FFmpeg
mpc8.c
Go to the documentation of this file.
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  return;
172  }
173  seekd = get_bits(&gb, 4);
174  for(i = 0; i < 2; i++){
175  pos = gb_get_v(&gb) + c->header_pos;
176  ppos[1 - i] = pos;
177  av_add_index_entry(s->streams[0], pos, i, 0, 0, AVINDEX_KEYFRAME);
178  }
179  for(; i < size; i++){
180  t = get_unary(&gb, 1, 33) << 12;
181  t += get_bits(&gb, 12);
182  if(t & 1)
183  t = -(t & ~1);
184  pos = (t >> 1) + ppos[0]*2 - ppos[1];
185  av_add_index_entry(s->streams[0], pos, i << seekd, 0, 0, AVINDEX_KEYFRAME);
186  ppos[1] = ppos[0];
187  ppos[0] = pos;
188  }
189  av_free(buf);
190 }
191 
192 static void mpc8_handle_chunk(AVFormatContext *s, int tag, int64_t chunk_pos, int64_t size)
193 {
194  AVIOContext *pb = s->pb;
195  int64_t pos, off;
196 
197  switch(tag){
198  case TAG_SEEKTBLOFF:
199  pos = avio_tell(pb) + size;
200  off = ffio_read_varlen(pb);
201  mpc8_parse_seektable(s, chunk_pos + off);
202  avio_seek(pb, pos, SEEK_SET);
203  break;
204  default:
205  avio_skip(pb, size);
206  }
207 }
208 
210 {
211  MPCContext *c = s->priv_data;
212  AVIOContext *pb = s->pb;
213  AVStream *st;
214  int tag = 0;
215  int64_t size, pos;
216 
217  c->header_pos = avio_tell(pb);
218  if(avio_rl32(pb) != TAG_MPCK){
219  av_log(s, AV_LOG_ERROR, "Not a Musepack8 file\n");
220  return AVERROR_INVALIDDATA;
221  }
222 
223  while(!avio_feof(pb)){
224  pos = avio_tell(pb);
225  mpc8_get_chunk_header(pb, &tag, &size);
226  if (size < 0) {
227  av_log(s, AV_LOG_ERROR, "Invalid chunk length\n");
228  return AVERROR_INVALIDDATA;
229  }
230  if(tag == TAG_STREAMHDR)
231  break;
232  mpc8_handle_chunk(s, tag, pos, size);
233  }
234  if(tag != TAG_STREAMHDR){
235  av_log(s, AV_LOG_ERROR, "Stream header not found\n");
236  return AVERROR_INVALIDDATA;
237  }
238  pos = avio_tell(pb);
239  avio_skip(pb, 4); //CRC
240  c->ver = avio_r8(pb);
241  if(c->ver != 8){
242  avpriv_report_missing_feature(s, "Stream version %d", c->ver);
243  return AVERROR_PATCHWELCOME;
244  }
245  c->samples = ffio_read_varlen(pb);
246  ffio_read_varlen(pb); //silence samples at the beginning
247 
248  st = avformat_new_stream(s, NULL);
249  if (!st)
250  return AVERROR(ENOMEM);
254 
255  if (ff_get_extradata(s, st->codecpar, pb, 2) < 0)
256  return AVERROR(ENOMEM);
257 
258  st->codecpar->channels = (st->codecpar->extradata[1] >> 4) + 1;
259  st->codecpar->sample_rate = mpc8_rate[st->codecpar->extradata[0] >> 5];
260  avpriv_set_pts_info(st, 32, 1152 << (st->codecpar->extradata[1]&3)*2, st->codecpar->sample_rate);
261  st->start_time = 0;
262  st->duration = c->samples / (1152 << (st->codecpar->extradata[1]&3)*2);
263  size -= avio_tell(pb) - pos;
264  if (size > 0)
265  avio_skip(pb, size);
266 
267  if (pb->seekable & AVIO_SEEKABLE_NORMAL) {
268  int64_t pos = avio_tell(s->pb);
270  avio_seek(s->pb, pos, SEEK_SET);
271  }
272 
273  return 0;
274 }
275 
277 {
278  MPCContext *c = s->priv_data;
279  int tag;
280  int64_t pos, size;
281 
282  while(!avio_feof(s->pb)){
283  pos = avio_tell(s->pb);
284 
285  /* don't return bogus packets with the ape tag data */
286  if (c->apetag_start && pos >= c->apetag_start)
287  return AVERROR_EOF;
288 
289  mpc8_get_chunk_header(s->pb, &tag, &size);
290  if (size < 0)
291  return -1;
292  if(tag == TAG_AUDIOPACKET){
293  if(av_get_packet(s->pb, pkt, size) < 0)
294  return AVERROR(ENOMEM);
295  pkt->stream_index = 0;
296  pkt->duration = 1;
297  return 0;
298  }
299  if(tag == TAG_STREAMEND)
300  return AVERROR_EOF;
301  mpc8_handle_chunk(s, tag, pos, size);
302  }
303  return AVERROR_EOF;
304 }
305 
306 static int mpc8_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
307 {
308  AVStream *st = s->streams[stream_index];
309  int index = av_index_search_timestamp(st, timestamp, flags);
310 
311  if(index < 0) return -1;
312  if (avio_seek(s->pb, st->index_entries[index].pos, SEEK_SET) < 0)
313  return -1;
314  ff_update_cur_dts(s, st, st->index_entries[index].timestamp);
315  return 0;
316 }
317 
318 
320  .name = "mpc8",
321  .long_name = NULL_IF_CONFIG_SMALL("Musepack SV8"),
322  .priv_data_size = sizeof(MPCContext),
327 };
#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:2039
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:4892
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:3957
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:1953
static void mpc8_handle_chunk(AVFormatContext *s, int tag, int64_t chunk_pos, int64_t size)
Definition: mpc8.c:192
uint8_t
#define av_malloc(s)
int64_t duration
Duration of this packet in AVStream->time_base units, 0 if unknown.
Definition: avcodec.h:1495
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:4465
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1426
uint32_t tag
Definition: movenc.c:1496
#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:2154
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:3953
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:4067
#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:306
#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:3312
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:790
#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:209
int bits_per_coded_sample
The number of bits per sample in the codedwords.
Definition: avcodec.h:3999
uint8_t * extradata
Extra binary data needed for initializing the decoder, codec-dependent.
Definition: avcodec.h:3971
int channels
Audio only.
Definition: avcodec.h:4063
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:276
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:1479
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:1454
AVInputFormat ff_mpc8_demuxer
Definition: mpc8.c:319
Definition: mpc.h:52
int ver
Definition: mpc.c:40