V2 Feature overhaul and improvements

lib/comparison/video-generator.js

@@ -0,0 +1,67 @@
+const ffmpeg = require('fluent-ffmpeg');
+const fs = require('fs');
+const path = require('path');
+const os = require('os');
+const { v4: uuidv4 } = require('uuid');
+
+/**
+ * Creates an MP4 video from an array of frame objects.
+ * @param {Array} frames - Array of { data: base64 } objects
+ * @param {number} outputFps - Frames per second
+ * @returns {Promise<string>} - Path to generated video file
+ */
+async function createVideoFromFrames(frames, outputFps = 10) {
+    if (!frames || frames.length === 0) throw new Error('No frames provided');
+
+    // Filter out invalid frames if any
+    const validFrames = frames.filter(f => f && f.data);
+    if (validFrames.length === 0) throw new Error('No valid frames found');
+
+    const tempDir = path.join(os.tmpdir(), 'frames-' + uuidv4());
+    fs.mkdirSync(tempDir, { recursive: true });
+
+    try {
+        // Save frames as images
+        for (let i = 0; i < validFrames.length; i++) {
+            const frame = validFrames[i];
+            // Remove header if present
+            const base64Data = frame.data.replace(/^data:image\/\w+;base64,/, "");
+            const buffer = Buffer.from(base64Data, 'base64');
+            const filePath = path.join(tempDir, `frame-${i.toString().padStart(5, '0')}.jpg`);
+            fs.writeFileSync(filePath, buffer);
+        }
+
+        const outputPath = path.join(os.tmpdir(), `video-${uuidv4()}.mp4`);
+
+        return new Promise((resolve, reject) => {
+            ffmpeg()
+                .input(path.join(tempDir, 'frame-%05d.jpg'))
+                .inputFPS(outputFps)
+                .output(outputPath)
+                .outputOptions([
+                    '-c:v libx264',
+                    '-pix_fmt yuv420p',
+                    '-crf 23',
+                    '-preset fast',
+                    '-movflags +faststart' // Optimize for web playback
+                ])
+                .on('end', () => {
+                    // Cleanup frames
+                    try { fs.rmSync(tempDir, { recursive: true, force: true }); } catch(e) {}
+                    resolve(outputPath);
+                })
+                .on('error', (err) => {
+                    // Cleanup frames
+                    try { fs.rmSync(tempDir, { recursive: true, force: true }); } catch(e) {}
+                    console.error('FFmpeg video generation error:', err);
+                    reject(err);
+                })
+                .run();
+        });
+    } catch (e) {
+        try { fs.rmSync(tempDir, { recursive: true, force: true }); } catch(err) {}
+        throw e;
+    }
+}
+
+module.exports = { createVideoFromFrames };