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.
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.)
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.
It was stupid. The only thing that still effectively used it was
sd_lavc_conv - all other "filters" were the subtitle decoder/renderers
for text (sd_ass) and bitmap (sd_lavc) subtitles.
While having a subtitle filter chain was interesting (and actually
worked in almost the same way as the audio/video ones), I didn't
manage to use it in a meaningful way, and I couldn't e.g. factor
secondary features like fixing subtitle timing into filters.
Refactor the shit and drop unneeded things as it goes.
This affects non-ASS text subtitles (those which go through libavcodec's
subtitle converter), which are muxed with video/audio. (Typically srt
subs in mkv.)
The problem is that seeking in the file can send a subtitle packet to
the decoder multiple times. These packets are interlaved with video,
and thus can't be all read when opening the file. Rather, subtitle
packets can essentially be randomly skipped or repeated (by seeking).
Until recently, this was solved by scanning the libass event list for
duplicates. Then our builtin srt-to-ass converter was removed, and
the problem was handled by fully clearing the subtitle list on each
seek.
This resulted in sub-seek not working properly for this type of file.
Since the subtitle list was cleared on seek, it was not possible to
do e.g. sub-seeks to subtitles before the current playback position.
Fix this by not clearing the list, and intead explicitly rejecting
duplicate packets. We use the packet file position was unique ID for
subtitles; this is confirmed working for most file formats (although
it is slightly risky - new demuxers may not necessarily set the file
position to something unique, or at all).
The list of seen packets is sorted, and the lookup uses binary search.
This is to avoid quadratic complexity when subtitles are added in
bulks, such as when opening a text subtitle file.
In some places, the code has to be adjusted to pass through the packet
file position correctly.
With the FFmpeg subtitle decoder used for _all_ non-ASS text subtitle
format, this code is simply unused now.
Ironically, the FFmpeg subtitle decoder does not handle things correctly
in a bunch of cases. Should it turn out they actually matter, they will
have to hack back.
The extend_event one is a candidate, although even though there were
allegedly files which need it, I couldn't get samples from the user who
originally reported such files. As such, extend_event was only confirmed
to handle trailing events with no (endless) duration like with MicroDVD
and LRC, but FFmpeg "fudges" these anyway, so no special handling is
needed.
This code also had logic to handle seeking with muxed srt subtitles,
which made the sub-seek command work. But this has been broken before
this commit already. Currently, seeking with muxed srt subs will clear
all subtitles, as the broken FFmpeg ASS format output by the libavcodec
subtitle converters does not check for duplicates. Since the subtitles
are all cleared, ass_step_sub() can not work properly and sub-seek can
not seek to already seen subtitles.
I feel like it's better there. Note that there is no reduced
functionality, as bitmaps subs (i.e. not handled by sd_ass.c) were never
fully read on init, and thus never went through sub_read_all_packets().
On the other hand, this might lead to confusion, as --sub-fps etc. will
now also affect muxed subtitles (which makes not much sense).
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.
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.
Instead of parsing the ASS file in demux_libass.c and trying to pass the
ASS_Track to the subtitle renderer, just read all file data in
demux_libass.c, and let the subtitle renderer pass the file contents to
ass_process_codec_private(). (This happens to parse full files too.)
Makes the code simpler, though it also relies harder on the (messy)
probe logic in demux_libass.c.
The mplayer decoder (spudec.c) actually handled this. There was explicit
code for binary palettes (16 32 bit values), and the subtitle resolution
was handled by video resolution coincidentally matching the subtitle
resolution.
Whoever puts vobsub into mp4 should be punished.
Fixes the sample gundam_sample.mp4, closes github issue #547.
This means the direct libass usage can be removed from command.c, and no
weird hacks for retrieving the ASS_Track are needed.
Also fix a bug when using this feature with ordered chapters.
When e.g. converting SRT to ASS, we certainly don't want them stretched
by video aspect ratio, even if that's necessary for native ASS
subtitles.
Annoying weird details...
This mirrors commit "sub: remove check_duplicate_plaintext_event()".
That code was basically duplicated. In general, this code is still
needed when doing conversion during demuxing (mostly because you can
seek during demuxing, which will cause duplicate events by replaying).
This allows using some formats that were not supported until now, like
WebVTT.
We still prefer the internal subtitle reader (subreader.c), because
1. Libav, and 2. random things which we probably want to keep, such as
control over formatting, codepage stuff, or various mysterious
postprecessing done in that code.
This means subassconvert.c is split in sd_srt.c and sd_microdvd.c. Now
this code is involved in the sub conversion chain like sd_movtext is.
The invocation of the converter in sd_ass.c is removed.
This requires some other changes to make the new sub converter code work
with loading external subtitles. Until now, subtitles loaded via
subreader.c was assumed to be in plaintext, or for some formats, in ASS
(except in -no-ass mode). Then these were added to an ASS_Track. Change
this so that subtitles are always in their original format (as far as
decoders/converters for them are available), and turn every sub event
read by subreader.c as packet to the dec_sub.c subtitle chain.
This removes differences between external/demuxed and -ass/-no-ass code
paths further.
Add a basic infrastructure for subtitle converters. These converters
work sort-of like decoders, except that they produce packets instead
of subtitle bitmaps. They are put in front of actual decoders.
Start with sd_movtext. 4 lines of code are blown up to a 55 lines file,
but fortunately this is not going to be that bad for the following
converters.
Make the sub decoder stuff independent from sh_sub (except for
initialization of course). Sub decoders now access a struct sd only,
instead of getting access to sh_sub. The glue code in dec_sub.c is
similarily independent from osd.
Some simplifications are made. For example, the switch_id stuff is
unneeded: the frontend code just has to make sure to call osd_changed()
any time subtitles are switched.
This is also preparation for introducing subtitle converters. It's much
cleaner to completely separate demuxer header/renderer glue/decoders
for this purpose, especially since sub converters might completely
change how demuxer headers have to be interpreted.
Also pass data as demux_packets. Currently, this doesn't help much, but
libavcodec converters might need scary stuff like packet side data, so
it's perhaps better to go with passing packets.
The -no-ass switch used to disable any use of libass for text subtitles.
This is not really the case anymore, because libass is now always
involved when rendering text. The only remaining use of -no-ass is
disabling styling or showing subtitles on the terminal. On the other
hand, the old subtitle rendering path is a big reason why the subtitle
code is still a big mess with an awful number of obscure special cases.
In order to simplify it, remove the old subtitle rendering code, and
always go through sd_ass.c. Basically, we use ASS_Track as central data
structure for storing text subtitles instead of struct sub_data. This
also makes libass mandatory for all text subs, even if they are printed
to the terminal in -no-video mode. (We could add something like sd_text
to avoid this, but it's not worth the trouble.)
struct sub_data and subreader.c are still around, even its ASS/SSA
reader. But struct sub_data is freed right after converting it to
ASS_Track. The internal ASS reader actually can handle some obscure
cases libass can't, like files encoded in UTF-16.
Get rid of the 1-char subtitle type field. Use sh_stream->codec instead
just like audio and video do. Use codec names as defined by libavcodec
for simplicity, even if they're somewhat verbose and annoying.
Note that ffmpeg might switch to "ass" as codec name for ASS, so we
don't bother with the current silly "ssa" name.
Remove VFCTRL_DRAW_OSD, VFCAP_EOSD_FILTER, VFCAP_EOSD_RGBA, VFCAP_EOSD,
VOCTRL_DRAW_EOSD, VOCTRL_GET_EOSD_RES, VOCTRL_QUERY_EOSD_FORMAT.
Remove draw_osd_with_eosd(), which rendered the OSD by calling
VOCTRL_DRAW_EOSD. Change VOs to call osd_draw() directly, which takes
a callback as argument. (This basically works like the old OSD API,
except multiple OSD bitmap formats are supported and caching is
possible.)
Remove all mentions of "eosd". It's simply "osd" now.
Make OSD size per-OSD-object, as they can be different when using
vf_sub. Include display_par/video_par in resolution change detection.
Fix the issue with margin borders in vo_corevideo.
Passing parameters from caller to subtitle renderer was done by
temporarily setting certain members in the osd_state struct (which for
all practical purposes are as good as global variables). This was the
only purpose of these members.
Rather than using such a messy way to pass parameter, put these into a
struct sub_render_params. The struct was already introduced in earlier
commits, and this commit just removes the parameter passing hack.
Remove subtitle selection code setting osd->ass_track directly and
vf_ass/vf_vo code rendering the track directly with libass. Instead,
do track selection and rendering with dec_sub.c functions.
Before, mpctx->set_of_ass_tracks[] contained bare libass tracks
generated from external subtitle files. For use with dec_sub.c, it now
contains struct sh_sub instances with decoder already initialized.
This commit breaks the sub_step command ('g' and 'y' keys) for
libass-rendered subtitles. It could be fixed, but it's so useless -
especially as with the existing implementation there's no practical
way to get subtitle delay back to normal after using it - that I
didn't bother.
Conflicts:
command.c
mp_core.h
mplayer.c
Change libavcodec subtitle decoding code (used for some bitmap
subtitle types) to use the same decoding framework as sd_ass. The
functionality that was previously in av_sub.c and was directly called
from mplayer.c is now in sd_lavc.c.
Conflicts:
mplayer.c
sub/av_sub.h
sub/sd_lavc.c
Merged from mplayer2. The remaining use of is_av_sub() is replaced by
a check whether a subtitle decoder is active, which should give the
same results.
Add a framework for subtitle decoder modules that work more like
audio/video decoders do, and change libass rendering of demuxed
subtitles to use the new framework.
The old subtitle code is messy, with details specific to handling
particular subtitle types spread over high-level code. This should
make it easier to clean things up and fix some bugs/limitations.