1 /*
2 * Musepack SV8 demuxer
3 * Copyright (c) 2007 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 "libavcodec/get_bits.h"
23 #include "libavcodec/unary.h"
24 #include "apetag.h"
25 #include "avformat.h"
26 #include "internal.h"
27 #include "avio_internal.h"
28
29 /// Two-byte MPC tag
30 #define MKMPCTAG(a, b) ((a) | ((b) << 8))
31
32 #define TAG_MPCK MKTAG('M','P','C','K')
33
34 /// Reserved MPC tags
35 enum MPCPacketTags{
36 TAG_STREAMHDR = MKMPCTAG('S','H'),
37 TAG_STREAMEND = MKMPCTAG('S','E'),
38
39 TAG_AUDIOPACKET = MKMPCTAG('A','P'),
40
41 TAG_SEEKTBLOFF = MKMPCTAG('S','O'),
42 TAG_SEEKTABLE = MKMPCTAG('S','T'),
43
44 TAG_REPLAYGAIN = MKMPCTAG('R','G'),
45 TAG_ENCINFO = MKMPCTAG('E','I'),
46 };
47
48 static const int mpc8_rate[8] = { 44100, 48000, 37800, 32000, -1, -1, -1, -1 };
49
50 typedef struct MPCContext {
51 int ver;
52 int64_t header_pos;
53 int64_t samples;
54
55 int64_t apetag_start;
56 } MPCContext;
57
bs_get_v(const uint8_t ** bs)58 static inline int64_t bs_get_v(const uint8_t **bs)
59 {
60 uint64_t v = 0;
61 int br = 0;
62 int c;
63
64 do {
65 c = **bs; (*bs)++;
66 v <<= 7;
67 v |= c & 0x7F;
68 br++;
69 if (br > 10)
70 return -1;
71 } while (c & 0x80);
72
73 return v - br;
74 }
75
mpc8_probe(const AVProbeData * p)76 static int mpc8_probe(const AVProbeData *p)
77 {
78 const uint8_t *bs = p->buf + 4;
79 const uint8_t *bs_end = bs + p->buf_size;
80 int64_t size;
81
82 if (p->buf_size < 16)
83 return 0;
84 if (AV_RL32(p->buf) != TAG_MPCK)
85 return 0;
86 while (bs < bs_end + 3) {
87 int header_found = (bs[0] == 'S' && bs[1] == 'H');
88 if (bs[0] < 'A' || bs[0] > 'Z' || bs[1] < 'A' || bs[1] > 'Z')
89 return 0;
90 bs += 2;
91 size = bs_get_v(&bs);
92 if (size < 2)
93 return 0;
94 if (size >= bs_end - bs + 2)
95 return AVPROBE_SCORE_EXTENSION - 1; // seems to be valid MPC but no header yet
96 if (header_found) {
97 if (size < 11 || size > 28)
98 return 0;
99 if (!AV_RL32(bs)) //zero CRC is invalid
100 return 0;
101 return AVPROBE_SCORE_MAX;
102 } else {
103 bs += size - 2;
104 }
105 }
106 return 0;
107 }
108
gb_get_v(GetBitContext * gb)109 static inline int64_t gb_get_v(GetBitContext *gb)
110 {
111 uint64_t v = 0;
112 int bits = 0;
113 while(get_bits1(gb) && bits < 64-7){
114 v <<= 7;
115 v |= get_bits(gb, 7);
116 bits += 7;
117 }
118 v <<= 7;
119 v |= get_bits(gb, 7);
120
121 return v;
122 }
123
mpc8_get_chunk_header(AVIOContext * pb,int * tag,int64_t * size)124 static void mpc8_get_chunk_header(AVIOContext *pb, int *tag, int64_t *size)
125 {
126 int64_t pos;
127 pos = avio_tell(pb);
128 *tag = avio_rl16(pb);
129 *size = ffio_read_varlen(pb);
130 *size -= avio_tell(pb) - pos;
131 }
132
mpc8_parse_seektable(AVFormatContext * s,int64_t off)133 static void mpc8_parse_seektable(AVFormatContext *s, int64_t off)
134 {
135 MPCContext *c = s->priv_data;
136 int tag;
137 int64_t size, pos, ppos[2];
138 uint8_t *buf;
139 int i, t, seekd, ret;
140 GetBitContext gb;
141
142 if (s->nb_streams == 0) {
143 av_log(s, AV_LOG_ERROR, "No stream added before parsing seek table\n");
144 return;
145 }
146
147 avio_seek(s->pb, off, SEEK_SET);
148 mpc8_get_chunk_header(s->pb, &tag, &size);
149 if(tag != TAG_SEEKTABLE){
150 av_log(s, AV_LOG_ERROR, "No seek table at given position\n");
151 return;
152 }
153 if (size > INT_MAX/10 || size<=0) {
154 av_log(s, AV_LOG_ERROR, "Bad seek table size\n");
155 return;
156 }
157 if(!(buf = av_malloc(size + AV_INPUT_BUFFER_PADDING_SIZE)))
158 return;
159 ret = avio_read(s->pb, buf, size);
160 if (ret != size) {
161 av_log(s, AV_LOG_ERROR, "seek table truncated\n");
162 av_free(buf);
163 return;
164 }
165 memset(buf+size, 0, AV_INPUT_BUFFER_PADDING_SIZE);
166
167 init_get_bits(&gb, buf, size * 8);
168 size = gb_get_v(&gb);
169 if(size > UINT_MAX/4 || size > c->samples/1152){
170 av_log(s, AV_LOG_ERROR, "Seek table is too big\n");
171 av_free(buf);
172 return;
173 }
174 seekd = get_bits(&gb, 4);
175 for(i = 0; i < 2; i++){
176 pos = gb_get_v(&gb) + c->header_pos;
177 ppos[1 - i] = pos;
178 av_add_index_entry(s->streams[0], pos, i, 0, 0, AVINDEX_KEYFRAME);
179 }
180 for(; i < size; i++){
181 t = get_unary(&gb, 1, 33) << 12;
182 t += get_bits(&gb, 12);
183 if(t & 1)
184 t = -(t & ~1);
185 pos = (t >> 1) + ppos[0]*2 - ppos[1];
186 av_add_index_entry(s->streams[0], pos, i << seekd, 0, 0, AVINDEX_KEYFRAME);
187 ppos[1] = ppos[0];
188 ppos[0] = pos;
189 }
190 av_free(buf);
191 }
192
mpc8_handle_chunk(AVFormatContext * s,int tag,int64_t chunk_pos,int64_t size)193 static void mpc8_handle_chunk(AVFormatContext *s, int tag, int64_t chunk_pos, int64_t size)
194 {
195 AVIOContext *pb = s->pb;
196 int64_t pos, off;
197
198 switch(tag){
199 case TAG_SEEKTBLOFF:
200 pos = avio_tell(pb) + size;
201 off = ffio_read_varlen(pb);
202 mpc8_parse_seektable(s, chunk_pos + off);
203 avio_seek(pb, pos, SEEK_SET);
204 break;
205 default:
206 avio_skip(pb, size);
207 }
208 }
209
mpc8_read_header(AVFormatContext * s)210 static int mpc8_read_header(AVFormatContext *s)
211 {
212 MPCContext *c = s->priv_data;
213 AVIOContext *pb = s->pb;
214 AVStream *st;
215 int tag = 0, ret;
216 int64_t size, pos;
217
218 c->header_pos = avio_tell(pb);
219 if(avio_rl32(pb) != TAG_MPCK){
220 av_log(s, AV_LOG_ERROR, "Not a Musepack8 file\n");
221 return AVERROR_INVALIDDATA;
222 }
223
224 while(!avio_feof(pb)){
225 pos = avio_tell(pb);
226 mpc8_get_chunk_header(pb, &tag, &size);
227 if (size < 0) {
228 av_log(s, AV_LOG_ERROR, "Invalid chunk length\n");
229 return AVERROR_INVALIDDATA;
230 }
231 if(tag == TAG_STREAMHDR)
232 break;
233 mpc8_handle_chunk(s, tag, pos, size);
234 }
235 if(tag != TAG_STREAMHDR){
236 av_log(s, AV_LOG_ERROR, "Stream header not found\n");
237 return AVERROR_INVALIDDATA;
238 }
239 pos = avio_tell(pb);
240 avio_skip(pb, 4); //CRC
241 c->ver = avio_r8(pb);
242 if(c->ver != 8){
243 avpriv_report_missing_feature(s, "Stream version %d", c->ver);
244 return AVERROR_PATCHWELCOME;
245 }
246 c->samples = ffio_read_varlen(pb);
247 ffio_read_varlen(pb); //silence samples at the beginning
248
249 st = avformat_new_stream(s, NULL);
250 if (!st)
251 return AVERROR(ENOMEM);
252 st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
253 st->codecpar->codec_id = AV_CODEC_ID_MUSEPACK8;
254 st->codecpar->bits_per_coded_sample = 16;
255
256 if ((ret = ff_get_extradata(s, st->codecpar, pb, 2)) < 0)
257 return ret;
258
259 st->codecpar->channels = (st->codecpar->extradata[1] >> 4) + 1;
260 st->codecpar->sample_rate = mpc8_rate[st->codecpar->extradata[0] >> 5];
261 avpriv_set_pts_info(st, 32, 1152 << (st->codecpar->extradata[1]&3)*2, st->codecpar->sample_rate);
262 st->start_time = 0;
263 st->duration = c->samples / (1152 << (st->codecpar->extradata[1]&3)*2);
264 size -= avio_tell(pb) - pos;
265 if (size > 0)
266 avio_skip(pb, size);
267
268 if (pb->seekable & AVIO_SEEKABLE_NORMAL) {
269 int64_t pos = avio_tell(s->pb);
270 c->apetag_start = ff_ape_parse_tag(s);
271 avio_seek(s->pb, pos, SEEK_SET);
272 }
273
274 return 0;
275 }
276
mpc8_read_packet(AVFormatContext * s,AVPacket * pkt)277 static int mpc8_read_packet(AVFormatContext *s, AVPacket *pkt)
278 {
279 MPCContext *c = s->priv_data;
280 int tag, ret;
281 int64_t pos, size;
282
283 while(!avio_feof(s->pb)){
284 pos = avio_tell(s->pb);
285
286 /* don't return bogus packets with the ape tag data */
287 if (c->apetag_start && pos >= c->apetag_start)
288 return AVERROR_EOF;
289
290 mpc8_get_chunk_header(s->pb, &tag, &size);
291 if (size < 0)
292 return -1;
293 if(tag == TAG_AUDIOPACKET){
294 if ((ret = av_get_packet(s->pb, pkt, size)) < 0)
295 return ret;
296 pkt->stream_index = 0;
297 pkt->duration = 1;
298 return 0;
299 }
300 if(tag == TAG_STREAMEND)
301 return AVERROR_EOF;
302 mpc8_handle_chunk(s, tag, pos, size);
303 }
304 return AVERROR_EOF;
305 }
306
mpc8_read_seek(AVFormatContext * s,int stream_index,int64_t timestamp,int flags)307 static int mpc8_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
308 {
309 AVStream *st = s->streams[stream_index];
310 int index = av_index_search_timestamp(st, timestamp, flags);
311
312 if(index < 0) return -1;
313 if (avio_seek(s->pb, st->index_entries[index].pos, SEEK_SET) < 0)
314 return -1;
315 ff_update_cur_dts(s, st, st->index_entries[index].timestamp);
316 return 0;
317 }
318
319
320 AVInputFormat ff_mpc8_demuxer = {
321 .name = "mpc8",
322 .long_name = NULL_IF_CONFIG_SMALL("Musepack SV8"),
323 .priv_data_size = sizeof(MPCContext),
324 .read_probe = mpc8_probe,
325 .read_header = mpc8_read_header,
326 .read_packet = mpc8_read_packet,
327 .read_seek = mpc8_read_seek,
328 };
329