Frequently Asked Questions (FAQ)

How do I request RTC Client library support for a new platform/architecture?​

The RTC Client (stm_open_*) is provided as a precompiled static library. It currently supports:

• macOS arm64
• Linux x86_64 / aarch64
• Linux ARM (Rockchip830)
• MIPS (Ingenic)

To request a new platform:

1. Prepare the information: target platform name, toolchain information (gcc -v output), target triple, and BSP link
2. Submit the request through Tuya technical support or your project lead
3. A precompiled library for the new platform can usually be delivered within 1-2 weeks

Alternative: Use the RTC TCP Client (source form); you only need to implement the pal.h interfaces to run on any platform. See Porting to a new platform for details.

Does the device need VAD?​

Not required. The cloud provides Server VAD, so the device can simply keep sending audio; the cloud notifies the device when it detects that the user has stopped speaking. Currently the cloud uses TAI_EVT_CHAT_BREAK as the end-of-turn signal (TAI_EVT_SERVER_VAD is no longer sent; the constant is retained only for protocol compatibility). Note: in cloud VAD mode, after receiving the end-of-turn signal, do not call tai_send_audio_end(); keep the uplink audio stream open for the whole Session.

However, device-side VAD is recommended for the following scenarios:

See VAD and interruptions for details.

What is the difference between RTC TCP Client and RTC Client, and which should I use?​

The UDP implementation has excellent weak-network performance and works well even under poor network conditions. If your use case involves weak networks, prefer the rtc-client.

For other scenarios, use whichever you prefer.

Which audio formats are supported?​

Uplink (device → cloud):

• PCM: 16 kHz / 16-bit / mono (recommended; simple to implement)
• Opus: 16 kHz / mono (recommended for bandwidth-constrained scenarios)

Downlink (cloud → device):

• Determined by the cloud Agent TTS configuration
• Usually PCM or Opus
• Format information is provided in the first audio callback (sample_rate, frame_duration)

See the Audio format configuration guide for details.

What should I do if session_token expires?​

RTC Client:

• A token is usually valid for 12-24 hours
• After expiry you receive an STM_ETOKEN_EXPIRED error or an on_state callback
• Call iot_client_get_session_token() again to obtain a new token, then create a new Session

RTC TCP Client:

• Establishing a connection requires an agent_token (obtained via iot_client_get_session_token()), but once established it uses a long-lived connection with Ping/Pong keepalive, so the token does not need periodic refreshing
• If the connection drops (the on_disconnect callback), the thread that holds the tai_ctx_t can simply call tai_connect() again

What kind of network conditions does the device need?​

• Using Opus encoding can greatly reduce bandwidth requirements
• Offline mode is not supported — a continuous network connection is required
• Reconnect after a dropped connection is supported (the RTC Client has a Recovering state; the RTC TCP Client requires application-level reconnect)