Rework to use the melt binary

.gitignore

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+/.log/

kdenlive.mjs

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+#!/usr/bin/zx --quiet
+
+import { formatDuration } from "./util.mjs";
+import Producer from "./producer.mjs";
+
+export default class Project {
+  constructor(fps) {
+    this.producers = [];
+    this.clips = [];
+    this.fps = fps;
+  }
+
+  addProducer(file) {
+    this.producers.push(new Producer(file));
+    return this;
+  }
+
+  async toXML() {
+    return `<?xml version='1.0' encoding='utf-8'?>
+<mlt LC_NUMERIC="C" producer="main_bin" version="7.0.0" root="/home/kuba/Downloads">
+ <profile frame_rate_num="${
+   this.fps
+ }" sample_aspect_num="1" display_aspect_den="9" colorspace="601" progressive="1" description="1920x1080 29.90fps" display_aspect_num="16" frame_rate_den="1" width="1920" height="1080" sample_aspect_den="1"/>
+${(
+  await Promise.all(this.producers.map((producer) => producer.toXML(this.fps)))
+).join("\n")}
+ <playlist id="main_bin">
+  <property name="kdenlive:docproperties.activeTrack">2</property>
+  <property name="kdenlive:docproperties.audioChannels">2</property>
+  <property name="kdenlive:docproperties.audioTarget">1</property>
+  <property name="kdenlive:docproperties.disablepreview">0</property>
+  <property name="kdenlive:docproperties.documentid">1633881496938</property>
+  <property name="kdenlive:docproperties.groups">[
+]
+</property>
+  <property name="kdenlive:docproperties.kdenliveversion">21.08.1</property>
+g  <property name="kdenlive:docproperties.version">1.02</property>
+  <property name="kdenlive:expandedFolders"/>
+  <property name="kdenlive:documentnotes"/>
+  <property name="xml_retain">1</property>
+${this.producers
+  .map((producer) => `<entry producer="producer${producer.index}"/>`)
+  .join("\n")}  
+ </playlist>
+ <producer id="black_track" in="00:00:00.000" out="00:08:20.000">
+  <property name="length">2147483647</property>
+  <property name="eof">continue</property>
+  <property name="resource">black</property>
+  <property name="aspect_ratio">1</property>
+  <property name="mlt_service">color</property>
+  <property name="mlt_image_format">rgb24a</property>
+  <property name="set.test_audio">0</property>
+ </producer>
+ <playlist id="playlist0">
+  <property name="kdenlive:audio_track">1</property>
+<blank length="1000"/>
+<entry producer="producer1"/>
+ </playlist>
+ <playlist id="playlist1">
+  <property name="kdenlive:audio_track">1</property>
+ </playlist>
+ <tractor id="tractor0" in="00:00:00.000">
+  <property name="kdenlive:audio_track">1</property>
+  <property name="kdenlive:timeline_active">1</property>
+  <track hide="video" producer="playlist0"/>
+  <track hide="video" producer="playlist1"/>
+ </tractor>
+ <playlist id="playlist2">
+  <property name="kdenlive:audio_track">1</property>
+ </playlist>
+ <playlist id="playlist3">
+  <property name="kdenlive:audio_track">1</property>
+ </playlist>
+ <tractor id="tractor1" in="00:00:00.000">
+  <property name="kdenlive:audio_track">1</property>
+  <track hide="video" producer="playlist2"/>
+  <track hide="video" producer="playlist3"/>
+ </tractor>
+ <playlist id="playlist4"/>
+ <playlist id="playlist5"/>
+ <tractor id="tractor2" in="00:00:00.000">
+  <track hide="audio" producer="playlist4"/>
+  <track hide="audio" producer="playlist5"/>
+ </tractor>
+ <playlist id="playlist6"/>
+ <playlist id="playlist7"/>
+ <tractor id="tractor3" in="00:00:00.000">
+  <track hide="audio" producer="playlist6"/>
+  <track hide="audio" producer="playlist7"/>
+ </tractor>
+ <tractor id="tractor4" in="00:00:00.000" out="00:08:20.000">
+  <track producer="black_track"/>
+  <track producer="tractor0"/>
+  <track producer="tractor1"/>
+  <track producer="tractor2"/>
+  <track producer="tractor3"/>
+ </tractor>
+</mlt>
+`;
+  }
+}
+
+const project = new Project(30);
+
+project.addProducer("/home/kuba/Videos/5min.mp4");
+project.addProducer("/home/kuba/Videos/5min.wav");
+
+await $`echo ${await project.toXML()} > project-generated.kdenlive`;

producer.mjs

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+import {
+  getStream,
+  indexOf,
+  renderAllProps,
+  getStreamIndex,
+  formatDuration,
+} from "./util.mjs";
+import { makeIDGen } from "./util.mjs";
+
+const makeId = makeIDGen(1);
+const producerIndexGen = makeIDGen(0);
+
+export default class Producer {
+  constructor(path) {
+    this.path = path;
+    this.index = producerIndexGen.next().value;
+  }
+
+  async toXML(fps) {
+    const xml = (
+      await $`melt ${
+        this.path
+      } -consumer xml ${`frame_rate_num=${fps}`} | htmlq producer`
+    ).stdout;
+
+    return xml.replace("producer0", `producer${this.index}`);
+  }
+}

util.mjs

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+export function indexOf(array, predicate) {
+  for (let i in array) {
+    if (predicate(array[i])) {
+      return i;
+    }
+  }
+  return -1;
+}
+
+export async function renderProperty(
+  name,
+  fn,
+  metadata,
+  project_settings,
+  prefix = ""
+) {
+  let value;
+  if (typeof fn === "string") {
+    value = fn;
+  } else {
+    value = await fn(metadata, project_settings);
+  }
+  if (value === null) {
+    return "";
+  } else if (value && value.$replace) {
+    return value.$replace;
+  } else {
+    return `<property name="${prefix}${name}">${value}</property>`;
+  }
+}
+
+export async function renderAllProps(
+  props,
+  metadata,
+  project_settings,
+  prefix = ""
+) {
+  return (
+    await Promise.all(
+      Object.entries(props).map(([name, fn]) =>
+        renderProperty(name, fn, metadata, project_settings, prefix)
+      )
+    )
+  ).join("\n");
+}
+
+export function getStream(tracks, type) {
+  return tracks.find((track) => track["@type"] == type);
+}
+
+const HOUR = 60 * 60;
+const MINUTE = 60;
+
+export function formatDuration(float_s) {
+  const hours = Math.floor(float_s / HOUR);
+  float_s = float_s - hours * HOUR;
+  const minutes = Math.floor(float_s / MINUTE);
+  const seconds = float_s - minutes * MINUTE;
+  return `${twoDigits(hours)}:${twoDigits(minutes)}:${twoDigits(seconds, 5)}`;
+}
+
+export function twoDigits(number, decimal = 0) {
+  let [int, dec] = number.toFixed(decimal).split(".");
+  dec = dec || "";
+  if (dec == "") {
+    return int.padStart(2, "0");
+  } else {
+    return int.padStart(2, "0") + "." + dec;
+  }
+}
+
+export function getStreamIndex(trackarray, type) {
+  const array_index = indexOf(trackarray, (e) => e["@type"] == type);
+  return array_index == -1 ? -1 : trackarray[array_index].StreamOrder || 0;
+}
+
+export function* makeIDGen(first = 1) {
+  let i = first;
+  while (true) {
+    yield i;
+    i++;
+  }
+}