AssemblyAI Universal 3.5 Pro vs GPT-4o Mini Transcribe
Accuracy and speed
Left gets fewer words wrong. Lower has the final text ready sooner.
- Universal 3.5 Pro1.93% · 180ms
- 4o Mini Transcribe3.35% · 630ms
AssemblyAI Universal 3.5 Pro is ahead of GPT-4o Mini Transcribe on both datasets together, the Pipecat Dataset and final-text delay. The Ocular Dataset is too close to call. AssemblyAI Universal 3.5 Pro has a newer release: AssemblyAI Universal 3.6 Pro vs GPT-4o Mini Transcribe.
Last updated Methodology by Dileep Chagam
Who is better at what
- Overall WER2.72%3.73%
- Pipecat Dataset WER1.93%3.35%
- Ocular Dataset WER4.23%4.45%
- Time to first text489msn/a
- Final-text delay180ms630ms
Lower is better on every measure. Too close to call means the likely ranges overlap.
Universal 3.5 Pro vs 4o Mini Transcribe FAQ
Which is more accurate, AssemblyAI Universal 3.5 Pro or GPT-4o Mini Transcribe?
AssemblyAI Universal 3.5 Pro is more accurate on both datasets. On the 1,000 public Pipecat clips, AssemblyAI Universal 3.5 Pro scores 2.72% and GPT-4o Mini Transcribe 3.73%, so AssemblyAI Universal 3.5 Pro makes fewer errors by 1.01 points. On the eight licensed Ocular recordings, AssemblyAI Universal 3.5 Pro scores 1.93% and GPT-4o Mini Transcribe 3.35%, so AssemblyAI Universal 3.5 Pro makes fewer errors by 1.43 points. Word error rate counts incorrect, missing, and extra words, so lower is better.
AssemblyAI Universal 3.5 Pro is more accurate on both datasets. On the 1,000 public Pipecat clips, AssemblyAI Universal 3.5 Pro scores 2.72% and GPT-4o Mini Transcribe 3.73%, so AssemblyAI Universal 3.5 Pro makes fewer errors by 1.01 points. On the eight licensed Ocular recordings, AssemblyAI Universal 3.5 Pro scores 1.93% and GPT-4o Mini Transcribe 3.35%, so AssemblyAI Universal 3.5 Pro makes fewer errors by 1.43 points. Word error rate counts incorrect, missing, and extra words, so lower is better.
Final-text delay was not measured for one or both, so speed cannot be compared. Both are measured on the same 206 streamed turns.
AssemblyAI Universal 3.5 Pro makes fewer errors on real conversations, and the two are not separated on speed. A voice agent cannot reply until the final transcript arrives, and the Ocular recordings are real conversations.
Only AssemblyAI Universal 3.5 Pro. GPT-4o Mini Transcribe returns no text until the speaker stops, which matters if your agent reacts to partial transcripts.
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