The previous commit to dynamically load VapourSynth R74 would fail to work
for VapourSynth R73 and before on Linux due to load mode RTLD_LOCAL. To
make it work on all VapourSynth version, switch to use RTLD_GLOBAL mode.
Add library handle closing in drv_vss_uninit for completeness.
VapourSynth R74 changed two things relevant to mpv build process:
1) VSScript no longer has static library to link to, and only support runtime loading.
This is reflected on the new VSScript example in VapourSynth SDK.
2) The VSScript library name is changed from libvapoursynth-script to libvsscript for Linux
and MacOS.
The new VSScript initialization code is modified from their SDK example to utilize
mpv's mechanisms. Build dependency is also updated accordingly.
Currently by default mpv sets --all-subs when calling yt-dlp for JSON
info. --all-subs is an option that simply expands to --sub-langs all
--write-subs. --write-subs is special that without it yt-dlp will no
longer extract any subtitle info.
mpv's yt-dlp hook has a logic that if user specify any sub-langs in
--ytdl-raw-options, it no longer uses --all-subs. Unfortunately, this
means unaware users will not get any subtitle any more until they study
the mpv internal code and add their own --write-subs.
This PR always specifies --write-srt, an alias of --write-subs, in the
hook, so users don't have to. The alias is used to maintain
compatibility with youtube-dl.
Fixes issue #14818
VapourSynth introduced their version 4 API in R55, 3 years ago. mpv is
still using the deprecated version 3. I think it is good to migrate
before VapourSynth completely removes it.
The most impacted area is the video format. Previously we have a fixed
table of supported formats, each represented by an integer. In v4, the
integer is replaced by pointer to the full struct of the format.
Second, the way to create video filter is changed. Previously caller
needs to supply a "initialization" callback to `createFilter()`, which
sets up video info etc. In v4, video info is prepared first, passed to
the `createVideoFilter2()` and we get back the node.
Also, previously mpv was using the `fmSerial` filter mode, which means
VapourSynth 1) can only request one frame from mpv at a time, and 2) the
order of frames requested must be sequential. I propose to change it to
the parallel request mode, which requests multiple frames at a time in
semi random order. The reasons are, for 1), the get frame function,
`infiltGetFrame()`, unlocks the mutex during output image generation,
thus can benefit from parallel requests. For 2) thanks to the frame
buffer, unordered frame requests are acceptable. Just make sure the
buffer is large enough.
Third, the way VapourSynth scripting environment works change. In v4,
the scripting API is operated through struct pointer, much like the
exist `vsapi` pointer. The "finalize" function is also no longer needed.
Currently the vapoursynth video filter does not accept any argument for
passing arbitrary user data. This limits what the VS script can do.
Ideally, the vapoursynth filter has an user-data parameter that contain
string value. mpv passes that value to the VS script just like
container_fps and others. Once the VS script gets the data, it can do
all sorts of data extraction and transformation.
Another benefit is that instead of mpv always have to catch up to user
needs for this filter, with this users can just pass whatever needed
themselves, thus becomes more future-proof.
Fixes#14214
Currently the documentation for building on Windows, specifically the
"Native Compilation with Clang (Windows SDK Build)" route, could use a
few minor improvement to make the development onboarding experience more
smoothly.
Fixes#14214
In win32 build, if libass and libfontconfig appear after libmingwex
during linking, crash happens whenever fontconfig calls to opendir().
Moving them before ffmpeg makes sure they always appear first.
More info on https://github.com/shinchiro/mpv-winbuild-cmake/issues/217.
Crend King