Coverart mode has the same issue as no-video mode, except that the video
chain is fully active. It shows only 1 frame at the start, which would
normally mean that only the subtitle at timestamp 0 is shown. Use the
no-video subtitle rendering mode in this case instead.
(This still doesn't handle subtitle display when playing cover-art
without audio, or playing a single image. This is because there's
nothing that will advance playback_pts.)
This code would just keep it busy while e.g. being paused. Even if it's
not paused, it couldn't help with anything since we obviously still lock
display to the externally updated PTS.
If a VO is created, but no video is playing (i.e. --force-window is
used), then until now no subtitles were shown. This is because VO
subtitle display normally depends on video frame timing. If there are no
video frames, there can be no subtitles.
Change this and add some code to handle this situation specifically. Set
a subtitle PTS manually and request VO redrawing manually, which gets
the subtitles rendered somehow.
This is kind of shaky. The subtitles are essentially sampled at
arbitrary times (such as when new audio data is decoded and pushed to
the AO, or on user interaction). To make a it slightly more consistent,
force a completely arbitrary minimum FPS of 10.
Other solutions (such as creating fake video) would be more intrusive or
would require VO-level API changes.
Fixes#3684.
When switching a subtitle track, the subtitle wasn't necessarily
updated, especially when playback was paused.
Some awfully subtle and complex interactions here.
First off (and not so subtle), the subtitle decoder will read packets
only on explicit update_subtitles() calls, which, if video is active, is
called only when a new video frame is shown. (A simply video frame
redraw doesn't trigger this.) So call it explicitly. But only if
playback is "initialized", i.e. not when it does initial track selection
and decoder init, during which no packets should be read.
The second issue is that the demuxer thread simply will not read new
packets just because a track was switched, especially if playback is
paused. That's fine, but if a refresh seek is to be done, it really
should do this. So if there's either 1. a refresh seek requested, or 2.
a refresh seek ongoing, then read more packets.
Note that it's entirely possible that we overflow the packet queue with
this in unpredicated weird corner cases, but the queue limit will still
be enforced, so this shouldn't make the situation worse.
No need to have them everywhere. The only exception/annoyance is
MAX_OSD_PARTS, which is now basically duplicated (and at runtime
initialization is checked with an assert()).
Subtitles can be preloaded, which means they're fully read and copied
into ASS_Track. This in turn is mainly for the sake of being able to do
subtitle seeking (when it comes down to it, subtitle seeking is the
cause for most trouble here).
Commit a714f8e92 broke preloaded subtitles which have events with
unknown duration, such as some MicroDVD samples. The event list gets
cleared on every seek, so the property of being preloaded obviously gets
lost.
Fix this by moving most of the preloading logic to dec_sub.c. If the
subtitle list gets cleared, they are not considered preloaded anymore,
and the logic for demuxed subtitles is used.
As another minor thing, preloadeding subtitles did neither disable the
demux stream, nor did it discard packets. Thus you could get queue
overflows in theory (harmless, but annoying). Fix this by explicitly
discarding packets in preloaded mode.
In summary, now the only difference between preloaded and normal
demuxing are:
1. a seek is issued, and all packets are read on start
2. during playback, discard the packets instead of feeding them to the
subtitle decoder
This is still petty annoying. It would be nice if maintaining the
subtitle index (and maybe a subtitle packet cache for instant subtitle
presentation when seeking back) could be maintained in the demuxer
instead. Half of all file formats with interleaved subtitles have
this anyway (mp4, mkv muxed with newer mkvmerge).
Commit 8d4a179c made subtitle decoders pick up fonts strictly from the
same source file (i.e. the same demuxer).
It breaks some fucked up use-case, and 2 people on this earth complained
about the change because of this. Add it back.
This copies all attached fonts on each subtitle init. I considered
converting attachments to use refcounting, but it'd probably be much
more complex.
Since it's slightly harder to get a list of active demuxers with
duplicate removed, the prev_demuxer variable serves as a hack to achieve
almost the same thing, except in weird corner cases. (In which fonts
could be added twice.)
Ever since a change in mplayer2 or so, relative seeks were translated to
absolute seeks before sending them to the demuxer in most cases. The
only exception in current mpv is DVD seeking.
Remove the SEEK_ABSOLUTE flag; it's not the implied default. SEEK_FACTOR
is kept, because it's sometimes slightly useful for seeking in things
like transport streams. (And maybe mkv files without duration set?)
DVD seeking is terrible because DVD and libdvdnav are terrible, but
mostly because libdvdnav is terrible. libdvdnav does not expose seeking
with seek tables. (Although I know xbmc/kodi use an undocumented API
that is not declared in the headers by dladdr()ing it - I think the
function is dvdnav_jump_to_sector_by_time().) With the current mpv
policy if not giving a shit about DVD, just revert our half-working seek
hacks and always use dvdnav_time_search(). Relative seeking might get
stuck sometimes; in this case --hr-seek=always is recommended.
Most text subtitles are read completely on loading (libavformat works
this way, and there are good reasons to do it on the higher levels too).
This leads to some messy problems. For example, the subtitle path is the
only one which might read packets during decoder initialization. This is
not neccessary; get rid of it.
This fixes a potential problem of seeking to position 0 for image
subtitles on init, and if the start position is not at the beginning of
the timeline.
Eventually we want the VO be driven by a A->V filter, so a decoder
doesn't even have to exist. Some features definitely require a decoder
though (like reporting the decoder in use, hardware decoding, etc.), so
for each thing which accessed d_video, it has to be redecided if and how
it can access decoder state.
At least the "framedrop" property slightly changes semantics: you can
now always set this property, even if no video is active.
Some untested changes in this commit, but our bio-based distributed
test suite has to take care of this.
Lots of noise to remove the vfilter/vo fields from dec_video.
From now on, video filtering and output will still be done together,
summarized under struct vo_chain.
There is the question where exactly the vf_chain should go in such a
decoupled architecture. The end goal is being able to place a "complex"
filter between video decoders and output (which will culminate in
natural integration of A->V filters for natural integration of
libavfilter audio visualizations). The vf_chain is still useful for
"final" processing, such as format conversions and deinterlacing. Also,
there's only 1 VO and 1 --vf option. So having 1 vf_chain for a VO seems
ideal, since otherwise there would be no natural way to handle all these
existing options and mechanisms.
There is still some work required to truly decouple decoding.
Instead of handling this on filter chain reinit, do it directly after
the decoder. This makes the code less entangled. In particular, this
gets rid of the really weird "override params" concept in the video
filter code.
The last_format/fixed_formats have some redundance with decoder_output,
but unfortunately the latter has a slightly different use.
This is mainly a refactor. I'm hoping it will make some things easier
in the future due to cleanly separating codec metadata and stream
metadata.
Also, declare that the "codec" field can not be NULL anymore. demux.c
will set it to "" if it's NULL when added. This gets rid of a corner
case everything had to handle, but which rarely happened.
Slightly change how it is decided when a new packet should be read.
Switch to demux_read_packet_async(), and let the player "wait properly"
until required subtitle packets arrive, instead of blocking everything.
Move distinguishing the cases of passive and active reading into the
demuxer, where it belongs.
Just simplify by removing parts not needed anymore. This includes
merging dec_sub allocation and initialization (since things making
initialization complicated were removed), or format support queries (it
simply tries to create a decoder, and if that fails, tries the next
one).
So that the video FPs is not required at initialization, and can be set
later.
(As for whether this MicroDVD crap is worth the trouble to handle it
"correctly": MicroDVD files are unfortunately still around, and in at
least one case using the video FPS seemed to help indeed.)
Keeping ASS_Renderers around for a potentially large number of subtitle
tracks could lead to excessive memory usage, especially since the libass
cache is broken (caches even unneeded data), and might consume up to
~500MB of memory for no reason.
This includes the case of switching ordered chapter boundaries. It will
now be recreated on each timeline part switch. This shouldn't be much of
a problem with modern libass. (Older libass versions use fontconfig for
memory fonts, and will be very slow to reinitialize memory fonts.)
Since commit 6d9cb893, subtitle state doesn't survive timeline switches
(ordered chapters etc.). So there is no point in caching the state per
sh_stream anymore (which would be required to deal with multiple
segments). Move the cache to struct track.
(Whether it's worth caching the subtitle state just for the situation
when subtitle tracks get reselected is questionable. But for now, it's
nice to have the subtitles immediately show up when reselecting a
subtitle.)
The demuxer infrastructure was originally single-threaded. To make it
suitable for multithreading (specifically, demuxing and decoding on
separate threads), some sort of tripple-buffering was introduced. There
are separate "struct demuxer" allocations. The demuxer thread sets the
state on d_thread. If anything changes, the state is copied to d_buffer
(the copy is protected by a lock), and the decoder thread is notified.
Then the decoder thread copies the state from d_buffer to d_user (again
while holding a lock). This avoids the need for locking in the
demuxer/decoder code itself (only demux.c needs an internal, "invisible"
lock.)
Remove the streams/num_streams fields from this tripple-buffering
schema. Move them to the internal struct, and protect them with the
internal lock. Use accessors for read access outside of demux.c.
Other than replacing all field accesses with accessors, this separates
allocating and adding sh_streams. This is needed to avoid race
conditions. Before this change, this was awkwardly handled by first
initializing the sh_stream, and then sending a stream change event. Now
the stream is allocated, then initialized, and then declared as
immutable and added (at which point it becomes visible to the decoder
thread immediately).
This change is useful for PR #2626. And eventually, we should probably
get entirely of the tripple buffering, and this makes a nice first step.
Apparently, this was replaced by the SD_CTRL_SET_VIDEO_PARAMS set
dimensions. But I can't find out when this happened - possibly, these
fields were never used by sd_lavc.c, and only by the (long removed)
MPlayer dvdsub decoder.
Until now, feeding packets to the decoder in advance was done for text
subtitles only. This was possible because libass buffers all subtitle
data anyway (in ASS_Track). sd_lavc, responsible for bitmap subs, does
not do this. But it can buffer a small number of subtitle frames ahead.
Enable this.
Repurpose the sub_accept_packets_in_advance(). Instead of "can take all
packets" it means "can take 1 packet" now. (The old meaning is still
needed locally in dec_sub.c; keep it there.) It asks the decoder whether
there is place for at least 1 subtitle packet. sd_lavc implements it and
returns true if its internal fixed-size subtitle queue still has a free
slot. (The implementation of this in dec_sub.c isn't entirely clean.
For one, decode_chain() ignores this mechanism, so it's implied that
bitmap subtitles do not use the subtitle filter chain in any advanced
way.)
Also fix 2 bugs in the sd_lavc queue handling. Subtitles must be checked
in reverse, because the first entry will often have endpts==NOPTS, which
would always match. alloc_sub() must cycle the queue buffer, because it
reuses memory allocations (like sub.imgs) by design.
This was used with --no-sub-ass (aka --no-ass). This option (which is
not yet removed) strips all styling from the subtitles, and renders them
as plaintext only. For some reason, it originally seemed convenient to
reuse all the OSD text rendering code (osd_libass.c). While this was
indeed simple, it had a bad influence on the rest of the code. For
example, it had to decide whether to go through the OSD code path, or
the proper subtitle renderer in sd_ass.c.
Kill the OSD subtitle renderer. Reimplement --no-sub-ass and also
"secondary" subtitles in sd_ass.c. fill_plaintext() contains some rather
minor code duplication with osd_libass.c for setting up a dummy
ASS_Event and escaping the stripped text. Since sd_ass.c already has to
handle "normal" text subtitles, and has code for stripping ASS tags,
this remains all relatively simple.
Remove all the unnecessary crap from the rest of the code.
Use the demux_set_ts_offset() added in the previous commit to base each
timeline segment to use timestamps according to its relative position
within the overall timeline. As a consequence we don't need to care
about these timestamps anymore, and everything becomes simpler.
(Another minor but delicious nugget of sanity.)
ass_set_fonts() is called by mp_ass_configure_fonts(), which was called
every time a subtitle renderer was initialized. I'm not sure why this
was done - I can't find a good reason, and most likely there's none.
However, it did cause problems with an experimental libass branch. It
crashed some time after switching to a second subtitle track. The branch
will hopefully be merged soon, and it seems unlikely that libass wants
to fix its problems with its ridiculous API (rather it should normalize
its API so that the issue doesn't happen in the first place), so just
apply this change. It makes our code simpler too.
Each subtitle track gets its own decoder instance (sd_ass). But they use
a shared ASS_Renderer. This is done mainly because of fontconfig.
Initializing fontconfig is very slow when using it with memory fonts, so
there's a practical need to cache this memory font state, which is done
by not creating separate ASS_Renderers. This is very dirty and very
evil, but we probably can't get rid of it any time soon.
The shared ASS_Renderer was not properly synchronized. While the program
logic guarantees that only one sd_ass instance is visible at a time,
there are other interactions that require synchronization. In
particular, I suspect concurrent execution of mp_ass_configure_fonts()
and sd_ass.get_bitmaps cause issues in a newer libass development
branch.
So here's a shitty hack that hopefully fixes things, hopefully only
until libass becomes less dependent on fontconfig.
Includes some logic for not starting the demuxer thread for fully read
subtitles. (Well, the cache will still waste _lots_ of resources, and
the cache always has to be created, because we don't know whether it'll
be needed _before_ opening the file.)
See #1597.
On uninitialization, the player will unselect all subtitles, and then
destroy the subtitle decoder. But it didn't correctly remove the
subtitle decoder from the OSD state, so it could happen that it would
access it after the decoder was destroyed.
Could lead to random crashes when switching files often.
Fixes#1389.
reset_subtitles() works in mpctx->d_sub[], which is set to NULL before
calling it from uninit_sub(). This fixes resetting the subtitle when
cycling subtitle tracks.
Actually, this was probably a feature, because it's annoying if
subtitles don't show up when cycling them. But it also can have
unintended consequences, so get rid of it.
This should clearly be impossible, but it seems to happen with ordered
chapters for a user.
Since I can't tell what the actual bug is and it seems impossible to
know the details without downloading possibly huge files, this is
probably the best we can do.
Should at least partially fix#1319.
libass won't use embedded fonts, unless ass_set_fonts() (called by
mp_ass_configure_fonts()) is called. However, we call this function when
the ASS_Renderer is initialized, which is long before the .ass file is
actually loaded. (I'm not sure why it tries to keep 1 ASS_Renderer, but
it always did this.)
Fix by calling mp_ass_configure_fonts() after loading them. This also
means this function will be called multiple times - hopefully this is
harmless (it will reinit fontconfig every time, though).
While we're at it, also initialize the ASS_Renderer lazily.
Fixes#1244.
For example, if --force-window is used, and video is switched off during
playback, then you need to redecide the rendering method to get subs
displayed correctly.
Do this by moving the state setup code into a function, and call it on
every frame.
Also recreate ASS_Library on every file played. This means we can move
the code out of main.c as well.
Recreating the ASS_Library object has no disadvantages, because it
literally stores only the message callback, the (per-file) font
attachment as byte arrays, and the set of style overrides. Hopefully
this thing can be removed from the libass API entirely at some point.
The only reason why the player core creates the ASS_Renderer, instead
of the subtitle renderer, is because we want to cache the loaded fonts
across ordered chapter transitions, so this probably still has to stay
around for now.
Each subsystem (or similar thing) had an INITIALIZED_ flag assigned. The
main use of this was that you could pass a bitmask of these flags to
uninit_player(). Except in some situations where you wanted to
uninitialize nearly everything, this wasn't really useful. Moreover, it
was quite annoying that subsystems had most of the code in a specific
file, but the uninit code in loadfile.c (because that's where
uninit_player() was implemented).
Simplify all this. Remove the flags; e.g. instead of testing for the
INITIALIZED_AO flag, test whether mpctx->ao is set. Move uninit code
to separate functions, e.g. uninit_audio_out().
This makes subtitle display somewhat work if no video is displayed, but
a VO window exists (--force-window or cover art display).
The main problem with normal subtitle display is that it's locked to
video: it uses the video PTS as reference, and the subtitles advance
only if a new video frame is displayed. In audio-only mode on the other
hand, no video frame is ever displayed (or only 1 in the cover art
case). You would need a workaround to adjust the subtitle PTS, and you
would have to decide with what frequency to update the display. In
general, there is no "right" display FPS for subtitles. Some formats
(ASS) have animations parameterized by time, and any refresh rate could
be used.
Sidestep these problems by enabling the text OSD-based subtitle
mechanism. This is similar to --no-sub-ass, and updates and renders
subtitles with plain OSD. It has some caveats: no bitmap subs, somewhat
incorrect timing, no formatting. Timing in particular is a bit strange
and depends how often the audio output asks for new data, or other
events that happen to wakeup the playloop.
This is a deadlock caused by a lock order issue: sub/osd.c locks the OSD
first, then the subtitle decoder lock. player/sub.c does the reverse.
Fix this by discussing away the requirement for locking (see below),
which allows us to drop the broken sub lock. sub_get_text() still
acquires and releases the sub decoder lock, but it's not held at the
same time as the OSD lock anymore, so it should be fine.
Originally, the sub lock was acquired because sub_get_text() returns a
pointer to a mutable string. We simply declare that it's ok to call it
unlocked, as long as only 1 thread accesses it, which works out fine in
this case.
Apparently users prefer this behavior.
It was used for subtitles too, so move the code to calculate the video
offset into a separate function. Seeking also needs to be fixed.
Fixes#1018.
sub_reset() was called on cycling subtitle tracks and on seeking. Since
we don't want that subtitles disppear on cycling, sd_lavc.c didn't clear
its internal subtitle queue on reset, which meant that seeking with PGS
subtitles could leave the subtitle on screen (PGS subtitles usually
don't have a duration set).
Call it only on seeking, so we can also strictly clear the subtitle
queue in sd_lavc.
(This still can go very wrong if you disable a subtitle, seek, and
enable it again - for example, if used with libavformat that uses "SSA"
style demuxed ASS subtitle packets. That shouldn't happen with newer
libavformat versions, and the user can "correct" it anyway by executing
a seek while the subtitle is selected.)
wm4
Dmitrij D. Czarkoff
Marcin Kurczewski