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1 package Audio::Opusfile;
2
3 use 5.014000;
4 use strict;
5 use warnings;
6 use Carp;
7
8 use parent qw/Exporter/;
9 use AutoLoader;
10
11 my @constants =
12 qw/OPUS_CHANNEL_COUNT_MAX
13 OP_ABSOLUTE_GAIN
14 OP_DEC_FORMAT_FLOAT
15 OP_DEC_FORMAT_SHORT
16 OP_DEC_USE_DEFAULT
17 OP_EBADHEADER
18 OP_EBADLINK
19 OP_EBADPACKET
20 OP_EBADTIMESTAMP
21 OP_EFAULT
22 OP_EIMPL
23 OP_EINVAL
24 OP_ENOSEEK
25 OP_ENOTAUDIO
26 OP_ENOTFORMAT
27 OP_EOF
28 OP_EREAD
29 OP_EVERSION
30 OP_FALSE
31 OP_GET_SERVER_INFO_REQUEST
32 OP_HEADER_GAIN
33 OP_HOLE
34 OP_HTTP_PROXY_HOST_REQUEST
35 OP_HTTP_PROXY_PASS_REQUEST
36 OP_HTTP_PROXY_PORT_REQUEST
37 OP_HTTP_PROXY_USER_REQUEST
38 OP_PIC_FORMAT_GIF
39 OP_PIC_FORMAT_JPEG
40 OP_PIC_FORMAT_PNG
41 OP_PIC_FORMAT_UNKNOWN
42 OP_PIC_FORMAT_URL
43 OP_SSL_SKIP_CERTIFICATE_CHECK_REQUEST
44 OP_TRACK_GAIN/;
45
46 our @EXPORT_OK = @constants;
47 our @EXPORT = @constants;
48
49 our $VERSION = '0.005001';
50
51 sub AUTOLOAD {
52 # This AUTOLOAD is used to 'autoload' constants from the constant()
53 # XS function.
54
55 my $constname;
56 our $AUTOLOAD;
57 ($constname = $AUTOLOAD) =~ s/.*:://;
58 croak "&Audio::Opusfile::constant not defined" if $constname eq 'constant';
59 my ($error, $val) = constant($constname);
60 if ($error) { croak $error; }
61 {
62 no strict 'refs';
63 # Fixed between 5.005_53 and 5.005_61
64 #XXX if ($] >= 5.00561) {
65 #XXX *$AUTOLOAD = sub () { $val };
66 #XXX }
67 #XXX else {
68 *$AUTOLOAD = sub { $val };
69 #XXX }
70 }
71 goto &$AUTOLOAD;
72 }
73
74 require XSLoader;
75 XSLoader::load('Audio::Opusfile', $VERSION);
76 require Audio::Opusfile::Head;
77 require Audio::Opusfile::Tags;
78 require Audio::Opusfile::PictureTag;
79
80 # Preloaded methods go here.
81
82 sub new_from_file {
83 my ($class, $file) = @_;
84 open_file($file)
85 }
86
87 sub new_from_memory {
88 my ($class, $buf) = @_;
89 open_memory($buf)
90 }
91
92 1;
93 __END__
94
95 =encoding utf-8
96
97 =head1 NAME
98
99 Audio::Opusfile - partial interface to the libopusfile Ogg Opus library
100
101 =head1 SYNOPSIS
102
103 use Audio::Opusfile;
104 my $of = Audio::Opusfile->new_from_file('silence.opus');
105 my $tags = $of->tags;
106 say $tags->query('TITLE'); # Cellule
107
108 =head1 DESCRIPTION
109
110 Opus is a totally open, royalty-free, highly versatile audio codec.
111 Opus is unmatched for interactive speech and music transmission over
112 the Internet, but is also intended for storage and streaming
113 applications. It is standardized by the Internet Engineering Task
114 Force (IETF) as RFC 6716 which incorporated technology from Skype's
115 SILK codec and Xiph.Org's CELT codec.
116
117 libopusfile is a library for decoding and basic manipulation of Ogg
118 Opus files.
119
120 Audio::Opusfile is an interface to libopusfile. It exports nearly all
121 of the functions for obtaining metadata of an Opus file or buffer in
122 that library. Future versions will additionally provide functions for
123 decoding Opus data into PCM.
124
125 The API might change in future versions.
126
127 =head1 METHODS
128
129 =over
130
131 =item Audio::Opusfile->B<new_from_file>(I<$file>)
132
133 Creates a new Audio::Opusfile object from an Ogg Opus file.
134
135 Dies if the given file does not exist or is not a valid Ogg Opus file.
136
137 =item Audio::Opusfile->B<new_from_memory>(I<$buffer>)
138
139 Creates a new Audio::Opusfile object from a buffer containing Ogg Opus
140 data.
141
142 Dies if the given buffer does not contain valid data.
143
144 =item Audio::Opusfile::test(I<$buffer>)
145
146 Returns true if the given buffer looks like the beginning of a valid
147 Ogg Opus file, false otherwise.
148
149 Dies if the given buffer does not have sufficient data to tell if it
150 is an Opus stream or if it looks like a Opus stream but parsing it
151 failed.
152
153 =item $of->B<head>
154
155 Returns an L<Audio::Opusfile::Head> object corresponding to the file.
156
157 =item $of->B<tags>
158
159 Returns an L<Audio::Opusfile::Tags> object corresponding to the file.
160
161 =item $of->B<seekable>
162
163 Returns whether or not the data source being read is seekable.
164
165 =item $of->B<link_count>
166
167 Returns the number of links in this chained stream. Always returns 1
168 for unseekable sources.
169
170 =item $of->B<serialno>([I<$link_index>])
171
172 Get the serial number of the given link in a (possibly-chained) Ogg
173 Opus stream. If the given index is greater than the total number of
174 links, this returns the serial number of the last link.
175
176 If the source is not seekable, I<$link_index> is negative, or
177 I<$link_index> is not given, then this function returns the serial
178 number of the current link.
179
180 =item $of->B<raw_total>([I<$link_index>])
181
182 Get the total (compressed) size of the stream (with no arguments), or
183 of an individual link in a (possibly-chained) Ogg Opus stream (with
184 one nonnegative argument), including all headers and Ogg muxing
185 overhead.
186
187 The stream must be seekable to get the total. A negative value is
188 returned if the stream is not seekable.
189
190 B<Warning:> If the Opus stream (or link) is concurrently multiplexed
191 with other logical streams (e.g., video), this returns the size of the
192 entire stream (or link), not just the number of bytes in the first
193 logical Opus stream. Returning the latter would require scanning the
194 entire file.
195
196 =item $of->B<pcm_total>([I<$link_index>])
197
198 Get the total PCM length (number of samples at 48 kHz) of the stream
199 (with no arguments), or of an individual link in a (possibly-chained)
200 Ogg Opus stream (with one nonnegative argument).
201
202 Users looking for op_time_total() should use this function instead.
203 Because timestamps in Opus are fixed at 48 kHz, there is no need for a
204 separate function to convert this to seconds.
205
206 The stream must be seekable to get the total. A negative value is
207 returned if the stream is not seekable.
208
209 =item $of->B<current_link>
210
211 Retrieve the index of the current link.
212
213 This is the link that produced the data most recently read by
214 op_read_float() or its associated functions, or, after a seek, the
215 link that the seek target landed in. Reading more data may advance the
216 link index (even on the first read after a seek).
217
218 =item $of->B<bitrate>([I<$link_index>])
219
220 Computes the bitrate of the stream (with no arguments), or of an
221 individual link in a (possibly-chained) Ogg Opus stream (with one
222 nonnegative argument).
223
224 The stream must be seekable to compute the bitrate. A negative value
225 is returned if the stream is not seekable.
226
227 B<Warning:> If the Opus stream (or link) is concurrently multiplexed with
228 other logical streams (e.g., video), this uses the size of the entire
229 stream (or link) to compute the bitrate, not just the number of bytes
230 in the first logical Opus stream.
231
232 =item $of->B<bitrate_instant>
233
234 Compute the instantaneous bitrate, measured as the ratio of bits to
235 playable samples decoded since a) the last call to B<bitrate_instant>,
236 b) the last seek, or c) the start of playback, whichever was most
237 recent.
238
239 This will spike somewhat after a seek or at the start/end of a chain
240 boundary, as pre-skip, pre-roll, and end-trimming causes samples to be
241 decoded but not played.
242
243 =item $of->B<raw_tell>
244
245 Obtain the current value of the position indicator of I<$of>. This is
246 the byte position that is currently being read from.
247
248 =item $of->B<pcm_tell>
249
250 Obtain the PCM offset of the next sample to be read.
251
252 If the stream is not properly timestamped, this might not increment by
253 the proper amount between reads, or even return monotonically
254 increasing values.
255
256 =item $of->B<raw_seek>(I<$offset>)
257
258 Seek to a byte offset relative to the compressed data.
259
260 This also scans packets to update the PCM cursor. It will cross a
261 logical bitstream boundary, but only if it can't get any packets out
262 of the tail of the link to which it seeks.
263
264 =item $of->B<pcm_seek>(I<$offset>)
265
266 Seek to the specified PCM offset, such that decoding will begin at
267 exactly the requested position. The PCM offset is in samples at 48 kHz
268 relative to the start of the stream.
269
270 =item $of->B<set_gain_offset>(I<$gain_type>, I<$gain_offset>)
271
272 Sets the gain to be used for decoded output.
273
274 By default, the gain in the header is applied with no additional
275 offset. The total gain (including header gain and/or track gain, if
276 applicable, and this offset), will be clamped to [-32768,32767]/256
277 dB. This is more than enough to saturate or underflow 16-bit PCM.
278
279 B<Note:> The new gain will not be applied to any already buffered,
280 decoded output. This means you cannot change it sample-by-sample, as
281 at best it will be updated packet-by-packet. It is meant for setting a
282 target volume level, rather than applying smooth fades, etc.
283
284 I<$gain_type> is one of OP_HEADER_GAIN, OP_TRACK_GAIN, or
285 OP_ABSOLUTE_GAIN. I<$gain_offset> is in 1/256ths of a dB.
286
287 =item $of->B<set_dither_enabled>(I<$enabled>)
288
289 Sets whether or not dithering is enabled for 16-bit decoding.
290
291 By default, when libopusfile is compiled to use floating-point
292 internally, calling read() or read_stereo() will first decode to
293 float, and then convert to fixed-point using noise-shaping dithering.
294 This flag can be used to disable that dithering. When the application
295 uses read_float() or read_float_stereo(), or when the library has been
296 compiled to decode directly to fixed point, this flag has no effect.
297
298 =item $of->B<read>([I<$bufsize>])
299
300 It is recommended to use B<read_float> instead of this method if the
301 rest of your audio processing chain can handle floating point.
302
303 Reads more samples from the stream. I<$bufsize> is the maximum number
304 of samples read, and it defaults to 1048576. Returns a list whose
305 first element is the link index this data was decoded from, and the
306 rest of the elements are PCM samples, as signed 16-bit values at 48
307 kHz with a nominal range of [-32768,32767). Multiple channels are
308 interleaved using the L<Vorbis channel ordering|https://www.xiph.org/vorbis/doc/Vorbis_I_spec.html#x1-810004.3.9>.
309
310 You can use C<< $of->head($li)->channel_count >> to find out the
311 channel count of a given link index.
312
313 =item $of->B<read_float>([I<$bufsize>])
314
315 Like B<read>, but samples are signed floats with a nominal range of
316 [-1.0, 1.0].
317
318 =item $of->B<read_stereo>([I<$bufsize>])
319
320 Like B<read>, but downmixes the stream to stereo (therefore you will
321 always get two channels) and does NOT return the link index (the first
322 return value is the first sample).
323
324 =item $of->B<read_float_stereo>([I<$bufsize>])
325
326 Like B<read_float>, but downmixes the stream to stereo (therefore you
327 will always get two channels) and does NOT return the link index (the
328 first return value is the first sample).
329
330 =back
331
332 =head1 EXPORT
333
334 All constants are exported by default:
335
336 OPUS_CHANNEL_COUNT_MAX
337 OP_ABSOLUTE_GAIN
338 OP_DEC_FORMAT_FLOAT
339 OP_DEC_FORMAT_SHORT
340 OP_DEC_USE_DEFAULT
341 OP_EBADHEADER
342 OP_EBADLINK
343 OP_EBADPACKET
344 OP_EBADTIMESTAMP
345 OP_EFAULT
346 OP_EIMPL
347 OP_EINVAL
348 OP_ENOSEEK
349 OP_ENOTAUDIO
350 OP_ENOTFORMAT
351 OP_EOF
352 OP_EREAD
353 OP_EVERSION
354 OP_FALSE
355 OP_GET_SERVER_INFO_REQUEST
356 OP_HEADER_GAIN
357 OP_HOLE
358 OP_HTTP_PROXY_HOST_REQUEST
359 OP_HTTP_PROXY_PASS_REQUEST
360 OP_HTTP_PROXY_PORT_REQUEST
361 OP_HTTP_PROXY_USER_REQUEST
362 OP_PIC_FORMAT_GIF
363 OP_PIC_FORMAT_JPEG
364 OP_PIC_FORMAT_PNG
365 OP_PIC_FORMAT_UNKNOWN
366 OP_PIC_FORMAT_URL
367 OP_SSL_SKIP_CERTIFICATE_CHECK_REQUEST
368 OP_TRACK_GAIN
369
370
371 =head1 SEE ALSO
372
373 L<Audio::Opusfile::Head>,
374 L<Audio::Opusfile::Tags>,
375 L<http://opus-codec.org/>,
376 L<http://opus-codec.org/docs/opusfile_api-0.7/index.html>
377
378 =head1 AUTHOR
379
380 Marius Gavrilescu, E<lt>marius@ieval.roE<gt>
381
382 =head1 COPYRIGHT AND LICENSE
383
384 Copyright (C) 2016-2017 by Marius Gavrilescu
385
386 This library is free software; you can redistribute it and/or modify
387 it under the same terms as Perl itself, either Perl version 5.24.0 or,
388 at your option, any later version of Perl 5 you may have available.
389
390
391 =cut
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