1 package Audio
::Opusfile
;
8 use parent qw
/Exporter/;
12 qw
/OPUS_CHANNEL_COUNT_MAX
31 OP_GET_SERVER_INFO_REQUEST
34 OP_HTTP_PROXY_HOST_REQUEST
35 OP_HTTP_PROXY_PASS_REQUEST
36 OP_HTTP_PROXY_PORT_REQUEST
37 OP_HTTP_PROXY_USER_REQUEST
43 OP_SSL_SKIP_CERTIFICATE_CHECK_REQUEST
46 our @EXPORT_OK = @constants;
47 our @EXPORT = @constants;
49 our $VERSION = '0.005';
52 # This AUTOLOAD is used to 'autoload' constants from the constant()
57 ($constname = $AUTOLOAD) =~ s/.*:://;
58 croak
"&Audio::Opusfile::constant not defined" if $constname eq 'constant';
59 my ($error, $val) = constant
($constname);
60 if ($error) { croak
$error; }
63 # Fixed between 5.005_53 and 5.005_61
64 #XXX if ($] >= 5.00561) {
65 #XXX *$AUTOLOAD = sub () { $val };
68 *$AUTOLOAD = sub { $val };
75 XSLoader
::load
('Audio::Opusfile', $VERSION);
76 require Audio
::Opusfile
::Head
;
77 require Audio
::Opusfile
::Tags
;
78 require Audio
::Opusfile
::PictureTag
;
80 # Preloaded methods go here.
83 my ($class, $file) = @_;
88 my ($class, $buf) = @_;
99 Audio::Opusfile - partial interface to the libopusfile Ogg Opus library
104 my $of = Audio::Opusfile->new_from_file('silence.opus');
105 my $tags = $of->tags;
106 say $tags->query('TITLE'); # Cellule
110 Opus is a totally open, royalty-free, highly versatile audio codec.
111 Opus is unmatched for interactive speech and music transmission over
112 the Internet, but is also intended for storage and streaming
113 applications. It is standardized by the Internet Engineering Task
114 Force (IETF) as RFC 6716 which incorporated technology from Skype's
115 SILK codec and Xiph.Org's CELT codec.
117 libopusfile is a library for decoding and basic manipulation of Ogg
120 Audio::Opusfile is an interface to libopusfile. It exports nearly all
121 of the functions for obtaining metadata of an Opus file or buffer in
122 that library. Future versions will additionally provide functions for
123 decoding Opus data into PCM.
125 The API might change in future versions.
131 =item Audio::Opusfile->B<new_from_file>(I<$file>)
133 Creates a new Audio::Opusfile object from an Ogg Opus file.
135 Dies if the given file does not exist or is not a valid Ogg Opus file.
137 =item Audio::Opusfile->B<new_from_memory>(I<$buffer>)
139 Creates a new Audio::Opusfile object from a buffer containing Ogg Opus
142 Dies if the given buffer does not contain valid data.
144 =item Audio::Opusfile::test(I<$buffer>)
146 Returns true if the given buffer looks like the beginning of a valid
147 Ogg Opus file, false otherwise.
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
155 Returns an L<Audio::Opusfile::Head> object corresponding to the file.
159 Returns an L<Audio::Opusfile::Tags> object corresponding to the file.
161 =item $of->B<seekable>
163 Returns whether or not the data source being read is seekable.
165 =item $of->B<link_count>
167 Returns the number of links in this chained stream. Always returns 1
168 for unseekable sources.
170 =item $of->B<serialno>([I<$link_index>])
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.
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.
180 =item $of->B<raw_total>([I<$link_index>])
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
187 The stream must be seekable to get the total. A negative value is
188 returned if the stream is not seekable.
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
196 =item $of->B<pcm_total>([I<$link_index>])
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).
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.
206 The stream must be seekable to get the total. A negative value is
207 returned if the stream is not seekable.
209 =item $of->B<bitrate>([I<$link_index>])
211 Computes the bitrate of the stream (with no arguments), or of an
212 individual link in a (possibly-chained) Ogg Opus stream (with one
213 nonnegative argument).
215 The stream must be seekable to compute the bitrate. A negative value
216 is returned if the stream is not seekable.
218 B<Warning:> If the Opus stream (or link) is concurrently multiplexed with
219 other logical streams (e.g., video), this uses the size of the entire
220 stream (or link) to compute the bitrate, not just the number of bytes
221 in the first logical Opus stream.
223 =item $of->B<bitrate_instant>
225 Compute the instantaneous bitrate, measured as the ratio of bits to
226 playable samples decoded since a) the last call to B<bitrate_instant>,
227 b) the last seek, or c) the start of playback, whichever was most
230 This will spike somewhat after a seek or at the start/end of a chain
231 boundary, as pre-skip, pre-roll, and end-trimming causes samples to be
232 decoded but not played.
234 =item $of->B<raw_tell>
236 Obtain the current value of the position indicator of I<$of>. This is
237 the byte position that is currently being read from.
239 =item $of->B<pcm_tell>
241 Obtain the PCM offset of the next sample to be read.
243 If the stream is not properly timestamped, this might not increment by
244 the proper amount between reads, or even return monotonically
247 =item $of->B<raw_seek>(I<$offset>)
249 Seek to a byte offset relative to the compressed data.
251 This also scans packets to update the PCM cursor. It will cross a
252 logical bitstream boundary, but only if it can't get any packets out
253 of the tail of the link to which it seeks.
255 =item $of->B<pcm_seek>(I<$offset>)
257 Seek to the specified PCM offset, such that decoding will begin at
258 exactly the requested position. The PCM offset is in samples at 48 kHz
259 relative to the start of the stream.
261 =item $of->B<set_gain_offset>(I<$gain_type>, I<$gain_offset>)
263 Sets the gain to be used for decoded output.
265 By default, the gain in the header is applied with no additional
266 offset. The total gain (including header gain and/or track gain, if
267 applicable, and this offset), will be clamped to [-32768,32767]/256
268 dB. This is more than enough to saturate or underflow 16-bit PCM.
270 B<Note:> The new gain will not be applied to any already buffered,
271 decoded output. This means you cannot change it sample-by-sample, as
272 at best it will be updated packet-by-packet. It is meant for setting a
273 target volume level, rather than applying smooth fades, etc.
275 I<$gain_type> is one of OP_HEADER_GAIN, OP_TRACK_GAIN, or
276 OP_ABSOLUTE_GAIN. I<$gain_offset> is in 1/256ths of a dB.
278 =item $of->B<set_dither_enabled>(I<$enabled>)
280 Sets whether or not dithering is enabled for 16-bit decoding.
282 By default, when libopusfile is compiled to use floating-point
283 internally, calling read() or read_stereo() will first decode to
284 float, and then convert to fixed-point using noise-shaping dithering.
285 This flag can be used to disable that dithering. When the application
286 uses read_float() or read_float_stereo(), or when the library has been
287 compiled to decode directly to fixed point, this flag has no effect.
289 =item $of->B<read>([I<$bufsize>])
291 It is recommended to use B<read_float> instead of this method if the
292 rest of your audio processing chain can handle floating point.
294 Reads more samples from the stream. I<$bufsize> is the maximum number
295 of samples read, and it defaults to 1048576. Returns a list whose
296 first element is the link index this data was decoded from, and the
297 rest of the elements are PCM samples, as signed 16-bit values at 48
298 kHz with a nominal range of [-32768,32767). Multiple channels are
299 interleaved using the L<Vorbis channel ordering|https://www.xiph.org/vorbis/doc/Vorbis_I_spec.html#x1-810004.3.9>.
301 You can use C<< $of->head($li)->channel_count >> to find out the
302 channel count of a given link index.
304 =item $of->B<read_float>([I<$bufsize>])
306 Like B<read>, but samples are signed floats with a nominal range of
309 =item $of->B<read_stereo>([I<$bufsize>])
311 Like B<read>, but downmixes the stream to stereo (therefore you will
312 always get two channels) and does NOT return the link index (the first
313 return value is the first sample).
315 =item $of->B<read_float_stereo>([I<$bufsize>])
317 Like B<read_float>, but downmixes the stream to stereo (therefore you
318 will always get two channels) and does NOT return the link index (the
319 first return value is the first sample).
325 All constants are exported by default:
327 OPUS_CHANNEL_COUNT_MAX
346 OP_GET_SERVER_INFO_REQUEST
349 OP_HTTP_PROXY_HOST_REQUEST
350 OP_HTTP_PROXY_PASS_REQUEST
351 OP_HTTP_PROXY_PORT_REQUEST
352 OP_HTTP_PROXY_USER_REQUEST
356 OP_PIC_FORMAT_UNKNOWN
358 OP_SSL_SKIP_CERTIFICATE_CHECK_REQUEST
364 L<Audio::Opusfile::Head>,
365 L<Audio::Opusfile::Tags>,
366 L<http://opus-codec.org/>,
367 L<http://opus-codec.org/docs/opusfile_api-0.7/index.html>
371 Marius Gavrilescu, E<lt>marius@ieval.roE<gt>
373 =head1 COPYRIGHT AND LICENSE
375 Copyright (C) 2016 by Marius Gavrilescu
377 This library is free software; you can redistribute it and/or modify
378 it under the same terms as Perl itself, either Perl version 5.24.0 or,
379 at your option, any later version of Perl 5 you may have available.