[PD] Android latency status?

[Simon Wise]

On 06/08/14 20:17, Filippo Beck Peccoz wrote:
> Dear list,
>
> I'm in the process of starting another PD based project, but was wondering if
> the latency on Android devices is still terrible compared to any other
> platform? I've seen this list and the numbers are staggering…
>
> is there really no solution at all to this problem? Anything that need to be
> closer synced is basically impossible with that kind of latency :Z
>
> Not whining of course, just curious as to why this is still a problem on
> Android.

perhaps because the gadgets being sold are set up for media playback, as devices 
where the user can buy connection to an ISP then buy downloadable media and apps 
through the company store, that kind of thing. Big buffers make all that 
smoother and more reliable. Then, partly to make sure they are plug and play, 
that they have a reasonable chance at offering support to naive users and those 
that apps and media downloaded will "just work" on whatever (cheaper or more 
powerful device) ... and I'd guess also partly to keep control of the platform 
and help keep most digital sales in house etc ... the manufacturers deliver them 
set up so that the user and the apps they download can only use the API that is 
provided and with big warnings whenever said users strays from the path. You are 
wishing to use them for a different purpose, with different API needs.

It is possible to install an unrestricted android OS, but the magic incantation 
"void the warranty" scares many away from this (so does the incessant, but 
vague, message of "beware of pirates"). So if your project is for devices you 
have control of, and warranty fuse bits are not a concern, then it is possible 
to try using the usual linux audio stack alongside androids user interface, and 
get the kind of audio latencies possible with linux on that hardware.

But ... you probably want the option of distributing more widely than that, and 
if you don't stick to the rules you can't distribute to devices that are 
restricted in the usual way, while if you want to use the devices as hardware 
you probably don't care to much whether it is android or GNU that is running on 
top of the linux kernel.

You can certainly try hardware such as the Udoo, which has full GNU- and 
Android- linux support, with the same quad CPU that the 2013 Samsung Note (and 
others) use, and with touchscreens available, considerably cheaper than a 
Samsung. Not in the same compact form of course, and the screen isn't as nice. 
For that you might try some of the tablets that sold with less restrictive 
setups, more admin/root access etc.


Simon