ha-hls-player to provide updates on current video time to make sure camera cast to Nest Hub actually plays video and didn't get stuck

[maxosprojects]

I've created a dashboard with camera feed via hui-picture-entity-card. The dashboard worked fine at first, but pretty quickly started to turn off, get stuck on the page with HA icon saying "Connected", or the picture card showing HA icon and no camera feed.
I've made a few automations that would track the status of the cast and regularly restart the cast, like the one proposed here. However, eventually that stopped working too, to the point that restarting the cast gets stuck on the "Connected" page right away, so another restart is requiered right away, or having to issue a reload for the dashboard several times with this:

  - service: cast.show_lovelace_view
    data:
      entity_id: media_player.kitchen_display
      dashboard_path: nest-hub-dash
      view_path: home

Plus, cast blinking every minute when it restarts, event when unnecessary (so just in case) is quite annoying.

The fundamental problem is that there doesn't seem to be a way to tell that the video is actually playing when HA thinks the cast is in playing state.

Those issues led me to make this HACS hack-card, which:

• finds the video element on the page (including shadow DOMs)
• reads currentTime property of the video every 2 seconds
• updates input_number.nest_hub_cast_liveness_video_curr_time number helper with that time

On the backend side:

• in configuration.yml that input_number.nest_hub_cast_liveness_video_curr_time is excluded from recorder since that would record too much of unnecessary data
• an automation that runs every 10 seconds and under the condition that input_number.nest_hub_cast_liveness_video_curr_time hasn't changed in the last 30 seconds, restarts the cast

This is the code of that card:

Expand

let intervalIds = {
	liveness: null
};

class VideoLivenessCard extends HTMLElement {
	set hass(hass) {
		if (this.content) {
			return;
		}

		const card = document.createElement('HA-card');
		this.content = document.createElement('div');
		card.appendChild(this.content);
		this.appendChild(card);
		var content = this.content;
		let videoEl = null;
		startTime();

		if (intervalIds.liveness !== null) {
			clearInterval(intervalIds.liveness);
		}
		intervalIds.liveness = setInterval(updateLiveness, 2000);

		function querySelectorAllWithShadow(el, selector) {
			let expectedNodes = el.querySelectorAll(selector);
			if (expectedNodes.length > 0) {
				return expectedNodes;
			}
			let nodes = el.querySelectorAll('*');
			for (let i = 0; i < nodes.length; i++) {
				let node = nodes[i];
				expectedNodes = node.querySelectorAll(selector);
				if (expectedNodes.length > 0) {
					return expectedNodes;
				}
				if (node.shadowRoot) {
					expectedNodes = querySelectorAllWithShadow(node.shadowRoot, selector);
				}
				if (expectedNodes.length > 0) {
					return expectedNodes;
				}
				expectedNodes = querySelectorAllWithShadow(node, selector);
				if (expectedNodes.length > 0) {
					return expectedNodes;
				}
			}
			return expectedNodes;
		}

		function updateLiveness() {
			if (!videoEl) {
				let nodes = querySelectorAllWithShadow(document, 'video');
				if (nodes.length == 0) {
					console.log("didn't find video element");
					return;
				}
				if (nodes.length > 1) {
					console.log("found more video elements than expected");
					return;
				}
				videoEl = nodes[0];
				console.log("found video element", videoEl);
			}

			hass.callApi(
				'post',
				'states/input_number.nest_hub_cast_liveness_video_curr_time',
				{ state: Math.trunc(videoEl.currentTime) }
			)
				.catch(err => console.log('There was an error while updating nest_hub_cast_liveness_video_curr_time', err));
		}
	}

	getCardSize() {
		return 1;
	}
}

customElements.define('video-liveness-card', VideoLivenessCard);

So the ask is to include something like the above code into ha-hls-player, and perhaps other cards that support video, to have the feedback from the ui that the video is actually playing, and not stuck for whatever reason.

I could make a PR with the necessary changes once/if there is an agreement on the value of this feature and the way to implement that.