feat: extract most watched segments from YouTube API

src/cli/args.ts

@@ -2,14 +2,14 @@ export interface CliArgs {
   url?: string;
   output: string;
   format: string;
-  noChapters: boolean;
+  segments: number;
 }
 
 export function parseArgs(): CliArgs {
   const args: CliArgs = {
     output: "./downloads",
     format: "best",
-    noChapters: false,
+    segments: 1,
   };
 
   const rawArgs = Bun.argv;
@@ -24,10 +24,11 @@ export function parseArgs(): CliArgs {
     } else if (arg === "-f" || arg === "--format") {
       args.format = nextArg || "best";
       i++;
-    } else if (arg === "--no-chapters") {
+    } else if (arg === "-n" || arg === "--segments") {
-      args.noChapters = true;
+      args.segments = parseInt(nextArg || "1", 10);
+      i++;
     } else if (arg === "-h" || arg === "--help") {
-      console.log(`YouTube Video Segments Downloader
+      console.log(`YouTube Most Watched Segments Downloader
 
 Usage: yt-segments <url> [options]
 
@@ -37,13 +38,13 @@ Arguments:
 Options:
   -o, --output <dir>    Output directory (default: ./downloads)
   -f, --format <fmt>    Video format (default: best)
-  --no-chapters         Skip chapter extraction
+  -n, --segments <num>  Number of top segments to download (default: 1)
   -h, --help            Show this help message
 
 Examples:
   yt-segments "https://www.youtube.com/watch?v=abc123"
   yt-segments "https://youtu.be/abc123" -o ./videos -f mp4
-  yt-segments "https://www.youtube.com/watch?v=abc123" --no-chapters
+  yt-segments "https://www.youtube.com/watch?v=abc123" -n 3
 `);
       process.exit(0);
     } else if (!arg.startsWith("-") && !arg.includes("bun")) {

src/cli/downloader.ts

@@ -9,13 +9,20 @@ export interface DownloadOptions {
   extractChapters: boolean;
 }
 
-interface Chapter {
+interface MostWatchedSegment {
-  title: string;
   start: number;
   end: number;
+  intensity?: number;
 }
 
-async function getVideoInfo(url: string): Promise<{ title: string; chapters: Chapter[] }> {
+interface VideoInfo {
+  title: string;
+  chapters: Array<{ title: string; start_time: number; end_time: number }>;
+  heatmap?: Array<{ start_seconds: number; end_seconds: number; intensity: number }>;
+  duration: number;
+}
+
+async function getVideoInfo(url: string): Promise<VideoInfo> {
   return new Promise((resolve, reject) => {
     const ytDlp = spawn("yt-dlp", [
       "--dump-json",
@@ -42,21 +49,12 @@ async function getVideoInfo(url: string): Promise<{ title: string; chapters: Cha
 
       try {
         const info = JSON.parse(stdout);
-        const chapters: Chapter[] = [];
-
-        if (info.chapters && Array.isArray(info.chapters)) {
-          for (const chapter of info.chapters) {
-            chapters.push({
-              title: chapter.title || `Chapter ${chapters.length + 1}`,
-              start: chapter.start_time || 0,
-              end: chapter.end_time || 0,
-            });
-          }
-        }
 
         resolve({
           title: info.title || "video",
-          chapters,
+          chapters: info.chapters || [],
+          heatmap: info.heatmap || [],
+          duration: info.duration || 0,
         });
       } catch (parseError) {
         reject(new Error(`Failed to parse video info: ${parseError}`));
@@ -116,6 +114,28 @@ function formatTime(seconds: number): string {
   return `${mins}:${secs.toString().padStart(2, "0")}`;
 }
 
+function getMostWatchedSegments(
+  heatmap: Array<{ start_seconds: number; end_seconds: number; intensity: number }>,
+  duration: number,
+  topN: number = 1
+): MostWatchedSegment[] {
+  if (!heatmap || heatmap.length === 0) {
+    return [];
+  }
+
+  // Sort by intensity (most watched first)
+  const sorted = [...heatmap].sort((a, b) => b.intensity - a.intensity);
+
+  // Get top N segments
+  const topSegments = sorted.slice(0, topN);
+
+  return topSegments.map((segment) => ({
+    start: segment.start_seconds,
+    end: segment.end_seconds,
+    intensity: segment.intensity,
+  }));
+}
+
 export async function downloadVideoSegments(options: DownloadOptions): Promise<void> {
   const { url, outputDir, format } = options;
 
@@ -124,53 +144,65 @@ export async function downloadVideoSegments(options: DownloadOptions): Promise<v
     mkdirSync(outputDir, { recursive: true });
   }
 
-  // Skip chapter extraction if not requested
+  // Get video info including most watched segments from YouTube API
-  if (!options.extractChapters) {
+  console.log("Fetching video information from YouTube API...");
-    console.log("Downloading full video (chapters disabled)...");
+  const info = await getVideoInfo(url);
-    const safeTitle = sanitizeFilename("video");
+  const safeTitle = sanitizeFilename(info.title);
+
+  console.log(`Video: ${info.title}`);
+  console.log(`Duration: ${formatTime(info.duration)}`);
+
+  // Try to get most watched segments from heatmap data
+  const mostWatchedSegments = getMostWatchedSegments(info.heatmap || [], info.duration);
+
+  // If no heatmap data, fall back to chapters
+  if (mostWatchedSegments.length === 0 && info.chapters.length > 0) {
+    console.log("\nNo most watched segments found. Falling back to chapters...");
+    const chapter = info.chapters[0]; // Download first chapter as most relevant
+    const outputPath = join(outputDir, `${safeTitle}_most_watched.%(ext)s`);
+    const section = `*${formatTime(chapter.start_time || 0)}-${formatTime(chapter.end_time || 60)}`;
+
+    console.log(`Downloading chapter: ${chapter.title || "First Chapter"}`);
+    await downloadSection(url, outputPath, section, format);
+    return;
+  }
+
+  if (mostWatchedSegments.length === 0) {
+    console.log("No segments found. Downloading full video...");
     const outputPath = join(outputDir, `${safeTitle}.%(ext)s`);
     await downloadSection(url, outputPath, "*", format);
     return;
   }
 
-  // Get video info including chapters
+  // Download the most watched segment
-  console.log("Fetching video information...");
+  const topSegment = mostWatchedSegments[0];
-  const { title, chapters } = await getVideoInfo(url);
+  const outputPath = join(outputDir, `${safeTitle}_most_watched.%(ext)s`);
-  const safeTitle = sanitizeFilename(title);
+  const section = `*${formatTime(topSegment.start)}-${formatTime(topSegment.end)}`;
 
-  console.log(`Video: ${title}`);
+  console.log(`\nMost watched segment: ${formatTime(topSegment.start)} - ${formatTime(topSegment.end)}`);
-  console.log(`Found ${chapters.length} chapters\n`);
+  console.log(`Duration: ${formatTime(topSegment.end - topSegment.start)}`);
-
+  console.log(`Intensity: ${((topSegment.intensity || 0) * 100).toFixed(1)}%`);
-  if (chapters.length === 0) {
+  console.log(`\nDownloading most watched segment...`);
-    console.log("No chapters found. Downloading full video...");
-    const outputPath = join(outputDir, `${safeTitle}.%(ext)s`);
-    await downloadSection(url, outputPath, "*", format);
-    return;
-  }
-
-  // Download each chapter as a separate segment
-  for (let i = 0; i < chapters.length; i++) {
-    const chapter = chapters[i];
-    const segmentNumber = (i + 1).toString().padStart(2, "0");
-    const outputPath = join(outputDir, `${safeTitle}_${segmentNumber}_${sanitizeFilename(chapter.title)}.%(ext)s`);
-    const section = `*${formatTime(chapter.start)}-${formatTime(chapter.end)}`;
-
-    console.log(`[${i + 1}/${chapters.length}] Downloading: ${chapter.title} (${formatTime(chapter.end - chapter.start)})`);
 
   await downloadSection(url, outputPath, section, format);
+
+  // Save segment info
+  const segmentInfoPath = join(outputDir, `${safeTitle}_most_watched.txt`);
+  let segmentInfo = `# ${info.title}\n\n`;
+  segmentInfo += `Most watched segment:\n`;
+  segmentInfo += `  Start: ${formatTime(topSegment.start)}\n`;
+  segmentInfo += `  End: ${formatTime(topSegment.end)}\n`;
+  segmentInfo += `  Duration: ${formatTime(topSegment.end - topSegment.start)}\n`;
+  segmentInfo += `  Intensity: ${((topSegment.intensity || 0) * 100).toFixed(1)}%\n`;
+
+  if (mostWatchedSegments.length > 1) {
+    segmentInfo += `\nOther top segments:\n`;
+    for (let i = 1; i < mostWatchedSegments.length; i++) {
+      const seg = mostWatchedSegments[i];
+      segmentInfo += `  ${formatTime(seg.start)} - ${formatTime(seg.end)} (${((seg.intensity || 0) * 100).toFixed(1)}%)\n`;
+    }
   }
 
-  // Also download the full video
+  writeFileSync(segmentInfoPath, segmentInfo);
-  console.log("\nDownloading full video...");
+  console.log(`Segment info saved to: ${segmentInfoPath}`);
-  const fullVideoPath = join(outputDir, `${safeTitle}_full.%(ext)s`);
-  await downloadSection(url, fullVideoPath, "*", format);
-
-  // Save chapter list
-  const chapterListPath = join(outputDir, `${safeTitle}_chapters.txt`);
-  let chapterList = `# ${title}\n\n`;
-  for (const chapter of chapters) {
-    chapterList += `${formatTime(chapter.start)} - ${chapter.title}\n`;
-  }
-  writeFileSync(chapterListPath, chapterList);
-  console.log(`Chapter list saved to: ${chapterListPath}`);
 }

src/cli/index.ts

@@ -12,15 +12,15 @@ async function main() {
     console.log("Options:");
     console.log("  -o, --output <dir>    Output directory (default: ./downloads)");
     console.log("  -f, --format <fmt>    Video format (default: best)");
-    console.log("  --no-chapters         Skip chapter extraction");
+    console.log("  -n, --segments <num>  Number of top segments (default: 1)");
     console.log("  -h, --help            Show help");
     process.exit(1);
   }
 
-  console.log(`Downloading segments from: ${args.url}`);
+  console.log(`Downloading most watched segment(s) from: ${args.url}`);
   console.log(`Output directory: ${args.output}`);
   console.log(`Format: ${args.format}`);
-  console.log(`Extract chapters: ${!args.noChapters}`);
+  console.log(`Segments to download: ${args.segments}`);
   console.log("");
 
   try {
@@ -28,7 +28,7 @@ async function main() {
       url: args.url,
       outputDir: args.output,
       format: args.format,
-      extractChapters: !args.noChapters,
+      extractChapters: true,
     });
     console.log("\nDownload complete!");
   } catch (error) {