How do you add MP3 sound effects to a video ?

1. First upload your video
2. Open a new browser tab and get a noise from an online sound database (For instance : https://freesound.org). You can also upload your own MP3 sound inside the tab browser with the command CTRL+O.
3. Come back to 011.video web app and start the capture Don’t forget to Share the audio.
4. Start to play your sound.  If the audio length is shorter than the video length select the audio loop.
5. Go back to 011.video and start recording For your ears comfort, mute browser tab to get only one audio source send to your speaker.
6. When it is finish pause and download your video with a background sound.

 
Here is a video sample “Diet advises against the Flu Winter 2019-2020” with sound effect made with 011.video :