fix: making the correct image adjustments on the cloud functions (#299)

* fix: making the correct image adjustments on the cloud functions

* fixing lint and timeout issue

functions/package.json

@@ -27,6 +27,7 @@
     "firebase-functions": "^4.1.0",
     "fluent-ffmpeg": "^2.1.2",
     "fs": "^0.0.1-security",
+    "jimp": "^0.16.2",
     "mustache": "^4.2.0",
     "uuid": "^9.0.0"
   },

functions/src/convert/index.spec.ts

@@ -120,7 +120,6 @@ function setUpReadable(currentEvent: string) {
   return readable;
 }
 
-
 jest.mock('busboy', () => () => {
   return {
     end: jest.fn(),
@@ -135,6 +134,20 @@ jest.mock('busboy', () => () => {
   };
 });
 
+jest.mock('jimp', () => {
+  return {
+    read: jest.fn().mockImplementation((name) => {
+      const _name = name || '';
+      return {
+        bitmap: {
+          width: _name.indexOf('odd') != -1 ? 501 : 600,
+          height: _name.indexOf('odd') != -1 ? 301 : 400,
+        },
+      };
+    }),
+  };
+});
+
 jest.mock('fluent-ffmpeg', () => () => {
   return {
     addInput: jest.fn().mockReturnThis(),
@@ -340,6 +353,33 @@ describe('convertToVideo', () => {
     ).resolves.toBe(`${tempDir}/video.mp4`);
   });
 
+  describe('when the dimensions of the image are even', () => {
+    it('keeps the dimension on the scale flag', async () => {
+      setUpFfmpeg('end');
+      await convert.convertToVideo(ffmpeg, [ `${tempDir}/frame_1.png` ], tempDir);
+
+      expect(ffmpeg.addOptions).toHaveBeenCalledWith([
+        '-codec:v libx264',
+        '-s 600x400',
+        '-pix_fmt yuv420p',
+      ]);
+    });
+  });
+
+  describe('when the dimensions of the image are odd', () => {
+    it('uses the nearest (down) even number', async () => {
+      setUpFfmpeg('end');
+
+      await convert.convertToVideo(ffmpeg, [ `${tempDir}/frame_odd.png` ], tempDir);
+
+      expect(ffmpeg.addOptions).toHaveBeenCalledWith([
+        '-codec:v libx264',
+        '-s 500x300',
+        '-pix_fmt yuv420p',
+      ]);
+    });
+  });
+
   it('throws error when unable to convert frames.', async () => {
     setUpFfmpeg('error');
 

functions/src/convert/index.ts

@@ -4,6 +4,8 @@ import * as path from 'path';
 
 import { UPLOAD_PATH, ALLOWED_HOSTS } from '../config';
 import ffmpeg from 'fluent-ffmpeg';
+import Jimp from 'jimp';
+
 import fs from 'fs';
 import os from 'os';
 import _busboy from 'busboy';
@@ -33,7 +35,7 @@ export const convert = functions.https.onRequest(async (req, res) => {
 export async function convertImages(
   req: functions.https.Request,
 ): Promise<{
-  status: number;
+  status: number,
   videoUrl: string,
   gifUrl: string,
 }> {
@@ -59,8 +61,10 @@ export async function convertImages(
     const videoPath = await convertToVideo(ffmpeg(), frames, tempDir);
     const gifPath = await convertVideoToGif(ffmpeg(), videoPath, tempDir);
 
-    const videoUrl = await uploadFile(userId + '.mp4', videoPath);
-    const gifUrl = await uploadFile(userId + '.gif', gifPath);
+    const [ videoUrl, gifUrl ] = await Promise.all([
+      uploadFile(userId + '.mp4', videoPath),
+      uploadFile(userId + '.gif', gifPath),
+    ]);
 
     return { status: 200, videoUrl, gifUrl };
   } catch (error) {
@@ -132,16 +136,35 @@ export async function proceedFile(
   });
 }
 
+function adjustDimensions(width: number, height: number): {
+  width: number,
+  height: number,
+} {
+  const w = width % 2 == 0 ? width : width - 1;
+  const h = height % 2 == 0 ? height : height - 1;
+
+  return { width: w, height: h };
+}
+
 export async function convertToVideo(
   ffmpeg: ffmpeg,
   frames: string[],
   folder: string
 ): Promise<string> {
   const videoPath = `${folder}/video.mp4`;
+
+  const image = await Jimp.read(frames[0]);
+  const adjustedDimensions = adjustDimensions(
+    image.bitmap.width,
+    image.bitmap.height,
+  );
+
+  const scaleArg = `${adjustedDimensions.width}x${adjustedDimensions.height}`;
+
   return new Promise((resolve, reject) => {
     ffmpeg
       .addInput(folder + '/frame_%d.png')
-      .addOptions([ '-codec:v libx264', '-s 980x620', '-pix_fmt yuv420p' ])
+      .addOptions([ '-codec:v libx264', `-s ${scaleArg}`, '-pix_fmt yuv420p' ])
       .inputFPS(frames.length / 5)
       .mergeToFile(videoPath)
       .on('end', () => {