This library seems to take a very long time to convert a large raw

[Pomax]

I decided to give this a shot as part of a simple Lightroom catalog helper utility (lrcat files are just sqlite3 databases, so finding image locations and creating thumbnails for them is basically trivial), but it takes 20 seconds to convert a 6000x4000px, 26MB NEF to a 76MB (!) TIFF, on an i7-6700 with more RAM than makes sense in almost any machine.

Is there a way to tell this port to do a resize-while-loading of the NEF data, so that it only tries to work with 600x400px data, for instance? 20 seconds per thumbnail (even with result-caching) isn't really all that much better than "it doesn't work at all" =(

(using the dedicated thumbnail extraction is quite fast, but there are plenty of raws without a built in thumbnail...)

[krognome]

I second this. I am looking for a solution. Did you happen to find anything Promax? Some of the RAWs work well but ARW from one of our clients took 10 minutes for 60 previews to show. Maybe these do not have the thumbnail/preview?

[Pomax]

honestly, I ended up going the "make dcraw itself do this", with the -h flag to speed up the conversion to tiff, and then using ffmpeg to create the actual thumbnail:

import { spawn } from "node:child_node";

function createImageProcessingCommands(path, width=200, height=-1) {
  const ext = path.substring(path.lastIndexOf(`.`)+1);
  const dcraw = `dcraw -h -T "${path}.${ext}"`;
  const ffmpeg = `ffmpeg -i "${path}.tiff" -vf scale=${width}:${height} "${path}.thumbnail.png -y"`;
  return `${dcraw} && ${ffmpeg}`.split(` `);
}

/* async */ function createThumbnail(imagePath, width, height) {
  return new Promise((resolve, reject) => {
    const [command, ...args] = createImageProcessingCommands(imagePath, width, height);
    const process = spawn(command, args);
    process.on(`exit`, (...args) => resolve(...args));
    process.on(`kill`, (...args) => reject(...args));
    process.on(`error`, (...args) => reject(...args));
  });
}