Google’s multitouch operating system is far behind Apple’s iOS regarding musical creation possibilities. The lag is measurable: about 350 milliseconds. It seems insignificant but it is not. This latency problem on Android stops developers from writing musical apps that could compete with those available on iPhone or iPad.
When we started this blog, most recording or synth apps were on iOS. At the time Android’s rise was so overwhelming that we expected things to evolve. We even believed that WebOS or Windows would compete. That was in theory. In practice, iOS is still the king of the castle and will be in the foreseeable future, and as long as Google does not decide to provide development tools that are more powerful, as developers have been asking for.
We interviewed Kevin Chartier, developer for Wizdom music. He is in charge of MorphWiz, SampleWiz, and Geo Synthesizer, real time touch instruments for iPad and iPhone. The live functionality is crucial for these apps as Jordan Rudess, Dream Theater’s keyboardist, uses them in front of thousands of persons during his concerts. In spite of his will to port these apps to Android he can’t because of one main problem: audio latency.
The system mixing buffer is where the differences between iOS and Android are most apparent. On iOS, you have the ability to request any buffer size you want, and the OS will give it to you, if the processor is fast enough to handle it. (…) At a 44.1kHz sampling rate, a 256-sample buffer is about 5.8 milliseconds (…) On our latest Android devices, the minimum buffer size is 16384 samples long, which is about 371.5 milliseconds long.
The best Android phones have a latency of 108.8 ms. What does it mean? It is best understood with a practical example. These four audio files illustrate the lag called latency. In the first the click and the piano are synched : latency zero. In the second we hear latency for iOS, it is so little that one can hardly hear time between which the finger touches the screen and the note is heard. The two last show that it is not possible to play music with an Android phone.
That’s why musicians choose Apple rather Google. For the time being, iOS is for creatives while Android is for content consumption. This will remain the case until Google starts to listen to what audio developers have been asking for more than two years. Then, Android features would be equivalent to those of the first generation iPhone.
[Update]: Check out More thoughts on audio latency in Android and our Open letter to Google
13 Commentaires
1 CharlieH a écrit:
Just to expand on this a bit, the latency is more than just the audio rendering buffer size. There are also D-to-A converter delays, and transport to converter delays, but these are rather small. NOT small are the touch-to-start-of-rendering delays. Even on iOS devices these are several tens of milliseconds. Yes, Android apps are unplayable, and iOS app are quite playable, but I wish the touch-to-sound delays on iOS devices were even lower.
2 Sebastian a écrit:
Can you elaborate the technical deails of your measurement?
How did you measure the latency?
Merci!
3 CharlieH a écrit:
Hey Sebastian,
We have measured iOS latency in the 40-80 msec range using small CoreAudio buffers. Doesn’t sound great, eh? Well the Android measurements are in the hundreds of msec!
The measurement technique I used was to put a piezo-electric element under the device, and to send its signal along with the device’s audio output signal to a 2-channel oscilloscope set to trigger once. I tap the device and then measure the time difference between the piezo output and the audio output.
It is important to have a known very « sharp » sound to play.
Hope that helps.
4 Dentaku a écrit:
Who did these tests? I’d like to know exactly how they where done to be able to do the same thing on a Windows Phone 7.5 device.
We’ve been discussing WP7.5 latency here http://channel9.msdn.com/Forums/Coffeehouse/Audio-latency-in-WP75-compared-to-AndroidiOS-#c2251330344da4dc5adc99fb6016d65e4
5 Dentaku a écrit:
Aah, I just read more and I see that you DID explain how this experiment was done. That’s a very smart way of measuring latency actually.
6 BitFlipper a écrit:
I did a similar test on 1st gen Samsung Focus Windows Phone 7.5 and found the latency to be ~65 ms +-5ms. I used a microphone to record both the physical tap of the finger on the screen, as well as the sound coming out of the speaker. I then looked at the waveform and calculated the lag time between the two events. This was with simple unoptimized test code. It shows WP is at least within the same range (40 ms to 80 ms) of iOS.
7 BitFlipper a écrit:
BTW, I would just like to add that the listed latencies (5.8 ms, 108.8 ms etc) are not the true latencies. Those are just the buffer sizes. The true latency is determined by adding the following values:
1. How long it takes for the event to be triggered in software after the tap on the screen.
2. The amount of time it takes for the software to prepare and submit a buffer of audio via API.
3. The amount of time it takes for the audio to come out of the speaker once it has been submitted via API.
Those things do not happen in realtime and they each add additional latency. That is why doing a test that includes the time from when the finger hits the screen to when it becomes audible is much more accurate and useful than simply listing the buffer size.
8 David a écrit:
What should I do to support this? I’m not a developer but I am a musician. Is there any petition to sign online or something?
9 Julien Guillot a écrit:
Just sign the « Open letter to Google » in the right hand corner of this page !
10 Whitney Mussman a écrit:
Ne vous contentez pas retirer de quelque chose ; avoir quelque chose à retirer .
Il ya deux sortes de sociétés, celles qui travaillent pour essayer de payer plus et ceux qui travaillent à payer moins. Je serai le 2ème .
11 obat alami asam urat a écrit:
your publisher its okay .
12 wi-fi blu-ray a écrit:
Hi everyone, it’s my first visit at this site, and article is really fruitful in support of me, keep up posting such posts.
13 Zabezpiecz swoje Tra a écrit:
Czy jesteś w podróży za granicę dla przyjemności lub firmy, coraz dość nie coś może być przygotowany na czas na wakacje, gdyż może to spowodować uszkodzenie właściwie pre zorganizowany urlop jest.Mądry gość zawsze wybiera ubezpieczenie zdrowotne za granicą i gwarantuje podróż z mniej zmartwień i satysfakcji więcej.
11 Trackbacks