Re: [Jack-Devel] JACK2 for Android newly released!

2014. 1. 25. ¿ÀÀü 1:40 Bradley Justice <[hidden]> ÀÛŒº:

> I have not had an opportunity to look at the new release, but I did attend the presentation at the San Francisco developers conference in October 2013. I have released an app based on their JACK-based pro audio framework. I believe it was the first 3rd party app. (https://play.google.com/store/apps/details?id=com.blueverdi.myruckus) . 
> 
> At the developers conference Samsung stated the pro audio framework was supported only on Note 3 and Galaxy Tab 10.1 2014. My experience is on Note 3.
> 
> First, the framework only supported I/O via built-in audio devices. No USB. This means audio quality is compromised by their audio hardware. Importantly, they are restricted to 48k/16 bit.
Yes, it is true, but most of things are platform dependent. Not a jack domain.

> 
> Second, per their conference presentation they are running with two 512 sample buffers. At 48k this misses the mark for low latency. Even at that level of latency I saw significant xruns. Using only their example simple client - which generates a stereo sine wave from a table -  I heard numerous audio artifacts. Logcat output showed 29 xruns in a two minute test. This was completely reproducible. I reported this on their developer forum on Jan 2 and as of today there has been no Samsung response.
I think these XRUNS related cpufreq on demand governor when a jack client runs during low CPU frequency mode in mobile device.
Please refer:
http://bamboopuppy.com/android-cpu-frequency-using-cpufreq-ondemand-governor/
As I know, there were already discussion in here, so I found Robin's jackfreqd, How do you think for solution?
http://rg42.org/oss/jackfreqd/start

> 
> In the interests of full disclosure I have ported JACK to Android myself. The  project is on hold due to the Samsung release, in spite of better performance. 
> 
> 
> 
>> On Fri, Jan 24, 2014 at 7:08 AM, ±èÁ€¿¬ <[hidden]> wrote:
>> > Does that mean JACK2 will already come installed on upcoming Samsung devices?
>> Yes.
>> 
>> >
>> > What about low latency/RT stabilty, have you tested running JACK2 with low
>> > latency period settings (i.e. <= 5ms) on Android? Does it run quite stable
>> > without xruns?
>> Well, it is hard to say, latency depends on platform limitation or hw spec.
>> for example, android's fast mixer introduces 10ms of latency.
>> http://source.android.com/devices/latency_design.html
>> 
>> Generally, mobile devices do control power consumption much sensitive
>> than PC, of course this limitation may possible occur XRUNS in some
>> scenarios.
>> We always think how to improve performance better, *** so I need
>> expert's advice here. ***
>> But, modern mobile devices increase number of cores(quad-core or
>> more...), so I guess JACK2 works better performance along with number
>> of cores. Of course, it works stable if allows reasonable clock-speed
>> and cores.
>> 
>> Thanks,
>> KimJeongYeon
>> 
>> Jack-Devel mailing list
>> [hidden]
>> http://lists.jackaudio.org/listinfo.cgi/jack-devel-jackaudio.org
> 

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