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
|
/*
* Musepack demuxer
* Copyright (c) 2006 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 "libavutil/channel_layout.h"
#include "avformat.h"
#include "internal.h"
#include "apetag.h"
#include "id3v1.h"
#include "libavutil/dict.h"
#define MPC_FRAMESIZE 1152
#define DELAY_FRAMES 32
static const int mpc_rate[4] = { 44100, 48000, 37800, 32000 };
typedef struct MPCFrame {
int64_t pos;
int size, skip;
}MPCFrame;
typedef struct MPCContext {
int ver;
uint32_t curframe, lastframe;
uint32_t fcount;
MPCFrame *frames;
int curbits;
int frames_noted;
} MPCContext;
static int mpc_probe(const AVProbeData *p)
{
const uint8_t *d = p->buf;
if (d[0] == 'M' && d[1] == 'P' && d[2] == '+' && (d[3] == 0x17 || d[3] == 0x7))
return AVPROBE_SCORE_MAX;
return 0;
}
static int mpc_read_header(AVFormatContext *s)
{
MPCContext *c = s->priv_data;
AVStream *st;
int ret;
if(avio_rl24(s->pb) != MKTAG('M', 'P', '+', 0)){
av_log(s, AV_LOG_ERROR, "Not a Musepack file\n");
return AVERROR_INVALIDDATA;
}
c->ver = avio_r8(s->pb);
if(c->ver != 0x07 && c->ver != 0x17){
av_log(s, AV_LOG_ERROR, "Can demux Musepack SV7, got version %02X\n", c->ver);
return AVERROR_INVALIDDATA;
}
c->fcount = avio_rl32(s->pb);
if((int64_t)c->fcount * sizeof(MPCFrame) >= UINT_MAX){
av_log(s, AV_LOG_ERROR, "Too many frames, seeking is not possible\n");
return AVERROR_INVALIDDATA;
}
c->curframe = 0;
c->lastframe = -1;
c->curbits = 8;
c->frames_noted = 0;
st = avformat_new_stream(s, NULL);
if (!st)
return AVERROR(ENOMEM);
if (c->fcount) {
c->frames = av_malloc(c->fcount * sizeof(MPCFrame));
if (!c->frames) {
av_log(s, AV_LOG_ERROR, "Cannot allocate seektable\n");
return AVERROR(ENOMEM);
}
st->priv_data = c->frames;
} else {
av_log(s, AV_LOG_WARNING, "Container reports no frames\n");
}
st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
st->codecpar->codec_id = AV_CODEC_ID_MUSEPACK7;
st->codecpar->channels = 2;
st->codecpar->channel_layout = AV_CH_LAYOUT_STEREO;
st->codecpar->bits_per_coded_sample = 16;
if ((ret = ff_get_extradata(s, st->codecpar, s->pb, 16)) < 0)
return ret;
st->codecpar->sample_rate = mpc_rate[st->codecpar->extradata[2] & 3];
avpriv_set_pts_info(st, 32, MPC_FRAMESIZE, st->codecpar->sample_rate);
/* scan for seekpoints */
st->start_time = 0;
st->duration = c->fcount;
/* try to read APE tags */
if (s->pb->seekable & AVIO_SEEKABLE_NORMAL) {
int64_t pos = avio_tell(s->pb);
ff_ape_parse_tag(s);
if (!av_dict_get(s->metadata, "", NULL, AV_DICT_IGNORE_SUFFIX))
ff_id3v1_read(s);
avio_seek(s->pb, pos, SEEK_SET);
}
return 0;
}
static int mpc_read_packet(AVFormatContext *s, AVPacket *pkt)
{
MPCContext *c = s->priv_data;
int ret, size, size2, curbits, cur = c->curframe;
unsigned tmp;
int64_t pos;
if (c->curframe >= c->fcount && c->fcount)
return AVERROR_EOF;
if(c->curframe != c->lastframe + 1){
avio_seek(s->pb, c->frames[c->curframe].pos, SEEK_SET);
c->curbits = c->frames[c->curframe].skip;
}
c->lastframe = c->curframe;
c->curframe++;
curbits = c->curbits;
pos = avio_tell(s->pb);
tmp = avio_rl32(s->pb);
if(curbits <= 12){
size2 = (tmp >> (12 - curbits)) & 0xFFFFF;
}else{
size2 = (tmp << (curbits - 12) | avio_rl32(s->pb) >> (44 - curbits)) & 0xFFFFF;
}
curbits += 20;
avio_seek(s->pb, pos, SEEK_SET);
size = ((size2 + curbits + 31) & ~31) >> 3;
if(cur == c->frames_noted && c->fcount){
c->frames[cur].pos = pos;
c->frames[cur].size = size;
c->frames[cur].skip = curbits - 20;
av_add_index_entry(s->streams[0], cur, cur, size, 0, AVINDEX_KEYFRAME);
c->frames_noted++;
}
c->curbits = (curbits + size2) & 0x1F;
if ((ret = av_new_packet(pkt, size + 4)) < 0)
return ret;
pkt->data[0] = curbits;
pkt->data[1] = (c->curframe > c->fcount) && c->fcount;
pkt->data[2] = 0;
pkt->data[3] = 0;
pkt->stream_index = 0;
pkt->pts = cur;
ret = avio_read(s->pb, pkt->data + 4, size);
if(c->curbits)
avio_seek(s->pb, -4, SEEK_CUR);
if(ret < size){
return ret < 0 ? ret : AVERROR(EIO);
}
pkt->size = ret + 4;
return 0;
}
/**
* Seek to the given position
* If position is unknown but is within the limits of file
* then packets are skipped unless desired position is reached
*
* Also this function makes use of the fact that timestamp == frameno
*/
static int mpc_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
{
AVStream *st = s->streams[stream_index];
MPCContext *c = s->priv_data;
AVPacket pkt1, *pkt = &pkt1;
int ret;
int index = av_index_search_timestamp(st, FFMAX(timestamp - DELAY_FRAMES, 0), flags);
uint32_t lastframe;
/* if found, seek there */
if (index >= 0 && st->internal->index_entries[st->internal->nb_index_entries-1].timestamp >= timestamp - DELAY_FRAMES){
c->curframe = st->internal->index_entries[index].pos;
return 0;
}
/* if timestamp is out of bounds, return error */
if(timestamp < 0 || timestamp >= c->fcount)
return -1;
timestamp -= DELAY_FRAMES;
/* seek to the furthest known position and read packets until
we reach desired position */
lastframe = c->curframe;
if(c->frames_noted) c->curframe = c->frames_noted - 1;
while(c->curframe < timestamp){
ret = av_read_frame(s, pkt);
if (ret < 0){
c->curframe = lastframe;
return ret;
}
av_packet_unref(pkt);
}
return 0;
}
AVInputFormat ff_mpc_demuxer = {
.name = "mpc",
.long_name = NULL_IF_CONFIG_SMALL("Musepack"),
.priv_data_size = sizeof(MPCContext),
.read_probe = mpc_probe,
.read_header = mpc_read_header,
.read_packet = mpc_read_packet,
.read_seek = mpc_read_seek,
.extensions = "mpc",
};
|
