Enable color parameters in NVENC test on FFmpeg 4 and 6

import subprocess
import torch
import json
from torchcodec.encoders import VideoEncoder

# Create test frames and encode with specific color parameters
frames = torch.randint(0, 256, (5, 3, 256, 256), dtype=torch.uint8).to("cuda")
encoder = VideoEncoder(frames=frames, frame_rate=30)

encoder.to_file(
    dest="/tmp/test_video.mp4",
    codec="h264_nvenc",
    extra_options={
        "colorspace": "bt709",
        "color_range": "pc",
    }
)

result = subprocess.run(
        [
          "ffprobe",
          "-v",
          "error",
          "-select_streams",
          "v:0",
          "-show_entries",
          "stream=color_space,color_range,pix_fmt",
          "-of",
          "json",
          "/tmp/test_video.mp4"
        ],
        capture_output = True,
        text = True,
        check = True)

metadata = json.loads(result.stdout)["streams"][0]
print(json.dumps(metadata, indent=2))