I was recently informed that unicode has official symbols for
window controls, and I put together a change to use them, which
worked, as long as a suitable font was installed. However, it's
not that hard to get a normal system that lacks an appropriate
font, and libass wants to print warnings if the symbols aren't
in the default font, which will almost always be true.
So, I gave up and added the symbols to the custom osd font that
we already have. This ensures they are always available, and
that they are aligned consistently on all platforms.
I took the symbols from the `symbola` font, as this has a suitable
licence and the symbols look nice enough.
Symbola Licence:
Fonts are free for any use; they may be opened, edited,
modified, regenerated, packaged and redistributed.
Finally, as we now have access to an un-maximize symbol, I added
logic to use it when the window is maximized.
Do what we do best in multimedia: add conflicting hacks on top of other
hacks, that fix a single sample, and may break other ones.
In this case, it only happens if the file is most likely already broken
(subtitle bounding boxes go outside of the subtitle "canvas"), so it's
OK. The file still looks broken (and, in fact, the file is completely
fucking broken), but you can see the subtitles.
But in summary, this is not actually something I should have bothered
about.
I noticed that MPlayer shows the subtitles "correctly", but this is only
because they have a hack that extends subtitles with small resolution to
a larger hardcoded resolution. This hack was removed from mpv, because
it broke some completely legitimate files. As another really funny fact,
MPlayer's default video output (vdpau) appears to display this file
correctly, but only because it handles narrow aspect ratios (that extend
the height instead of the width) incorrectly. It extends the height, but
leaves the video with 1:1 aspect ratio at the top. It seems to repeat
the last video line. (-vo xv and -vo gl show it correctly, i.e.
stretched like mpv, by the way.) For some reason, the sample file at
hand is extended with black, so the subtitles are rendered into a black
area below the video, which is almost reasonable. So, MPlayer may
display this file "correctly", but in fact it only happens to do so
because of 1 hack that breaks legitimate files, and 1 bug. What the
fuck.
Fixes: #7218 (sort of)
Sometimes the atlas can get so large that it exceeds the maximum allowed
size for an mp_image. Since the atlas will never shrink naturally, this
breaks subtitles entirely until mpv is restarted. Reset the packer so
that subtitles can rendered properly once the atlas fits again.
This is a partial workaround for #6286.
libass had an API to configure this since 2013. mpv always used
ASS_FONTPROVIDER_AUTODETECT, because usually there's little reason to
use anything else. The intention of the now added option is to allow
users to disable use of system fonts.
I didn't consider it worth the trouble to add the coretext and
directwrite enum items from ASS_DefaultFontProvider. The "auto" choice
will have the same effect if they're available. Also, the part of the
code which defines the option does not necessarily have libass available
(it's still optional!), so defining all enum items as choices is icky. I
still added fontconfig, since that may be nice to emulate a nostalgic
2010 feeling of mpv freezing on fontconfig.
The option for OSD is even less useful. (But you get it for free, and
why pass up a chance to add yet another useless option?)
This is not quite what was requested in #6947, but as close as it gets.
First we shift the values up to the actual amount of bits in draw_ass,
so that they will be drawn correctly when using formats with more than
8 bpc. (draw_rgba is already correct w.r.t. RGB formats with 9 or more
bpc)
Then, in scale_sb_rgba, by setting the amount of bits per channel used
for planar RGB formats (formats are always planar at this point in
draw_bmp) to be the same as the source from 9 to 16 bpc (in effect all
the various GBRP formats) we manage to fit the special case that does
not require any conversion in chroma_up and chroma_down when handling
these formats (as long as the source itself is a planar format),
instead writing directly to the combined dst/src buffer. This in turn
works around a bug (incorrect colors) in libswscale when scaling
between GBRP formats with 9 or more bpc. Additionally this should be
more efficient, since we skip up- and down-conversion and temporary
buffers.
During initial testing with US closed captions, ARIB captions,
timed text in MP4 or the specific external SRT files I tested with
there were no hints that this flag would be needed for seeking to
work.
Unfortunately, that result seems to have been incorrect.
Fixes#6970
Simple enough to do. May have mixed results. Typically, bitmap subtitles
will have a tight bounding box around the rendered text. But if for
example there is text on the top and bottom, it may be a single big
bitmap with a large transparent area between top and bottom. In
particular, DVD subtitles are really just a single screen-sized
RLE-encoded bitmap, though libavcodec will crop off transparent areas.
Like with sd_ass, you can't move subtitles _down_ if they are already in
their origin position. This could probably be improved, but I don't want
to deal with that right now.
See manpage additions. This is a huge hack. You can bet there are shit
tons of bugs. It's literally forcing square pegs into round holes.
Hopefully, the manpage wall of text makes it clear enough that the whole
shit can easily crash and burn. (Although it shouldn't literally crash.
That would be a bug. It possibly _could_ start a fire by entering some
sort of endless loop, not a literal one, just something where it tries
to do work without making progress.)
(Some obvious bugs I simply ignored for this initial version, but
there's a number of potential bugs I can't even imagine. Normal playback
should remain completely unaffected, though.)
How this works is also described in the manpage. Basically, we demux in
reverse, then we decode in reverse, then we render in reverse.
The decoding part is the simplest: just reorder the decoder output. This
weirdly integrates with the timeline/ordered chapter code, which also
has special requirements on feeding the packets to the decoder in a
non-straightforward way (it doesn't conflict, although a bugmessmass
breaks correct slicing of segments, so EDL/ordered chapter playback is
broken in backward direction).
Backward demuxing is pretty involved. In theory, it could be much
easier: simply iterating the usual demuxer output backward. But this
just doesn't fit into our code, so there's a cthulhu nightmare of shit.
To be specific, each stream (audio, video) is reversed separately. At
least this means we can do backward playback within cached content (for
example, you could play backwards in a live stream; on that note, it
disables prefetching, which would lead to losing new live video, but
this could be avoided).
The fuckmess also meant that I didn't bother trying to support
subtitles. Subtitles are a problem because they're "sparse" streams.
They need to be "passively" demuxed: you don't try to read a subtitle
packet, you demux audio and video, and then look whether there was a
subtitle packet. This means to get subtitles for a time range, you need
to know that you demuxed video and audio over this range, which becomes
pretty messy when you demux audio and video backwards separately.
Backward display is the most weird (and potentially buggy) part. To
avoid that we need to touch a LOT of timing code, we negate all
timestamps. The basic idea is that due to the navigation, all
comparisons and subtractions of timestamps keep working, and you don't
need to touch every single of them to "reverse" them.
E.g.:
bool before = pts_a < pts_b;
would need to be:
bool before = forward
? pts_a < pts_b
: pts_a > pts_b;
or:
bool before = pts_a * dir < pts_b * dir;
or if you, as it's implemented now, just do this after decoding:
pts_a *= dir;
pts_b *= dir;
and then in the normal timing/renderer code:
bool before = pts_a < pts_b;
Consequently, we don't need many changes in the latter code. But some
assumptions inhererently true for forward playback may have been broken
anyway. What is mainly needed is fixing places where values are passed
between positive and negative "domains". For example, seeking and
timestamp user display always uses positive timestamps. The main mess is
that it's not obvious which domain a given variable should or does use.
Well, in my tests with a single file, it suddenly started to work when I
did this. I'm honestly surprised that it did, and that I didn't have to
change a single line in the timing code past decoder (just something
minor to make external/cached text subtitles display). I committed it
immediately while avoiding thinking about it. But there really likely
are subtle problems of all sorts.
As far as I'm aware, gstreamer also supports backward playback. When I
looked at this years ago, I couldn't find a way to actually try this,
and I didn't revisit it now. Back then I also read talk slides from the
person who implemented it, and I'm not sure if and which ideas I might
have taken from it. It's possible that the timestamp reversal is
inspired by it, but I didn't check. (I think it claimed that it could
avoid large changes by changing a sign?)
VapourSynth has some sort of reverse function, which provides a backward
view on a video. The function itself is trivial to implement, as
VapourSynth aims to provide random access to video by frame numbers (so
you just request decreasing frame numbers). From what I remember, it
wasn't exactly fluid, but it worked. It's implemented by creating an
index, and seeking to the target on demand, and a bunch of caching. mpv
could use it, but it would either require using VapourSynth as demuxer
and decoder for everything, or replacing the current file every time
something is supposed to be played backwards.
FFmpeg's libavfilter has reversal filters for audio and video. These
require buffering the entire media data of the file, and don't really
fit into mpv's architecture. It could be used by playing a libavfilter
graph that also demuxes, but that's like VapourSynth but worse.
There are 3 packet reading functions in the demux API, which all
function completely differently. One of them, demux_read_packet(), has
only 1 caller, which is in dec_sub.c. Change this caller to use
demux_read_packet_async() instead. Since it really wants to do a
blocking call, setup some proper waiting. This uses mp_dispatch_queue,
because even though it's overkill, it needs the least code.
In practice, waiting actually never happens. This code is only called on
code paths where everything is already read into memory (libavformat's
subtitle demuxers simply behave this way). It's still a bit of a
"coincidence", so implement it properly anyway.
If suubtitle decoder init fails, we still need to unset the demuxer
wakeup callback. Add a sub_destroy() call to the failure path. This also
happens to fix a missed pthread_mutex_destroy() call (in practice this
was a nop, or a memory leak on BSDs).
UB-sanitizer complains that we shift bits into the sign (when a is
used). Change it to unsigned, which in theory is more correct and
silences the warning.
Doesn't matter in practice, both the "bug" and the fix have 0 impact.
It would always autodetect it based on the passed style block,
but as we are defining it - we might as well define it always.
(As far as I can see all decoders in libavcodec utilize 4+ style
blocks)
Manual changes done:
* Merged the interface-changes under the already master'd changes.
* Moved the hwdec-related option changes to video/decode/vd_lavc.c.
Only printable ASCII characters were considered to be valid texts. Make
it possible that UTF-8 contents are also considered valid.
This does not make the SDH subtitle filter support non-English
languages. This just prevents the filter from blindly marking lines that
have only UTF-8 characters as empty.
Fixes#6502
libavcodec normally drops subtitle lines that fail a check for invalid
UTF-8 (their check is slightly broken too, by the way). This was always
annoying and inconvenient, but now there is a mechanism to prevent
it from doing this. Requires newst libavcodec.
Remove them from the big MPOpts struct and move them to their sub
structs. In the places where their fields are used, create a private
copy of the structs, instead of accessing the semi-deprecated global
option struct instance (mpv_global.opts) directly.
This actually makes accessing these options finally thread-safe. They
weren't even if they should have for years. (Including some potential
for undefined behavior when e.g. the OSD font was changed at runtime.)
This is mostly transparent. All options get moved around, but most users
of the options just need to access a different struct (changing sd.opts
to a different type changes a lot of uses, for example).
One thing which has to be considered and could cause potential
regressions is that the new option copies must be explicitly updated.
sub_update_opts() takes care of this for example.
Another thing is that writing to the option structs manually won't work,
because the changes won't be propagated to other copies. Apparently the
only affected case is the implementation of the sub-step command, which
tries to change sub_delay. Handle this one explicitly (osd_changed()
doesn't need to be called anymore, because changing the option triggers
UPDATE_OSD, and updates the OSD as a consequence). The way the option
value is propagated is rather hacky, but for now this will do.
It was split at least across osd.c and sd_ass.c/sd_lavc.c. sd_lavc.c
actually ignored most of the more obscure subtitle timing things.
There's no reason for this - just move it all to dec_sub.c (mostly from
sd_ass.c, because it has some of the most complex stuff).
Now timestamps are transformed as they enter or leave dec_sub.c.
There appear to have been some subtle mismatches about how subtitle
timestamps were transformed, e.g. sd_functions.accepts_packet didn't
apply the subtitle speed to the timestamp. This patch should fix them,
although it's not clear if they caused actual misbehavior.
The semantics of SD_CTRL_SUB_STEP are slightly changed, which is the
reason for the changes in command.c and sd_lavc.c.
I've decided that MP_TRACE means “noisy spam per frame”, whereas
MP_DBG just means “more verbose debugging messages than MSGL_V”.
Basically, MSGL_DBG shouldn't create spam per frame like it currently
does, and MSGL_V should make sense to the end-user and provide mostly
additional informational output.
MP_DBG is basically what I want to make the new default for --log-file,
so the cut-off point for MP_DBG is if we probably want to know if for
debugging purposes but the user most likely doesn't care about on the
terminal.
Also, the debug callbacks for libass and ffmpeg got bumped in their
verbosity levels slightly, because being external components they're a
bit less relevant to mpv debugging, and a bit too over-eager in what
they consider to be relevant information.
I exclusively used the "try it on my machine and remove messages from
MSGL_* until it does what I want it to" approach of refactoring, so
YMMV.
The OpenType Font File specification recommends that "Collection fonts
that use CFF or CFF2 outlines should have an .OTC extension." mpv
should accept .otc as a fallback extension for font detection should
the mimetype detection fail.
IETF RFC8081 added the "font" top-level media type,
including font/ttf, font/otf, font/sfnt, and also
font/collection. These font formats are all supported
by mpv/libass but they are not accepted as valid
Matroska mime types. mpv can load them via file extension
and they work as expected, so files using the new types
should not trigger a warning from mpv.
The current invocation of bstr_cut is as good as no cutting at all.
Almost the entire header is reread in every iteration of the loop.
I don't know how many styles libavcodec tends to generate, but if
(now or in the future) it generates many, then this loop is slow
for no good reason. If anything, the code would be more clear and
have the same performance if it didn't call bstr_cut at all.
The intention here (and the sensible thing regardless) seems to be
to skip the part of the string that bstr_find has already looked
through and found nothing. This commit additionally skips the whole
substring, because overlapping matches are impossible.
In some cases, demux_mkv will detect a start time slightly above 0, but
there might still be a subtitle starting at exactly 0. When the player
rebases the timestamps to assumed start time, the subtitle will have a
slightly negative timestamp in the end. libavcodec's subtitle converter
turns this into a larger number due to underflow. Fix by clamping
subtitles always to 0, which may or may not be what you want.
At least it fixes#5047.
The new_segment field was used to track the decoder data flow handler of
timeline boundaries, which are used for ordered chapters etc. (anything
that sets demuxer_desc.load_timeline). This broke seeking with the
demuxer cache enabled. The demuxer is expected to set the new_segment
field after every seek or segment boundary switch, so the cached packets
basically contained incorrect values for this, and the decoders were not
initialized correctly.
Fix this by getting rid of the flag completely. Let the decoders instead
compare the segment information by content, which is hopefully enough.
(In theory, two segments with same information could perhaps appear in
broken-ish corner cases, or in an attempt to simulate looping, and such.
I preferred the simple solution over others, such as generating unique
and stable segment IDs.)
We still add a "segmented" field to make it explicit whether segments
are used, instead of doing something silly like testing arbitrary other
segment fields for validity.
Cached seeking with timeline stuff is still slightly broken even with
this commit: the seek logic is not aware of the overlap that segments
can have, and the timestamp clamping that needs to be performed in
theory to account for the fact that a packet might contain a frame that
is always clipped off by segment handling. This can be fixed later.
If a VO-area option changes, gl_video_resize() is called
unconditionally. This function does something even if the size does not
change (at least it discards buffered frames for interpolation), which
can lead to stutter when you keep firing option change events during
playback.
Check for an actual resize, and if nothing changes, exit early.
Lua scripts can call osd_set_external() early (before the VO window is
created and obj->vo_res is filled), in which case the PlayResX field
would be set to nonsense, and libass would print a pointless warning.
There's an easy and a hard fix: either just go on and pass dummy values
to libass (basically like before, just clamp them to avoid the values
which make libass print the warning). Or attempt to update the PlayRes
field to correct values on rendering (since at rendering time, you
always know the screen size and the correct values). Do the latter.
Since various things use PlayRes for scaling things, this might still
not be fully ideal. This is a general problem with the async scripting
interface.
This API isn't deprecated (yet?), but it's still inferior and harder to
use than avcodec_free_context().
Leave the call only in 1 case in af_lavcac3enc.c, where we apparently
seriously close and reopen the encoder for whatever reason.
List of changes:
1. Rename `signfs` to `scale`, to better match what it actually does
(force --sub-scale to apply to ASS subtitles), and fix the blatantly
wrong documentation (it actually specifically does *not* apply to
signs)
2. Rename `--sub-ass-style-override` to `--sub-ass-override` to help
reduce confusion between it and `--sub-ass-force-style`, as well as
pointing out that it doesn't necessarily actually override styles.
(The new `scale` option, for example, only sets
ASS_OVERRIDE_BIT_FONT_SIZE, but not ASS_OVERRIDE_BIT_STYLE)
3. Mention that `--sub-ass-override` is generally sort of smart about
only overriding dialog, not signs.
All contributors of the code used for these files agreed to the LGPL
relicensing.
There are some unaccounted contributors, but all of their code was
completely removed before. (The only exception is one contributor whose
only line left was "#include <string.h>". I don't know if that's
copyrightable, but it wasn't needed anyway, so just remove it.)
These files started out as libvo/sub.* (renamed to sub/sub.*, then
renamed again to sub/osd.*). They used to contain code for rendering
the OSD (as in, actual pixel manipulation and text layouting). But
later all this code was dropped, and libass was used to render the OSD
instead. Actual subtitle rendering was reimplemented in other files
(the old subtitle rendering path is completely gone).
One potential problem are the option declarations, which makes this
harder, as these options involve more history. But it turns out most of
them were reimplemented since 80270218cb, rather than taken from old
code. (Although not all - but the rest covered by relicensing
agreements.)
This also affects osd_state.h, which was apparently incorrectly implied
to be LGPL.
All contributors have agreed.
Compared to sd_ass.c, this has a pretty simple history:
av_sub.c -> sub/av_sub.c -> sub/sd_lavc.c
At one point, some code from spudec.c was added to it, but it was
removed again later.
All contributors of the code used for sd_ass.c agreed to the LGPL
relicensing. Some code has a very chaotic history, due to MPlayer
subtitle handling being awful, chaotic, and having been refactored a
dozen of times. Most of the subtitle code was actually rewritten from
scratch (a few times), and the initial sd_ass.c was pretty tiny. So we
should be fine, but it's still a good idea to look at this closely.
Potentially problematic cases of old code leaking into sd_ass.c are
mentioned below.
Some code originates from demux_mkv. Most of this was added by eugeni,
and later moved into mplayer.c or mpcommon.c. The old demux_mkv ASS/SSA
subtitle code is somewhat dangerous from a legal perspective, because it
involves 2 patches by a certain Tristan/z80, who disagreed with LGPL,
and who told us to "rewrite" parts we need. These patches were for
converting the ASS packet data to the old MPlayer text subtitle data
structures. None of that survived in the current code base.
Moving the subtitle handling out of demux_mkv happened in the following
commits: bdb6a07d2a, de73d4dd97, 61e4a80191. The code by
z80 was removed in b44202b69f.
At this time, the z80 code was located in mplayer.c and subreader.c.
The code was fully removed, being unnecessary due to the entire old
subtitle rendering code being removed. This adds a ass_to_plaintext(),
function, which replaces the old ASS tag stripping code in
sub_add_text(), which was based on the z80 code. The new function was
intended to strip ASS tags in a correct way, instead of somehow
dealing with other subtitle types (like HTML-style SRT tags), so it
was written from scratch.
Another potential issue is the --sub-fix-timing option is based on
-overlapsub added in d459e64463. But the implementation is new, and
no code from that commit is used in sd_ass.c. The new implementation
started out in 64b1374a44. (The following commit, bd45eb468c
removes the original code that was replaced.) The code was later
moved into sd_ass.c.
The --sub-fps option has a similar history.
Somewhat chaostic history: libass/ass_mp.* -> ass_mp.* -> sub/ass_mp.*
As far as I can tell, everyone who ever touched these files has agreed
to the relicensing.
