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 "demux.h"
27 #include "internal.h"
28 #include "avio_internal.h"
29
30 /// Two-byte MPC tag
31 #define MKMPCTAG(a, b) ((a) | ((b) << 8))
32
33 #define TAG_MPCK MKTAG('M','P','C','K')
34
35 /// Reserved MPC tags
36 enum MPCPacketTags{
37 TAG_STREAMHDR = MKMPCTAG('S','H'),
38 TAG_STREAMEND = MKMPCTAG('S','E'),
39
40 TAG_AUDIOPACKET = MKMPCTAG('A','P'),
41
42 TAG_SEEKTBLOFF = MKMPCTAG('S','O'),
43 TAG_SEEKTABLE = MKMPCTAG('S','T'),
44
45 TAG_REPLAYGAIN = MKMPCTAG('R','G'),
46 TAG_ENCINFO = MKMPCTAG('E','I'),
47 };
48
49 static const int mpc8_rate[8] = { 44100, 48000, 37800, 32000, -1, -1, -1, -1 };
50
51 typedef struct MPCContext {
52 int ver;
53 int64_t header_pos;
54 int64_t samples;
55
56 int64_t apetag_start;
57 } MPCContext;
58
bs_get_v(const uint8_t **bs)59 static inline int64_t bs_get_v(const uint8_t **bs)
60 {
61 uint64_t v = 0;
62 int br = 0;
63 int c;
64
65 do {
66 c = **bs; (*bs)++;
67 v <<= 7;
68 v |= c & 0x7F;
69 br++;
70 if (br > 10)
71 return -1;
72 } while (c & 0x80);
73
74 return v - br;
75 }
76
mpc8_probe(const AVProbeData *p)77 static int mpc8_probe(const AVProbeData *p)
78 {
79 const uint8_t *bs = p->buf + 4;
80 const uint8_t *bs_end = bs + p->buf_size;
81 int64_t size;
82
83 if (p->buf_size < 16)
84 return 0;
85 if (AV_RL32(p->buf) != TAG_MPCK)
86 return 0;
87 while (bs < bs_end + 3) {
88 int header_found = (bs[0] == 'S' && bs[1] == 'H');
89 if (bs[0] < 'A' || bs[0] > 'Z' || bs[1] < 'A' || bs[1] > 'Z')
90 return 0;
91 bs += 2;
92 size = bs_get_v(&bs);
93 if (size < 2)
94 return 0;
95 if (size >= bs_end - bs + 2)
96 return AVPROBE_SCORE_EXTENSION - 1; // seems to be valid MPC but no header yet
97 if (header_found) {
98 if (size < 11 || size > 28)
99 return 0;
100 if (!AV_RL32(bs)) //zero CRC is invalid
101 return 0;
102 return AVPROBE_SCORE_MAX;
103 } else {
104 bs += size - 2;
105 }
106 }
107 return 0;
108 }
109
gb_get_v(GetBitContext *gb)110 static inline int64_t gb_get_v(GetBitContext *gb)
111 {
112 uint64_t v = 0;
113 int bits = 0;
114 while(get_bits1(gb) && bits < 64-7){
115 v <<= 7;
116 v |= get_bits(gb, 7);
117 bits += 7;
118 }
119 v <<= 7;
120 v |= get_bits(gb, 7);
121
122 return v;
123 }
124
mpc8_get_chunk_header(AVIOContext *pb, int *tag, int64_t *size)125 static void mpc8_get_chunk_header(AVIOContext *pb, int *tag, int64_t *size)
126 {
127 int64_t pos;
128 pos = avio_tell(pb);
129 *tag = avio_rl16(pb);
130 *size = ffio_read_varlen(pb);
131 pos -= avio_tell(pb);
132 if (av_sat_add64(*size, pos) != (uint64_t)*size + pos) {
133 *size = -1;
134 } else
135 *size += pos;
136 }
137
mpc8_parse_seektable(AVFormatContext *s, int64_t off)138 static void mpc8_parse_seektable(AVFormatContext *s, int64_t off)
139 {
140 MPCContext *c = s->priv_data;
141 int tag;
142 int64_t size, pos, ppos[2];
143 uint8_t *buf;
144 int i, t, seekd, ret;
145 GetBitContext gb;
146
147 if (s->nb_streams == 0) {
148 av_log(s, AV_LOG_ERROR, "No stream added before parsing seek table\n");
149 return;
150 }
151
152 avio_seek(s->pb, off, SEEK_SET);
153 mpc8_get_chunk_header(s->pb, &tag, &size);
154 if(tag != TAG_SEEKTABLE){
155 av_log(s, AV_LOG_ERROR, "No seek table at given position\n");
156 return;
157 }
158 if (size > INT_MAX/10 || size<=0) {
159 av_log(s, AV_LOG_ERROR, "Bad seek table size\n");
160 return;
161 }
162 if(!(buf = av_malloc(size + AV_INPUT_BUFFER_PADDING_SIZE)))
163 return;
164 ret = avio_read(s->pb, buf, size);
165 if (ret != size) {
166 av_log(s, AV_LOG_ERROR, "seek table truncated\n");
167 av_free(buf);
168 return;
169 }
170 memset(buf+size, 0, AV_INPUT_BUFFER_PADDING_SIZE);
171
172 init_get_bits(&gb, buf, size * 8);
173 size = gb_get_v(&gb);
174 if(size > UINT_MAX/4 || size > c->samples/1152){
175 av_log(s, AV_LOG_ERROR, "Seek table is too big\n");
176 av_free(buf);
177 return;
178 }
179 seekd = get_bits(&gb, 4);
180 for(i = 0; i < 2; i++){
181 pos = gb_get_v(&gb);
182 if (av_sat_add64(pos, c->header_pos) != pos + (uint64_t)c->header_pos) {
183 av_free(buf);
184 return;
185 }
186
187 pos += c->header_pos;
188 ppos[1 - i] = pos;
189 av_add_index_entry(s->streams[0], pos, i, 0, 0, AVINDEX_KEYFRAME);
190 }
191 for(; i < size; i++){
192 if (get_bits_left(&gb) < 13) {
193 av_free(buf);
194 return;
195 }
196 t = get_unary(&gb, 1, 33) << 12;
197 t += get_bits(&gb, 12);
198 if(t & 1)
199 t = -(t & ~1);
200 pos = (t >> 1) + (uint64_t)ppos[0]*2 - ppos[1];
201 av_add_index_entry(s->streams[0], pos, (int64_t)i << seekd, 0, 0, AVINDEX_KEYFRAME);
202 ppos[1] = ppos[0];
203 ppos[0] = pos;
204 }
205 av_free(buf);
206 }
207
mpc8_handle_chunk(AVFormatContext *s, int tag, int64_t chunk_pos, int64_t size)208 static void mpc8_handle_chunk(AVFormatContext *s, int tag, int64_t chunk_pos, int64_t size)
209 {
210 AVIOContext *pb = s->pb;
211 int64_t pos, off;
212
213 switch(tag){
214 case TAG_SEEKTBLOFF:
215 pos = avio_tell(pb);
216 off = ffio_read_varlen(pb);
217 if (pos > INT64_MAX - size || off < 0 || off > INT64_MAX - chunk_pos)
218 return;
219 pos += size;
220 mpc8_parse_seektable(s, chunk_pos + off);
221 avio_seek(pb, pos, SEEK_SET);
222 break;
223 default:
224 avio_skip(pb, size);
225 }
226 }
227
mpc8_read_header(AVFormatContext *s)228 static int mpc8_read_header(AVFormatContext *s)
229 {
230 MPCContext *c = s->priv_data;
231 AVIOContext *pb = s->pb;
232 AVStream *st;
233 int tag = 0, ret;
234 int channels;
235 int64_t size, pos;
236
237 c->header_pos = avio_tell(pb);
238 if(avio_rl32(pb) != TAG_MPCK){
239 av_log(s, AV_LOG_ERROR, "Not a Musepack8 file\n");
240 return AVERROR_INVALIDDATA;
241 }
242
243 while(!avio_feof(pb)){
244 pos = avio_tell(pb);
245 mpc8_get_chunk_header(pb, &tag, &size);
246 if (size < 0) {
247 av_log(s, AV_LOG_ERROR, "Invalid chunk length\n");
248 return AVERROR_INVALIDDATA;
249 }
250 if(tag == TAG_STREAMHDR)
251 break;
252 mpc8_handle_chunk(s, tag, pos, size);
253 }
254 if(tag != TAG_STREAMHDR){
255 av_log(s, AV_LOG_ERROR, "Stream header not found\n");
256 return AVERROR_INVALIDDATA;
257 }
258 pos = avio_tell(pb);
259 avio_skip(pb, 4); //CRC
260 c->ver = avio_r8(pb);
261 if(c->ver != 8){
262 avpriv_report_missing_feature(s, "Stream version %d", c->ver);
263 return AVERROR_PATCHWELCOME;
264 }
265 c->samples = ffio_read_varlen(pb);
266 ffio_read_varlen(pb); //silence samples at the beginning
267
268 st = avformat_new_stream(s, NULL);
269 if (!st)
270 return AVERROR(ENOMEM);
271 st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
272 st->codecpar->codec_id = AV_CODEC_ID_MUSEPACK8;
273 st->codecpar->bits_per_coded_sample = 16;
274
275 if ((ret = ff_get_extradata(s, st->codecpar, pb, 2)) < 0)
276 return ret;
277
278 channels = (st->codecpar->extradata[1] >> 4) + 1;
279 st->codecpar->ch_layout.nb_channels = channels;
280 st->codecpar->sample_rate = mpc8_rate[st->codecpar->extradata[0] >> 5];
281 avpriv_set_pts_info(st, 64, 1152 << (st->codecpar->extradata[1]&3)*2, st->codecpar->sample_rate);
282 st->start_time = 0;
283 st->duration = c->samples / (1152 << (st->codecpar->extradata[1]&3)*2);
284 size -= avio_tell(pb) - pos;
285 if (size > 0)
286 avio_skip(pb, size);
287
288 if (pb->seekable & AVIO_SEEKABLE_NORMAL) {
289 int64_t pos = avio_tell(s->pb);
290 c->apetag_start = ff_ape_parse_tag(s);
291 avio_seek(s->pb, pos, SEEK_SET);
292 }
293
294 return 0;
295 }
296
mpc8_read_packet(AVFormatContext *s, AVPacket *pkt)297 static int mpc8_read_packet(AVFormatContext *s, AVPacket *pkt)
298 {
299 MPCContext *c = s->priv_data;
300 int tag, ret;
301 int64_t pos, size;
302
303 while(!avio_feof(s->pb)){
304 pos = avio_tell(s->pb);
305
306 /* don't return bogus packets with the ape tag data */
307 if (c->apetag_start && pos >= c->apetag_start)
308 return AVERROR_EOF;
309
310 mpc8_get_chunk_header(s->pb, &tag, &size);
311 if (size < 0 || size > INT_MAX)
312 return -1;
313 if(tag == TAG_AUDIOPACKET){
314 if ((ret = av_get_packet(s->pb, pkt, size)) < 0)
315 return ret;
316 pkt->stream_index = 0;
317 pkt->duration = 1;
318 return 0;
319 }
320 if(tag == TAG_STREAMEND)
321 return AVERROR_EOF;
322 mpc8_handle_chunk(s, tag, pos, size);
323 }
324 return AVERROR_EOF;
325 }
326
mpc8_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)327 static int mpc8_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
328 {
329 AVStream *st = s->streams[stream_index];
330 FFStream *const sti = ffstream(st);
331 int index = av_index_search_timestamp(st, timestamp, flags);
332
333 if(index < 0) return -1;
334 if (avio_seek(s->pb, sti->index_entries[index].pos, SEEK_SET) < 0)
335 return -1;
336 avpriv_update_cur_dts(s, st, sti->index_entries[index].timestamp);
337 return 0;
338 }
339
340
341 const AVInputFormat ff_mpc8_demuxer = {
342 .name = "mpc8",
343 .long_name = NULL_IF_CONFIG_SMALL("Musepack SV8"),
344 .priv_data_size = sizeof(MPCContext),
345 .read_probe = mpc8_probe,
346 .read_header = mpc8_read_header,
347 .read_packet = mpc8_read_packet,
348 .read_seek = mpc8_read_seek,
349 };
350