| /* |
| * Musepack SV8 demuxer |
| * Copyright (c) 2007 Konstantin Shishkov |
| * |
| * This file is part of FFmpeg. |
| * |
| * FFmpeg is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2.1 of the License, or (at your option) any later version. |
| * |
| * FFmpeg is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with FFmpeg; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| #include "libavcodec/bitstream.h" |
| #include "libavcodec/unary.h" |
| #include "avformat.h" |
| |
| /// Two-byte MPC tag |
| #define MKMPCTAG(a, b) (a | (b << 8)) |
| |
| #define TAG_MPCK MKTAG('M','P','C','K') |
| |
| /// Reserved MPC tags |
| enum MPCPacketTags{ |
| TAG_STREAMHDR = MKMPCTAG('S','H'), |
| TAG_STREAMEND = MKMPCTAG('S','E'), |
| |
| TAG_AUDIOPACKET = MKMPCTAG('A','P'), |
| |
| TAG_SEEKTBLOFF = MKMPCTAG('S','O'), |
| TAG_SEEKTABLE = MKMPCTAG('S','T'), |
| |
| TAG_REPLAYGAIN = MKMPCTAG('R','G'), |
| TAG_ENCINFO = MKMPCTAG('E','I'), |
| }; |
| |
| static const int mpc8_rate[8] = { 44100, 48000, 37800, 32000, -1, -1, -1, -1 }; |
| |
| typedef struct { |
| int ver; |
| int frame; |
| int64_t header_pos; |
| int64_t samples; |
| } MPCContext; |
| |
| static int mpc8_probe(AVProbeData *p) |
| { |
| if (AV_RL32(p->buf) == TAG_MPCK) |
| return AVPROBE_SCORE_MAX; |
| return 0; |
| } |
| |
| static inline int64_t gb_get_v(GetBitContext *gb) |
| { |
| int64_t v = 0; |
| int bits = 0; |
| while(get_bits1(gb) && bits < 64-7){ |
| v <<= 7; |
| v |= get_bits(gb, 7); |
| bits += 7; |
| } |
| v <<= 7; |
| v |= get_bits(gb, 7); |
| |
| return v; |
| } |
| |
| static void mpc8_get_chunk_header(ByteIOContext *pb, int *tag, int64_t *size) |
| { |
| int64_t pos; |
| pos = url_ftell(pb); |
| *tag = get_le16(pb); |
| *size = ff_get_v(pb); |
| *size -= url_ftell(pb) - pos; |
| } |
| |
| static void mpc8_parse_seektable(AVFormatContext *s, int64_t off) |
| { |
| MPCContext *c = s->priv_data; |
| int tag; |
| int64_t size, pos, ppos[2]; |
| uint8_t *buf; |
| int i, t, seekd; |
| GetBitContext gb; |
| |
| url_fseek(s->pb, off, SEEK_SET); |
| mpc8_get_chunk_header(s->pb, &tag, &size); |
| if(tag != TAG_SEEKTABLE){ |
| av_log(s, AV_LOG_ERROR, "No seek table at given position\n"); |
| return; |
| } |
| if(!(buf = av_malloc(size))) |
| return; |
| get_buffer(s->pb, buf, size); |
| init_get_bits(&gb, buf, size * 8); |
| size = gb_get_v(&gb); |
| if(size > UINT_MAX/4 || size > c->samples/1152){ |
| av_log(s, AV_LOG_ERROR, "Seek table is too big\n"); |
| return; |
| } |
| seekd = get_bits(&gb, 4); |
| for(i = 0; i < 2; i++){ |
| pos = gb_get_v(&gb) + c->header_pos; |
| ppos[1 - i] = pos; |
| av_add_index_entry(s->streams[0], pos, i, 0, 0, AVINDEX_KEYFRAME); |
| } |
| for(; i < size; i++){ |
| t = get_unary(&gb, 1, 33) << 12; |
| t += get_bits(&gb, 12); |
| if(t & 1) |
| t = -(t & ~1); |
| pos = (t >> 1) + ppos[0]*2 - ppos[1]; |
| av_add_index_entry(s->streams[0], pos, i << seekd, 0, 0, AVINDEX_KEYFRAME); |
| ppos[1] = ppos[0]; |
| ppos[0] = pos; |
| } |
| av_free(buf); |
| } |
| |
| static void mpc8_handle_chunk(AVFormatContext *s, int tag, int64_t chunk_pos, int64_t size) |
| { |
| ByteIOContext *pb = s->pb; |
| int64_t pos, off; |
| |
| switch(tag){ |
| case TAG_SEEKTBLOFF: |
| pos = url_ftell(pb) + size; |
| off = ff_get_v(pb); |
| mpc8_parse_seektable(s, chunk_pos + off); |
| url_fseek(pb, pos, SEEK_SET); |
| break; |
| default: |
| url_fskip(pb, size); |
| } |
| } |
| |
| static int mpc8_read_header(AVFormatContext *s, AVFormatParameters *ap) |
| { |
| MPCContext *c = s->priv_data; |
| ByteIOContext *pb = s->pb; |
| AVStream *st; |
| int tag = 0; |
| int64_t size, pos; |
| |
| c->header_pos = url_ftell(pb); |
| if(get_le32(pb) != TAG_MPCK){ |
| av_log(s, AV_LOG_ERROR, "Not a Musepack8 file\n"); |
| return -1; |
| } |
| |
| while(!url_feof(pb)){ |
| pos = url_ftell(pb); |
| mpc8_get_chunk_header(pb, &tag, &size); |
| if(tag == TAG_STREAMHDR) |
| break; |
| mpc8_handle_chunk(s, tag, pos, size); |
| } |
| if(tag != TAG_STREAMHDR){ |
| av_log(s, AV_LOG_ERROR, "Stream header not found\n"); |
| return -1; |
| } |
| pos = url_ftell(pb); |
| url_fskip(pb, 4); //CRC |
| c->ver = get_byte(pb); |
| if(c->ver != 8){ |
| av_log(s, AV_LOG_ERROR, "Unknown stream version %d\n", c->ver); |
| return -1; |
| } |
| c->samples = ff_get_v(pb); |
| ff_get_v(pb); //silence samples at the beginning |
| |
| st = av_new_stream(s, 0); |
| if (!st) |
| return AVERROR(ENOMEM); |
| st->codec->codec_type = CODEC_TYPE_AUDIO; |
| st->codec->codec_id = CODEC_ID_MUSEPACK8; |
| st->codec->bits_per_coded_sample = 16; |
| |
| st->codec->extradata_size = 2; |
| st->codec->extradata = av_mallocz(st->codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE); |
| get_buffer(pb, st->codec->extradata, st->codec->extradata_size); |
| |
| st->codec->channels = (st->codec->extradata[1] >> 4) + 1; |
| st->codec->sample_rate = mpc8_rate[st->codec->extradata[0] >> 5]; |
| av_set_pts_info(st, 32, 1152 << (st->codec->extradata[1]&3)*2, st->codec->sample_rate); |
| st->duration = c->samples / (1152 << (st->codec->extradata[1]&3)*2); |
| size -= url_ftell(pb) - pos; |
| |
| return 0; |
| } |
| |
| static int mpc8_read_packet(AVFormatContext *s, AVPacket *pkt) |
| { |
| MPCContext *c = s->priv_data; |
| int tag; |
| int64_t pos, size; |
| |
| while(!url_feof(s->pb)){ |
| pos = url_ftell(s->pb); |
| mpc8_get_chunk_header(s->pb, &tag, &size); |
| if(tag == TAG_AUDIOPACKET){ |
| if(av_get_packet(s->pb, pkt, size) < 0) |
| return AVERROR(ENOMEM); |
| pkt->stream_index = 0; |
| pkt->pts = c->frame; |
| return 0; |
| } |
| if(tag == TAG_STREAMEND) |
| return AVERROR(EIO); |
| mpc8_handle_chunk(s, tag, pos, size); |
| } |
| return 0; |
| } |
| |
| static int mpc8_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags) |
| { |
| AVStream *st = s->streams[stream_index]; |
| MPCContext *c = s->priv_data; |
| int index = av_index_search_timestamp(st, timestamp, flags); |
| |
| if(index < 0) return -1; |
| url_fseek(s->pb, st->index_entries[index].pos, SEEK_SET); |
| c->frame = st->index_entries[index].timestamp; |
| return 0; |
| } |
| |
| |
| AVInputFormat mpc8_demuxer = { |
| "mpc8", |
| NULL_IF_CONFIG_SMALL("Musepack SV8"), |
| sizeof(MPCContext), |
| mpc8_probe, |
| mpc8_read_header, |
| mpc8_read_packet, |
| NULL, |
| mpc8_read_seek, |
| }; |