node-faststart VS FFmpeg

The key to understanding this issue seems to be "-movflags +faststart". The TLDR is that Apple apparently isn't "fast-starting" their MPEG-4 files before distribution.

This became a thing when distributing QuickTime Movies on the internet became a thing (it's not an issue with random-access media), because one needed Movie metadata at the front of the file in order to support progressive playback. Because the MPEG-4 file format is effectively the QuickTime Movie file format, the need to put metadata at the front of the file continues if you want viewers/listeners to be able to play files as they're downloading.

That Apple isn't performing this extremely trivial pre-distribution process is extremely curious. It makes me wonder if this "common knowledge" was lost along the way, or if the people who would know this kind of super-obvious production step just aren't the same people in charge of Apple Music standards.

For anyone curious about what fast-start implementations look like:

https://github.com/FFmpeg/FFmpeg/blob/master/tools/qt-fastst...

https://github.com/kanongil/node-faststart

FFmpeg (https://ffmpeg.org/)

GPL2

Since FFmpeg is GPL2, doesn’t that require CompressX to disclose its source code?

IANAL, apologies if I miss understand license requirements.

https://github.com/FFmpeg/FFmpeg?tab=License-1-ov-file

This turns out to be a lot of assembly macros to help write one x86 assembly. https://github.com/FFmpeg/FFmpeg/blob/master/libavutil/x86/x...

The sibling comment recommending compiler intrinsics is probably the best way to go for writing SIMD code. A mixture of `` style types and intrinsics to specify instructions is a solid 90% solution compared to assembly.

If you want that last 10%, I think macros are putting the emphasis in the wrong place. They're a somewhat easy way to build up a language abstraction which will work if held carefully, but I'm confident the dev experience using this abstraction when you write invalid code will be deeply confusing.

I would suggest to write a parser instead of the macros. That'll tell you clearly when the syntax is invalid (though possibly not with much precision) and it'll give you a place to put semantic analysis for where valid syntax encodes nonsense. Do the equivalent of the macro expansions on the parsed tree instead of on the text. Emit asm as the "back end".

You might have heard of FFMPEG or ImageMagick for image and video edition in a programmatic way. MoviePy is a Python module for video editing (Python wrapper for FFMPEG and ImageMagick). It provides functions for cutting, concatenations, title insertions, video compositing, video processing, and the creation of custom effects. It can read and write common video and audio formats and be run on any platform with Python 2.7 or 3+.

There are many cloud-based tools and websites that can convert your images, but the problem with these tools is that you usually have to upload the files for them to be processed, and some of their services are not free. In this article, I'd like to introduce a piece of software called FFmpeg, which allows you convert the images locally with one simple command.

To run the demo locally, be sure to have Python 3.11 and FFmpeg installed.