1 /*
2 * Musepack demuxer
3 * Copyright (c) 2006 Konstantin Shishkov
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 #include "libavutil/channel_layout.h"
23
24 #include "avformat.h"
25 #include "demux.h"
26 #include "internal.h"
27 #include "apetag.h"
28 #include "id3v1.h"
29 #include "libavutil/dict.h"
30
31 #define MPC_FRAMESIZE 1152
32 #define DELAY_FRAMES 32
33
34 static const int mpc_rate[4] = { 44100, 48000, 37800, 32000 };
35 typedef struct MPCFrame {
36 int64_t pos;
37 int size, skip;
38 }MPCFrame;
39
40 typedef struct MPCContext {
41 int ver;
42 uint32_t curframe, lastframe;
43 uint32_t fcount;
44 MPCFrame *frames;
45 int curbits;
46 int frames_noted;
47 } MPCContext;
48
mpc_probe(const AVProbeData * p)49 static int mpc_probe(const AVProbeData *p)
50 {
51 const uint8_t *d = p->buf;
52 if (d[0] == 'M' && d[1] == 'P' && d[2] == '+' && (d[3] == 0x17 || d[3] == 0x7))
53 return AVPROBE_SCORE_MAX;
54 return 0;
55 }
56
mpc_read_header(AVFormatContext * s)57 static int mpc_read_header(AVFormatContext *s)
58 {
59 MPCContext *c = s->priv_data;
60 AVStream *st;
61 int ret;
62
63 if(avio_rl24(s->pb) != MKTAG('M', 'P', '+', 0)){
64 av_log(s, AV_LOG_ERROR, "Not a Musepack file\n");
65 return AVERROR_INVALIDDATA;
66 }
67 c->ver = avio_r8(s->pb);
68 if(c->ver != 0x07 && c->ver != 0x17){
69 av_log(s, AV_LOG_ERROR, "Can demux Musepack SV7, got version %02X\n", c->ver);
70 return AVERROR_INVALIDDATA;
71 }
72 c->fcount = avio_rl32(s->pb);
73 if((int64_t)c->fcount * sizeof(MPCFrame) >= UINT_MAX){
74 av_log(s, AV_LOG_ERROR, "Too many frames, seeking is not possible\n");
75 return AVERROR_INVALIDDATA;
76 }
77 c->curframe = 0;
78 c->lastframe = -1;
79 c->curbits = 8;
80 c->frames_noted = 0;
81
82 st = avformat_new_stream(s, NULL);
83 if (!st)
84 return AVERROR(ENOMEM);
85
86 if (c->fcount) {
87 c->frames = av_malloc(c->fcount * sizeof(MPCFrame));
88 if (!c->frames) {
89 av_log(s, AV_LOG_ERROR, "Cannot allocate seektable\n");
90 return AVERROR(ENOMEM);
91 }
92 st->priv_data = c->frames;
93 } else {
94 av_log(s, AV_LOG_WARNING, "Container reports no frames\n");
95 }
96
97 st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
98 st->codecpar->codec_id = AV_CODEC_ID_MUSEPACK7;
99 st->codecpar->ch_layout = (AVChannelLayout)AV_CHANNEL_LAYOUT_STEREO;
100 st->codecpar->bits_per_coded_sample = 16;
101
102 if ((ret = ff_get_extradata(s, st->codecpar, s->pb, 16)) < 0)
103 return ret;
104 st->codecpar->sample_rate = mpc_rate[st->codecpar->extradata[2] & 3];
105 avpriv_set_pts_info(st, 32, MPC_FRAMESIZE, st->codecpar->sample_rate);
106 /* scan for seekpoints */
107 st->start_time = 0;
108 st->duration = c->fcount;
109
110 /* try to read APE tags */
111 if (s->pb->seekable & AVIO_SEEKABLE_NORMAL) {
112 int64_t pos = avio_tell(s->pb);
113 ff_ape_parse_tag(s);
114 if (!av_dict_get(s->metadata, "", NULL, AV_DICT_IGNORE_SUFFIX))
115 ff_id3v1_read(s);
116 avio_seek(s->pb, pos, SEEK_SET);
117 }
118
119 return 0;
120 }
121
mpc_read_packet(AVFormatContext * s,AVPacket * pkt)122 static int mpc_read_packet(AVFormatContext *s, AVPacket *pkt)
123 {
124 MPCContext *c = s->priv_data;
125 int ret, size, size2, curbits, cur = c->curframe;
126 unsigned tmp;
127 int64_t pos;
128
129 if (c->curframe >= c->fcount && c->fcount)
130 return AVERROR_EOF;
131
132 if(c->curframe != c->lastframe + 1){
133 avio_seek(s->pb, c->frames[c->curframe].pos, SEEK_SET);
134 c->curbits = c->frames[c->curframe].skip;
135 }
136 c->lastframe = c->curframe;
137 c->curframe++;
138 curbits = c->curbits;
139 pos = avio_tell(s->pb);
140 tmp = avio_rl32(s->pb);
141 if(curbits <= 12){
142 size2 = (tmp >> (12 - curbits)) & 0xFFFFF;
143 }else{
144 size2 = (tmp << (curbits - 12) | avio_rl32(s->pb) >> (44 - curbits)) & 0xFFFFF;
145 }
146 curbits += 20;
147 avio_seek(s->pb, pos, SEEK_SET);
148
149 size = ((size2 + curbits + 31) & ~31) >> 3;
150 if(cur == c->frames_noted && c->fcount){
151 c->frames[cur].pos = pos;
152 c->frames[cur].size = size;
153 c->frames[cur].skip = curbits - 20;
154 av_add_index_entry(s->streams[0], cur, cur, size, 0, AVINDEX_KEYFRAME);
155 c->frames_noted++;
156 }
157 c->curbits = (curbits + size2) & 0x1F;
158
159 if ((ret = av_new_packet(pkt, size + 4)) < 0)
160 return ret;
161
162 pkt->data[0] = curbits;
163 pkt->data[1] = (c->curframe > c->fcount) && c->fcount;
164 pkt->data[2] = 0;
165 pkt->data[3] = 0;
166
167 pkt->stream_index = 0;
168 pkt->pts = cur;
169 ret = avio_read(s->pb, pkt->data + 4, size);
170 if(c->curbits)
171 avio_seek(s->pb, -4, SEEK_CUR);
172 if(ret < size){
173 return ret < 0 ? ret : AVERROR(EIO);
174 }
175 pkt->size = ret + 4;
176
177 return 0;
178 }
179
180 /**
181 * Seek to the given position
182 * If position is unknown but is within the limits of file
183 * then packets are skipped unless desired position is reached
184 *
185 * Also this function makes use of the fact that timestamp == frameno
186 */
mpc_read_seek(AVFormatContext * s,int stream_index,int64_t timestamp,int flags)187 static int mpc_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
188 {
189 AVStream *st = s->streams[stream_index];
190 FFStream *const sti = ffstream(st);
191 MPCContext *c = s->priv_data;
192 AVPacket pkt1, *pkt = &pkt1;
193 int ret;
194 int index = av_index_search_timestamp(st, FFMAX(timestamp - DELAY_FRAMES, 0), flags);
195 uint32_t lastframe;
196
197 /* if found, seek there */
198 if (index >= 0 && sti->index_entries[sti->nb_index_entries-1].timestamp >= timestamp - DELAY_FRAMES) {
199 c->curframe = sti->index_entries[index].pos;
200 return 0;
201 }
202 /* if timestamp is out of bounds, return error */
203 if(timestamp < 0 || timestamp >= c->fcount)
204 return -1;
205 timestamp -= DELAY_FRAMES;
206 /* seek to the furthest known position and read packets until
207 we reach desired position */
208 lastframe = c->curframe;
209 if(c->frames_noted) c->curframe = c->frames_noted - 1;
210 while(c->curframe < timestamp){
211 ret = av_read_frame(s, pkt);
212 if (ret < 0){
213 c->curframe = lastframe;
214 return ret;
215 }
216 av_packet_unref(pkt);
217 }
218 return 0;
219 }
220
221
222 const AVInputFormat ff_mpc_demuxer = {
223 .name = "mpc",
224 .long_name = NULL_IF_CONFIG_SMALL("Musepack"),
225 .priv_data_size = sizeof(MPCContext),
226 .read_probe = mpc_probe,
227 .read_header = mpc_read_header,
228 .read_packet = mpc_read_packet,
229 .read_seek = mpc_read_seek,
230 .extensions = "mpc",
231 };
232