Duktape
mpv
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Duktape | mpv | |
---|---|---|
10 | 830 | |
5,830 | 25,874 | |
- | 2.4% | |
6.4 | 9.9 | |
about 1 month ago | 6 days ago | |
JavaScript | C | |
MIT License | GNU General Public License v3.0 or later |
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
Duktape
- Roll your own JavaScript runtime, pt. 3
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How to Create a Modern C Project with CMake and Conan
Im my projects I search for single file libs.(like https://github.com/svaarala/duktape etc...)
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Is there anyway to bypass the limit of rand()?
Use lrand48(), or better, implement a high-quality RNG like PCG or splitmix64.
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Libgrapheme: A simple freestanding C99 library for Unicode
You can also refer to the Unicode routines of other small JS engines[1,2], those don’t use ICU either, although the implementations are mercilessly size-optimized (to put it politely) and restricted to what the target JS version requires (e.g. casemapping but no normalization).
[1] https://github.com/bellard/quickjs/blob/master/libunicode.c
[2] https://github.com/svaarala/duktape/blob/master/src-input/du...
- Duktape
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Nan Boxing
> memcpy from bytes to a NaN should work fine
Signaling NaNs are explicitly undefined in C11 F.2.1.: "This specification does not define the behavior of signaling NaNs." - and in practice may be "quieted" by conversion to Quiet NaNs, changing their bit patterns. Fast math optimization flags will also break the hell out of your code by assuming NaNs are impossible. I want to say there are more circumstances where optimizers and compiler generated code can butcher your NaN payloads, but I'd be working off recollected hearsay and I can't find a source, so don't quote me on that.
NaN boxing is common enough that, if you take the right precautions, a modern compiler should probably support it, maybe. NaN boxing is uncommon enough that, if your codebase needs to be sufficiently portable, you need an opt out for when it breaks. Let's review duktape's scars:
https://github.com/svaarala/duktape/blob/123d9426d5e5b36d5da...
https://github.com/svaarala/duktape/blob/5252b7a50611a3cb8bf...
https://github.com/svaarala/duktape/blob/224a0b89ca08a36e37e...
Note that "the right precautions" involve unions and proper integer types to avoid optimizer-invoked rewrites of the value and debugging when things go wrong, not simply YOLOing bytes into a double via memcpy. Note that debugging when it all goes terribly wrong can be quite painful. I've personally had the misfortune of being forced to debug duktape being built with fast math optimizatoins enabled on one "rare" platform + build configuration that wasn't caught by duktape's #if defined(__FAST_MATH__) checks linked above (wasn't Clang nor GCC, so go figure it didn't make the same #define)
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YouTube-dl has a JavaScript interpreter written in 870 lines of Python
I was expecting this to be about Duktape <https://github.com/svaarala/duktape>, but heh, for sure no. I'd bet $1 there's no way youtube-dl would switch, but I wonder if yt-dlp would?
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Optimizations Enabled by -ffast-Math
Fast math optimizations can break code like this by breaking isNaN.
I was porting a C++ project to a certain platform - and that platform enabled a -ffast-math equivalent by default in Release (but not Debug) builds! This broke duktape, a JS engine said project embedded, in some nasty and subtle ways. Instead of storing a number/pointer/??? (8 bytes) + type tag (4? bytes) for each dynamically typed JS value, duktape can bit-pack values into a single 8 byte "double" value by storing object/string handles as NaN values - this isn't an uncommon trick for dynamically typed scripting stuff:
https://github.com/svaarala/duktape/blob/c3722054ea4a4e50f48...
Naturally, the -ffast-math equivalent broke isNaN checks, which caused random object/string handles to be mistakenly reinterpreted as "numbers" - but only in Release builds, for this one particular platform, in one rarely taken branch, so neither QA nor CI caught it, leading to hours of manufacturing a repro case, stepping through an absurd amount of code, and then finally looking at the default build rules and facepalming.
Cursing the platform vendor under my breath, I overrode the defaults to align with the defaults of every other config x platform combination we already had: no fast math. If you want those optimizations, use SSE-friendly NaN-avoiding intrinsics - or, if you must use the compiler flags, ensure you do so consistently across build configs and platforms, perhaps limited to a few TUs or modules if possible. This allows you to have a chance at using your Debug builds to debug the resulting "optimizations".
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Can C++ and JS be used together?
Sure. For example, DukTape is an implementation of Javascript designed to be embedded in other projects. Google's V8 Javascript engine (used in Chrome), can also be embedded, see Node.Js for example.
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[AskJS] Do you use JavaScript on Microcontrollers? Which engine / interpreter?
- Duktape (4.8k stars)
mpv
- MPV: Vulkan Video Decoding: Usage Guide and FAQ
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Firefox slow to load YouTube? Just another front in Google's war on ad blockers
https://mpv.io/ has yt-dlp support, if yt-dlp is installed you just need to throw the URL at it and it plays the video (without download).
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Can't save frame as JPG
See https://github.com/mpv-player/mpv/issues/9053
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Video stops on furst frame, audio continues to play,seek works
I apologise for not following procedure. I am in the middle of building mpv 0.37 from source. Irrespective of the outcome I will document what I had to do in addition to the instructions on mpv.io and if the problem perststs, where it happens and where not with kernel version, mpv version taken from the screen, and the terminal output.
- PC Gopro playback help needed
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S23 8k video freezes when played on VLC computer
Use MPV. Partticularily shinchiro's builds. Extract the folder where you want its installation directory to be, if you decide to install it. Otherwise, just drag and drop files on top of its window or executable.
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Ripgrep is faster than {grep, ag, Git grep, ucg, pt, sift}
Author of ripgrep here.
Like automatic encoding detection and transparently searching UTF-16?
Or simple ways for composing character classes, e.g., `[\pL&&\p{Greek}]` for all codepoints in the Greek script that are letters. Another favorite of mine is `\P{ascii}`, which will search for any codepoint that isn't in the ASCII subset.
Or more sophisticated filtering features that let you automatically respect things like gitignore rules.
Those are all things that ripgrep does that grep does not. So I do not favor this explanation personally.
ripgrep has just about all of the functionality that GNU grep does. I would say the two biggest missing pieces at this point are:
* POSIX locale support. (But this might be a feature[1].)
* Support for "basic" regexes or some equivalent that flips the escaping rules around. i.e., You need to write `\+` to match 1 or more things, where as `+` will just match `+ literally.
Otherwise, ripgrep has unfortunately grown just about as many flags as GNU grep.
[1]: https://github.com/mpv-player/mpv/commit/1e70e82baa9193f6f02...
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PCSX2 Disables Wayland Support
- https://github.com/mpv-player/mpv/issues/8692
- C Locales
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Yorick is an interpreted programming language for scientific simulations
https://mpv.io played it without fuss.
What are some alternatives?
V8 - The official mirror of the V8 Git repository
GStreamer - GStreamer open-source multimedia framework
quickjs - Public repository of the QuickJS Javascript Engine.
yt-dlp - A feature-rich command-line audio/video downloader
Lua - Lua is a powerful, efficient, lightweight, embeddable scripting language. It supports procedural programming, object-oriented programming, functional programming, data-driven programming, and data description.
celluloid - A simple GTK+ frontend for mpv
jerryscript - Ultra-lightweight JavaScript engine for the Internet of Things.
FFmpeg - Mirror of https://git.ffmpeg.org/ffmpeg.git
ChaiScript - Embedded Scripting Language Designed for C++
glsl-shaders - This repo is for glsl shaders converted by hand from libretro's common-shaders repo, since some don't play nicely with the cg2glsl script.
SWIG - SWIG is a software development tool that connects programs written in C and C++ with a variety of high-level programming languages.
VideoLAN Client (VLC) - VLC media player - All pull requests are ignored, please follow https://wiki.videolan.org/Sending_Patches_VLC/