# What is the difference FMOD\_OUTPUTTYPE\_OPENSL to (FMOD\_OUTPUTTYPE\_AUDIOTRACK in Android **URL:** \ **Category:** FMOD Engine\ **Created:** [September 17, 2017, 6:20pm UTC](https://qa.fmod.com/t/what-is-the-difference-fmod-outputtype-opensl-to-fmod-outputtype-audiotrack-in-android/13444 "2017-09-17T18:20:07Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![talpa](https://avatars.discourse-cdn.com/v4/letter/t/97f17d/32.png) [@talpa](https://qa.fmod.com/u/talpa)\ **Post date:** [September 17, 2017, 6:20pm UTC](https://qa.fmod.com/t/what-is-the-difference-fmod-outputtype-opensl-to-fmod-outputtype-audiotrack-in-android/13444/1 "2017-09-17T18:20:07Z")
hi, when i setOutput FMOD\_OUTPUTTYPE\_OPENSL or FMOD\_OUTPUTTYPE\_AUDIOTRACK i get 512 buffer size and 2 buffers with 240000 sample rate. on bluetooth i get shutring sound over FMOD\_OUTPUTTYPE\_OPENSL , supposed to be low latency?. i want to know what fmod does to the audio system when i use each of them and why i have delay over bluetooth when im using android 8.0 on my nexus 6p where my device latency is only 8-10ms with the loopback App writing by google engineers(drrickorang). Thanks, tal ---
**Author:** ![cameron-fmod](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/cameron-fmod/32/261_2.png) [@cameron-fmod](https://qa.fmod.com/u/cameron-fmod)\ **Post date:** [September 24, 2017, 11:39pm UTC](https://qa.fmod.com/t/what-is-the-difference-fmod-outputtype-opensl-to-fmod-outputtype-audiotrack-in-android/13444/2 "2017-09-24T23:39:40Z")
AudioTrack is the default audio output for devices running Android 2.2 or earlier: [https://developer.android.com/reference/android/media/AudioTrack.html](https://developer.android.com/reference/android/media/AudioTrack.html) OpenSL is the default, for most but not all, devices running Android 2.3 or later: [https://developer.android.com/ndk/guides/audio/opensl-for-android.html](https://developer.android.com/ndk/guides/audio/opensl-for-android.html) We do attempt to determine what would run best on the device, but the results can vary dramatically depending on device hardware. Pairing with a BlueTooth speaker or headset will incur significant extra latency, 120ms in some tests. This is currently unavoidable due to the OS taking extra buffering beyond developer control. If you are using an app that has much lower latency with bluetooth, let us know what it is and where we can find it and we will investigate. ---
**Author:** ![talpa](https://avatars.discourse-cdn.com/v4/letter/t/97f17d/32.png) [@talpa](https://qa.fmod.com/u/talpa)\ **Post date:** [September 25, 2017, 9:00am UTC](https://qa.fmod.com/t/what-is-the-difference-fmod-outputtype-opensl-to-fmod-outputtype-audiotrack-in-android/13444/3 "2017-09-25T09:00:08Z")
hi, im using this app : > > > Measure round-trip audio latency using Dr. Rick O'Rang audio loopback connecto... from the play store… or you can find the source code in github: > **[gkasten/drrickorang](https://github.com/gkasten/drrickorang/tree/master/LoopbackApp)** > > Dr. Rick O'Rang. Contribute to gkasten/drrickorang development by creating an account on GitHub. another thing, in call im not having a bluetooth latency over voice, so maybe its not the phone latency is fault. check it out and let me know… thanks, tal ---
**Author:** ![cameron-fmod](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/cameron-fmod/32/261_2.png) [@cameron-fmod](https://qa.fmod.com/u/cameron-fmod)\ **Post date:** [September 26, 2017, 4:02am UTC](https://qa.fmod.com/t/what-is-the-difference-fmod-outputtype-opensl-to-fmod-outputtype-audiotrack-in-android/13444/4 "2017-09-26T04:02:55Z")
For best results we recommend to use AudioTrack with the default buffer settings for bluetooth audio. The OpenSL Low Latency mode is only available on certain hardware and software configurations, using bluetooth will automatically disable this mode.