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315 lines
8.6 KiB
315 lines
8.6 KiB
/* |
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* Musepack SV8 demuxer |
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* Copyright (c) 2007 Konstantin Shishkov |
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* |
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* This file is part of Libav. |
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* |
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* Libav is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* Libav is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with Libav; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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#include "libavcodec/get_bits.h" |
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#include "libavcodec/unary.h" |
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#include "apetag.h" |
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#include "avformat.h" |
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#include "internal.h" |
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#include "avio_internal.h" |
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/// Two-byte MPC tag |
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#define MKMPCTAG(a, b) (a | (b << 8)) |
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#define TAG_MPCK MKTAG('M','P','C','K') |
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/// Reserved MPC tags |
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enum MPCPacketTags{ |
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TAG_STREAMHDR = MKMPCTAG('S','H'), |
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TAG_STREAMEND = MKMPCTAG('S','E'), |
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TAG_AUDIOPACKET = MKMPCTAG('A','P'), |
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TAG_SEEKTBLOFF = MKMPCTAG('S','O'), |
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TAG_SEEKTABLE = MKMPCTAG('S','T'), |
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TAG_REPLAYGAIN = MKMPCTAG('R','G'), |
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TAG_ENCINFO = MKMPCTAG('E','I'), |
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}; |
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static const int mpc8_rate[8] = { 44100, 48000, 37800, 32000, -1, -1, -1, -1 }; |
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typedef struct MPCContext { |
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int ver; |
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int64_t header_pos; |
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int64_t samples; |
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int64_t apetag_start; |
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} MPCContext; |
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static inline int64_t bs_get_v(uint8_t **bs) |
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{ |
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int64_t v = 0; |
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int br = 0; |
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int c; |
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do { |
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c = **bs; (*bs)++; |
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v <<= 7; |
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v |= c & 0x7F; |
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br++; |
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if (br > 10) |
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return -1; |
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} while (c & 0x80); |
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return v - br; |
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} |
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static int mpc8_probe(AVProbeData *p) |
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{ |
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uint8_t *bs = p->buf + 4; |
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uint8_t *bs_end = bs + p->buf_size; |
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int64_t size; |
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if (p->buf_size < 16) |
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return 0; |
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if (AV_RL32(p->buf) != TAG_MPCK) |
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return 0; |
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while (bs < bs_end + 3) { |
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int header_found = (bs[0] == 'S' && bs[1] == 'H'); |
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if (bs[0] < 'A' || bs[0] > 'Z' || bs[1] < 'A' || bs[1] > 'Z') |
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return 0; |
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bs += 2; |
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size = bs_get_v(&bs); |
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if (size < 2) |
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return 0; |
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if (bs + size - 2 >= bs_end) |
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return AVPROBE_SCORE_EXTENSION - 1; // seems to be valid MPC but no header yet |
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if (header_found) { |
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if (size < 11 || size > 28) |
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return 0; |
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if (!AV_RL32(bs)) //zero CRC is invalid |
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return 0; |
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return AVPROBE_SCORE_MAX; |
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} else { |
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bs += size - 2; |
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} |
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} |
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return 0; |
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} |
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static inline int64_t gb_get_v(GetBitContext *gb) |
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{ |
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int64_t v = 0; |
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int bits = 0; |
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while(get_bits1(gb) && bits < 64-7){ |
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v <<= 7; |
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v |= get_bits(gb, 7); |
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bits += 7; |
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} |
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v <<= 7; |
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v |= get_bits(gb, 7); |
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return v; |
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} |
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static void mpc8_get_chunk_header(AVIOContext *pb, int *tag, int64_t *size) |
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{ |
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int64_t pos; |
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pos = avio_tell(pb); |
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*tag = avio_rl16(pb); |
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*size = ffio_read_varlen(pb); |
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*size -= avio_tell(pb) - pos; |
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} |
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static void mpc8_parse_seektable(AVFormatContext *s, int64_t off) |
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{ |
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MPCContext *c = s->priv_data; |
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int tag; |
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int64_t size, pos, ppos[2]; |
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uint8_t *buf; |
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int i, t, seekd; |
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GetBitContext gb; |
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if (s->nb_streams == 0) { |
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av_log(s, AV_LOG_ERROR, "No stream added before parsing seek table\n"); |
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return; |
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} |
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avio_seek(s->pb, off, SEEK_SET); |
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mpc8_get_chunk_header(s->pb, &tag, &size); |
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if(tag != TAG_SEEKTABLE){ |
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av_log(s, AV_LOG_ERROR, "No seek table at given position\n"); |
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return; |
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} |
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if (size < 0 || size >= INT_MAX / 2) { |
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av_log(s, AV_LOG_ERROR, "Bad seek table size\n"); |
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return; |
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} |
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if(!(buf = av_malloc(size + AV_INPUT_BUFFER_PADDING_SIZE))) |
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return; |
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avio_read(s->pb, buf, size); |
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init_get_bits(&gb, buf, size * 8); |
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size = gb_get_v(&gb); |
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if(size > UINT_MAX/4 || size > c->samples/1152){ |
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av_log(s, AV_LOG_ERROR, "Seek table is too big\n"); |
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return; |
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} |
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seekd = get_bits(&gb, 4); |
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for(i = 0; i < 2; i++){ |
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pos = gb_get_v(&gb) + c->header_pos; |
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ppos[1 - i] = pos; |
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av_add_index_entry(s->streams[0], pos, i, 0, 0, AVINDEX_KEYFRAME); |
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} |
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for(; i < size; i++){ |
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t = get_unary(&gb, 1, 33) << 12; |
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t += get_bits(&gb, 12); |
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if(t & 1) |
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t = -(t & ~1); |
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pos = (t >> 1) + ppos[0]*2 - ppos[1]; |
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av_add_index_entry(s->streams[0], pos, i << seekd, 0, 0, AVINDEX_KEYFRAME); |
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ppos[1] = ppos[0]; |
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ppos[0] = pos; |
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} |
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av_free(buf); |
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} |
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static void mpc8_handle_chunk(AVFormatContext *s, int tag, int64_t chunk_pos, int64_t size) |
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{ |
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AVIOContext *pb = s->pb; |
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int64_t pos, off; |
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switch(tag){ |
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case TAG_SEEKTBLOFF: |
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pos = avio_tell(pb) + size; |
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off = ffio_read_varlen(pb); |
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mpc8_parse_seektable(s, chunk_pos + off); |
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avio_seek(pb, pos, SEEK_SET); |
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break; |
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default: |
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avio_skip(pb, size); |
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} |
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} |
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static int mpc8_read_header(AVFormatContext *s) |
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{ |
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MPCContext *c = s->priv_data; |
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AVIOContext *pb = s->pb; |
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AVStream *st; |
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int tag = 0; |
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int64_t size, pos; |
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c->header_pos = avio_tell(pb); |
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if(avio_rl32(pb) != TAG_MPCK){ |
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av_log(s, AV_LOG_ERROR, "Not a Musepack8 file\n"); |
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return AVERROR_INVALIDDATA; |
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} |
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while(!pb->eof_reached){ |
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pos = avio_tell(pb); |
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mpc8_get_chunk_header(pb, &tag, &size); |
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if(tag == TAG_STREAMHDR) |
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break; |
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mpc8_handle_chunk(s, tag, pos, size); |
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} |
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if(tag != TAG_STREAMHDR){ |
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av_log(s, AV_LOG_ERROR, "Stream header not found\n"); |
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return AVERROR_INVALIDDATA; |
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} |
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pos = avio_tell(pb); |
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avio_skip(pb, 4); //CRC |
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c->ver = avio_r8(pb); |
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if(c->ver != 8){ |
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av_log(s, AV_LOG_ERROR, "Unknown stream version %d\n", c->ver); |
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return AVERROR_PATCHWELCOME; |
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} |
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c->samples = ffio_read_varlen(pb); |
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ffio_read_varlen(pb); //silence samples at the beginning |
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st = avformat_new_stream(s, NULL); |
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if (!st) |
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return AVERROR(ENOMEM); |
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st->codec->codec_type = AVMEDIA_TYPE_AUDIO; |
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st->codec->codec_id = AV_CODEC_ID_MUSEPACK8; |
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st->codec->bits_per_coded_sample = 16; |
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st->codec->extradata_size = 2; |
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st->codec->extradata = av_mallocz(st->codec->extradata_size + AV_INPUT_BUFFER_PADDING_SIZE); |
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avio_read(pb, st->codec->extradata, st->codec->extradata_size); |
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st->codec->channels = (st->codec->extradata[1] >> 4) + 1; |
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st->codec->sample_rate = mpc8_rate[st->codec->extradata[0] >> 5]; |
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avpriv_set_pts_info(st, 32, 1152 << (st->codec->extradata[1]&3)*2, st->codec->sample_rate); |
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st->start_time = 0; |
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st->duration = c->samples / (1152 << (st->codec->extradata[1]&3)*2); |
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size -= avio_tell(pb) - pos; |
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if (pb->seekable) { |
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int64_t pos = avio_tell(s->pb); |
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c->apetag_start = ff_ape_parse_tag(s); |
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avio_seek(s->pb, pos, SEEK_SET); |
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} |
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return 0; |
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} |
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static int mpc8_read_packet(AVFormatContext *s, AVPacket *pkt) |
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{ |
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MPCContext *c = s->priv_data; |
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int tag; |
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int64_t pos, size; |
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while(!s->pb->eof_reached){ |
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pos = avio_tell(s->pb); |
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/* don't return bogus packets with the ape tag data */ |
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if (c->apetag_start && pos >= c->apetag_start) |
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return AVERROR_EOF; |
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mpc8_get_chunk_header(s->pb, &tag, &size); |
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if (size < 0) |
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return -1; |
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if(tag == TAG_AUDIOPACKET){ |
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if(av_get_packet(s->pb, pkt, size) < 0) |
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return AVERROR(ENOMEM); |
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pkt->stream_index = 0; |
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pkt->duration = 1; |
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return 0; |
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} |
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if(tag == TAG_STREAMEND) |
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return AVERROR(EIO); |
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mpc8_handle_chunk(s, tag, pos, size); |
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} |
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return AVERROR_EOF; |
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} |
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static int mpc8_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags) |
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{ |
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AVStream *st = s->streams[stream_index]; |
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int index = av_index_search_timestamp(st, timestamp, flags); |
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if(index < 0) return -1; |
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if (avio_seek(s->pb, st->index_entries[index].pos, SEEK_SET) < 0) |
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return -1; |
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ff_update_cur_dts(s, st, st->index_entries[index].timestamp); |
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return 0; |
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} |
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AVInputFormat ff_mpc8_demuxer = { |
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.name = "mpc8", |
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.long_name = NULL_IF_CONFIG_SMALL("Musepack SV8"), |
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.priv_data_size = sizeof(MPCContext), |
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.read_probe = mpc8_probe, |
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.read_header = mpc8_read_header, |
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.read_packet = mpc8_read_packet, |
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.read_seek = mpc8_read_seek, |
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};
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