dziurkacz/dziurkacz-fast.mjs

#!/usr/bin/zx

const { extname } = require("path");

const args = process.argv.slice(-2);

const video = args[0];
const labels = args[1];
const ext = extname(video);

const FREQ = 48000;
const FRAMERATE = parseFloat(
  (await $`mediainfo --Output="Video;%FrameRate%" ${video}`).stdout
);

const labels_contents = (await $`awk '{print $3, $4, $5}' < ${labels}`).stdout;

const cuts = labels_contents
  .split(os.EOL)
  .slice(0, -1)
  .map((e) =>
    e
      .split(" ")
      .slice(1)
      .map((x) => parseFloat(x))
  )
  .map(([samples, start]) => ({
    duration: samples / FREQ,
    start,
    end: start + samples / FREQ,
  }));

console.log(cuts);

let all_frames = [];

const frame_count = parseInt(
  (await $`mediainfo --Output="Video;%FrameCount%" ${video}`).stdout
);

for (let i = 0; i < frame_count; i++) {
  all_frames.push(i);
}

console.log(all_frames);

for (let cut of cuts) {
  all_frames = [
    ...all_frames.slice(0, Math.round(cut.start * FRAMERATE)),
    ...all_frames.slice(Math.round(cut.end * FRAMERATE)),
  ];
}

console.log(all_frames);

const pieces = [];

let current_piece = { start: all_frames[0] };

let predicted_frame_number = 0;

// skipping the first one, as we're doing lookback
for (let i = 1; i < all_frames.length; i++) {
  if (all_frames[i] != all_frames[i - 1] + 1) {
    current_piece.end = all_frames[i - 1];
    pieces.push(current_piece);
    current_piece = { start: all_frames[i] };
  }
}

current_piece.end = all_frames[all_frames.length - 1];

pieces.push(current_piece);

// discarding this as using a filter requires reencoding the entire video:
const filter = pieces
  .map(
    ({ start, end }) =>
      `between(t,${(start / FRAMERATE).toFixed(5)},${(end / FRAMERATE).toFixed(
        5
      )})`
  )
  .join("+");

await $`ffmpeg -i ${video} \
               -vf ${`select='${filter}',setpts=N/FRAME_RATE/TB`} \
               -af ${`aselect='${filter}',asetpts=N/SR/TB`} \
               ${video + ".cut.mp4"}`;

// let ffmpeg_args = [];
// const parts = [];
// for (let i in pieces) {
//   const piece = pieces[i];
//   const output_filename = video + "-" + i + ".mp4";
//   ffmpeg_args = [
//     ...ffmpeg_args,
//     "-ss",
//     (piece.start / FRAMERATE).toFixed(5),
//     "-t",
//     ((piece.end - piece.start) / FRAMERATE).toFixed(5),
//     "-c",
//     "copy",
//     output_filename,
//   ];
//   parts.push(output_filename);
// }

// console.log(ffmpeg_args);

// await $`ffmpeg -i ${video} ${ffmpeg_args}`;

// await $`echo ${parts.map((s) => `file ${s}`).join("\n")} > /tmp/vdlist.txt`;

// await $`ffmpeg -f concat -safe 0 -i /tmp/vdlist.txt -c copy -y ${
//   video + "final.mp4"
// } `;