How to upload base64 image on transloadit?

I am trying to upload base64 image to transloadit but enable to do it. Getting error:
The argument 'path' must be a string or Uint8Array without null bytes. Received <Buffer

Code:

const Transloadit = require('transloadit')
 
const transloadit = new Transloadit({
    authKey: '',
    authSecret: '',
})
 
(async () => {
    try {
        // const file = b64toBlob('abc');
 
        const b = 'UklGRmgSAAB......';
 
        let bufferObj = Buffer.from(b, "base64");
 
        console.log("bufferObj", bufferObj) ---> shows buffer data
 
        const options = {
            files: {
                file1: bufferObj,
            },
            params: {
                steps: {
                    // You can have many Steps. In this case we will just resize any inputs (:original)
                    resize: {
                        use: ':original',
                        robot: '/image/resize',
                        result: true,
                        width: 75,
                        height: 75,
                    },
                },
                // OR if you already created a template, you can use it instead of "steps":
                // template_id: 'YOUR_TEMPLATE_ID',
            },
            waitForCompletion: true, // Wait for the Assembly (job) to finish executing before returning
        }
 
        const status = await transloadit.createAssembly(options)
 
        if (status.results.resize) {
            console.log('✅ Success - Your resized image:', status.results.resize[0].ssl_url)
        } else {
            console.log(
                "❌ The Assembly didn't produce any output. Make sure you used a valid image file"
            )
        }
    } catch (err) {
        console.error('❌ Unable to process Assembly.', err)
        if (err.assemblyId) {
            console.error(`💡 More info: https://transloadit.com/assemblies/${err.assemblyId}`)
        }
    }
})()