implement platform audio on python

Author: xianshijing-lk

examples/README.md

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+# LiveKit Python SDK Examples
+
+This directory contains examples demonstrating various features of the LiveKit Python SDK.
+
+## Prerequisites
+
+Set the following environment variables:
+
+```bash
+export LIVEKIT_URL=ws://localhost:7880
+export LIVEKIT_API_KEY=devkey
+export LIVEKIT_API_SECRET=secret
+```
+
+## Examples Overview
+
+| Example | Description |
+|---------|-------------|
+| [basic_room.py](#basic_roompy) | Room connection with PlatformAudio and synthetic audio modes |
+| [room_example.py](#room_examplepy) | Basic room connection and event handling |
+| [api.py](#apipy) | Room management via LiveKit API |
+| [e2ee.py](#e2eepy) | End-to-end encryption demo |
+| [rpc.py](#rpcpy) | Remote Procedure Call between participants |
+| [multiple_connections.py](#multiple_connectionspy) | Sequential connections for sync frameworks |
+| [participant_attributes.py](#participant_attributespy) | Dynamic participant attributes |
+| [publish_wave.py](#publish_wavepy) | Publish sine wave audio |
+| [publish_hue.py](#publish_huepy) | Publish color-cycling video |
+| [play_audio_stream.py](#play_audio_streampy) | Play received audio with sounddevice |
+| [webhook.py](#webhookpy) | Webhook event handling |
+| [agent_dispatch.py](#agent_dispatchpy) | Manual agent dispatch |
+
+### Subdirectories
+
+| Directory | Description |
+|-----------|-------------|
+| [face_landmark/](face_landmark/) | Facial landmark detection using MediaPipe |
+| [video-stream/](video-stream/) | Video/audio sync with AVSynchronizer |
+| [data_tracks/](data_tracks/) | Data channel examples |
+| [data-streams/](data-streams/) | Data streaming examples |
+| [local_audio/](local_audio/) | Local audio capture examples |
+
+---
+
+## basic_room.py
+
+The most comprehensive example, demonstrating room connection with audio capabilities. It showcases two audio capture modes that can be used independently or combined.
+
+### Quick Start
+
+```bash
+# List available audio devices
+python basic_room.py --list-devices
+
+# Connect with PlatformAudio (recommended)
+python basic_room.py --platform-audio --room my-room
+
+# Connect with specific devices
+python basic_room.py --platform-audio --mic-id "device-guid" --speaker-id "device-guid"
+
+# Publish a WAV file
+python basic_room.py --file audio.wav --room my-room
+
+# Mix microphone + WAV file (both modes together)
+python basic_room.py --platform-audio --file background.wav --room my-room
+```
+
+### Audio Modes
+
+#### PlatformAudio Mode (`--platform-audio`)
+
+Uses WebRTC's Audio Device Module (ADM) for microphone capture. **Recommended for most applications.**
+
+**Features:**
+- Built-in voice processing:
+  - **Echo Cancellation (AEC)** - removes echo from speaker playback
+  - **Noise Suppression (NS)** - reduces background noise
+  - **Auto Gain Control (AGC)** - normalizes audio levels
+- Hardware-accelerated processing on supported platforms (e.g., iOS VPIO)
+- Automatic speaker playout for received audio
+- Device enumeration and selection
+- No external audio libraries required
+
+**Limitations:**
+- No direct access to raw audio frames (ADM sends directly to WebRTC)
+- Cannot apply custom audio processing before publishing
+
+```python
+platform_audio = rtc.PlatformAudio()
+source = platform_audio.create_audio_source(
+    rtc.PlatformAudioOptions(
+        echo_cancellation=True,
+        noise_suppression=True,
+        auto_gain_control=True,
+    )
+)
+track = rtc.LocalAudioTrack.create_audio_track("microphone", source)
+```
+
+#### Synthetic Mode (Default)
+
+Manual control over audio frames via `AudioSource.capture_frame()`. Use this for custom audio processing or programmatic audio generation.
+
+**Features:**
+- Full control over audio data
+- Access to raw audio frames for custom processing
+- Generate synthetic audio (files, TTS, audio synthesis)
+- Apply custom filters, effects, or ML models
+
+**Limitations:**
+- No built-in AEC/NS/AGC - implement yourself or use `AudioProcessingModule`
+- Must handle speaker playout manually via `AudioStream`
+- Requires external audio libraries for mic capture (sounddevice, pyaudio)
+
+```python
+source = rtc.AudioSource(sample_rate=48000, num_channels=1)
+track = rtc.LocalAudioTrack.create_audio_track("audio", source)
+
+frame = rtc.AudioFrame(data=audio_bytes, sample_rate=48000, ...)
+await source.capture_frame(frame)
+```
+
+#### Mixing Both Modes
+
+PlatformAudio and Synthetic modes can run simultaneously. The `--file` option demonstrates this by publishing a WAV file (synthetic) alongside microphone capture (PlatformAudio).
+
+```bash
+python basic_room.py --platform-audio --file music.wav --room my-room
+```
+
+This creates two audio tracks:
+1. **Microphone** - via PlatformAudio with voice processing
+2. **File** - via synthetic mode from WAV
+
+Use cases: background music while speaking, sound effects, mixing pre-recorded audio with live input.
+
+### Command Line Options
+
+| Option | Description |
+|--------|-------------|
+| `--list-devices` | List available audio devices and exit |
+| `--platform-audio` | Use PlatformAudio for microphone (recommended) |
+| `--file WAV_PATH` | Publish audio from WAV file (synthetic mode) |
+| `--room NAME` | Room name (default: my-room) |
+| `--mic-id ID` | Select microphone by device ID |
+| `--speaker-id ID` | Select speaker by device ID |
+
+### When to Use Each Mode
+
+| Use Case | Mode |
+|----------|------|
+| Voice/video calls | PlatformAudio |
+| Conferencing apps | PlatformAudio |
+| Playing audio files | Synthetic |
+| Text-to-speech | Synthetic |
+| Custom audio processing | Synthetic |
+| ML audio effects | Synthetic |
+| Background music + voice | Both |
+
+---
+
+## room_example.py
+
+Basic room connection demonstrating event handling and participant tracking.
+
+```bash
+python room_example.py
+```
+
+---
+
+## api.py
+
+Room management using the LiveKit API (create rooms, list rooms).
+
+```bash
+python api.py
+```
+
+---
+
+## e2ee.py
+
+End-to-end encryption with a rotating 3D cube visualization.
+
+```bash
+python e2ee.py
+```
+
+---
+
+## rpc.py
+
+Remote Procedure Call (RPC) between participants - greetings, math operations, timeout handling.
+
+```bash
+python rpc.py
+```
+
+---
+
+## multiple_connections.py
+
+Sequential room connections in a single thread. Useful for Django/Flask integration.
+
+```bash
+python multiple_connections.py
+```
+
+---
+
+## participant_attributes.py
+
+Set, update, and delete participant attributes dynamically.
+
+```bash
+python participant_attributes.py
+```
+
+---
+
+## publish_wave.py
+
+Publish a sine wave audio track at a specified frequency.
+
+```bash
+python publish_wave.py
+```
+
+---
+
+## publish_hue.py
+
+Publish a color-cycling animated video track.
+
+```bash
+python publish_hue.py
+```
+
+---
+
+## play_audio_stream.py
+
+Play incoming audio from remote participants using sounddevice.
+
+```bash
+pip install sounddevice
+python play_audio_stream.py
+```
+
+---
+
+## webhook.py
+
+Handle LiveKit webhook events using aiohttp.
+
+```bash
+python webhook.py
+```
+
+---
+
+## agent_dispatch.py
+
+Manually dispatch agents to rooms (instead of automatic dispatch).
+
+```bash
+python agent_dispatch.py
+```