This is a simple VapourSynth plugin which encodes a VideoFrame to a JPEG (libjpeg-turbo), PNG (fpnge) or WebP (libwebp). It is built primarily for Anime Tosho’s frame server, but can also be useful as a fast image exporter (alternative to imwri).

Requirements

• VapourSynth R65 or later (earlier versions have a bug which breaks returned bytes data)
• x86 CPU with SSE4.1 support (required by fpnge)
• TurboJPEG (optional)
• libwebp (optional)

Building

meson setup build
ninja -C build
ninja -C build install

If TurboJPEG or libwebp isn't found, respective JPEG/WebP support will be disabled.

Note: fpnge is only built with SSE4.1 support by default. Add -Disa=avx2 to the first command above to set AVX2 as the baseline.

Example Usage

Write the first frame of a video to a PNG file:

import vapoursynth as vs

# open input
clip = vs.core.bs.VideoSource("some_video.mkv")
# convert to RGB24
clip = vs.core.resize.Bicubic(clip, format=vs.RGB24)

# encode first frame to PNG
with clip.get_frame(0) as frame:
	data = vs.core.encodeframe.EncodeFrame(frame, "PNG")

# write PNG to file
with open("first_frame.png", "wb") as f:
	f.write(data)

API

encodeframe.EncodeFrame(frame: VideoFrame, imgformat: string [, quality: int] [, effort: int] [, alpha: VideoFrame=None])

Converts a VideoFrame (frame) to the format specified by imgformat ("PNG", "JPEG", "WEBP" or "WEBP-VP8") and returns the result as a bytes object.
Note that "WEBP" is lossless WebP whilst "WEBP-VP8" is lossy WebP.

Optionally accepts a grayscale VideoFrame (alpha) for PNG/WebP.
quality is a lossy quality level (0-100, default 75) and has a different meaning for lossless WebP. Ignored for PNG.
effort is a WebP or fpnge PNG compression level (1-5 for PNG or 1-6 for WebP, default 4). Ignored for JPEG.

Note that frame must be in either an RGB or Grayscale colourspace. If alpha is supplied, it must have the same colour depth as frame.
PNG supports 8 to 16-bit samples, whilst JPEG/WebP only allows 8-bit samples. 9 to 15-bit samples will be upsampled to 16-bit.
WebP doesn't support Grayscale input.

See Also

vsfpng: only supports RGB24/RGB32 PNG output to files, but uses the other fast PNG encoder, fpng

License

This module is Public Domain or CC0 (or equivalent) if PD isn’t recognised.

fpnge itself is licensed under the Apache License 2.0