fix for holding frames in output queue if no publisher

[ad-astra-video]

Quick fix for when a publisher is not started because video egress is turned off to not add to output queue.

Output queue has a max of 200 but at larger frame size memory usage expands quite a bit.

[eliteprox]

@ad-astra-video Thanks for resolving this critical bug which was likely introduced in #36

I noticed the tests are hanging on your change. Can you test if the change in #93 solves the issue the same?

pytrickle/pytrickle/protocol.py

Lines 367 to 371 in ac2cbbc

	if self.publish_task is None:
	logger.debug("Skipping enqueuing frame to publish queue (no publisher configured)")
	continue
	await asyncio.to_thread(enqueue_frame, frame)

This will make it easier to reference publish_task and ensure the frames make it back to the protocol for keeping egress fps accurate

[ad-astra-video]

The fix in #93 seems to work as well so I have used that fix here now in the protocol rather than the client.

Do you think we should record egress metrics if not sending or put the continue before that?

I think there are two sides of it:

• may be confusing if we record egress metrics if nothing actually is being returned
• other side of the argument is having egress metrics would continue to provide a throughput measurement of the pipeline to enable comparing ingress/egress fps metrics

[eliteprox]

You make a good point, I could see it both ways.

I think we should not record egress FPS when there is no media publisher. It might be confusing to see egress_fps in stream metrics with no media publishing configured.

For a pipeline which has no video/audio output and only produces text, perhaps we could later add a new metric like "data messages per second"

[eliteprox]

I'm also fine with keeping the egress metric, it is good for visibility and analyzing frame processor performance

[eliteprox]

LGTM