From dfb23823443fc9065b984f3a9ba4f2a9fbdc8219 Mon Sep 17 00:00:00 2001
From: Kuba Orlik <kontatk@kuba-orlik.name>
Date: Sat, 18 Sep 2021 14:17:40 +0200
Subject: [PATCH] Add newer, faster version

---
 README.md          |   2 +-
 dziurkacz-fast.mjs | 116 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 117 insertions(+), 1 deletion(-)
 create mode 100755 dziurkacz-fast.mjs

diff --git a/README.md b/README.md
index ff3fdc8..9a60119 100644
--- a/README.md
+++ b/README.md
@@ -42,7 +42,7 @@ ffmpeg -i video.mp4 -vn -acodec copy audio.aac
 
 3. Wyeksportuj wszystkie labelki do pliku tekstowego (export -> labels)
 
-4. Uruchom `zx --quiet dziurkacz.mjs /ścieżka/do/pliku/video.mp4 /ścieżka/do/pliku/z/wyeskportowanymi/labelkami.txt`
+4. Uruchom `zx --quiet dziurkacz-fast.mjs /ścieżka/do/pliku/video.mp4 /ścieżka/do/pliku/z/wyeskportowanymi/labelkami.txt`
 
 Plik wynikowy znajdziesz w /tmp/dziurkacz/working.mp4
 
diff --git a/dziurkacz-fast.mjs b/dziurkacz-fast.mjs
new file mode 100755
index 0000000..0a77da7
--- /dev/null
+++ b/dziurkacz-fast.mjs
@@ -0,0 +1,116 @@
+#!/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"
+// } `;