The sound for video playback is unavailable.

[miaomiao620]

Hello everyone. I'm developing a video player using Theia. The video can play normally, but the volume control button in the video is not functional, and there is no sound. I've added some logs. Here are the screenshots of video playback and the logs.

I created a demo with the same versions of Electron, TypeScript, and React, and the video plays with sound. Here is the screenshot.

May I ask what settings are required in Theia? This problem has been really troublesome for me and has been bothering me for several days

[msujew]

Hey @miaomiao620,

By default, Electron ships with a version of ffmpeg that contains a bunch of proprietary audio and video codecs. See also this stackoverflow post on the topic. That's why it works for you in your simple Electron app. To prevent any legal troubles for adopters of Theia, the framework removes all proprietary codecs from the deployed ffmpeg version. This however prevents certain audio/video formats from playing as expected. There is no fix for this, as it works as intended.

VS Code places the same restrictions on users. See microsoft/vscode#187525 (comment).

[miaomiao620]

Thank you very much for your answer. It helped me understand this issue very clearly.
May I ask how to use the default version of Electron? Is there any relevant configuration in Theia?

[msujew]

There is no relevant configuration, mainly because there was no need for it yet. You can probably create a postinstall script that replaces the ffmpeg library with one that contains those proprietary codecs. See https://github.com/eclipse-theia/theia/blob/master/dev-packages/ffmpeg/src/replace-ffmpeg.ts for the code that is in charge of replacing ffmpeg. However, this likely isn't something that we plan to support in our framework.

Note that using those codecs in your (commercial) app makes you legally liable for royalties for those codecs. See also ffmpeg's own legal page.