Another thing nobody will read. I'm attempting to document the rules by
which incompatible changes can be made. These rules have always been
present in this project, but I don't think they were written down. Or
maybe they were, but I forgot where.
I think due to the time of the day it became increasingly incoherent
(not necessarily near the end of the text). Hopefully no logical or
freudian lapses in there.
This allows stream_cb backends to implement blocking
behavior inside read_fn, and still get notified when the user
wants to cancel and stop playback.
Signed-off-by: Aman Gupta <aman@tmm1.net>
I think a popular libmpv application did exactly this: enabling advanced
control, and then receiving deadlocks. I didn't confirm it, though. In
any case, the API docs should avoid tricking users into making this easy
mistake.
The render API (vo_libmpv) had potential deadlock problems with
MPV_RENDER_PARAM_ADVANCED_CONTROL. This required vd-lavc-dr to be
enabled (the default). I never observed these deadlocks in the wild
(doesn't mean they didn't happen), although I could specifically provoke
them with some code changes.
The problem was mostly about DR (direct rendering, letting the video
decoder write to OpenGL buffer memory). Allocating/freeing a DR image
needs to be done on the OpenGL thread, even though _lots_ of threads are
involved with handling images. Freeing a DR image is a special case that
can happen any time. dr_helper.c does most of the evil magic of
achieving this. Unfortunately, there was a (sort of) circular lock
dependency: freeing an image while certain internal locks are held would
trigger the user's context update callback, which in turn would call
mpv_render_context_update(), which processed all pending free requests,
and then acquire an internal lock - which the caller might not release
until a further DR image could be freed.
"Solve" this by making freeing DR images asynchronous. This is slightly
risky, but actually not much. The DR images will be free'd eventually.
The biggest disadvantage is probably that debugging might get trickier.
Any solution to this problem will probably add images to free to some
sort of queue, and then process it later. I considered making this more
explicit (so there'd be a point where the caller forcibly waits for all
queued items to be free'd), but discarded these ideas as this probably
would only increase complexity.
Another consequence is that freeing DR images on the GL thread is not
synchronous anymore. Instead, it mpv_render_context_update() will do it
with a delay. This seems roundabout, but doesn't actually change
anything, and avoids additional code.
This also fixes that the render API required the render API user to
remain on the same thread, even though this wasn't documented. As such,
it was a bug. OpenGL essentially forces you to do all GL usage on a
single thread, but in theory the API user could for example move the GL
context to another thread.
The API bump is because I think you can't make enough noise about this.
Since we don't backport fixes to old versions, I'm specifically stating
that old versions are broken, and I'm supplying workarounds.
Internally, dr_helper_create() does not use pthread_self() anymore, thus
the vo.c change. I think it's better to make binding to the current
thread as explicit as possible.
Of course it's not sure that this fixes all deadlocks (probably not).
Extending the client-allocated mpv_opengl_drm_params struct
constituted a break of ABI that could cause UB.
Create a clean break by deprecating "drm_params" and related structs
and enum values, and replacing it with "drm_params_v2".
Also fix some comments and code that wrongly assumed that open could
return any other negative number than -1 for failure.
This commit updates the libmpv version to 1.104
This commit bumps the libmpv version to 1.102
drm-osd-plane -> drm-draw-plane
drm-video-plane -> drm-drmprime-video-plane
drm-osd-size -> drm-draw-surface-size
"draw plane", as in the plane that OpenGL draws to, whether it be
video + OSD or just OSD.
"drmprime video plane", as in the plane used for hwdec video imported
via drmprime.
"draw surface size", as in the size of the surface used for the draw plane
The new names are invariant whether or not hwdec_drmprime_drm is being
used or not. The original naming was very confusing, as when doing
regular rendering (swdec or vaapi) the video would be displayed on the
"OSD plane", and the "Video plane" would remain unused.
Many asynchronous commands are potentially long running operations, such
as loading something from network or running a foreign process.
Obviously it shouldn't just be possible for them to freeze the player if
they don't terminate as expected. Also, there will be situations where
you want to explicitly stop some of those operations explicitly. So add
an infrastructure for this.
Commands have to support this explicitly. The next commit uses this to
actually add support to a command.
Attempts to enable the following things:
- let a render API user do "proper" audio-sync video timing itself
- make it possible to not re-render repeated frames if the API user has
better mechanisms available (e.g. waiting for a DisplayLink cycle
instead)
- allow the user to delay or skip redraws if it makes sense
Basically this information will be needed by API users who want to be
"clever" about optimizing timing and rendering.
DR (letting the decoder allocate texture memory) requires running the
allocation on the render thread. This is rather hard with the render
API, because the user controls this thread and when it's entered. It was
not possible until now.
This commit adds a bunch of infrastructure to make this possible. We add
a new optional mode (MPV_RENDER_PARAM_ADVANCED_CONTROL) which basically
lets the user's render thread and libmpv agree how this should be done.
Misuse would lead to deadlocks. To make this less likely, strictly
document thread safety/locking issues. In particular, document which
libmpv functions can be called without issues. (The rest has to be
assumed unsafe.)
The worst issue is destruction of the render context while video is
still active. To avoid certain unintended recursive locks (i.e.
deadlocks, unless we'd make the locks recursive), make the update
callback lock separate. Make "killing" the video chain asynchronous, so
we can do extra work while video is being destroyed.
Because losing wakeups is a big deal, setting the update callback now
triggers a wakeup. (It would have been better if the wakeup callback
were a parameter to mpv_render_context_create(), but too late.)
This commit does not add DR yet; the following commit does this.
As it turns out, there are multiple libmpv users who saw a need to
use the hook API. The API is kind of shitty and was never meant to be
actually public (it was mostly a hack for the ytdl script).
Introduce a proper API and deprecate the old one. The old one will
probably continue to work for a few releases, but will be removed
eventually.
There are some slight changes to the old API, but if a user followed
the manual properly, it won't break.
Mostly untested. Appears to work with ytdl_hook.
Hardware decoding things often need access to additional handles from
the windowing system, such as the X11 or Wayland display when using
vaapi. The opengl-cb had nothing dedicated for this, and used the weird
GL_MP_MPGetNativeDisplay GL extension (which was mpv specific and not
officially registered with OpenGL).
This was awkward, and a pain due to having to emulate GL context
behavior (like needing a TLS variable to store context for the pseudo GL
extension function). In addition (and not inherently due to this), we
could pass only one resource from mpv builtin context backends to
hwdecs. It was also all GL specific.
Replace this with a newer mechanism. It works for all RA backends, not
just GL. the API user can explicitly pass the objects at init time via
mpv_render_context_create(). Multiple resources are naturally possible.
The API uses MPV_RENDER_PARAM_* defines, but internally we use strings.
This is done for 2 reasons: 1. trying to leave libmpv and internal
mechanisms decoupled, 2. not having to add public API for some of the
internal resource types (especially D3D/GL interop stuff).
To remain sane, drop support for obscure half-working opengl-cb things,
like the DRM interop (was missing necessary things), the RPI window
thing (nobody used it), and obscure D3D interop things (not needed with
ANGLE, others were undocumented). In order not to break ABI and the C
API, we don't remove the associated structs from opengl_cb.h.
The parts which are still needed (in particular DRM interop) needs to be
ported to the render API.
It's a WTF that we have something as specific in the API. It could be
argued that we should provide helpers for other language and GUI toolkit
combinations. Obviously that's not going to scale, and it's somewhat
likely that it will bitrot. The rest is said in the API changelog.
Before this change, mpv_wait_event() could inconsistently return
multiple MPV_EVENT_SHUTDOWN events to a single mpv_handle, up to the
point of spamming the event queue under certain circumstances. Change
this and just send it exactly once to each mpv_handle.
Some client API users might have weird requirements about destroying
their state asynchronously (and not reacting immediately to the SHUTDOWN
event). This change will help a bit to make this less weird and
surprising.
This changes how mpv_terminate_destroy() and mpv_detach_destroy()
behave. The doxygen in client.h tries to point out the differences. The
goal is to make this more useful to the API user (making it behave like
refcounting).
This will be refined in follow up commits.
Initialization is unfortunately closely tied to termination, so that
changes as well. This also removes earlier hacks that make sure that
some parts of FFmpeg initialization are run in the playback thread
(instead of the user's thread). This does not matter with standard
FFmpeg, and I have no reason to care about this anymore.
The purpose of the new API is to make it useable with other APIs than
OpenGL, especially D3D11 and vulkan. In theory it's now possible to
support other vo_gpu backends, as well as backends that don't use the
vo_gpu code at all.
This also aims to get rid of the dumb mpv_get_sub_api() function. The
life cycle of the new mpv_render_context is a bit different from
mpv_opengl_cb_context, and you explicitly create/destroy the new
context, instead of calling init/uninit on an object returned by
mpv_get_sub_api().
In other to make the render API generic, it's annoyingly EGL style, and
requires you to pass in API-specific objects to generic functions. This
is to avoid explicit objects like the internal ra API has, because that
sounds more complicated and annoying for an API that's supposed to never
change.
The opengl_cb API will continue to exist for a bit longer, but
internally there are already a few tradeoffs, like reduced
thread-safety.
Mostly untested. Seems to work fine with mpc-qt.
This should be helpful for the new OSX Cocoa backend, which uses
opengl-cb internally. Since it comes with a behavior change that could
possibly interfere with libmpv/opengl_cb users, we mark it as explicit
API change.
A release has been made, so drop options deprecated for that release.
Also drop some options which have been deprecated a much longer time
before.
Also fix a typo in client-api-changes.rst.
This was off for mpv CLI, but on for libmpv. The motivation behind this
was that it would be confusing for applications if libmpv continued
playback in a severely "degraded" way (without either audio or video),
and that it would be better to fail early.
In reality the behavior was just a confusing difference to mpv CLI, and
has confused actual users as well. Get rid of it.
Not bothering with a version bump, since this is so minor, and it's easy
to ensure compatibility in affected applications by just setting the
option explicitly.
(Also adding the missing next-release-marker in client-api-changes.rst.)
You could do mpv_set_option(h, "no-fs", ""), which would behave like
"--no-fs" on the command line. At one point, this had to be emulated for
compatibility, and printed a deprecation warning. This was almost a year
ago, so remove it.
As threatened by the API changes document.
This commit also removes or stubs equivalent calls in IPC and Lua
scripting.
The stubs are left to maintain ABI compatibility. The semantics of the
API functions have been close enough to doing nothing that this probably
won't even break existing API users. Probably.
Since the recent release was named 0.22.0 instead of 0.21.1, bump all
mentions of 0.22.0 to 0.23.0. These were planned removals of deprecated
versions, which obviously didn't happen in 0.22.0.
With the merging of options and properties, the mpv_set_option()
function is close to being useless, and mpv_set_property() can be used
for everything instead. There are certain conflicts remaining, which are
explained in depth in the docs. For now, none of this should affect
existing code using the client API.
Make mpv_set_property() redirect to mpv_set_option() before
initialization.
Remove some options marked as M_OPT_FIXED. The "pause" and "speed"
options cannot be written anymore without the playloop being notified by
it, so the M_OPT_FIXED does nothing. For "vo-mmcss-profile", the problem
was lack of synchronization, which has been added. I'm not sure what the
problem was with "frames" - I think it was only marked as M_OPT_FIXED
because changing it during playback will have no effect. Except for
pause/speed, these changes are needed to make them writable as
properties after mpv_initialize().
Also replace all remaining uses of CONF_GLOBAL with M_OPT_FIXED.
My original idea was making mpv_initialize() a no-op, but it seems this
can't happen after all. The problem is especially with subtle
interactions in option parsing (basically all pre-parse options).
Instead, I might go into the opposite direction, and add a new API
function that takes over the role of mpv_create+mpv_initialize, and
which will take a list of options. This list will be for the purpose
of setting options that can be set only at initialization time (such
as config-dir). This would also make it more uniform with the command-
line player initialization.
Maybe.
In any case, for now revert parts of commit 453fea87 to remove the
initialization-related freedoms it added. Fortunately, this wasn't
released yet, so we remove it from the API as if it never happened.
(The rest of that commit is still fine, just not the additional
freedom.)
They're useless, and I have no idea what they're actually supposed to do
(wrt. pending input processing changes).
Also remove their implicit uses from the IPC handlers.
This workaround prevented that libmpv users could accidentally crash
when the SIGPIPE signal was triggered by FFmpeg's OpenSSL/GnuTLS usage.
But it also modifies the global signal handler state, so remove it now
that this workaround is not required anymore.
Create the core thread right in mpv_create(), and reduce what
mpv_initialize() does further. This is simpler, and allows the API user
to do more before calling mpv_initialize(). The latter is not the real
goal, rather we'd like mpv_intialize() reduced to do almost nothing. It
still does a lot, but nothing truly special anymore that is absolutely
required for basic mpv workings.
One thing we want the user to be able to do is changing properties
before mpv_initialize() to reduce the special status of
mpv_set_option().
The client API can do this (and there are apparently some libmpv using
projects which rely on this). But it's just unnecessary bloat as it
requires a separate code path from the option parser. It would be better
to remove this code. Formally deprecate it, including API bump and
warning in the API changes file to make it really clear.
Forgotten in previous commit.
Also minor semi-related change: remove the extra "," from the
mpv_sub_api enum, which I accidentally added in the previous commit.
(C99 is fine with trailing ",", C89 strictly speaking not. So do
this for maximum compatibility.)
Although it appears to be accepted by the function, MSGL_STATUS messages
are never passed to the client API. Consequently "status" has the same
meaning as "v" and is useless.
Instead of implicitly resetting the options to defaults and then
applying the options, they're always applied on top of the current
options (in the same way adding new options to the CLI command line
will).
This does not apply to vo_opengl_cb, because that has an even worse mess
which I refuse to deal with.
Options/properties that are choices, and which include "yes" or "no"
values (or both) can now be read and written as MPV_FORMAT_FLAG.
For write access, rejecting flags in these cases was obnoxiously
unintuitive and inconvenient.
For read access, the value of this is less convincing, and actually it's
a major API change. At this point I probably have to admit that the
finer details of the client API are very unstable.
If a mpv_node wrapped a string, the behavior was different from calling
mpv_set_property() with MPV_FORMAT_STRING directly. Change this.
The original intention was to be strict about types if MPV_FORMAT_NODE
is used. But I think the result was less than ideal, and the same change
towards less strict behavior was made to mpv_set_option() ages ago.
This is a pseudo-OpenGL extension for letting libmpv query native
windowing system handles from the API user. (It uses the OpenGL
extension mechanism because I'm lazy. In theory it would be nicer to let
the user pass them with mpv_opengl_cb_init_gl(), but this would require
a more intrusive API change to extend its argument list.)
The naming of the extension and associated function was unnecessarily
Windows specific (using "D3D"), even though it would work just fine for
other platforms. So deprecate the old names and introduce new ones. The
old ones still work.
Make it so that they don't need to be edited on release (no change in
tense). Also, move the "stray" changes after client API version 1.19 to
1.19 itself.
This is basically a hack for drivers which prevent the mpv DXVA2 decoder
glue from working if OpenGL is in fullscreen mode.
Since it doesn't add any "hard" new API to the client API, some of the
code would be required for a true zero-copy hw decoding pipeline, and
sine it isn't too much code after all, this is probably acceptable.
wm4