startFollow , produces vibration in the game

[tiuvi]

In this example, I test startFollow at a slow speed and zoomed in, which is how it looks best.
Then I comment out startFollow and use my function, which I have enabled in a prerender.

https://cell1.tiuvi.com:1029/mp4/startFollowVibration.mp4

In this video, I test my function, which is my least favorite part: having to round the player's x and y positions.
Also, the camera speed needs to be slightly slower than the player's.
https://cell1.tiuvi.com:1029/mp4/newFunctionStartFollow.mp4

If this function could be done natively, it might perform better.

        state.events.on('prerender', () => {
                
                const velocity = state.global.player.body.velocity;

                const speedPlayerPx = Math.sqrt(velocity.x * velocity.x + velocity.y * velocity.y);

                // Accedemos a la cámara principal y al jugador
                const cam = state.cameras.main;
                const player = state.global.player;

                const px = player.x;
                const py = player.y;

                const centerMapX = cam.width / 2
                const centerMapY = cam.height / 2

                const playerPositionX = px + centerMapX;
                const playerPositionY = py + centerMapY

                const cameraPositionX = cam.scrollX + centerMapX;
                const cameraPositionY = cam.scrollY + centerMapY;

                const marginWidth = (cam.width * (cam.zoom * cam.zoom) / 2) * 0.2

                const marginHeight = (cam.height * (cam.zoom * cam.zoom) / 2) * 0.2


                let moviment = speedPlayerPx === 0 ? 1 : speedPlayerPx * 0.7
                if(moviment < 1){
                    moviment = 1;
                }

                let newCamX = cam.scrollX;
                let newCamY = cam.scrollY;

                if ((cameraPositionX + marginWidth) > playerPositionX) {

                    newCamX = cam.scrollX - moviment;

                } else if ((cameraPositionX + cam.width - marginWidth) < playerPositionX) {

                    newCamX = cam.scrollX + moviment;
                }


                if ((cameraPositionY + marginHeight) > playerPositionY) {

                    newCamY = cam.scrollY - moviment;

                } else if ((cameraPositionY + cam.height - marginHeight) < playerPositionY) {


                    newCamY = cam.scrollY + moviment;
                }

                if (cam.scrollX === newCamX && cam.scrollY === newCamY) {
                    return;
                }


                player.x = Math.round(px)
                player.y = Math.round(py)

                newCamX = Math.round(newCamX);
                newCamY = Math.round(newCamY);


                cam.scrollX = newCamX;
                cam.scrollY = newCamY;
            });

[tiuvi]

Looking further into the character's speed, it appears that at no point can the camera go slower than 1 pixel per frame, nor faster than 70% of the character's speed.
It's possible that the problem with startfollow is that it has too low a refresh rate, causing judder at low speeds.