aboutsummaryrefslogtreecommitdiffstats
path: root/libavformat/mpc8.c
blob: 6ede777b5fe901935bcf34763949e82c856ddd35 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
/*
 * 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_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,
};