Samsung Smt-700 bad latency Vs. LG G3 great latency

[shaulhadar]

Hi Planet, how are you doing?
I have a samsung tablet. a sm-t700 with 8.4 inch screen.
I was really happy to hear you have the latency in the new version really low, so i tried using it on my tablet, but for some reason, on the samsung, with lollipop, it only gave 20ms latency, and it was unplayable sadly

But, I have a LG G3 phone, with lollipop, and i tried the new gstomper, and it worked amazing with a record best latency i ever say, it had 5ms!!

5ms is even better than iphone!!! I can't believe it.
But, this causes a problem for me, because i sometimes DJ , and i use the samsung tablet, which is supposed to be more powerful than the lg phone, but i can't understand why i cant get to 5ms latency with it also..

Is there anything i can do to fix this?
any help would be welcome,
Thanks for your time,
Shaul.

[planet-h]

Thanks for your message, Shaul.

I have a samsung tablet. a sm-t700 with 8.4 inch screen.
I was really happy to hear you have the latency in the new version really low, so i tried using it on my tablet, but for some reason, on the samsung, with lollipop, it only gave 20ms latency, and it was unplayable sadly

What you mean with 'unplayable'?
Unplayable because of the latency?
Or unplayable because of audio glitches?

Regarding the cpu, it should run smooth theoretically at 10ms.
The gtab s 8.4 has the same cpu as a gtab pro (which I have successfully tested at 10ms on lollipop these days)
Here are the specs of both devices:
http://www.gsmarena.com/samsung_galaxy_tab_s_8_4-6439.php
http://www.gsmarena.com/samsung_galaxy_tab_pro_12_2-6212.php
Did you set the latency level to "LOW" in the audio settings of G-Stomper?
And did you turn all the power saving features OFF (that might change a lot)?

But, I have a LG G3 phone, with lollipop, and i tried the new gstomper, and it worked amazing with a record best latency i ever say, it had 5ms!!

5ms is even better than iphone!!! I can't believe it.
But, this causes a problem for me, because i sometimes DJ , and i use the samsung tablet, which is supposed to be more powerful than the lg phone, but i can't understand why i cant get to 5ms latency with it also..
Is there anything i can do to fix this?

Unfortunately, the ugly truth is, that the gtab s 8.4 is not more powerful than the LG G3.
http://www.gsmarena.com/lg_g3-6294.php
As you see in the specs, the LG comes with a 'Quad-core 2.5 GHz Krait 400' which is way more powerful than the 'Quad-core 1.9 GHz Cortex-A15 ' of the Gtab S 8.4.
Of course, the gtab s is an octa-core, but also here, the ugly truth about octa-core Android devices is that they're in fact dual quad-core.

In case of the gtab s there are 2 cpu's built in:

Quad-core 1.9 GHz Cortex-A15
Quad-core 1.3 GHz Cortex-A7

But the second one most likely won't run at the same time with the first one. The second quad core is just there for the case when the battery is low... to save battery at lower clock rate. So simply said, an android device with a true octa-core with 8 identical and concurrent running cores (as we know from the intel desktop computers) does not exist yet.

So in fact the LG runs at quad 2.5ghz and the Gtab at quad 1.9gz. And in addition the Krait 400 simply seems to be the better cpu (overall). The nexus 9 for example also comes with a Krait, and runs at 5ms too.

Why the gtab cannot get down to the 5ms has multiple reasons:
Every device has a base min latency, which is given by the AudioTrack system, on your LG G3 this is probably 40ms, on the samsung gtab s it sounds like it's 80ms (if you really only get down to 20ms). While claiming the audio hardware, I'm bound to that base min latency, I simply cannot just choose a fantasy value.
How much this base min latency value is, depends on the audio diver and on the underlaying hardware. Both, the driver and the hardware is built by the hardware manufacturer (in case of the gtab this is samsung).

Depending on various factors G-Stomper can strip down the latency to smaller values, but only to partials of the base latency.
How small that partial actually is (at lowest latency setting 1/2, 1/4 or 1/8 of the base min latency) depends on the android version and on the cpu speed.

The LG G3 with its quad 2.5ghz can go down to 1/8 of its base min latency of 40ms, which results in 5ms.
The Gtab S on the other hand with its quad 1.9ghz is too slow to get down to 1/8. I'll do some further tests on that soon and see if there's some headroom left, but I suspect that it'll result in too many glitches. So bottom line, the Gtab S can only go down to 1/4 of its base min latency, which seems to result in 20ms.
So that's one suspect.

The other one is that the power saving functions of your gtab are all enabled and therefore it's running at the slower cpu the 1.3ghz quad.
You can check that in the settings of your tab. Just make sure that all the powersaving functions are completely turned OFF.
Power saving mechanisms are the worst enemy of low latency.
Once you've turned power saving off, restart your device, then start G-Stomper, enable OpenSL and set the latency level to LOW.
Finally restart G-Stomper.

What internal latency does it show now in the G-Stomper Audio settings?

What you can try is to disable all power saving

[planet-h]

I just did some tests with the SM-T900 (gtab pro 12.2), running at 5ms (which is 1/8 of the base min latency reported by the audio driver).
As expected, it resulted in too many glitches (not really a lot, but too many for a professional level)
The problem is clearly the too slow cpu for such a low latency: Quad-core 1.9 GHz Cortex-A15
To go down to that value (actually 1/8 of the base min latency of a device), at least a quad core 2.3ghz cpu is required to get stable results.

Another thing you should know regarding the playability:
I compared the 5ms of the gtab pro with the 5ms of the nexus9.
There's definitely a measurable difference between those two devices, which is caused by the different display reaction times (there the nexus9 wins by far) and also by the android internal latency, which happens after the audio stream leaves the G-Stomper app (also here, the nexus9 wins, but not that significant).

In short, even if two devices report the same latency, the playability may vary, because of the different touch screen reaction times and the different audio driver latency times.