ffmpeg/bulk-reduce-bitrate

Uses ffmpeg to reduce the bitrate of all videos matched by a glob. Videos are copied, not replaced.

Usage

npx @lukasbach/scripts ffmpeg/bulk-reduce-bitrate

You can call the script directly if you have installed it globally:

npm i -g @lukasbach/scripts
ldo ffmpeg/bulk-reduce-bitrate

Options

• --source, -s: Where are the video files to compress?
• --dest, -d: Where should the files be stored?
• --crf: What CRF value should be used (0=lossless, 51=worst)?
• -r: What framerate (0 = undefined)?
• --size, -S: What is the maximum height/width? (aspect-ratio will be maintained, put 0 to use original size)
• -v, --verbose: Verbose logging

You can also omit options, and will be asked for them interactively.

Add --yes to skip all confirmations.

Script source

View Source on GitHub

/** Uses ffmpeg to reduce the bitrate of all videos matched by a glob. Videos are copied, not replaced. */

import path from "path";

const filesGlob = await ask.text("source,s", "Where are the video files to compress?", "**/*.mp4");
const files = glob.sync(filesGlob);
log.info(`Glob matched ${files.length} files.`);

const outputTemplate = await ask.text(
  "dest,d",
  "Where should the files be stored?",
  "{{folder}}/compressed/{{name}}.mp4"
);
const crf = await ask.number("crf", "What CRF value should be used (0=lossless, 51=worst)?", "24");
const framerate = await ask.number("r", "What framerate (0 = undefined)?", "0");
const frString = framerate && framerate !== 0 ? ` -r ${framerate} ` : "";

const maxSize = await ask.number(
  "size,S",
  "What is the maximum height/width? (aspect-ratio will be maintained, put 0 to use original size)",
  "0"
);
const sizeString =
  maxSize > 0
    ? `-vf "scale=if(gte(iw\\,ih)\\,min(${maxSize}\\,iw)\\,-2):if(lt(iw\\,ih)\\,min(${maxSize}\\,ih)\\,-2)"`
    : "";

log.info("Found files:", files);
if (!(await ask.confirm("Run on the matched files?"))) {
  process.exit(0);
}

for (const file of files) {
  const vars = {
    folder: path.dirname(file),
    name: path.basename(file, path.extname(file)),
    ext: path.extname(file),
  };
  const newTarget = utils.replaceTemplateText(outputTemplate, vars);

  if (await fs.exists(newTarget)) {
    log.warn(`File ${newTarget} already exists, skipping...`);
    continue;
  }
  log.verbose(`Compressing ${file} to ${newTarget}`);

  // utils.assert(!(await fs.exists(newTarget)), `Output file ${newTarget} already exist!`);
  await fs.ensureDir(path.dirname(newTarget));
  const command = `ffmpeg -i "${file}" ${sizeString} -vcodec libx265 -crf ${crf} ${frString} "${newTarget}"`;
  log.verbose("running", command);
  await $({ stdio: "inherit" })`${command}`;
}