The BD-J VM progresses only on reads. With playback at EOF or on a
held still nothing reads anymore, applet playlist switches never
surface and menus freeze, libbluray documents this polling requirement
for idle states. Drive one nav read per tick and keep the core awake.
The slave demuxer latches its EOF and stops touching the stream, so
the read path peeks the stream itself to run its event loop. Poll the
same way while paused in a menu, highlight redraws would otherwise
wait for the next core wakeup. dvdnav stills release on user input,
not reads, and the pump bypasses the cache limits, so no pumping
outside these states.
The resync seek that follows a disc-initiated jump must not reposition
the VM. On BD the jump is handled out-of-band by reopening the slave
demuxer on the packet-read path, and the VM already sits at the jump
destination. Repositioning it with the (stale) seek target time would
hop to the wrong place. Adopting the discontinuity counter here would
leave the old slave demuxer parsing the new playlist's data with the
wrong codec context. Flush our side only, and keep the counter stale so
the read path still performs the reopen.
The player's default track selection picks the first probed audio
track, but the substream the disc's current PGC actually plays is
decided by the DVD VM and may be a different one. On discs whose menu
domain plays LPCM while the mux also carries an (unreferenced) AC3
substream, mpv selected the AC3 track, which has no data. We have to
keep track of what VM wants to output and what LAVF expects.
When the disc VM jumps (menu activation, end of title), the demuxer
and player have to flush and reinitialize exactly at the boundary.
Hold an EOF at the boundary until the demuxer acks it, and resync
the player with a regular seek, which already orders flush, decoder
reset and restart. d_seek recognizes the held boundary and releases
it instead of repositioning the VM.
Also log the VM domain in nav event messages.
The highlight rectangle and palette were passed around as loose fields
in three places. Bundle them into a struct, pass the whole nav state to
the sd_lavc control.
Keep DVD SPU streams always enabled at the slave level and retain the
last subpicture per substream. Re-deliver the retained copy when a sub
track is (re)selected and when the player resets playback state.
DVDNAV_STILL_FRAME means the VM is holding a frame indefinitely (menu
pages, some logos) or for a timed duration. Report the indefinite case
via nav state so the player holds playback at EOF instead of ending
the file, and skip timed stills, which would otherwise stall playback.
The disc VM selects audio and subpicture streams itself (menu SPU
highlights, title-authored stream changes on jumps). Follow the VM's
selection on every hop, and turn subtitles on/off with the disc's
sub_visible flag.
The sync only applies while the corresponding track selection is on
auto. An explicitly chosen track (--aid/--sid or runtime cycling) is
never overridden.
The new player/discnav.c owns the player-side state for the in-disc
menu UI, shared between stream_bluray and stream_dvdnav. Once per
playloop iteration it pulls the stream's nav state and
- pushes the BD menu plane to the OSD (OSDTYPE_DISC_MENU) and the DVD
highlight state to the dvd_subtitle decoders,
- resyncs playback when the disc VM jumped on its own, detected
through the stream's discontinuity counter,
- mirrors the disc's current title into demuxer->edition,
- force-selects a dvd_subtitle track while a DVD menu is up, so the
menu graphics decoded by sd_lavc reach the OSD, and
- enables the {discnav} input section while a menu is interactive.
The per-file state is reset on every new playlist entry.
Nobody wanted to restore this, so it gets the boot.
If anyone still wants to volunteer to restore menu support, this would
be welcome. (I might even try it myself if I feel masochistic and like
wasting a lot of time for nothing.) But if it does get restored, it
should be done differently. There were many stupid things about how it
was done. For example, it somehow tried to pull mp_nav_events through
all the layers (including needing to "buffer" them in the demuxer),
which was needlessly complicated. It could be done simpler.
This code was already inactive, so this commit actually changes nothing.
Also keep in mind that normal DVD/BD playback still works.
DVD/BD menu support never worked right, and are a pain to maintain. In
particular, DVD menus never actually worked correctly, because
highlights were not rendered correctly. Fixing this requires major
effort, which I'm not interested to spend.
Most importantly, the requirement to switch streams without losing the
DVD/BD state caused major weirdness in the playback core. It was
implemented by somehow syncing the playback state to the DVD/BD
implementation (in stream_dvdnav.c etc.), and then reloading the demuxer
without destroying and recreating the stream. This caused a bunch of
special-cases which I'm looking forward to remove.
For now, don't just remove everything related to menu support and just
disable it. If someone volunteers, it can be restored (i.e. rewritten)
in a reasonable way. If nobody volunteers soon, it goes.
This was completely breaking any low-level caching. Change it so that at
least demuxer caching will work.
Do this by using the metadata cache mechanism to funnel through the menu
commands.
For some incomprehensible reason, I had to reorder the events (which
affects their delivery priority), or they would be ignored. Probably
some crap about the event state being cleared before it could be
delivered. I don't give a shit.
All this code sucks. It would probably be better to let discnav.c access
the menu event "queue" directly, and to synchronize access with a mutex,
instead of going through all the caching layers, making things
complicated and slow.
Getting subtitle scaling and positioning right even if there are video
filters, which completely change the image (like cropping), doesn't seem
to have a single, correct solution. To some degree, the results are
arbitrary, so we may as well do what is most useful to the user.
In this case, if the PGS resolution aspect ratio and the video output
aspect ratio mismatch, letter-box it, instead of stretching the subs
over the video frame. (This will require additional fixes, should it
turn out that there are PGS subtitles which are stretched by design.)
Fixes#1205.
Run opening the stream and opening the demuxer in a separate thread.
This should remove the last code paths in which the player can normally
get blocked on network.
When the stream is opened, the player will still react to input and so
on. Commands to abort opening can also be handled properly, instead of
using some of the old hacks in input.c. The only thing the user can
really do is aborting loading by navigating the playlist or quitting.
Whether playback abort works depends on the stream implementation; with
normal network, this will depend on what libavformat (via "interrupt"
callback) does.
Some pain is caused by DVD/BD/DVB. These want to reload the demuxer
sometimes. DVB wants it in order to discard old, inactive streams.
DVD/BD for the same reason, and also for reloading stream languages
and similar metadata. This means the stream and the demuxer have to
be loaded separately.
One minor detail is that we now need to copy all global options. This
wasn't really needed before, because the options were accessed on
opening only, but since opening is now on a separate thread, this
obviously becomes a necessity.
This adds a thread to the demuxer which reads packets asynchronously.
It will do so until a configurable minimum packet queue size is
reached. (See options.rst additions.)
For now, the thread is disabled by default. There are some corner cases
that have to be fixed, such as fixing cache behavior with webradios.
Note that most interaction with the demuxer is still blocking, so if
e.g. network dies, the player will still freeze. But this change will
make it possible to remove most causes for freezing.
Most of the new code in demux.c actually consists of weird caches to
compensate for thread-safety issues (with the previously single-threaded
design), or to avoid blocking by having to wait on the demuxer thread.
Most of the changes in the player are due to the fact that we must not
access the source stream directly. the demuxer thread already accesses
it, and the stream stuff is not thread-safe.
For timeline stuff (like ordered chapters), we enable the thread for the
current segment only. We also clear its packet queue on seek, so that
the remaining (unconsumed) readahead buffer doesn't waste memory.
Keep in mind that insane subtitles (such as ASS typesetting muxed into
mkv files) will practically disable the readahead, because the total
queue size is considered when checking whether the minimum queue size
was reached.
The main issue was actually that the OSD callback locked the subtitle
decoder, which does not necessarily work, because the OSD code is
already allowed to lock it. The state was already protected by
unsetting the callback (which involes the OSD lock). So, in summary,
this is probably just a cleanup.
stream.start_pos was needed for optical media only, and (apparently) not
for very good reasons. Just get rid of it.
For stream_dvd, we don't need to do anything. Byte seeking was already
removed from it earlier.
For stream_cdda and stream_vcd, emulate the start_pos by offsetting the
stream pos as seen by the rest of mpv.
The bits in discnav.c and loadfile.c were for dealing with the code
seeking back to the start in demux.c. Handle this differently by
assuming the demuxer is always initialized with the stream at start
position, and instead seek back if initializing the demuxer fails.
Remove the --sb option, which worked by modifying stream.start_pos. If
someone really wants this option, it could be added back by creating a
"slice" stream (actually ffmpeg already has such a thing).
Kacper Michajłow