Add prompt enhancement feature to video generation

- Introduced `enhance_prompt`, `max_tokens`, and `temperature` parameters in `generate_video` function for improved prompt handling.
- Implemented prompt enhancement logic using the new `enhance_t2v` method in the text encoder.
- Added command-line arguments for prompt enhancement options.
- Created new system prompt files for T2V and I2V generation to guide the enhancement process.

mlx_video/generate.py

@@ -160,6 +160,9 @@ def generate_video(
     output_path: str = "output.mp4",
     save_frames: bool = False,
     verbose: bool = True,
+    enhance_prompt: bool = False,
+    max_tokens: int = 512,
+    temperature: float = 0.7,
 ):
     """Generate video from text prompt.
 
@@ -206,6 +209,12 @@ def generate_video(
     text_encoder.load(model_path=model_path, text_encoder_path=text_encoder_path)
     mx.eval(text_encoder.parameters())
 
+    # Optionally enhance the prompt
+    if enhance_prompt:
+        print(f"{Colors.MAGENTA}✨ Enhancing prompt...{Colors.RESET}")
+        prompt = text_encoder.enhance_t2v(prompt, max_tokens=max_tokens, temperature=temperature, seed=seed, verbose=verbose)
+        print(f"{Colors.DIM}Enhanced: {prompt[:150]}{'...' if len(prompt) > 150 else ''}{Colors.RESET}")
+
     text_embeddings, _ = text_encoder(prompt)
     mx.eval(text_embeddings)
 
@@ -373,7 +382,7 @@ Examples:
         help="Frames per second for output video (default: 24)"
     )
     parser.add_argument(
-        "--output", "-o",
+        "--output-path",
         type=str,
         default="output.mp4",
         help="Output video path (default: output.mp4)"
@@ -400,20 +409,27 @@ Examples:
         action="store_true",
         help="Verbose output"
     )
+    parser.add_argument(
+        "--enhance-prompt",
+        action="store_true",
+        help="Enhance the prompt using Gemma before generation"
+    )
+    parser.add_argument(
+        "--max-tokens",
+        type=int,
+        default=512,
+        help="Maximum number of tokens to generate (default: 512)"
+    )
+    parser.add_argument(
+        "--temperature",
+        type=float,
+        default=0.7,
+        help="Temperature for prompt enhancement (default: 0.7)"
+    )
     args = parser.parse_args()
 
     generate_video(
-        model_repo=args.model_repo,
-        text_encoder_repo=args.text_encoder_repo,
-        prompt=args.prompt,
-        height=args.height,
-        width=args.width,
-        num_frames=args.num_frames,
-        seed=args.seed,
-        fps=args.fps,
-        output_path=args.output,
-        save_frames=args.save_frames,
-        verbose=args.verbose,
+        **vars(args)
     )