How to beginner · 3 min read

Whisper audio format not supported fix

Quick answer

To fix the Whisper audio format not supported error, convert your audio file to a supported format like mp3, wav, or m4a before transcription. Use tools like ffmpeg to convert unsupported formats to these standard ones compatible with the openai Whisper API.

PREREQUISITES

Python 3.8+
OpenAI API key (free tier works)
pip install openai>=1.0
ffmpeg installed and accessible in system PATH

Setup

Install the openai Python package and ensure ffmpeg is installed on your system for audio conversion.

Install OpenAI Python SDK: pip install openai
Install ffmpeg via your OS package manager or from ffmpeg.org

bash

pip install openai

Step by step

Convert unsupported audio formats to mp3 or wav using ffmpeg in Python, then transcribe with Whisper API.

python

import os
import subprocess
from openai import OpenAI

# Convert audio to mp3 using ffmpeg
input_file = "input_audio.unsupported"
converted_file = "converted_audio.mp3"

subprocess.run(["ffmpeg", "-y", "-i", input_file, converted_file], check=True)

# Transcribe with Whisper API
client = OpenAI(api_key=os.environ["OPENAI_API_KEY"])
with open(converted_file, "rb") as audio_file:
    transcript = client.audio.transcriptions.create(
        model="whisper-1",
        file=audio_file
    )

print("Transcription:", transcript.text)

output

Transcription: This is the transcribed text from the audio.

Common variations

You can convert audio to other supported formats like wav or m4a by changing the ffmpeg output filename extension. Async transcription is also possible with async libraries but requires additional setup.

python

import os
import subprocess
from openai import OpenAI

# Convert to wav instead of mp3
input_file = "input_audio.unsupported"
converted_file = "converted_audio.wav"
subprocess.run(["ffmpeg", "-y", "-i", input_file, converted_file], check=True)

client = OpenAI(api_key=os.environ["OPENAI_API_KEY"])
with open(converted_file, "rb") as audio_file:
    transcript = client.audio.transcriptions.create(
        model="whisper-1",
        file=audio_file
    )

print("Transcription:", transcript.text)

output

Transcription: This is the transcribed text from the audio.

Troubleshooting

If you get audio format not supported errors, verify your ffmpeg installation and that the converted file is a valid mp3, wav, or m4a.
Check file size limits (max 25MB for Whisper API).
Use ffmpeg -i input_file to inspect audio format details.

✅

Key Takeaways

Always convert unsupported audio formats to mp3, wav, or m4a before using Whisper API.
Use ffmpeg for reliable audio format conversion in Python scripts.
Check audio file size and format compatibility to avoid transcription errors.

Verified 2026-04 · whisper-1

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