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Audio Recorder For Smart Wearables

This sample shows an example of a voice recorder that captures microphone audio with AudioCapturer, writes it to disk as a playable WAV file, and plays it back with AVPlayer. Raw PCM frames are written directly to a file descriptor, and a 44-byte RIFF/WAVE header is patched in once the total size is known. Recording duration is derived from file size rather than stored separately.

Preview

Use Cases

• Microphone capture with AudioCapturer using a raw PCM stream (16 kHz, mono, 16-bit)
• Writing a valid WAV file by reserving a header and seeking back to fill it on stop
• Playback of recorded files with AVPlayer driven by its stateChange lifecycle
• File management with fileIo for creating, listing, and deleting recordings in the app sandbox
• Handling audio interrupts and output device changes during capture and playback

Technology

Stack

• Languages: ArkTS
• Framework: HarmonyOS SDK 6.1.1(24)
• Tools: DevEco Studio 6.1.1 Release
• Libraries: @kit.AudioKit @kit.MediaKit @kit.CoreFileKit @kit.AbilityKit @kit.BasicServicesKit

Required Permissions

• ohos.permission.MICROPHONE Required to capture audio from the microphone.

Directory Structure

.\entry\src\main
│   module.json5
│
├───ets
│   ├───common
│   │       Permissions.ets
│   │       PlayerEngine.ets
│   │       RecorderEngine.ets
│   │       RecordingStore.ets
│   │
│   ├───entryability
│   │       EntryAbility.ets
│   │
│   ├───pages
│   │       Index.ets
│   │
│   └───view
│           RecordView.ets
│           RecordingsView.ets
│
└───resources
    └───base
        ├───element
        │       color.json
        │       string.json
        │
        └───profile
                main_pages.json

Constraints and Restrictions

DevEco Studio Simulator is not supported, as microphone capture requires a physical device.

Recordings are stored uncompressed in the application sandbox, which consumes roughly 32 KB per second of audio and is removed when the application is uninstalled.

Supported Devices

• Huawei Watch 5

License

Audio Recorder For Smart Wearables is distributed under the terms of the MIT License. See the LICENSE for more information.