android The State of Affairs Concerning Display Output from Android

[jonathan.pl]

First of all, if you use Apple: cool, please dont advertise how "compatible" your stuff is – this thread is mainly for Android users.

 

I suppose a clarification is needed, concerning an average smartphone user ability of outputting image generated on this device to an external monitor. Clarification that I seek, because I'm really confused what do I really need in order for this to work.

 

To begin with, I'd like to note, that the USB-C "revolution" has made it's way, but things are really messy now, when it comes to actual cooperation of devices, aside the very possibility of connecting them together. Yes, there are dongles that fit both the phone, and the tip of a display cable, but when you connect it all together, you may find that nothing happens. The protocols are to blame – USB-C Alternate Modes, and Mobile High-Definition Link (MHL).

 

The latter – MHL is a propietary standard, developed prior to USB-C, by a consortium of Sony and alike. You could connect a display via a slightly modified micro-USB plug, but if – and only if – anyone along your device development chain has shelled out some cash for the licence. You may be among these lucky owners of MHL-compatible devices (made both with, and prior to USB-C). Any questions are more or less answered on http://www.mhltech.org , perhaps aside the fact that the display also has to be MHL-complatible, unless an active adapter is used (please correct me if I'm wrong).

If anyone is in the know, please give an insight, whether this technology still has any traction and whether it's worth investing in a device that supports this protocol over non-MHL devices.

 

USB-C alternate modes are another way. There is an MHL Alt Mode, which may or may not still require both devices to support MHL (info needed). There is Thunderbolt Alt Mode – Thunderbolt is well advertised, and quite rare, thus not worth of description here. Then, there are HDMI Alt Mode, and DisplayPort Alt Mode – these are your best bet, if you own a USB-C equipped device: certainly worth a shot. The thing about Alt Modes is that device makers are free to pick-and-choose whichever Alt Modes they see fit. If I understand this correctly, there is no official list of DP-Alt, or HDMI-Alt Mode compatible devices.

 

Here, I'd like to ask a key question: what are these protocols bound to? I mean, is DP Alt Mode compatibility a thing, that should be associated with SOC model, or is it a certain setup of SOC-to-display circuit jumble? In the first case, the SOC maker decides whether his product has the given Alt Mode. In the second, the maker of the device decides, whether he'd like your model to be able to split the signal destined from the logic board to the screen.

Or is it a software thing? That TECHNICALLY all you'd need is to beep on the pins correctly – and hence something like an Android update, or a kinda-like-Cyanogen reflash could potentially bring this functionality to the device?

 

Of course, there is always an option of pushing video over WiFi with something like a Chromecast, or a compatible Smart TV. However, this option is relatively high-cost and not as portable, as a direct connection. Relying on a wireless device for this process also introduces unwanted lag, and is susceptible to packet loss or whatever. Only one question here: could this setup work directly? Precisely: if we were to connect Chromecast to the hotspot made on the device from which we're casting, would this be a viable solution?

 

Thank you for all the answers,

Keeping my hopes up,

- Jon

[WallacEngineering]

Not only do these problems exist but if you need to replace your cable you have to be quite careful in when choosing an aftermarket cable. These days cables have different amperage ratings, different USB generation ratings, and some are designed for display adaptation while others simply cannot do the job. To be honest, I have given up on the idea of a display cable adapter for mobile devices all together. Besides, USB to HDMI cables are rediculously expensive and there are far better solutions such as simply ensuring you buy a smart type TV or simply use Google Cast

[jonathan.pl]

You mean the USB-C cable? In theory, you wouldn't need one – just the dongle and a normal display cable (both obviously rated for display transmission). In case I would have both a display with USB-C, and a USB-C device, then I wouldn't cheap out on a cable. The thing is, I cheap out beforehand and won't get a USB-C screen, cause, y'know, I wait for the technology to become affordable.

 

So that's a Chromecast for Holiday, awesome.

 

I wish the question about who actually implements these protocols was answered – is it up to Qualcomm (chip-kind of design), or is it up to Xiaomi (assembly-kind of design)? Or is Google locking this option out from Android intentionally, thus leaving hardware as-is, another kind of software could do this function (which is certainly not the case with Thunderbolt)?

[WallacEngineering]

On 11/24/2018 at 2:58 PM, jonathan.pl said:

So that's a Chromecast for Holiday, awesome.

 

I wish the question about who actually implements these protocols was answered.

Well the thing is that you sort of answered your own question already: Currently there is no standard for who impliments what features on a phone, so you kinda just have to pick the right phone to get the features you want.

 

- Qualcomm and other SOC manufacturers are the ones who make these features possible. It doesnt matter if Sony or Samsung wants to make a device with display output modes if the SOC is incapable of it.

 

- From there, you have the manufacturer (so Sony or Samsung itself) that chooses whether or not these features will be implimented.

 

Hey man, Chromecast is awesome, I would be happy to receive one for holiday. Also, if you want a more extravagant gift capable of using the feature then go for a new TV for holiday. My Samsung MU6500 50" Curved Glass, Smart, 4K TV has Chromecast built in and it is an amazing TV.