FFmpeg
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 Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
23 
24 #include "avformat.h"
25 #include "internal.h"
26 #include "apetag.h"
27 #include "id3v1.h"
28 #include "libavutil/dict.h"
29 
30 #define MPC_FRAMESIZE 1152
31 #define DELAY_FRAMES 32
32 
33 static const int mpc_rate[4] = { 44100, 48000, 37800, 32000 };
34 typedef struct MPCFrame {
35  int64_t pos;
36  int size, skip;
37 }MPCFrame;
38 
39 typedef struct MPCContext {
40  int ver;
41  uint32_t curframe, lastframe;
42  uint32_t fcount;
44  int curbits;
46 } MPCContext;
47 
48 static int mpc_probe(const AVProbeData *p)
49 {
50  const uint8_t *d = p->buf;
51  if (d[0] == 'M' && d[1] == 'P' && d[2] == '+' && (d[3] == 0x17 || d[3] == 0x7))
52  return AVPROBE_SCORE_MAX;
53  return 0;
54 }
55 
57 {
58  MPCContext *c = s->priv_data;
59  AVStream *st;
60  int ret;
61 
62  if(avio_rl24(s->pb) != MKTAG('M', 'P', '+', 0)){
63  av_log(s, AV_LOG_ERROR, "Not a Musepack file\n");
64  return AVERROR_INVALIDDATA;
65  }
66  c->ver = avio_r8(s->pb);
67  if(c->ver != 0x07 && c->ver != 0x17){
68  av_log(s, AV_LOG_ERROR, "Can demux Musepack SV7, got version %02X\n", c->ver);
69  return AVERROR_INVALIDDATA;
70  }
71  c->fcount = avio_rl32(s->pb);
72  if((int64_t)c->fcount * sizeof(MPCFrame) >= UINT_MAX){
73  av_log(s, AV_LOG_ERROR, "Too many frames, seeking is not possible\n");
74  return AVERROR_INVALIDDATA;
75  }
76  c->curframe = 0;
77  c->lastframe = -1;
78  c->curbits = 8;
79  c->frames_noted = 0;
80 
81  st = avformat_new_stream(s, NULL);
82  if (!st)
83  return AVERROR(ENOMEM);
84 
85  if (c->fcount) {
86  c->frames = av_malloc(c->fcount * sizeof(MPCFrame));
87  if (!c->frames) {
88  av_log(s, AV_LOG_ERROR, "Cannot allocate seektable\n");
89  return AVERROR(ENOMEM);
90  }
91  st->priv_data = c->frames;
92  } else {
93  av_log(s, AV_LOG_WARNING, "Container reports no frames\n");
94  }
95 
98  st->codecpar->channels = 2;
101 
102  if ((ret = ff_get_extradata(s, st->codecpar, s->pb, 16)) < 0)
103  return ret;
104  st->codecpar->sample_rate = mpc_rate[st->codecpar->extradata[2] & 3];
106  /* scan for seekpoints */
107  st->start_time = 0;
108  st->duration = c->fcount;
109 
110  /* try to read APE tags */
111  if (s->pb->seekable & AVIO_SEEKABLE_NORMAL) {
112  int64_t pos = avio_tell(s->pb);
113  ff_ape_parse_tag(s);
115  ff_id3v1_read(s);
116  avio_seek(s->pb, pos, SEEK_SET);
117  }
118 
119  return 0;
120 }
121 
123 {
124  MPCContext *c = s->priv_data;
125  int ret, size, size2, curbits, cur = c->curframe;
126  unsigned tmp;
127  int64_t pos;
128 
129  if (c->curframe >= c->fcount && c->fcount)
130  return AVERROR_EOF;
131 
132  if(c->curframe != c->lastframe + 1){
133  avio_seek(s->pb, c->frames[c->curframe].pos, SEEK_SET);
134  c->curbits = c->frames[c->curframe].skip;
135  }
136  c->lastframe = c->curframe;
137  c->curframe++;
138  curbits = c->curbits;
139  pos = avio_tell(s->pb);
140  tmp = avio_rl32(s->pb);
141  if(curbits <= 12){
142  size2 = (tmp >> (12 - curbits)) & 0xFFFFF;
143  }else{
144  size2 = (tmp << (curbits - 12) | avio_rl32(s->pb) >> (44 - curbits)) & 0xFFFFF;
145  }
146  curbits += 20;
147  avio_seek(s->pb, pos, SEEK_SET);
148 
149  size = ((size2 + curbits + 31) & ~31) >> 3;
150  if(cur == c->frames_noted && c->fcount){
151  c->frames[cur].pos = pos;
152  c->frames[cur].size = size;
153  c->frames[cur].skip = curbits - 20;
154  av_add_index_entry(s->streams[0], cur, cur, size, 0, AVINDEX_KEYFRAME);
155  c->frames_noted++;
156  }
157  c->curbits = (curbits + size2) & 0x1F;
158 
159  if ((ret = av_new_packet(pkt, size + 4)) < 0)
160  return ret;
161 
162  pkt->data[0] = curbits;
163  pkt->data[1] = (c->curframe > c->fcount) && c->fcount;
164  pkt->data[2] = 0;
165  pkt->data[3] = 0;
166 
167  pkt->stream_index = 0;
168  pkt->pts = cur;
169  ret = avio_read(s->pb, pkt->data + 4, size);
170  if(c->curbits)
171  avio_seek(s->pb, -4, SEEK_CUR);
172  if(ret < size){
173  return ret < 0 ? ret : AVERROR(EIO);
174  }
175  pkt->size = ret + 4;
176 
177  return 0;
178 }
179 
180 /**
181  * Seek to the given position
182  * If position is unknown but is within the limits of file
183  * then packets are skipped unless desired position is reached
184  *
185  * Also this function makes use of the fact that timestamp == frameno
186  */
187 static int mpc_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
188 {
189  AVStream *st = s->streams[stream_index];
190  MPCContext *c = s->priv_data;
191  AVPacket pkt1, *pkt = &pkt1;
192  int ret;
193  int index = av_index_search_timestamp(st, FFMAX(timestamp - DELAY_FRAMES, 0), flags);
194  uint32_t lastframe;
195 
196  /* if found, seek there */
197  if (index >= 0 && st->index_entries[st->nb_index_entries-1].timestamp >= timestamp - DELAY_FRAMES){
198  c->curframe = st->index_entries[index].pos;
199  return 0;
200  }
201  /* if timestamp is out of bounds, return error */
202  if(timestamp < 0 || timestamp >= c->fcount)
203  return -1;
204  timestamp -= DELAY_FRAMES;
205  /* seek to the furthest known position and read packets until
206  we reach desired position */
207  lastframe = c->curframe;
208  if(c->frames_noted) c->curframe = c->frames_noted - 1;
209  while(c->curframe < timestamp){
210  ret = av_read_frame(s, pkt);
211  if (ret < 0){
212  c->curframe = lastframe;
213  return ret;
214  }
215  av_packet_unref(pkt);
216  }
217  return 0;
218 }
219 
220 
222  .name = "mpc",
223  .long_name = NULL_IF_CONFIG_SMALL("Musepack"),
224  .priv_data_size = sizeof(MPCContext),
229  .extensions = "mpc",
230 };
#define NULL
Definition: coverity.c:32
#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:2045
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:200
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:4938
int64_t pos
Definition: avformat.h:805
uint32_t fcount
Definition: mpc.c:42
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: codec_par.h:60
void ff_id3v1_read(AVFormatContext *s)
Read an ID3v1 tag.
Definition: id3v1.c:279
int size
Definition: packet.h:364
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:253
AVIndexEntry * index_entries
Only used if the format does not support seeking natively.
Definition: avformat.h:1105
void * priv_data
Definition: avformat.h:891
static AVPacket pkt
#define AV_CH_LAYOUT_STEREO
Format I/O context.
Definition: avformat.h:1351
Public dictionary API.
static int mpc_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: mpc.c:122
uint8_t
#define av_malloc(s)
static int mpc_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
Seek to the given position If position is unknown but is within the limits of file then packets are s...
Definition: mpc.c:187
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:4519
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1419
AVDictionaryEntry * av_dict_get(const AVDictionary *m, const char *key, const AVDictionaryEntry *prev, int flags)
Get a dictionary entry with matching key.
Definition: dict.c:40
uint8_t * data
Definition: packet.h:363
#define AVERROR_EOF
End of file.
Definition: error.h:55
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:557
uint32_t lastframe
Definition: mpc.c:41
static const int mpc_rate[4]
Definition: mpc.c:33
MPCFrame * frames
Definition: mpc.c:43
uint64_t channel_layout
Audio only.
Definition: codec_par.h:162
#define av_log(a,...)
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:637
int av_new_packet(AVPacket *pkt, int size)
Allocate the payload of a packet and initialize its fields with default values.
Definition: avpacket.c:88
#define AVINDEX_KEYFRAME
Definition: avformat.h:812
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:194
AVDictionary * metadata
Metadata that applies to the whole file.
Definition: avformat.h:1591
int frames_noted
Definition: mpc.c:45
int av_index_search_timestamp(AVStream *st, int64_t timestamp, int flags)
Get the index for a specific timestamp.
Definition: utils.c:2162
int size
Definition: mpc.c:36
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:759
int64_t timestamp
Timestamp in AVStream.time_base units, preferably the time from which on correctly decoded frames are...
Definition: avformat.h:806
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:153
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:56
#define DELAY_FRAMES
Definition: mpc.c:31
#define FFMAX(a, b)
Definition: common.h:94
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:628
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:443
int seekable
A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
Definition: avio.h:260
audio channel layout utility functions
uint32_t curframe
Definition: mpc.c:41
#define s(width, name)
Definition: cbs_vp9.c:257
int skip
Definition: mpc.c:36
AVInputFormat ff_mpc_demuxer
Definition: mpc.c:221
#define MPC_FRAMESIZE
Definition: mpc.c:30
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:527
Stream structure.
Definition: avformat.h:876
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
int64_t pos
Definition: mpc.c:35
AVIOContext * pb
I/O context.
Definition: avformat.h:1393
void av_packet_unref(AVPacket *pkt)
Wipe the packet.
Definition: avpacket.c:606
int nb_index_entries
Definition: avformat.h:1107
int index
Definition: gxfenc.c:89
Definition: mpc.c:34
This structure contains the data a format has to probe a file.
Definition: avformat.h:441
int av_read_frame(AVFormatContext *s, AVPacket *pkt)
Return the next frame of a stream.
Definition: utils.c:1773
#define flags(name, subs,...)
Definition: cbs_av1.c:560
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:925
int sample_rate
Audio only.
Definition: codec_par.h:170
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:453
Main libavformat public API header.
static int mpc_read_header(AVFormatContext *s)
Definition: mpc.c:56
int curbits
Definition: mpc.c:44
int64_t start_time
Decoding: pts of the first frame of the stream in presentation order, in stream time base...
Definition: avformat.h:915
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
int frames
Definition: mpc.h:62
void * priv_data
Format private data.
Definition: avformat.h:1379
int bits_per_coded_sample
The number of bits per sample in the codedwords.
Definition: codec_par.h:102
uint8_t * extradata
Extra binary data needed for initializing the decoder, codec-dependent.
Definition: codec_par.h:74
int channels
Audio only.
Definition: codec_par.h:166
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:650
#define AV_DICT_IGNORE_SUFFIX
Return first entry in a dictionary whose first part corresponds to the search key, ignoring the suffix of the found key string.
Definition: dict.h:70
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1023
unsigned int avio_rl24(AVIOContext *s)
Definition: aviobuf.c:751
int stream_index
Definition: packet.h:365
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
#define MKTAG(a, b, c, d)
Definition: common.h:406
static int mpc_probe(const AVProbeData *p)
Definition: mpc.c:48
This structure stores compressed data.
Definition: packet.h:340
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: packet.h:356
Definition: mpc.h:52
int ver
Definition: mpc.c:40
static uint8_t tmp[11]
Definition: aes_ctr.c:26