feat(screencast): use system ffmpeg on linux

.github/workflows/infra.yml

@@ -24,6 +24,7 @@ jobs:
         sudo apt-get update
         sudo apt-get install libgbm-dev
         sudo apt-get install xvfb
+        sudo apt-get install ffmpeg
     - run: npm ci
     - run: npm run build
     - run: npm run lint

src/server/chromium/videoRecorder.ts

@@ -14,7 +14,6 @@
  * limitations under the License.
  */
 
-const ffmpegPath = require('@ffmpeg-installer/ffmpeg').path;
 import { launchProcess } from '../processLauncher';
 import { ChildProcess } from 'child_process';
 import { Progress, runAbortableTask } from '../progress';
@@ -55,6 +54,8 @@ export class VideoRecorder {
     const args = `-f image2pipe -c:v mjpeg -i - -y -an -r ${fps} -c:v vp8 -vf pad=${w}:${h}:0:0:gray,crop=${w}:${h}:0:0`.split(' ');
     args.push(options.outputFile);
     const progress = this._progress;
+    // Use ffmpeg provided by the host system.
+    const ffmpegPath = process.platform === 'linux' ? 'ffmpeg' : require('@ffmpeg-installer/ffmpeg').path;
     const { launchedProcess, gracefullyClose } = await launchProcess({
       executablePath: ffmpegPath,
       args,

src/server/validateDependencies.ts

@@ -112,6 +112,8 @@ async function validateDependenciesLinux(browserPath: string, browser: BrowserDe
   }
   for (const dep of (await missingDLOPENLibraries(browser)))
     missingDeps.add(dep);
+  for (const dep of (await missingSystemBinaries(browser)))
+    missingDeps.add(dep);
   if (!missingDeps.size)
     return;
   // Check Ubuntu version.
@@ -231,6 +233,16 @@ async function missingDLOPENLibraries(browser: BrowserDescriptor): Promise<strin
   return libraries.filter(library => !isLibraryAvailable(library));
 }
 
+async function missingSystemBinaries(browser: BrowserDescriptor): Promise<string[]> {
+  if (browser.name !== 'chromium')
+    return [];
+  // Look for ffmpeg in PATH.
+  const {code, error} = await spawnAsync('ffmpeg', ['-version'], {});
+  if (code !== 0 || error)
+    return ['ffmpeg'];
+  return [];
+}
+
 function spawnAsync(cmd: string, args: string[], options: any): Promise<{stdout: string, stderr: string, code: number, error?: Error}> {
   const process = spawn(cmd, args, options);
 
@@ -423,5 +435,7 @@ const MANUAL_LIBRARY_TO_PACKAGE_NAME_UBUNTU: { [s: string]: string} = {
   // in the ldconfig cache, so we detect the actual library required for playing h.264
   // and if it's missing recommend installing missing gstreamer lib.
   // gstreamer1.0-libav -> libavcodec57 -> libx264-152
-  'libx264.so': 'gstreamer1.0-libav'
+  'libx264.so': 'gstreamer1.0-libav',
+  // Required for screencast in Chromium.
+  'ffmpeg': 'ffmpeg',
 };