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/*
* 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/get_bits.h"
#include "libavcodec/unary.h"
#include "apetag.h"
#include "avformat.h"
#include "internal.h"
#include "avio_internal.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;
int64_t header_pos;
int64_t samples;
int64_t apetag_start;
} MPCContext;
static inline int64_t bs_get_v(uint8_t **bs)
{
int64_t v = 0;
int br = 0;
int c;
do {
c = **bs; (*bs)++;
v <<= 7;
v |= c & 0x7F;
br++;
if (br > 10)
return -1;
} while (c & 0x80);
return v - br;
}
static int mpc8_probe(AVProbeData *p)
{
uint8_t *bs = p->buf + 4;
uint8_t *bs_end = bs + p->buf_size;
int64_t size;
if (p->buf_size < 16)
return 0;
if (AV_RL32(p->buf) != TAG_MPCK)
return 0;
while (bs < bs_end + 3) {
int header_found = (bs[0] == 'S' && bs[1] == 'H');
if (bs[0] < 'A' || bs[0] > 'Z' || bs[1] < 'A' || bs[1] > 'Z')
return 0;
bs += 2;
size = bs_get_v(&bs);
if (size < 2)
return 0;
if (bs + size - 2 >= bs_end)
return AVPROBE_SCORE_MAX / 4 - 1; //seems to be valid MPC but no header yet
if (header_found) {
if (size < 11 || size > 28)
return 0;
if (!AV_RL32(bs)) //zero CRC is invalid
return 0;
return AVPROBE_SCORE_MAX;
} else {
bs += size - 2;
}
}
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(AVIOContext *pb, int *tag, int64_t *size)
{
int64_t pos;
pos = avio_tell(pb);
*tag = avio_rl16(pb);
*size = ffio_read_varlen(pb);
*size -= avio_tell(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;
avio_seek(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 + FF_INPUT_BUFFER_PADDING_SIZE)))
return;
avio_read(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)
{
AVIOContext *pb = s->pb;
int64_t pos, off;
switch(tag){
case TAG_SEEKTBLOFF:
pos = avio_tell(pb) + size;
off = ffio_read_varlen(pb);
mpc8_parse_seektable(s, chunk_pos + off);
avio_seek(pb, pos, SEEK_SET);
break;
default:
avio_skip(pb, size);
}
}
static int mpc8_read_header(AVFormatContext *s)
{
MPCContext *c = s->priv_data;
AVIOContext *pb = s->pb;
AVStream *st;
int tag = 0;
int64_t size, pos;
c->header_pos = avio_tell(pb);
if(avio_rl32(pb) != TAG_MPCK){
av_log(s, AV_LOG_ERROR, "Not a Musepack8 file\n");
return AVERROR_INVALIDDATA;
}
while(!url_feof(pb)){
pos = avio_tell(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 AVERROR_INVALIDDATA;
}
pos = avio_tell(pb);
avio_skip(pb, 4); //CRC
c->ver = avio_r8(pb);
if(c->ver != 8){
av_log(s, AV_LOG_ERROR, "Unknown stream version %d\n", c->ver);
return AVERROR_PATCHWELCOME;
}
c->samples = ffio_read_varlen(pb);
ffio_read_varlen(pb); //silence samples at the beginning
st = avformat_new_stream(s, NULL);
if (!st)
return AVERROR(ENOMEM);
st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
st->codec->codec_id = AV_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);
avio_read(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];
avpriv_set_pts_info(st, 32, 1152 << (st->codec->extradata[1]&3)*2, st->codec->sample_rate);
st->start_time = 0;
st->duration = c->samples / (1152 << (st->codec->extradata[1]&3)*2);
size -= avio_tell(pb) - pos;
if (size > 0)
avio_skip(pb, size);
if (pb->seekable) {
int64_t pos = avio_tell(s->pb);
c->apetag_start = ff_ape_parse_tag(s);
avio_seek(s->pb, pos, SEEK_SET);
}
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 = avio_tell(s->pb);
/* don't return bogus packets with the ape tag data */
if (c->apetag_start && pos >= c->apetag_start)
return AVERROR_EOF;
mpc8_get_chunk_header(s->pb, &tag, &size);
if (size < 0)
return -1;
if(tag == TAG_AUDIOPACKET){
if(av_get_packet(s->pb, pkt, size) < 0)
return AVERROR(ENOMEM);
pkt->stream_index = 0;
pkt->duration = 1;
return 0;
}
if(tag == TAG_STREAMEND)
return AVERROR(EIO);
mpc8_handle_chunk(s, tag, pos, size);
}
return AVERROR_EOF;
}
static int mpc8_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
{
AVStream *st = s->streams[stream_index];
int index = av_index_search_timestamp(st, timestamp, flags);
if(index < 0) return -1;
if (avio_seek(s->pb, st->index_entries[index].pos, SEEK_SET) < 0)
return -1;
ff_update_cur_dts(s, st, st->index_entries[index].timestamp);
return 0;
}
AVInputFormat ff_mpc8_demuxer = {
.name = "mpc8",
.long_name = NULL_IF_CONFIG_SMALL("Musepack SV8"),
.priv_data_size = sizeof(MPCContext),
.read_probe = mpc8_probe,
.read_header = mpc8_read_header,
.read_packet = mpc8_read_packet,
.read_seek = mpc8_read_seek,
};
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