Anime4K Upscaling

Anime4K Upscaling

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The app can upscale episodes with the Anime4K GLSL shaders (e.g. 720p/1080p → 1080p/1440p/4K). The shaders ship with the app or are downloaded automatically when needed.

Modes

Mode	Description
disabled	No upscaling (default)
after_download	After a download finishes, all episodes of the job are added to the upscale queue as one entry (only if "Upscale" was checked on the job)
during_download	Upscaling within the download process

Independently of the mode, files can always be queued manually from the Library (single episodes, seasons or entire titles).

Settings

Setting	Values	Default
Engine	auto, mpv, libplacebo	auto
Shader preset	A, B, C, D	B
Shader quality	high, low	high
Target resolution	1080p, 1440p, 4k, source	1080p
Replace original	on/off	on
Output codec	libx264, libx265, copy	libx264
CRF	0–51	18
Encoder preset	ultrafast … veryslow	medium

About the Anime4K presets: A (restore, for heavily compressed sources), B (balanced, default), C (fast/lightweight), D (maximum quality). The quality level switches between the high-end and low-end shader variants.

Engines

• mpv: uses mpv in encoding mode with GLSL shaders. The UI checks whether the installed mpv supports encoding (on Windows mpv is downloaded automatically).
• libplacebo: FFmpeg's libplacebo filter with the same shaders.
• auto: picks an available engine automatically. The "Check engines" button shows what works on your system.

Queue behavior

• Dedicated worker, one upscale job at a time, with live progress (proportional per file for multi-file jobs).
• Jobs can be cancelled, deleted and reordered; interrupted jobs are reset after a restart.
• With "replace original", rendering goes to a temp file first (.upscale_tmp.mkv) and only replaces the original on success — a cancel never corrupts the original.
• If only some files fail, the job is marked completed with an error note.

Note: Upscaling is compute-intensive. CRF 18 with preset medium gives very good quality; on weaker systems set out_preset to fast/veryfast.