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Revision: 1.8
Committed: Mon Mar 20 11:12:40 2023 UTC (13 months, 4 weeks ago) by root
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# Content
1 =head1 NAME
2
3 AnyEvent::MPV - remote control mpv (https://mpv.io)
4
5 =head1 SYNOPSIS
6
7 use AnyEvent::MPV;
8
9 =head1 DESCRIPTION
10
11 This module allows you to remote control F<mpv> (a video player). It also
12 is an L<AnyEvent> user, you need to make sure that you use and run a
13 supported event loop.
14
15 There are other modules doing this, and I haven't looked much at them
16 other than to decide that they don't handle encodings correctly, and since
17 none of them use AnyEvent, I wrote my own. When in doubt, have a look at
18 them, too.
19
20 Knowledge of the L<mpv command
21 interface|https://mpv.io/manual/stable/#command-interface> is required to
22 use this module.
23
24 Features of this module are:
25
26 =over
27
28 =item uses AnyEvent, so integrates well into most event-based programs
29
30 =item supports asynchronous and synchronous operation
31
32 =item allows you to properly pass binary filenames
33
34 =item accepts data encoded in any way (does not crash when mpv replies with non UTF-8 data)
35
36 =item features a simple keybind/event system
37
38 =back
39
40 =head2 OVERVIEW OF OPERATION
41
42 This module forks an F<mpv> process and uses F<--input-ipc-client> (or
43 equivalent) to create a bidirectional communication channel between it and
44 the F<mpv> process.
45
46 It then speaks the somewhat JSON-looking (but not really being JSON)
47 protocol that F<mpv> implements to both send it commands, decode and
48 handle replies, and handle asynchronous events.
49
50 Here is a very simple client:
51
52 use AnyEvent;
53 use AnyEvent::MPV;
54
55 my $videofile = "./xyzzy.mp4";
56
57 my $mpv = AnyEvent::MPV->new (trace => 1);
58
59 $mpv->start ("--", $videofile);
60
61 my $timer = AE::timer 2, 0, my $quit = AE::cv;
62 $quit->recv;
63
64 This starts F<mpv> with the two arguments C<--> and C<$videofile>, which
65 it should load and play. It then waits two seconds by starting a timer and
66 quits. The C<trace> argument to the constructor makes F<mpv> more verbose
67 and also prints the commands and responses, so you can have an idea what
68 is going on.
69
70 In my case, the above example would output something like this:
71
72 [uosc] Disabled because original osc is enabled!
73 mpv> {"event":"start-file","playlist_entry_id":1}
74 mpv> {"event":"tracks-changed"}
75 (+) Video --vid=1 (*) (h264 480x480 30.000fps)
76 mpv> {"event":"metadata-update"}
77 mpv> {"event":"file-loaded"}
78 Using hardware decoding (nvdec).
79 mpv> {"event":"video-reconfig"}
80 VO: [gpu] 480x480 cuda[nv12]
81 mpv> {"event":"video-reconfig"}
82 mpv> {"event":"playback-restart"}
83
84 This is not usually very useful (you could just run F<mpv> as a simple
85 shell command), so let us load the file at runtime:
86
87 use AnyEvent;
88 use AnyEvent::MPV;
89
90 my $videofile = "./xyzzy.mp4";
91
92 my $mpv = AnyEvent::MPV->new (
93 trace => 1,
94 args => ["--pause", "--idle=yes"],
95 );
96
97 $mpv->start;
98 $mpv->cmd_recv (loadfile => $mpv->escape_binary ($videofile));
99 $mpv->cmd ("set", "pause", "no");
100
101 my $timer = AE::timer 2, 0, my $quit = AE::cv;
102 $quit->recv;
103
104 This specifies extra arguments in the constructor - these arguments are
105 used every time you C<< ->start >> F<mpv>, while the arguments to C<<
106 ->start >> are only used for this specific clal to0 C<start>. The argument
107 F<--pause> keeps F<mpv> in pause mode (i.e. it does not play the file
108 after loading it), and C<--idle=yes> tells F<mpv> to not quit when it does
109 not have a playlist - as no files are specified on the command line.
110
111 To load a file, we then send it a C<loadfile> command, which accepts, as
112 first argument, the URL or path to a video file. To make sure F<mpv> does
113 not misinterpret the path as a URL, it was prefixed with F<./> (similarly
114 to "protecting" paths in perls C<open>).
115
116 Since commands send I<to> F<mpv> are send in UTF-8, we need to escape the
117 filename (which might be in any encoding) using the C<esscape_binary>
118 method - this is not needed if your filenames are just ascii, or magically
119 get interpreted correctly, but if you accept arbitrary filenamews (e.g.
120 from the user), you need to do this.
121
122 The C<cmd_recv> method then queues the command, waits for a reply and
123 returns the reply data (or croaks on error). F<mpv> would, at this point,
124 load the file and, if everything was successful, show the first frame and
125 pause. Note that, since F<mpv> is implement rather synchronously itself,
126 do not expect commands to fail in many circumstances - for example, fit
127 he file does not exit, you will likely get an event, but the C<loadfile>
128 command itself will run successfully.
129
130 To unpause, we send another command, C<set>, to set the C<pause> property
131 to C<no>, this time using the C<cmd> method, which queues the command, but
132 instead of waiting for a reply, it immediately returns a condvar that cna
133 be used to receive results.
134
135 This should then cause F<mpv> to start playing the video.
136
137 It then again waits two seconds and quits.
138
139 Now, just waiting two seconds is rather, eh, unuseful, so let's look at
140 receiving events (using a somewhat embellished example):
141
142 use AnyEvent;
143 use AnyEvent::MPV;
144
145 my $videofile = "xyzzy.mp4";
146
147 my $quit = AE::cv;
148
149 my $mpv = AnyEvent::MPV->new (
150 trace => 1,
151 args => ["--pause", "--idle=yes"],
152 on_event => sub {
153 my ($mpv, $event, $data) = @_;
154
155 if ($event eq "start-file") {
156 $mpv->cmd ("set", "pause", "no");
157 } elsif ($event eq "end-file") {
158 print "end-file<$data->{reason}>\n";
159 $quit->send;
160 }
161 },
162 );
163
164 $mpv->start;
165 $mpv->cmd (loadfile => $mpv->escape_binary ($videofile));
166
167 $quit->recv;
168
169 This example uses a global condvar C<$quit> to wait for the file to finish
170 playing. Also, most of the logic is now in an C<on_event> callback, which
171 receives an event name and the actual event object.
172
173 The two events we handle are C<start-file>, which is emitted by F<mpv>
174 once it has loaded a new file, and C<end-file>, which signals the end
175 of a file.
176
177 In the former event, we again set the C<pause> property to C<no> so the
178 movie starts playing. For the latter event, we tell the main program to
179 quit by invoking C<$quit>.
180
181 This should conclude the basics of operation. There are a few more
182 examples later in the documentation.
183
184 =head2 ENCODING CONVENTIONS
185
186 As a rule of thumb, all data you pass to this module to be sent to F<mpv>
187 is expected to be in unicode. To pass something that isn't, you need to
188 escape it using C<escape_binary>.
189
190 Data received from C<$mpv>, however, is I<not> decoded to unicode, as data
191 returned by F<mpv> is not generally encoded in unicode, and the encoding
192 is usually unspecified. So if you receive data and expect it to be in
193 unicode, you need to first decode it from UTF-8, but note that this might
194 fail. This is not a limitation of this module - F<mpv> simply does not
195 specify nor guarantee a specific encoding, or any encoding at all, in its
196 protocol.
197
198 =head2 METHODS
199
200 =over
201
202 =cut
203
204 package AnyEvent::MPV;
205
206 use common::sense;
207
208 use Fcntl ();
209 use Scalar::Util ();
210
211 use AnyEvent ();
212 use AnyEvent::Util ();
213
214 our $JSON = eval { require JSON::XS; JSON::XS:: }
215 || do { require JSON::PP; JSON::PP:: };
216
217 our $JSON_CODER =
218
219 our $VERSION = '0.1';
220
221 our $mpv_path; # last mpv path used
222 our $mpv_optionlist; # output of mpv --list-options
223
224 =item $mpv = AnyEvent::MPV->new (key => value...)
225
226 Creates a new C<mpv> object, but does not yet do anything. The support key-value pairs are:
227
228 =over
229
230 =item mpv => $path
231
232 The path to the F<mpv> binary to use - by default, C<mpv> is used and
233 therefore, uses your C<PATH> to find it.
234
235 =item args => [...]
236
237 Arguments to pass to F<mpv>. These arguments are passed after the
238 hardcoded arguments used by this module, but before the arguments passed
239 ot C<start>. It does not matter whether you specify your arguments using
240 this key, or in the C<start> call, but when you invoke F<mpv> multiple
241 times, typically the arguments used for all invocations go here, while
242 arguments used for specific invocations (e..g filenames) are passed to
243 C<start>.
244
245 =item trace => false|true|coderef
246
247 Enables tracing if true. In trace mode, output from F<mpv> is printed to
248 standard error using a C<< mpv> >> prefix, and commands sent to F<mpv>
249 are printed with a C<< >mpv >> prefix.
250
251 If a code reference is passed, then instead of printing to standard
252 errort, this coderef is invoked with a first arfgument being either
253 C<< mpv> >> or C<< >mpv >>, and the second argument being a string to
254 display. The default implementation simply does this:
255
256 sub {
257 warn "$_[0] $_[1]\n";
258 }
259
260 =item on_eof => $coderef->($mpv)
261
262 =item on_event => $coderef->($mpv, $event, $data)
263
264 =item on_key => $coderef->($mpv, $string)
265
266 These are invoked by the default method implementation of the same name -
267 see below.
268
269 =back
270
271 =cut
272
273 sub new {
274 my ($class, %kv) = @_;
275
276 bless {
277 mpv => "mpv",
278 args => [],
279 %kv,
280 }, $class
281 }
282
283 =item $string = $mpv->escape_binary ($string)
284
285 This module excects all command data sent to F<mpv> to be in unicode. Some
286 things are not, such as filenames. To pass binary data such as filenames
287 through a comamnd, you need to escape it using this method.
288
289 The simplest example is a C<loadfile> command:
290
291 $mpv->cmd_recv (loadfile => $mpv->escape_binary ($path));
292
293 =cut
294
295 # can be used to escape filenames
296 sub escape_binary {
297 shift;
298 local $_ = shift;
299 # we escape every "illegal" octet using U+10e5df HEX. this is later undone in cmd
300 s/([\x00-\x1f\x80-\xff])/sprintf "\x{10e5df}%02x", ord $1/ge;
301 $_
302 }
303
304 =item $started = $mpv->start (argument...)
305
306 Starts F<mpv>, passing the given arguemnts as extra arguments to
307 F<mpv>. If F<mpv> is already running, it returns false, otherwise it
308 returns a true value, so you can easily start F<mpv> on demand by calling
309 C<start> just before using it, and if it is already running, it will not
310 be started again.
311
312 The arguments passwd to F<mpv> are a set of hardcoded built-in arguments,
313 followed by the arguments specified in the constructor, followed by the
314 arguments passwd to this method. The built-in arguments currently are
315 F<--no-input-terminal>, F<--really-quiet> (or F<--quiet> in C<trace>
316 mode), and C<--input-ipc-client> (or equivalent).
317
318 Some commonly used and/or even useful arguments you might want to pass are:
319
320 =over
321
322 =item F<--idle=yes> or F<--idle=once> to keep F<mpv> from quitting when you
323 don't specify a file to play.
324
325 =item F<--pause>, to keep F<mpv> from instantly starting to play a file, in case you want to
326 inspect/change properties first.
327
328 =item F<--force-window=no> (or similar), to keep F<mpv> from instantly opening a window, or to force it to do so.
329
330 =item F<--audio-client-name=yourappname>, to make sure audio streams are associated witht eh right program.
331
332 =item F<--wid=id>, to embed F<mpv> into another application.
333
334 =item F<--no-terminal>, F<--no-input-default-bindings>, F<--no-input-cursor>, F<--input-conf=/dev/null>, F<--input-vo-keyboard=no> - to ensure only you control input.
335
336 =back
337
338 The return value can be used to decide whether F<mpv> needs initializing:
339
340 if ($mpv->start) {
341 $mpv->bind_key (...);
342 $mpv->cmd (set => property => value);
343 ...
344 }
345
346 You can immediately starting sending commands when this method returns,
347 even if F<mpv> has not yet started.
348
349 =cut
350
351 sub start {
352 my ($self, @extra_args) = @_;
353
354 return 0 if $self->{fh};
355
356 # cache optionlist for same "path"
357 ($mpv_path, $mpv_optionlist) = ($self->{mpv}, scalar qx{\Q$self->{mpv}\E --list-options})
358 if $self->{mpv} ne $mpv_path;
359
360 my $options = $mpv_optionlist;
361
362 my ($fh, $slave) = AnyEvent::Util::portable_socketpair
363 or die "socketpair: $!\n";
364
365 AnyEvent::Util::fh_nonblocking $fh, 1;
366
367 $self->{pid} = fork;
368
369 if ($self->{pid} eq 0) {
370 AnyEvent::Util::fh_nonblocking $slave, 0;
371 fcntl $slave, Fcntl::F_SETFD, 0;
372
373 my $input_file = $options =~ /\s--input-ipc-client\s/ ? "input-ipc-client" : "input-file";
374
375 exec $self->{mpv},
376 qw(--no-input-terminal),
377 ($self->{trace} ? "--quiet" : "--really-quiet"),
378 "--$input_file=fd://" . (fileno $slave),
379 @{ $self->{args} },
380 @extra_args;
381 exit 1;
382 }
383
384 $self->{fh} = $fh;
385
386 my $trace = delete $self->{trace} || sub { };
387
388 $trace = sub { warn "$_[0] $_[1]\n" } if $trace && !ref $trace;
389
390 my $buf;
391
392 Scalar::Util::weaken $self;
393
394 $self->{rw} = AE::io $fh, 0, sub {
395 if (sysread $fh, $buf, 8192, length $buf) {
396 while ($buf =~ s/^([^\n]+)\n//) {
397 $trace->("mpv>" => "$1");
398
399 if ("{" eq substr $1, 0, 1) {
400 eval {
401 my $reply = $JSON->new->latin1->decode ($1);
402
403 if (exists $reply->{event}) {
404 if (
405 $reply->{event} eq "client-message"
406 and $reply->{args}[0] eq "AnyEvent::MPV"
407 ) {
408 if ($reply->{args}[1] eq "key") {
409 (my $key = $reply->{args}[2]) =~ s/\\x(..)/chr hex $1/ge;
410 $self->on_key ($key);
411 }
412 } else {
413 $self->on_event (delete $reply->{event}, $reply);
414 }
415 } elsif (exists $reply->{request_id}) {
416 my $cv = delete $self->{cmd_cv}{$reply->{request_id}};
417
418 unless ($cv) {
419 warn "no cv found for request id <$reply->{request_id}>\n";
420 next;
421 }
422
423 if (exists $reply->{data}) {
424 $cv->send ($reply->{data});
425 } elsif ($reply->{error} eq "success") { # success means error... eh.. no...
426 $cv->send;
427 } else {
428 $cv->croak ($reply->{error});
429 }
430
431 } else {
432 warn "unexpected reply from mpv, pleasew report: <$1>\n";
433 }
434 };
435 warn $@ if $@;
436 } else {
437 $trace->("mpv>" => "$1");
438 }
439 }
440 } else {
441 $self->stop;
442 $self->on_eof;
443 }
444 };
445
446 my $wbuf;
447 my $reqid;
448
449 $self->{_cmd} = sub {
450 my $cv = AE::cv;
451
452 $self->{cmd_cv}{++$reqid} = $cv;
453
454 my $cmd = $JSON->new->utf8->encode ({ command => ref $_[0] ? $_[0] : \@_, request_id => $reqid*1 });
455
456 # (un-)apply escape_binary hack
457 $cmd =~ s/\xf4\x8e\x97\x9f(..)/sprintf sprintf "\\x%02x", hex $1/ges; # f48e979f == 10e5df in utf-8
458
459 $wbuf .= "$cmd\n";
460
461 $trace->(">mpv" => "$_[0]");
462
463 $self->{ww} ||= AE::io $fh, 1, sub {
464 my $len = syswrite $fh, $wbuf;
465 substr $wbuf, 0, $len, "";
466 undef $self->{ww} unless length $wbuf;
467 };
468
469 $cv
470 };
471
472 1
473 }
474
475 sub DESTROY {
476 $_[0]->stop;
477 }
478
479 =item $mpv->stop
480
481 Ensures that F<mpv> is being stopped, by killing F<mpv> with a C<TERM>
482 signal if needed. After this, you can C<< ->start >> a new instance again.
483
484 =cut
485
486 sub stop {
487 my ($self) = @_;
488
489 delete $self->{rw};
490 delete $self->{ww};
491
492 if ($self->{pid}) {
493
494 close delete $self->{fh}; # current mpv versions should cleanup on their own on close
495
496 kill TERM => $self->{pid};
497
498 }
499
500 delete $self->{pid};
501 delete $self->{cmd_cv};
502 delete $self->{obsid};
503 delete $self->{wbuf};
504 }
505
506 =item $mpv->on_eof
507
508 This method is called when F<mpv> quits - usually unexpectedly. The
509 default implementation will call the C<on_eof> code reference specified in
510 the constructor, or do nothing if none was given.
511
512 For subclassing, see I<SUBCLASSING>, below.
513
514 =cut
515
516 sub on_eof {
517 my ($self) = @_;
518
519 $self->{on_eof}($self) if $self->{on_eof};
520 }
521
522 =item $mpv->on_event ($event, $data)
523
524 This method is called when F<mpv> sends an asynchronous event. The default
525 implementation will call the C<on_event> code reference specified in the
526 constructor, or do nothing if none was given.
527
528 The first/implicit argument is the C<$mpv> object, the second is the
529 event name (same as C<< $data->{event} >>, purely for convenience), and
530 the third argument is the event object as sent by F<mpv> (sans C<event>
531 key). See L<List of events|https://mpv.io/manual/stable/#list-of-events>
532 in its documentation.
533
534 For subclassing, see I<SUBCLASSING>, below.
535
536 =cut
537
538 sub on_event {
539 my ($self, $key) = @_;
540
541 $self->{on_event}($self, $key) if $self->{on_event};
542 }
543
544 =item $mpv->on_key ($string)
545
546 Invoked when a key declared by C<< ->bind_key >> is pressed. The default
547 invokes the C<on_key> code reference specified in the constructor with the
548 C<$mpv> object and the key name as arguments, or do nothing if none was
549 given.
550
551 For more details and examples, see the C<bind_key> method.
552
553 For subclassing, see I<SUBCLASSING>, below.
554
555 =cut
556
557 sub on_key {
558 my ($self, $key) = @_;
559
560 $self->{on_key}($self, $key) if $self->{on_key};
561 }
562
563 =item $mpv->cmd ($command => $arg, $arg...)
564
565 Queues a command to be sent to F<mpv>, using the given arguments, and
566 immediately return a condvar.
567
568 See L<the mpv
569 documentation|https://mpv.io/manual/stable/#list-of-input-commands> for
570 details on individual commands.
571
572 The condvar can be ignored:
573
574 $mpv->cmd (set_property => "deinterlace", "yes");
575
576 Or it can be used to synchronously wait for the command results:
577
578 $cv = $mpv->cmd (get_property => "video-format");
579 $format = $cv->recv;
580
581 # or simpler:
582
583 $format = $mpv->cmd (get_property => "video-format")->recv;
584
585 # or even simpler:
586
587 $format = $mpv->cmd_recv (get_property => "video-format");
588
589 Or you can set a callback:
590
591 $cv = $mpv->cmd (get_property => "video-format");
592 $cv->cb (sub {
593 my $format = $_[0]->recv;
594 });
595
596 On error, the condvar will croak when C<recv> is called.
597
598 =cut
599
600 sub cmd {
601 my $self = shift;
602
603 $self->{_cmd}->(@_)
604 }
605
606 =item $result = $mpv->cmd_recv ($command => $arg, $arg...)
607
608 The same as calling C<cmd> and immediately C<recv> on its return
609 value. Useful when you don't want to mess with F<mpv> asynchronously or
610 simply needs to have the result:
611
612 $mpv->cmd_recv ("stop");
613 $position = $mpv->cmd_recv ("get_property", "playback-time");
614
615 =cut
616
617 sub cmd_recv {
618 &cmd->recv
619 }
620
621 =item $mpv->bind_key ($INPUT => $string)
622
623 This is an extension implement by this module to make it easy to get key events. The way this is implemented
624 is to bind a C<client-message> witha first argument of C<AnyEvent::MPV> and the C<$string> you passed. This C<$string> is then
625 passed ot the C<on_key> handle when the key is proessed, e.g.:
626
627 my $mpv = AnyEvent::MPV->new (
628 on_key => sub {
629 my ($mpv, $key) = @_;
630
631 if ($key eq "letmeout") {
632 print "user pressed escape\n";
633 }
634 },
635 );
636
637 $mpv_>bind_key (ESC => "letmeout");
638
639 The key configuration is lost when F<mpv> is stopped and must be (re-)done
640 after every C<start>.
641
642 =cut
643
644 sub bind_key {
645 my ($self, $key, $event) = @_;
646
647 $event =~ s/([^A-Za-z0-9\-_])/sprintf "\\x%02x", ord $1/ge;
648 $self->cmd (keybind => $key => "no-osd script-message AnyEvent::MPV key $event");
649 }
650
651 =back
652
653 =head2 SUBCLASSING
654
655 Like most perl objects, C<AnyEvent::MPV> objects are implemented as
656 hashes, with the constructor simply storing all passed key-value pairs in
657 the object. If you want to subclass to provide your own C<on_*> methods,
658 be my guest and rummage around in the internals as much as you wish - the
659 only guarantee that this module dcoes is that it will not use keys with
660 double colons in the name, so youc an use those, or chose to simply not
661 care and deal with the breakage.
662
663 If you don't want to go to the effort of subclassing this module, you can
664 also specify all event handlers as constructor keys.
665
666 =head1 SEE ALSO
667
668 L<AnyEvent>, L<the mpv command documentation|https://mpv.io/manual/stable/#command-interface>.
669
670 =head1 AUTHOR
671
672 Marc Lehmann <schmorp@schmorp.de>
673 http://home.schmorp.de/
674
675 =cut
676
677 1
678