Help MHL cable connection is laggy :(

[Double44]

I recently purchased an MHL cable from Amazon for my Note 3, in hopes that i could play games on my 1080p plasma hdtv. The games i play receive inputs from a bluetooth controller i use, the speed of input is very similar to that of a console controller.

Anyway, the video on the tv lags behind the bluetooth's controller input by about a second, rendering games virtually unplayable. Am i doing something wrong, or is that just the way that it is? I was certain i bought the correct cable.. its a 2.0 mhl, 11pin cable designed for modern Samsungs, and I have the adapter connected to a 2A tablet charger. At the moment I'm debating as to whether i should return this cable, or if it might be usable some other way.

 

[mikedt]

Video out via MHL (Mobile High-Definition Link) might have some delay on it anyway, because of the way it works. i.e. the encoding/decoding and compression/decompression. Usually not a problem if you're just watching videos, as long as the sound is synced. How much delay, might be down to the actual phone or tablet itself and the TV, rather than the cable, which is passive. You could try another cable, but I don't think it's going to make any difference.

 

[EarlyMon]

MHL to HDMI adapters, even when the electronics are miniaturized to the point of appearing to be just a cable, aren't passive and do insert another delay in the signal chain.

The actual problem here sounds like the TV output is clicking along just fine - it's the Bluetooth game control signal that's lagging behind when the phone has to service that as well as MHL output.

 

[Double44]

I read something about plugging it into a 720p monitor, but i don't have any of those around me. Is there any way to tell the Note to output at 720 instead of 1080? Now that i think about it.. after connecting the two, shouldn't some form of hdmi options appear, like a TV Out?

The actual problem here sounds like the TV output is clicking along just fine - it's the Bluetooth game control signal that's lagging behind when the phone has to service that as well as MHL output.

I don't know.. when i tap a button, it should register like it always does. The video seems to reflect inputs a second after they've been tapped.

 

[EarlyMon]

The video output is selected after handshake with the TV and the signal passes through a video scalar chip in the phone - just like the scalar chip in the TV.

Your Note 3 is a 1080p device, so is your TV.

You're thinking about trying to change the transmission time and you're not accounting for scaling time - and there ain't no such thing as a free lunch.

No one with an MHL/HDMI/Bluetooth gaming setup like yourself has a zero lag system.

It ranges from some lag to lots but never zero.

 

[Double44]

But wouldn't a 720p experience make less work? I understand that lag is unavoidable, but i don't understand why this lag couldn't be minimized to a point where it isn't so obvious to the senses.

 

[mikedt]

But wouldn't a 720p experience make less work? I understand that lag is unavoidable, but i don't understand why this lag couldn't be minimized to a point where it isn't so obvious to the senses.

It probably could, very likely increase costs significantly though, faster processors, etc.

We have a low-cost DLP projector, that's got about 3/4 second delay on it, either on HDMI or analogue input. It would be terrible for gaming, even when just pointing using a mouse, the lag is quite annoying. But when it's showing Powerpoint presentations or videos, what we bought it for, it's not a problem.

 

[EarlyMon]

But wouldn't a 720p experience make less work?

I already answered this, let me try again.

Define work.

Your TV has a native resolution of 1080p.
If you give it a 720p signal, it has to do more work scaling from 720p to 1080p.

If your phone is outputting the true 1080p screen space to MHL, and it signals that it can only accept 720p at the TV, it has to scale 1080p down to 720p and do more work.

The actual signal going over the cable will be cut in half, so that part is less work.

At 60 fps, a 720p cable signal, assuming full frame updates per frame, is about 60 MB/s. 1080p is 120 MB/s.

That's the part your focusing on while not noticing that you first have to convert 120 MB/s down to 60 in the phone and then convert it back up to 120 MB/s inside the TV.

You're certainly going to change the work being done but you can't look at one number only and decide it's going to be less.

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If you give a 720p signal to a 1080p set, it doesn't display 720p - it doesn't just turn off half of its pixels. It's 1080p all the time.

If you give a 720p to a 720p TV, would that be faster?

You tell me. Not many high end 720p sets out there, so you have to mix apples and oranges to make more assumptions.