QOI Image Support

[basicer]

• Production edit: This closes Add support of QOI images godot-proposals#3726.

[basicer]

Thanks for the comments! I opened this as a draft as I knew I had a few more passes to go though before it was ready for review.

My biggest question is what should be done about MovieWriterPNGWAV? What I did makes a lot of sense, but then the name of the classes is a bit odd? Options as I see it are:

1. Don't change anything.
2. Rename this class to MovieWriterImgWAV
3. Make a new class MovieWriterQOIWAV, with mostly duplicate code.

[DeeJayLSP]

2. Rename this class to MovieWriterImgWAV

Renaming classes is considered compatibility break, and should only be done between major versions.

3. Make a new class MovieWriterQOIWAV, with mostly duplicate code.

I see some parallels with my QOA implementation. The original version was a module to import and play QOA files, but since QOA isn't a popular format to be converted to (unlike QOI, although not widely adopted as something like JPEG XL) I added a converter from WAV, with a lot of duplicated code.

But because I was never satisfied with that implementation, I ended up rewriting it inside the WAV code, as a compression mode rather than a separate format. No class renames and most importantly: no duplicated code.

IMHO, the best alternative would be 1. Making a new class and duplicating code has a considerable impact on binary size.

[Calinou]

I suggest keeping the class name as-is, while adding a note in the class reference about why the class is named PNGWAV even if it supports QOI.

For instance, you can add this at the bottom of doc/classes/MovieWriterPNGWAV.xml's <description> tag:

[b]Note:[/b] For historical reasons, this class is named MovieWriterPNGWAV even though it also supports writing the QOI image format.

[basicer]

2. Rename this class to MovieWriterImgWAV

Renaming classes is considered compatibility break, and should only be done between major versions.

3. Make a new class MovieWriterQOIWAV, with mostly duplicate code.

I see some parallels with my QOA implementation. The original version was a module to import and play QOA files, but since QOA isn't a popular format to be converted to (unlike QOI, although not widely adopted as something like JPEG XL) I added a converter from WAV, with a lot of duplicated code.

But because I was never satisfied with that implementation, I ended up rewriting it inside the WAV code, as a compression mode rather than a separate format. No class renames and most importantly: no duplicated code.

IMHO, the best alternative would be 1. Making a new class and duplicating code has a considerable impact on binary size.

I noticed in the QOA patch, you added the header file to misc instead of making a separate folder. I suppose I should do that here too.

[basicer]

MovieWriterPNGWAV

Seems like that class isnt documented because its not reflected directly.

[Calinou]

Tested locally on https://github.com/Calinou/godot-movie-maker-demo, it works as expected. Using an optimized editor build (optimize=speed lto=full).

PC specifications

• CPU: Intel Core i9-13900K
• GPU: NVIDIA GeForce RTX 4090
• RAM: 64 GB (2×32 GB DDR5-5800 C30)
• SSD: Solidigm P44 Pro 2 TB
• OS: Linux (Fedora 39)

Results:

Format	Time to record 30s	Total file size (audio + video)
AVI MJPEG quality 75	27s	166.8 MiB
AVI MJPEG quality 100	51s	861.2 MiB
PNG	6m19s	1.7 GiB
QOI	22s	1.9 GB

The output file size is a bit larger, but it's greatly made up for by having much faster write speeds – faster than MJPEG at quality 75, while being lossless. This makes QOI the best format for Movie Maker output now.

Stripped binary size grows by 12 KB with this PR, which is pretty reasonable considering the big difference in Movie Maker usability this PR provides.

I took a quick look at the code and it looks good to me.