FFmpeg
mpc8.c
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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
36  TAG_STREAMHDR = MKMPCTAG('S','H'),
37  TAG_STREAMEND = MKMPCTAG('S','E'),
38 
40 
42  TAG_SEEKTABLE = MKMPCTAG('S','T'),
43 
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 
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 
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 
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 
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 
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 
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 
211 {
212  MPCContext *c = s->priv_data;
213  AVIOContext *pb = s->pb;
214  AVStream *st;
215  int tag = 0;
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);
255 
256  if (ff_get_extradata(s, st->codecpar, pb, 2) < 0)
257  return AVERROR(ENOMEM);
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);
271  avio_seek(s->pb, pos, SEEK_SET);
272  }
273 
274  return 0;
275 }
276 
278 {
279  MPCContext *c = s->priv_data;
280  int tag;
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(av_get_packet(s->pb, pkt, size) < 0)
295  return AVERROR(ENOMEM);
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 
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 
321  .name = "mpc8",
322  .long_name = NULL_IF_CONFIG_SMALL("Musepack SV8"),
323  .priv_data_size = sizeof(MPCContext),
328 };
#define NULL
Definition: coverity.c:32
uint64_t ffio_read_varlen(AVIOContext *bc)
Definition: aviobuf.c:932
Bytestream IO Context.
Definition: avio.h:161
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
int av_add_index_entry(AVStream *st, int64_t pos, int64_t timestamp, int size, int distance, int flags)
Add an index entry into a sorted list.
Definition: utils.c:2049
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:379
void avpriv_set_pts_info(AVStream *s, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: utils.c:4929
int64_t pos
Definition: avformat.h:810
#define MKMPCTAG(a, b)
Two-byte MPC tag.
Definition: mpc8.c:30
static int read_seek(AVFormatContext *ctx, int stream_index, int64_t timestamp, int flags)
Definition: libcdio.c:153
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3968
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:246
AVIndexEntry * index_entries
Only used if the format does not support seeking natively.
Definition: avformat.h:1110
static int64_t bs_get_v(const uint8_t **bs)
Definition: mpc8.c:58
static void mpc8_get_chunk_header(AVIOContext *pb, int *tag, int64_t *size)
Definition: mpc8.c:124
static const int mpc8_rate[8]
Definition: mpc8.c:48
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:334
static AVPacket pkt
Format I/O context.
Definition: avformat.h:1358
void ff_update_cur_dts(AVFormatContext *s, AVStream *ref_st, int64_t timestamp)
Update cur_dts of all streams based on the given timestamp and AVStream.
Definition: utils.c:1963
static void mpc8_handle_chunk(AVFormatContext *s, int tag, int64_t chunk_pos, int64_t size)
Definition: mpc8.c:193
uint8_t
#define av_malloc(s)
int64_t duration
Duration of this packet in AVStream->time_base units, 0 if unknown.
Definition: avcodec.h:1498
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4502
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1426
uint32_t tag
Definition: movenc.c:1531
#define AVERROR_EOF
End of file.
Definition: error.h:55
bitstream reader API header.
int av_get_packet(AVIOContext *s, AVPacket *pkt, int size)
Allocate and read the payload of a packet and initialize its fields with default values.
Definition: utils.c:310
ptrdiff_t size
Definition: opengl_enc.c:100
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:557
#define av_log(a,...)
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:650
#define AVINDEX_KEYFRAME
Definition: avformat.h:817
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
int av_index_search_timestamp(AVStream *st, int64_t timestamp, int flags)
Get the index for a specific timestamp.
Definition: utils.c:2164
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:772
int64_t timestamp
Timestamp in AVStream.time_base units, preferably the time from which on correctly decoded frames are...
Definition: avformat.h:811
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
int64_t samples
Definition: mpc8.c:53
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3964
static int mpc8_probe(const AVProbeData *p)
Definition: mpc8.c:76
int64_t ff_ape_parse_tag(AVFormatContext *s)
Read and parse an APE tag.
Definition: apetag.c:118
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:641
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:449
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:448
unsigned int nb_streams
Number of elements in AVFormatContext.streams.
Definition: avformat.h:1414
int seekable
A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
Definition: avio.h:260
uint8_t * bits
Definition: mpc.h:63
MPCPacketTags
Reserved MPC tags.
Definition: mpc8.c:35
#define s(width, name)
Definition: cbs_vp9.c:257
static int64_t gb_get_v(GetBitContext *gb)
Definition: mpc8.c:109
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:530
Stream structure.
Definition: avformat.h:881
#define AVERROR_PATCHWELCOME
Not yet implemented in FFmpeg, patches welcome.
Definition: error.h:62
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
Definition: avio_reading.c:42
#define AVIO_SEEKABLE_NORMAL
Seeking works like for a local file.
Definition: avio.h:40
AVIOContext * pb
I/O context.
Definition: avformat.h:1400
void * buf
Definition: avisynth_c.h:766
static unsigned int get_bits1(GetBitContext *s)
Definition: get_bits.h:498
int index
Definition: gxfenc.c:89
static int init_get_bits(GetBitContext *s, const uint8_t *buffer, int bit_size)
Initialize GetBitContext.
Definition: get_bits.h:659
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:456
This structure contains the data a format has to probe a file.
Definition: avformat.h:446
void avpriv_report_missing_feature(void *avc, const char *msg,...) av_printf_format(2
Log a generic warning message about a missing feature.
#define flags(name, subs,...)
Definition: cbs_av1.c:561
static int read_probe(const AVProbeData *pd)
Definition: jvdec.c:55
int64_t duration
Decoding: duration of the stream, in stream time base.
Definition: avformat.h:930
int sample_rate
Audio only.
Definition: avcodec.h:4078
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:458
unsigned int avio_rl16(AVIOContext *s)
Definition: aviobuf.c:756
Main libavformat public API header.
static int mpc8_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
Definition: mpc8.c:307
#define TAG_MPCK
Definition: mpc8.c:32
static int get_unary(GetBitContext *gb, int stop, int len)
Get unary code of limited length.
Definition: unary.h:46
int64_t start_time
Decoding: pts of the first frame of the stream in presentation order, in stream time base...
Definition: avformat.h:920
int ff_get_extradata(AVFormatContext *s, AVCodecParameters *par, AVIOContext *pb, int size)
Allocate extradata with additional AV_INPUT_BUFFER_PADDING_SIZE at end which is always set to 0 and f...
Definition: utils.c:3339
int64_t header_pos
Definition: mpc8.c:52
#define AV_INPUT_BUFFER_PADDING_SIZE
Required number of additionally allocated bytes at the end of the input bitstream for decoding...
Definition: avcodec.h:793
#define av_free(p)
void * priv_data
Format private data.
Definition: avformat.h:1386
int64_t apetag_start
Definition: mpc8.c:55
static int mpc8_read_header(AVFormatContext *s)
Definition: mpc8.c:210
int bits_per_coded_sample
The number of bits per sample in the codedwords.
Definition: avcodec.h:4010
uint8_t * extradata
Extra binary data needed for initializing the decoder, codec-dependent.
Definition: avcodec.h:3982
int channels
Audio only.
Definition: avcodec.h:4074
static void mpc8_parse_seektable(AVFormatContext *s, int64_t off)
Definition: mpc8.c:133
static int mpc8_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: mpc8.c:277
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:654
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1028
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:361
int stream_index
Definition: avcodec.h:1482
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later.That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another.Frame references ownership and permissions
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_RL32
Definition: bytestream.h:87
This structure stores compressed data.
Definition: avcodec.h:1457
AVInputFormat ff_mpc8_demuxer
Definition: mpc8.c:320
Definition: mpc.h:52
int ver
Definition: mpc.c:40