vllm-omni/examples/online_serving/qwen3_omni

Qwen3-Omni

🛠️ Installation

Please refer to README.md

Run examples (Qwen3-Omni)

Launch the Server

vllm serve Qwen/Qwen3-Omni-30B-A3B-Instruct --omni --port 8091

If you want to open async chunking for qwen3-omni, launch the server with command below

vllm serve Qwen/Qwen3-Omni-30B-A3B-Instruct --omni --port 8091 --stage-configs-path vllm_omni/model_executor/stage_configs/qwen3_omni_moe_async_chunk.yaml

If you have custom stage configs file, launch the server with command below

vllm serve Qwen/Qwen3-Omni-30B-A3B-Instruct --omni --port 8091 --stage-configs-path /path/to/stage_configs_file

Send Multi-modal Request

Get into the example folder

cd examples/online_serving/qwen3_omni

Send request via python

python examples/online_serving/openai_chat_completion_client_for_multimodal_generation.py --model Qwen/Qwen3-Omni-30B-A3B-Instruct --query-type use_image --port 8091 --host "localhost"

Realtime WebSocket client (openai_realtime_client.py)

openai_realtime_client.py connects to ws://<host>:<port>/v1/realtime, uploads a local audio file as PCM16 mono @ 16 kHz chunks (OpenAI-style input_audio_buffer.append / commit), and prints streaming transcription (transcription.delta / transcription.done).

Dependencies:

pip install websockets numpy

From this directory (examples/online_serving/qwen3_omni):

python openai_realtime_client.py \
  --host localhost \
  --port 8091 \
  --model Qwen/Qwen3-Omni-30B-A3B-Instruct \
  --audio_path /path/to/your.wav

If --audio_path is omitted, the script uses a bundled default clip (mary_had_lamb via vLLM assets).

Arguments:

Flag	Default	Description
--host	localhost	API server host
--port	8000	API server port (match your vllm serve port, e.g. 8091)
--model	Qwen/Qwen3-Omni-30B-A3B-Instruct	Must match the served model (also sent in session.update)
--audio_path	(optional)	Path to input audio; resampled to 16 kHz mono inside the client

Ensure the vLLM-Omni server is running with realtime support for this endpoint, for example:

vllm serve Qwen/Qwen3-Omni-30B-A3B-Instruct --omni --port 8091

The Python client supports the following command-line arguments:

• --query-type (or -q): Query type (default: use_video). Options: text, use_audio, use_image, use_video
• --model (or -m): Model name/path (default: Qwen/Qwen3-Omni-30B-A3B-Instruct)
• --video-path (or -v): Path to local video file or URL. If not provided and query-type is use_video, uses default video URL. Supports local file paths (automatically encoded to base64) or HTTP/HTTPS URLs. Example: --video-path /path/to/video.mp4 or --video-path https://example.com/video.mp4
• --image-path (or -i): Path to local image file or URL. If not provided and query-type is use_image, uses default image URL. Supports local file paths (automatically encoded to base64) or HTTP/HTTPS URLs and common image formats: JPEG, PNG, GIF, WebP. Example: --image-path /path/to/image.jpg or --image-path https://example.com/image.png
• --audio-path (or -a): Path to local audio file or URL. If not provided and query-type is use_audio, uses default audio URL. Supports local file paths (automatically encoded to base64) or HTTP/HTTPS URLs and common audio formats: MP3, WAV, OGG, FLAC, M4A. Example: --audio-path /path/to/audio.wav or --audio-path https://example.com/audio.mp3
• --prompt (or -p): Custom text prompt/question. If not provided, uses default prompt for the selected query type. Example: --prompt "What are the main activities shown in this video?"
• --speaker: TTS speaker/voice for audio output when requesting audio (e.g. ethan, chelsie, aiden). Omit to use the model default. Example: --speaker "chelsie"

For example, to use a local video file with custom prompt:

python examples/online_serving/openai_chat_completion_client_for_multimodal_generation.py \
    --query-type use_video \
    --video-path /path/to/your/video.mp4 \
    --model Qwen/Qwen3-Omni-30B-A3B-Instruct \
    --prompt "What are the main activities shown in this video?"

Send request via curl

bash run_curl_multimodal_generation.sh use_image

FAQ

Modality control

You can control output modalities to specify which types of output the model should generate. This is useful when you only need text output and want to skip audio generation stages for better performance.

Supported modalities

Modalities	Output
["text"]	Text only
["audio"]	Audio only
["text", "audio"]	Text + Audio
Not specified	Text + Audio (default)

Using curl

Text only

curl http://localhost:8091/v1/chat/completions \
  -H "Content-Type: application/json" \
  -d '{
    "model": "Qwen/Qwen3-Omni-30B-A3B-Instruct",
    "messages": [{"role": "user", "content": "Describe vLLM in brief."}],
    "modalities": ["text"]
  }'

Text + Audio

curl -s http://localhost:8091/v1/chat/completions \
  -H "Content-Type: application/json" \
  -d '{
    "model": "Qwen/Qwen3-Omni-30B-A3B-Instruct",
    "messages": [{"role": "user", "content": "Describe vLLM in brief."}],
    "modalities": ["audio"]
  }' | jq -r '.choices[0].message.audio.data' | base64 -d > output.wav

Using Python client

python examples/online_serving/openai_chat_completion_client_for_multimodal_generation.py \
    --query-type use_image \
    --model Qwen/Qwen3-Omni-30B-A3B-Instruct \
    --modalities text

Using OpenAI Python SDK

Text only

from openai import OpenAI

client = OpenAI(base_url="http://localhost:8091/v1", api_key="EMPTY")

response = client.chat.completions.create(
    model="Qwen/Qwen3-Omni-30B-A3B-Instruct",
    messages=[{"role": "user", "content": "Describe vLLM in brief."}],
    modalities=["text"]
)
print(response.choices[0].message.content)

Text + Audio

import base64
from openai import OpenAI

client = OpenAI(base_url="http://localhost:8091/v1", api_key="EMPTY")

response = client.chat.completions.create(
    model="Qwen/Qwen3-Omni-30B-A3B-Instruct",
    messages=[{"role": "user", "content": "Describe vLLM in brief."}],
    modalities=["text", "audio"]
)
# Response contains two choices: one with text, one with audio
print(response.choices[0].message.content)  # Text response

# Save audio to file
audio_data = base64.b64decode(response.choices[1].message.audio.data)
with open("output.wav", "wb") as f:
    f.write(audio_data)

Speaker selection

When requesting audio output, you can choose the TTS speaker (voice) used for synthesis. If not specified, the model uses its default speaker.

Using curl

Pass a speaker field in the request body:

curl http://localhost:8091/v1/chat/completions \
  -H "Content-Type: application/json" \
  -d '{
    "model": "Qwen/Qwen3-Omni-30B-A3B-Instruct",
    "messages": [{"role": "user", "content": "Say hello in one sentence."}],
    "modalities": ["audio"],
    "speaker": "chelsie"
  }'

Using Python client

Use the --speaker argument when generating audio:

python examples/online_serving/openai_chat_completion_client_for_multimodal_generation.py \
    --query-type use_image \
    --modalities audio \
    --model Qwen/Qwen3-Omni-30B-A3B-Instruct \
    --speaker "chelsie"

Using OpenAI Python SDK

Pass speaker in extra_body:

from openai import OpenAI

client = OpenAI(base_url="http://localhost:8091/v1", api_key="EMPTY")

response = client.chat.completions.create(
    model="Qwen/Qwen3-Omni-30B-A3B-Instruct",
    messages=[{"role": "user", "content": "Say hello in one sentence."}],
    modalities=["audio"],
    extra_body={"speaker": "chelsie"}
)
# Audio uses the specified speaker
print(response.choices[1].message.audio)

Supported speaker names depend on the model (e.g. Ethan, Chelsie, Aiden). Omit speaker to use the default.

Streaming Output

If you want to enable streaming output, please set the argument as below. The final output will be obtained just after generated by corresponding stage. We support both text streaming output and audio streaming output. Other modalities can output normally.

python examples/online_serving/openai_chat_completion_client_for_multimodal_generation.py \
    --query-type use_image \
    --model Qwen/Qwen3-Omni-30B-A3B-Instruct \
    --stream

Run Local Web UI Demo

This Web UI demo allows users to interact with the model through a web browser.

Running Gradio Demo

The Gradio demo connects to a vLLM API server. You have two options:

Option 1: One-step Launch Script (Recommended)

The convenience script launches both the vLLM server and Gradio demo together:

./run_gradio_demo.sh --model Qwen/Qwen3-Omni-30B-A3B-Instruct --server-port 8091 --gradio-port 7861

This script will:

1. Start the vLLM server in the background
2. Wait for the server to be ready
3. Launch the Gradio demo
4. Handle cleanup when you press Ctrl+C

The script supports the following arguments:

• --model: Model name/path (default: Qwen/Qwen3-Omni-30B-A3B-Instruct)
• --server-port: Port for vLLM server (default: 8091)
• --gradio-port: Port for Gradio demo (default: 7861)
• --stage-configs-path: Path to custom stage configs YAML file (optional)
• --server-host: Host for vLLM server (default: 0.0.0.0)
• --gradio-ip: IP for Gradio demo (default: 127.0.0.1)
• --share: Share Gradio demo publicly (creates a public link)

Option 2: Manual Launch (Two-Step Process)

Step 1: Launch the vLLM API server

vllm serve Qwen/Qwen3-Omni-30B-A3B-Instruct --omni --port 8091

If you have custom stage configs file:

vllm serve Qwen/Qwen3-Omni-30B-A3B-Instruct --omni --port 8091 --stage-configs-path /path/to/stage_configs_file

Step 2: Run the Gradio demo

In a separate terminal:

python gradio_demo.py --model Qwen/Qwen3-Omni-30B-A3B-Instruct --api-base http://localhost:8091/v1 --port 7861

Then open http://localhost:7861/ on your local browser to interact with the web UI.

The gradio script supports the following arguments:

• --model: Model name/path (should match the server model)
• --api-base: Base URL for the vLLM API server (default: http://localhost:8091/v1)
• --ip: Host/IP for Gradio server (default: 127.0.0.1)
• --port: Port for Gradio server (default: 7861)
• --share: Share the Gradio demo publicly (creates a public link)