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 #include "libavutil/mem.h"
24 
25 #include "avformat.h"
26 #include "demux.h"
27 #include "internal.h"
28 #include "apetag.h"
29 #include "id3v1.h"
30 #include "libavutil/dict.h"
31 
32 #define MPC_FRAMESIZE 1152
33 #define DELAY_FRAMES 32
34 
35 static const int mpc_rate[4] = { 44100, 48000, 37800, 32000 };
36 typedef struct MPCFrame {
37  int64_t pos;
38  int size, skip;
39 }MPCFrame;
40 
41 typedef struct MPCContext {
42  int ver;
43  uint32_t curframe, lastframe;
44  uint32_t fcount;
46  int curbits;
48 } MPCContext;
49 
50 static int mpc_probe(const AVProbeData *p)
51 {
52  const uint8_t *d = p->buf;
53  if (d[0] == 'M' && d[1] == 'P' && d[2] == '+' && (d[3] == 0x17 || d[3] == 0x7))
54  return AVPROBE_SCORE_MAX;
55  return 0;
56 }
57 
59 {
60  MPCContext *c = s->priv_data;
61  AVStream *st;
62  int ret;
63 
64  if(avio_rl24(s->pb) != MKTAG('M', 'P', '+', 0)){
65  av_log(s, AV_LOG_ERROR, "Not a Musepack file\n");
66  return AVERROR_INVALIDDATA;
67  }
68  c->ver = avio_r8(s->pb);
69  if(c->ver != 0x07 && c->ver != 0x17){
70  av_log(s, AV_LOG_ERROR, "Can demux Musepack SV7, got version %02X\n", c->ver);
71  return AVERROR_INVALIDDATA;
72  }
73  c->fcount = avio_rl32(s->pb);
74  if((int64_t)c->fcount * sizeof(MPCFrame) >= UINT_MAX){
75  av_log(s, AV_LOG_ERROR, "Too many frames, seeking is not possible\n");
76  return AVERROR_INVALIDDATA;
77  }
78  c->curframe = 0;
79  c->lastframe = -1;
80  c->curbits = 8;
81  c->frames_noted = 0;
82 
83  st = avformat_new_stream(s, NULL);
84  if (!st)
85  return AVERROR(ENOMEM);
86 
87  if (c->fcount) {
88  c->frames = av_malloc(c->fcount * sizeof(MPCFrame));
89  if (!c->frames) {
90  av_log(s, AV_LOG_ERROR, "Cannot allocate seektable\n");
91  return AVERROR(ENOMEM);
92  }
93  st->priv_data = c->frames;
94  } else {
95  av_log(s, AV_LOG_WARNING, "Container reports no frames\n");
96  }
97 
102 
103  if ((ret = ff_get_extradata(s, st->codecpar, s->pb, 16)) < 0)
104  return ret;
105  st->codecpar->sample_rate = mpc_rate[st->codecpar->extradata[2] & 3];
107  /* scan for seekpoints */
108  st->start_time = 0;
109  st->duration = c->fcount;
110 
111  /* try to read APE tags */
112  if (s->pb->seekable & AVIO_SEEKABLE_NORMAL) {
113  int64_t pos = avio_tell(s->pb);
115  if (av_dict_count(s->metadata) == 0)
116  ff_id3v1_read(s);
117  avio_seek(s->pb, pos, SEEK_SET);
118  }
119 
120  return 0;
121 }
122 
124 {
125  MPCContext *c = s->priv_data;
126  int ret, size, size2, curbits, cur = c->curframe;
127  unsigned tmp;
128  int64_t pos;
129 
130  if (c->curframe >= c->fcount && c->fcount)
131  return AVERROR_EOF;
132 
133  if(c->curframe != c->lastframe + 1){
134  avio_seek(s->pb, c->frames[c->curframe].pos, SEEK_SET);
135  c->curbits = c->frames[c->curframe].skip;
136  }
137  c->lastframe = c->curframe;
138  c->curframe++;
139  curbits = c->curbits;
140  pos = avio_tell(s->pb);
141  tmp = avio_rl32(s->pb);
142  if(curbits <= 12){
143  size2 = (tmp >> (12 - curbits)) & 0xFFFFF;
144  }else{
145  size2 = (tmp << (curbits - 12) | avio_rl32(s->pb) >> (44 - curbits)) & 0xFFFFF;
146  }
147  curbits += 20;
148  avio_seek(s->pb, pos, SEEK_SET);
149 
150  size = ((size2 + curbits + 31) & ~31) >> 3;
151  if(cur == c->frames_noted && c->fcount){
152  c->frames[cur].pos = pos;
153  c->frames[cur].size = size;
154  c->frames[cur].skip = curbits - 20;
155  av_add_index_entry(s->streams[0], cur, cur, size, 0, AVINDEX_KEYFRAME);
156  c->frames_noted++;
157  }
158  c->curbits = (curbits + size2) & 0x1F;
159 
160  if ((ret = av_new_packet(pkt, size + 4)) < 0)
161  return ret;
162 
163  pkt->data[0] = curbits;
164  pkt->data[1] = (c->curframe > c->fcount) && c->fcount;
165  pkt->data[2] = 0;
166  pkt->data[3] = 0;
167 
168  pkt->stream_index = 0;
169  pkt->pts = cur;
170  ret = avio_read(s->pb, pkt->data + 4, size);
171  if(c->curbits)
172  avio_seek(s->pb, -4, SEEK_CUR);
173  if(ret < size){
174  return ret < 0 ? ret : AVERROR(EIO);
175  }
176  pkt->size = ret + 4;
177 
178  return 0;
179 }
180 
181 /**
182  * Seek to the given position
183  * If position is unknown but is within the limits of file
184  * then packets are skipped unless desired position is reached
185  *
186  * Also this function makes use of the fact that timestamp == frameno
187  */
188 static int mpc_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
189 {
190  AVStream *st = s->streams[stream_index];
191  FFStream *const sti = ffstream(st);
192  MPCContext *c = s->priv_data;
193  AVPacket pkt1, *pkt = &pkt1;
194  int ret;
195  int index = av_index_search_timestamp(st, FFMAX(timestamp - DELAY_FRAMES, 0), flags);
196  uint32_t lastframe;
197 
198  /* if found, seek there */
199  if (index >= 0 && sti->index_entries[sti->nb_index_entries-1].timestamp >= timestamp - DELAY_FRAMES) {
200  c->curframe = sti->index_entries[index].pos;
201  return 0;
202  }
203  /* if timestamp is out of bounds, return error */
204  if(timestamp < 0 || timestamp >= c->fcount)
205  return -1;
206  timestamp -= DELAY_FRAMES;
207  /* seek to the furthest known position and read packets until
208  we reach desired position */
209  lastframe = c->curframe;
210  if(c->frames_noted) c->curframe = c->frames_noted - 1;
211  while(c->curframe < timestamp){
212  ret = av_read_frame(s, pkt);
213  if (ret < 0){
214  c->curframe = lastframe;
215  return ret;
216  }
218  }
219  return 0;
220 }
221 
222 
224  .p.name = "mpc",
225  .p.long_name = NULL_IF_CONFIG_SMALL("Musepack"),
226  .p.extensions = "mpc",
227  .priv_data_size = sizeof(MPCContext),
232 };
av_packet_unref
void av_packet_unref(AVPacket *pkt)
Wipe the packet.
Definition: packet.c:427
AV_LOG_WARNING
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:186
AVCodecParameters::extradata
uint8_t * extradata
Extra binary data needed for initializing the decoder, codec-dependent.
Definition: codec_par.h:69
AVERROR
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
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:51
AV_CHANNEL_LAYOUT_STEREO
#define AV_CHANNEL_LAYOUT_STEREO
Definition: channel_layout.h:379
avformat_new_stream
AVStream * avformat_new_stream(AVFormatContext *s, const struct AVCodec *c)
Add a new stream to a media file.
AVStream::priv_data
void * priv_data
Definition: avformat.h:768
AVERROR_EOF
#define AVERROR_EOF
End of file.
Definition: error.h:57
av_dict_count
int av_dict_count(const AVDictionary *m)
Get number of entries in dictionary.
Definition: dict.c:39
DELAY_FRAMES
#define DELAY_FRAMES
Definition: mpc.c:33
apetag.h
tmp
static uint8_t tmp[11]
Definition: aes_ctr.c:28
AVPacket::data
uint8_t * data
Definition: packet.h:524
mpc_read_packet
static int mpc_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: mpc.c:123
ff_id3v1_read
void ff_id3v1_read(AVFormatContext *s)
Read an ID3v1 tag.
Definition: id3v1.c:278
MPCContext
Definition: mpc.h:54
FFMAX
#define FFMAX(a, b)
Definition: macros.h:47
av_read_frame
int av_read_frame(AVFormatContext *s, AVPacket *pkt)
Return the next frame of a stream.
Definition: demux.c:1538
id3v1.h
MPCFrame::size
int size
Definition: mpc.c:38
ff_ape_parse_tag
int64_t ff_ape_parse_tag(AVFormatContext *s)
Read and parse an APE tag.
Definition: apetag.c:110
av_malloc
#define av_malloc(s)
Definition: tableprint_vlc.h:30
MPCContext::frames
MPCFrame * frames
Definition: mpc.c:45
AVINDEX_KEYFRAME
#define AVINDEX_KEYFRAME
Definition: avformat.h:610
ff_get_extradata
int ff_get_extradata(void *logctx, 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: demux_utils.c:335
AVPROBE_SCORE_MAX
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:463
avpriv_set_pts_info
void avpriv_set_pts_info(AVStream *st, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: avformat.c:853
ffstream
static av_always_inline FFStream * ffstream(AVStream *st)
Definition: internal.h:417
read_seek
static int read_seek(AVFormatContext *ctx, int stream_index, int64_t timestamp, int flags)
Definition: libcdio.c:151
av_add_index_entry
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: seek.c:121
MPCContext::lastframe
uint32_t lastframe
Definition: mpc.c:43
avio_tell
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:494
AVStream::duration
int64_t duration
Decoding: duration of the stream, in stream time base.
Definition: avformat.h:802
MPCContext::frames_noted
int frames_noted
Definition: mpc.c:47
pkt
AVPacket * pkt
Definition: movenc.c:60
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
read_packet
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
Definition: avio_read_callback.c:42
s
#define s(width, name)
Definition: cbs_vp9.c:198
av_new_packet
int av_new_packet(AVPacket *pkt, int size)
Allocate the payload of a packet and initialize its fields with default values.
Definition: packet.c:98
AVInputFormat::name
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:553
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:453
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
AVIndexEntry::timestamp
int64_t timestamp
Timestamp in AVStream.time_base units, preferably the time from which on correctly decoded frames are...
Definition: avformat.h:604
mpc_rate
static const int mpc_rate[4]
Definition: mpc.c:35
AVFormatContext
Format I/O context.
Definition: avformat.h:1255
internal.h
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:766
read_header
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:550
NULL
#define NULL
Definition: coverity.c:32
FFStream::nb_index_entries
int nb_index_entries
Definition: internal.h:251
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:451
AVCodecParameters::ch_layout
AVChannelLayout ch_layout
Audio only.
Definition: codec_par.h:180
ff_mpc_demuxer
const FFInputFormat ff_mpc_demuxer
Definition: mpc.c:223
index
int index
Definition: gxfenc.c:90
c
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
AVCodecParameters::sample_rate
int sample_rate
Audio only.
Definition: codec_par.h:184
mpc_read_header
static int mpc_read_header(AVFormatContext *s)
Definition: mpc.c:58
avio_rl32
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:730
AVPacket::size
int size
Definition: packet.h:525
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:94
AVChannelLayout
An AVChannelLayout holds information about the channel layout of audio data.
Definition: channel_layout.h:303
FFStream
Definition: internal.h:193
MPCContext::curframe
uint32_t curframe
Definition: mpc.c:43
size
int size
Definition: twinvq_data.h:10344
MPC_FRAMESIZE
#define MPC_FRAMESIZE
Definition: mpc.c:32
FFInputFormat::p
AVInputFormat p
The public AVInputFormat.
Definition: demux.h:41
avio_r8
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:603
AVPacket::pts
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: packet.h:517
avio_rl24
unsigned int avio_rl24(AVIOContext *s)
Definition: aviobuf.c:722
mpc_read_seek
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:188
demux.h
ret
ret
Definition: filter_design.txt:187
AVStream
Stream structure.
Definition: avformat.h:743
avio_seek
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:231
pos
unsigned int pos
Definition: spdifenc.c:414
avformat.h
dict.h
MPCFrame::pos
int64_t pos
Definition: mpc.c:37
channel_layout.h
AVIO_SEEKABLE_NORMAL
#define AVIO_SEEKABLE_NORMAL
Seeking works like for a local file.
Definition: avio.h:41
avio_read
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:612
AVIndexEntry::pos
int64_t pos
Definition: avformat.h:603
MPCFrame
Definition: mpc.c:36
AVPacket::stream_index
int stream_index
Definition: packet.h:526
FFStream::index_entries
AVIndexEntry * index_entries
Only used if the format does not support seeking natively.
Definition: internal.h:249
MPCFrame::skip
int skip
Definition: mpc.c:38
read_probe
static int read_probe(const AVProbeData *p)
Definition: cdg.c:30
AVCodecParameters::bits_per_coded_sample
int bits_per_coded_sample
The number of bits per sample in the codedwords.
Definition: codec_par.h:110
mem.h
MPCContext::curbits
int curbits
Definition: mpc.c:46
AVCodecParameters::codec_id
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:55
AVPacket
This structure stores compressed data.
Definition: packet.h:501
FFInputFormat
Definition: demux.h:37
d
d
Definition: ffmpeg_filter.c:424
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:474
MPCContext::ver
int ver
Definition: mpc.c:42
mpc_probe
static int mpc_probe(const AVProbeData *p)
Definition: mpc.c:50
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:27
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:61
MKTAG
#define MKTAG(a, b, c, d)
Definition: macros.h:55
AVStream::start_time
int64_t start_time
Decoding: pts of the first frame of the stream in presentation order, in stream time base.
Definition: avformat.h:792
AV_CODEC_ID_MUSEPACK7
@ AV_CODEC_ID_MUSEPACK7
Definition: codec_id.h:468
MPCContext::fcount
uint32_t fcount
Definition: mpc.c:44
av_index_search_timestamp
int av_index_search_timestamp(AVStream *st, int64_t timestamp, int flags)
Get the index for a specific timestamp.
Definition: seek.c:244