENOMEM); 183 st->codec->codec_type = CODEC_TYPE_AUDIO; 184 st->codec->codec_id = CODEC_ID_MUSEPACK8; 185 st->codec->bits_per_coded_sample = 16; 186 187 st->codec->extradata_size = 2; 188 st->codec->extradata = av_mallocz(st->codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE); 189 get_buffer(pb, st->codec->extradata, st->codec->extradata_size); 190 191 st->codec->channels = (st->codec->extradata[1] >> 4) + 1; 192 st->codec->sample_rate = mpc8_rate[st->codec->extradata[0] >> 5]; 193 av_set_pts_info(st, 32, 1152 << (st->codec->extradata[1]&3)*2, st->codec->sample_rate); 194 st->duration = c->samples / (1152 << (st->codec->extradata[1]&3)*2); 195 size -= url_ftell(pb) - pos; 196 197 return 0; 198} 199 200static int mpc8_read_packet(AVFormatContext *s, AVPacket *pkt) 201{ 202 MPCContext *c = s->priv_data; 203 int tag; 204 int64_t pos, size; 205 206 while(!url_feof(s->pb)){ 207 pos = url_ftell(s->pb); 208 mpc8_get_chunk_header(s->pb, &tag, &size); 209 if(tag == TAG_AUDIOPACKET){ 210 if(av_get_packet(s->pb, pkt, size) < 0) 211 return AVERROR(ENOMEM); 212 pkt->stream_index = 0; 213 pkt->pts = c->frame; 214 return 0; 215 } 216 if(tag == TAG_STREAMEND) 217 return AVERROR(EIO); 218 mpc8_handle_chunk(s, tag, pos, size); 219 } 220 return 0; 221} 222 223static int mpc8_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags) 224{ 225 AVStream *st = s->streams[stream_index]; 226 MPCContext *c = s->priv_data; 227 int index = av_index_search_timestamp(st, timestamp, flags); 228 229 if(index < 0) return -1; 230 url_fseek(s->pb, st->index_entries[index].pos, SEEK_SET); 231 c->frame = st->index_entries[index].timestamp; 232 return 0; 233} 234 235 236AVInputFormat mpc8_demuxer = { 237 "mpc8", 238 NULL_IF_CONFIG_SMALL("Musepack SV8"), 239 sizeof(MPCContext), 240 mpc8_probe, 241 mpc8_read_header, 242 mpc8_read_packet, 243 NULL, 244 mpc8_read_seek, 245}; 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