Add system prompt to Qwen-Omni conversation

transcript.py

@@ -103,6 +103,7 @@ def main():
             model = Qwen2_5OmniForConditionalGeneration.from_pretrained("Qwen/Qwen2.5-Omni-7B", torch_dtype="auto", device_map="auto", trust_remote_code=True)
             processor = Qwen2_5OmniProcessor.from_pretrained("Qwen/Qwen2.5-Omni-7B", trust_remote_code=True)
             conversation = [
+                {"role": "system", "content": "You are Qwen, a virtual human developed by the Qwen Team, Alibaba Group, capable of perceiving auditory and visual inputs, as well as generating text and speech."},
                 {"role": "user", "content": [
                     {"type": "audio", "audio": {"waveform": audio_chunk, "sample_rate": sr}},
                     {"type": "text", "text": "Transcribe this audio segment exactly as spoken."}