I'm have implemented the picture in picture function for my web project on angular.

This is the basic component for it.

export class PlayerPipComponent implements OnInit {
  @Input() video!: HTMLVideoElement;
  isPlayerErrorOpen = false;
  constructor(@Inject(DOCUMENT) private document: Document, private dialog: MatDialog) {}

  ngOnInit(): void {}

  async togglePip(): Promise<void> {
    try {
      if (this.document.pictureInPictureEnabled) {
        if (this.video !== this.document.pictureInPictureElement) {
          await this.video.requestPictureInPicture();
        } else {
          await this.document.exitPictureInPicture();
        }
      } else {
        this.showGeneralError('000', "This browser doesn't have Picture in Picture enabled.");
      }
    } catch (error) {
      console.log('Error', error);
      this.showGeneralError('000', error);
    }
  }

I was trying to add the controls for seekforward and seekbackward, but for some reason they don't seem to work on it. But the previoustrack and nexttrack controls work fine.

          navigator.mediaSession.setActionHandler('previoustrack', (details) => {
            // Go to previous track
            console.log('previostrack', details);
          });
          navigator.mediaSession.setActionHandler('nexttrack', (details) => {
            // Go to next track
            console.log('nextrack', details);
          });

Just adding these few lines, it shows the controls in the picture in picture. But if add these next ones, it doesn't show the seekbackward o forward controls.

          navigator.mediaSession.setActionHandler('seekbackward', function (details) {
            // Do something
          });

          navigator.mediaSession.setActionHandler('seekforward', function (details) {
            //Do something
          });

Does anyone know if they are just not supported? Or if you could point out what I'm doing wrong, I would be very thankful.