We have also tried adding a nixpacks.toml file to the project in case that was required for ffmpeg, but no luck.

[phases.setup]

aptPkgs = ["ffmpeg"]

[start]

cmd = "node dist/index.js"

[build]

builder = "nixpacks"

[phases.build]

cmds = [

"npm install",

"npm run build"

]

[env]

NODE_ENV = "production"

This feels like an issue with the storage volume mount, but since this isn't a platform issue- there isn't much help we can offer here. Other users do happen to run FFMpeg just fine. (Although I think SSH would be a great addition to have to make it easier to debug.)

Don't the containers for projects have ephemeral storage regardless if a storage volume is attached? I would expect that I could save at least a few MB of data to a /tmp/ dir which would be lost next time the project initialises without a dedicated storage volume? I only recently added the storage volume to see if that would make any difference but it doesn't appear to have changed the output. So now I'm thinking its around how FFMPEG is initializing on linux or running in the container and its hard to tell exactly why it doesnt work on railway vs local which runs every time we trigger the job. I have included a screenshot of the logs from railway when we run the FFMPEG command using nodes spawnSync and then a screenshot from the output of FFMPEG when its running locally.

Paths when running local:

FFmpeg path: C:\Github\project\service-bullmq\node_modules\@ffmpeg-installer\win32-x64\ffmpeg.exe

FFprobe path: C:\Github\project\service-bullmq\node_modules\ffprobe-static\bin\win32\x64\ffprobe.exe

In the screenshots provided they are both using the same HLS url.

• In the screenshot for railway you can see in the logs the output states it completes the storyboard output almost instantly after we initialise ffmpeg, it doesnt even try to go through each .ts file.

• In the screenshot for local ffmpeg you can see once we initialise ffmpeg it starts to work through each of the .ts for the HLS url which is the expected behaviour.

• The 3rd screenshot includes the ffmpeg output from a completed run on my local machine for the same HLS url. So couple of things, one it takes a lot longer to finish as expected since its a 22 minute video, secondly it outputs a file to local directory /tmp, for the sake of being verbose the output file from ffmpeg is 243KB in size.

Thanks.

Chiming in here to say that @ffmpeg-installer is known to give strange issues in containerized environments.

Remove any npm package that installs ffmpeg or ffprobe, and instead, install it as a nix package via a nixpacks.toml file -

[phases.setup]
	nixPkgs = ['...', 'ffmpeg']

Not saying this is going to magically fix the issue, but it's best to at least use best practices first.

Thanks for the feedback, will try removing the node packages for sure - in my second post I did post my nixpacks.toml file which is using aptPkgs syntax, is nixPkgs what I should be using there?

The only thing that is unclear doing it this way would be how I get the ffmpeg path values to initialise ffmpeg, for example if I remove the ffmpeg node packages and use nixpacks what would the path be? /opt/bin/ffmpeg perhaps? This was something that we had to do when running this on an AWS lambda environment, so wondering if it would be similar path (not to familiar with containers to find that info easily). By that i mean that the current FFMPEG path when running on railway is:/app/node_modules/@ffmpeg-installer/linux-x64/ffmpeg .

> in my second post I did post my nixpacks.toml file which is using aptPkgs syntax, is nixPkgs what I should be using there?

Yes, nix will install both ffmpeg and ffprobe.

> The only thing that is unclear doing it this way would be how I get the ffmpeg path values to initialise ffmpeg

You don't need to, they will be in $PATH, and any good wrapper library should be able to pick that up without you configuring anything extra.

I will change the syntax to nixPkgs thank you for that.

Guess I can just output the path and see what it says when running on railway, as we arent using any wrappers we are just passing the FFMPEG args along with the FFMPEG path straight into nodes spawnSync functions which is part of node utils child_process. So we would need to have knowledge of where ffmpeg path is to initialise ffmpeg command we are running.

example of command syntax used:

import { spawnSync } from 'node:child_process'

const ffmpegResult = spawnSync(FFMPEG_PATH, ffmpegArgs, { stdio: 'inherit' });

You could call something like which to get the path, or there might even be a native node solution.

Looks to be working now after tweaking nixpacks.toml and FFMPEG paths. Guess if anyone comes across this and isn't doing ffmpeg via dockerfile and wants to run ffmpeg directly from a node project using spawnSync with just nixpacks then these 2 steps should be sufficient.

1. Add ffmpeg to nixpacks.toml as advised above.

2. Use which to find ffmpeg path using something like this to automatically set it: FFMPEG_PATH = execSync('which ffmpeg');

With those two changes I was able to use FFMPEG on railway and get the same output as my local env. So now I can simply just use an if statement when initializing the project and use @ffmpeg-installer packages if I'm running the project locally to debug and then use which to deterministically set it when running in a container environment like railway.

Awsome, glad it worked for you!