Topic: FFmpeg Video Processing
i want to encode a video using ffmpeg and the codecs vp9 and opus. please provide me with a high quality script using the CRF function

Topic: FFmpeg Video Processing
```
[
    {
        "Name": "libaom (Two-pass)",
        "Description": "2-pass, In order to create more efficient encodes when a particular target bitrate should be reached.",
        "First_pass": "-pass 1 -an -sn -c:v libaom-av1 -b:v 2M -usage good -cpu-used 4 -row-mt 1 -tiles 2x2 -g 250 -keyint_min 250 -pix_fmt yuv420p -f null",
        "Second_pass": "-pass 2 -c:v libaom-av1 -b:v 2M -usage good -cpu-used 4 -row-mt 1 -tiles 2x2 -g 250 -keyint_min 250 -pix_fmt yuv420p -map 0:v? -map_chapters 0 -map 0:s? -c:a: libopus -compression_level 5 -map 0:a:? -map_metadata 0",
        "Supported_list": "",
        "Output_extension": "mkv"
    }
]
```

Using the provided code block as reference, create a videomass preset that converts a video file to av1 with close to lossless quality while also reducing file size. make sure it is two-pass.