Kotlin / Android — Hello, avatar

Render an on-device AI avatar on Android in ~20 lines of Kotlin — Maven Central AAR, arm64-v8a, fully private lip-sync.

Prerequisites

• A bitHuman API secret — get one at Developer → API Keys; see Authentication. Read it from env or your app config at startup; never hardcode it.
• Android Studio with NDK 28.0.13004108 and compile SDK 35. Add the dependency:

implementation("ai.bithuman:sdk:1.17.1")   // Maven Central

• Device floor: an arm64-v8a device (physical phone or arm64 emulator image), Android 10+ (API 29+). Inference is fully on-device — no cloud round-trip.
• A .imx model file pushed to the device (the snippet reads from getExternalFilesDir(null)).

Note The Android / Kotlin SDK is in Beta. The API surface below is stable enough to build on, but expect minor changes ahead of GA. There is no standalone Android project under Examples/ yet — this snippet is the canonical starting point; track the Android SDK page for updates.

Run it

1. In app/build.gradle.kts, restrict to arm64-v8a and add the dependency.

android {
    defaultConfig {
        ndk { abiFilters += setOf("arm64-v8a") }
        minSdk = 29
    }
}
dependencies {
    implementation("ai.bithuman:sdk:1.17.1")   // Maven Central
}

2. Push your model and audio onto the device’s app-private external dir (or adapt the paths in the code).

adb push sample-avatar.imx /sdcard/Android/data/com.example.bithumanhello/files/
adb push speech.wav        /sdcard/Android/data/com.example.bithumanhello/files/

3. Drop the Full code into MainActivity.kt, then Build and Run on the device.

What you’ll see

A full-screen ImageView shows the avatar lip-syncing to speech.wav — 16 kHz mono PCM in, lip-synced Bitmaps out at 25 fps, rendered entirely on the phone with no network inference.

Full code

// MainActivity.kt — load model, compose frames, display them
package com.example.bithumanhello

import android.app.Activity
import android.os.Bundle
import android.widget.ImageView
import ai.bithuman.sdk.Avatar
import java.io.File

class MainActivity : Activity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        val imageView = ImageView(this).also { setContentView(it) }

        // Read .imx + WAV from app-private external files dir.
        val dir   = getExternalFilesDir(null)!!
        val model = File(dir, "sample-avatar.imx").absolutePath
        val audio = File(dir, "speech.wav").absolutePath

        // Compose runs off the main thread; each Bitmap is a 25 fps frame.
        Thread {
            Avatar.load(model).use { avatar ->
                avatar.composeFromFile(audio).forEach { frame ->
                    runOnUiThread { imageView.setImageBitmap(frame.toBitmap()) }
                }
            }
        }.start()
    }
}

Full source: Android SDK reference — no standalone Examples/ project yet; the SDK page carries the canonical streaming snippets.

Next steps

• Android SDK — full walkthrough: API surface, streaming, Fixture + Runtime.
• Audio streaming — the streaming contract that backs composeFromFile.
• Models — Essence vs Expression, which to ship.