Make MPC demuxer deal with ID3 tags at the beginning
[libav.git] / libavformat / mpc.c
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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 St, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21#include "avformat.h"
22#include "bitstream.h"
23
24#define MPC_FRAMESIZE 1152
25
26static const int mpc_rate[4] = { 44100, 48000, 37800, 32000 };
27typedef struct {
28 int64_t pos;
29 int size, skip;
30}MPCFrame;
31
32typedef struct {
33 int ver;
34 uint32_t curframe, lastframe;
35 uint32_t fcount;
36 MPCFrame *frames;
37 int curbits;
38 int frames_noted;
39} MPCContext;
40
41static int mpc_probe(AVProbeData *p)
42{
43 const uint8_t *d = p->buf;
44 if (p->buf_size < 32)
45 return 0;
46 if (d[0] == 'M' && d[1] == 'P' && d[2] == '+' && (d[3] == 0x17 || d[3] == 0x7))
47 return AVPROBE_SCORE_MAX;
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48 if (d[0] == 'I' && d[1] == 'D' && d[2] == '3')
49 return AVPROBE_SCORE_MAX / 2;
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50 return 0;
51}
52
53static int mpc_read_header(AVFormatContext *s, AVFormatParameters *ap)
54{
55 MPCContext *c = s->priv_data;
56 AVStream *st;
0587b0ca 57 int t;
185c7b6b 58
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59 t = get_le24(&s->pb);
60 if(t != MKTAG('M', 'P', '+', 0)){
61 if(t != MKTAG('I', 'D', '3', 0)){
62 av_log(s, AV_LOG_ERROR, "Not a Musepack file\n");
63 return -1;
64 }
65 /* skip ID3 tags and try again */
66 url_fskip(&s->pb, 3);
67 t = get_byte(&s->pb) << 21;
68 t |= get_byte(&s->pb) << 14;
69 t |= get_byte(&s->pb) << 7;
70 t |= get_byte(&s->pb);
71 av_log(s, AV_LOG_DEBUG, "Skipping %d(%X) bytes of ID3 data\n", t, t);
72 url_fskip(&s->pb, t);
73 if(get_le24(&s->pb) != MKTAG('M', 'P', '+', 0)){
74 av_log(s, AV_LOG_ERROR, "Not a Musepack file\n");
75 return -1;
76 }
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77 }
78 c->ver = get_byte(&s->pb);
79 if(c->ver != 0x07 && c->ver != 0x17){
80 av_log(s, AV_LOG_ERROR, "Can demux Musepack SV7, got version %02X\n", c->ver);
81 return -1;
82 }
83 c->fcount = get_le32(&s->pb);
84 if((int64_t)c->fcount * sizeof(MPCFrame) >= UINT_MAX){
85 av_log(s, AV_LOG_ERROR, "Too many frames, seeking is not possible\n");
86 return -1;
87 }
88 c->frames = av_malloc(c->fcount * sizeof(MPCFrame));
89 c->curframe = 0;
90 c->lastframe = -1;
91 c->curbits = 8;
e3113632 92 c->frames_noted = 0;
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93
94 st = av_new_stream(s, 0);
95 if (!st)
96 return AVERROR_NOMEM;
97 st->codec->codec_type = CODEC_TYPE_AUDIO;
98 st->codec->codec_id = CODEC_ID_MUSEPACK7;
99 st->codec->channels = 2;
100 st->codec->bits_per_sample = 16;
101
102 st->codec->extradata_size = 16;
103 st->codec->extradata = av_mallocz(st->codec->extradata_size+FF_INPUT_BUFFER_PADDING_SIZE);
104 get_buffer(&s->pb, st->codec->extradata, 16);
105 st->codec->sample_rate = mpc_rate[st->codec->extradata[2] & 3];
106 av_set_pts_info(st, 32, MPC_FRAMESIZE, st->codec->sample_rate);
107 /* scan for seekpoints */
108 s->start_time = 0;
109 s->duration = (int64_t)c->fcount * MPC_FRAMESIZE * AV_TIME_BASE / st->codec->sample_rate;
110
111 return 0;
112}
113
114static int mpc_read_packet(AVFormatContext *s, AVPacket *pkt)
115{
116 MPCContext *c = s->priv_data;
117 int ret, size, size2, curbits, cur = c->curframe;
118 int64_t tmp, pos;
119
120 if (c->curframe > c->fcount)
121 return -1;
122
123 if(c->curframe != c->lastframe + 1){
124 url_fseek(&s->pb, c->frames[c->curframe].pos, SEEK_SET);
125 c->curbits = c->frames[c->curframe].skip;
126 }
127 c->lastframe = c->curframe;
128 c->curframe++;
129 curbits = c->curbits;
130 pos = url_ftell(&s->pb);
131 tmp = get_le32(&s->pb);
132 if(curbits <= 12){
133 size2 = (tmp >> (12 - curbits)) & 0xFFFFF;
134 }else{
135 tmp = (tmp << 32) | get_le32(&s->pb);
136 size2 = (tmp >> (44 - curbits)) & 0xFFFFF;
137 }
138 curbits += 20;
139 url_fseek(&s->pb, pos, SEEK_SET);
140
141 size = ((size2 + curbits + 31) & ~31) >> 3;
142 if(cur == c->frames_noted){
143 c->frames[cur].pos = pos;
144 c->frames[cur].size = size;
145 c->frames[cur].skip = curbits - 20;
146 av_add_index_entry(s->streams[0], cur, cur, size, 0, AVINDEX_KEYFRAME);
147 c->frames_noted++;
148 }
149 c->curbits = (curbits + size2) & 0x1F;
150
151 if (av_new_packet(pkt, size) < 0)
152 return AVERROR_IO;
153
154 pkt->data[0] = curbits;
155 pkt->data[1] = (c->curframe > c->fcount);
156
157 pkt->stream_index = 0;
158 ret = get_buffer(&s->pb, pkt->data + 4, size);
159 if(c->curbits)
160 url_fseek(&s->pb, -4, SEEK_CUR);
161 if(ret < size){
162 av_free_packet(pkt);
163 return AVERROR_IO;
164 }
165 pkt->size = ret + 4;
166
167 return 0;
168}
169
170static int mpc_read_close(AVFormatContext *s)
171{
172 MPCContext *c = s->priv_data;
173
174 av_freep(&c->frames);
175 return 0;
176}
177
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178/**
179 * Seek to the given position
180 * If position is unknown but is within the limits of file
181 * then packets are skipped unless desired position is reached
182 *
183 * Also this function makes use of the fact that timestamp == frameno
184 */
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185static int mpc_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
186{
187 AVStream *st = s->streams[stream_index];
188 MPCContext *c = s->priv_data;
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189 AVPacket pkt1, *pkt = &pkt1;
190 int ret;
185c7b6b 191 int index = av_index_search_timestamp(st, timestamp, flags);
e3113632 192 uint32_t lastframe;
185c7b6b 193
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194 /* if found, seek there */
195 if (index >= 0){
196 c->curframe = st->index_entries[index].pos;
197 return 0;
198 }
199 /* if timestamp is out of bounds, return error */
200 if(timestamp < 0 || timestamp >= c->fcount)
201 return -1;
202 /* seek to the furthest known position and read packets until
203 we reach desired position */
204 lastframe = c->curframe;
205 if(c->frames_noted) c->curframe = c->frames_noted - 1;
206 while(c->curframe < timestamp){
207 ret = av_read_frame(s, pkt);
208 if (ret < 0){
209 c->curframe = lastframe;
210 return -1;
211 }
212 av_free_packet(pkt);
213 }
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214 return 0;
215}
216
217
218AVInputFormat mpc_demuxer = {
219 "mpc",
220 "musepack",
221 sizeof(MPCContext),
222 mpc_probe,
223 mpc_read_header,
224 mpc_read_packet,
225 mpc_read_close,
226 mpc_read_seek,
227 .extensions = "mpc",
228};