using ffmpeg/ffprobe to create a waveform json using php - php

Question

I have many ogg & opus files on my server and need to generate json-waveform numeric arrays on an as-needed basis (example below).
recently i discovered the node based waveform-util which uses ffmpeg/ffprobe for rendering a JSON waveform and it works perfectly. i am undecided if having a node process constantly running is the optimum solution to my issue.
since ffmpeg seems to be able to handle anything i can throw at it, i wish to stick with an ffmpeg solution.
i have three questions:
1) is there a php equivalent? i have found a couple that generate PNG images but not one that generates JSON-waveform numeric arrays
2) are there any significant advantages of going with the node-based solution rather than a php based solution (assuming there is a php based solution)?
3) is there a way using CLI ffmpeg/ffprobe to generate a json-waveform ? i saw all the -show_ options (-show_data, -show_streams, -show_frames) but nothing looked like it produced what i am looking for.
the json-waveform needs to be in this format:
[ 0.0002, 0.001, 0.15, 0.14, 0.356 .... ]
thank you all.

Answer 1

it sounds as if there is a conflict with the way my server is handling cgi. i am using virtualmin and am using the following setting:
PHP script execution mode: CGI wrapper (run as virtual server owner)
after much research, it appears that using pure node.js is more lightweight rather than using a shell executable. i was able to have some success merely by putting a schbang line to call node, but having a node.js script always memory resident is probably the way to go.

Answer 2

For anyone in the future looking to do this with RN:
// convert the file to pcm
await RNFFmpeg.execute(`-y -i ${filepath} -acodec pcm_s16le -f s16le -ac 1 -ar 1000 ${pcmPath}`)
// you're reading that right, we're reading the file using base64 only to decode the base64, because RN doesnt let us read raw data
const pcmFile = Buffer.from(await RNFS.readFile(pcmPath, 'base64'), 'base64')
let pcmData = []
// byte conversion pulled off stack overflow
for(var i = 0 ; i < pcmFile.length ; i = i + 2){
var byteA = pcmFile[i];
var byteB = pcmFile[i + 1];
var sign = byteB & (1 << 7);
var val = (((byteA & 0xFF) | (byteB & 0xFF) << 8)); // convert to 16 bit signed int
if (sign) { // if negative
val = 0xFFFF0000 | val; // fill in most significant bits with 1's
}
pcmData.push(val)
}
// pcmData is the resulting waveform array