Issue with Rendi's run-ffmpeg-command on Make.com - amix filter fails silently

[Ylia8241]

Hello,

I am using the official Rendi integration with Make.com to mix two audio files, and I'm facing a recurring issue. The Rendi - FFmpeg API module reports a successful execution but does not create an output file.

Goal: To mix two audio files (one from ElevenLabs, one from Google Drive) into a single file.

Scenario Configuration:

Module: Rendi - FFmpeg API (ID 13)

Action: Execute FFmpeg command

Input Files: The Rendi module is correctly configured to receive two input files.

FFmpeg Command: -i 0 -i 1 -filter_complex "[0]volume=1.0[a];[1]volume=0.25[b];[a][b]amix=inputs=2:duration=first" -y

Problem:

The Rendi module completes with a green success icon.

However, the output data is empty. The Data size consistently shows 56.0 B.

The subsequent Telegram module fails with the error: Missing value of required parameter 'data', because it receives no data from Rendi.

Troubleshooting Performed:

Both input files (from ElevenLabs and Google Drive) were verified as valid audio files (.mp3).

We replaced the Google Drive module with a direct HTTP request to rule out a data transfer issue. The problem persisted.

The FFmpeg command was simplified, but the result did not change.

The Rendi input settings for receiving two files were checked and are correctly configured (the Map toggle is off, and Item 1 and Item 2 are used).

Conclusion:
We have ruled out all possible issues on our side. It appears the FFmpeg command is failing with an internal error on your server but is not sending an error message back to Make.

Please check the execution logs for the FFmpeg command for this specific case.

[peternaf]

@Ylia8241

On a first look, I don't see an output file in your command
also, the -y flag is not required - your commands run encapsulated in rendi, so there will not be a file to overwrite

Rendi will return a successful response when you execute run-ffmpeg-command with the required fields.
But, since these are batch commands that could take a while to run, in order to see that the command finalized succesfully and access its output you need to use the polling endpoint:
https://docs.rendi.dev/api-reference/endpoint/poll-command

Please send a command id and the email you are using to support@rendi.dev so we could investigate this deeper.