OpenAI’s gpt-4o-transcribe family turns recorded speech into text over /v1/audio/transcriptions, with optional Realtime input on some SKUs. On OpenAI’s pricing page (checked October 30, 2026), gpt-4o-transcribe and gpt-4o-transcribe-diarize list an Estimated $0.006 per audio minute, gpt-4o-mini-transcribe lists Estimated $0.003/min, and the recommended successor gpt-transcribe lists $0.0045/min. Live mic paths sit higher: gpt-live-transcribe at Estimated $0.017/min.
The LecSync Realtime Speech API is a managed WebSocket for live meeting and lecture captions: preview and final text, translation between any two of 60 languages, a speaker and audio-aligned timestamps on every final segment, and running minutes. It costs $0.006 per audio minute ($0.36 per hour) with those features included.
Figures below were checked on October 30, 2026 against OpenAI pricing, the transcription and file transcription guides, the gpt-4o-transcribe / mini / diarize / gpt-transcribe / gpt-live-transcribe model cards, and the LecSync developers page. This post focuses on the gpt-4o-transcribe file and streaming SKUs and their listed successors. It is separate from the earlier LecSync vs AssemblyAI vs OpenAI realtime one-connection comparison, which covered live-transcribe and realtime-translate sessions.
What is gpt-4o-transcribe vs a realtime caption API?
gpt-4o-transcribe is a speech-to-text model powered by GPT-4o: you upload a finished recording (or stream deltas while a file is processed), and you get text. Some gpt-4o-transcribe integrations also accept Realtime audio. A realtime caption API such as LecSync keeps one managed socket open for live bilingual captions, speakers and minutes while people are still talking.
The short answer
If you need file transcription — including OpenAI’s cheaper mini SKU at Estimated $0.003/min, or the recommended gpt-transcribe at $0.0045/min — OpenAI is the stronger fit for same-language transcripts of completed audio. Speaker-labeled files still use the deprecated gpt-4o-transcribe-diarize path until February 26, 2027.
If you need live bilingual captions + speakers + minutes on one flat minute bill, LecSync is the closer product. gpt-4o-transcribe does not support the Realtime translation endpoint; live mic captions on OpenAI’s recommended path use gpt-live-transcribe at Estimated $0.017/min, and live translation is a separate realtime-translate session at Estimated $0.034/min.
How each path works
LecSync. Your server calls POST https://api.lecsync.com/v1/realtime/connect with the audio format, a language pair and the features you want, then streams 16 kHz mono PCM. Preview text arrives while someone is still talking; a final segment settles once the sentence confirms. Translations share the segment ID. With speakers: true, each final carries a speaker and startMs/endMs on the recording clock. With digest: true, minutes arrive section by section. The first word shows up about 0.28 seconds after speech starts; translation adds roughly 88 ms. Seven gateway regions (dal, jp3, kc, nj, ru2, ru3, uk) keep audio near the capture point; backlog is capped at 2 seconds.
OpenAI gpt-4o-transcribe family. Upload up to 25 MB (mp3, mp4, mpeg, mpga, m4a, wav, webm) to /v1/audio/transcriptions, or set stream=true to receive deltas while a completed file is processed. Model cards show gpt-4o-transcribe and gpt-4o-mini-transcribe on Transcription and Realtime endpoints; they do not support Realtime translation, dedicated Realtime transcription sessions, or /v1/audio/translations. gpt-4o-transcribe-diarize is Transcription-only (diarized_json, optional known-speaker references); OpenAI docs state speaker labeling is not available in Realtime transcription sessions. OpenAI marks whisper-1, gpt-4o-transcribe, gpt-4o-mini-transcribe, gpt-4o-transcribe-diarize, and /v1/audio/translations as deprecated, with shutdown on February 26, 2027. New file work should start on gpt-transcribe ($0.0045/min); new live mic work on gpt-live-transcribe ($0.017/min).
Pricing converted to dollars per hour (Calculated)
| Path | Published / Estimated rate | Implied $/hour of audio | Notes |
|---|---|---|---|
| LecSync Realtime Speech API | $0.006 / min all-in | $0.36 | STT + translation + speakers + digest included |
| gpt-4o-transcribe | Estimated $0.006 / min | $0.36 | Token rates $2.50 / $10 per 1M; Estimated $/min on pricing table |
| gpt-4o-transcribe-diarize | Estimated $0.006 / min | $0.36 | File diarization; deprecated |
| gpt-4o-mini-transcribe | Estimated $0.003 / min | $0.18 | Cheaper file STT; deprecated |
| gpt-transcribe (recommended file) | $0.0045 / min | $0.27 | Successor for completed recordings |
| gpt-live-transcribe (recommended live) | $0.017 / min | $1.02 | Live mic / streaming captions |
| gpt-realtime-translate | Estimated $0.034 / min | $2.04 | Separate live translation session |
Minute math (Calculated from OpenAI Estimated or listed $/min): gpt-4o-transcribe → 1,000 hours ≈ $360; mini → ≈ $180; gpt-transcribe → ≈ $270; gpt-live-transcribe → ≈ $1,020. LecSync stays $0.006/min whether translation and speakers are on or off → 1,000 hours = $360.
Side-by-side facts (checked October 30, 2026)
| LecSync Realtime Speech API | OpenAI gpt-4o-transcribe family | |
|---|---|---|
| Primary job | Live meeting/lecture captions + MT | File (and some Realtime) same-language STT |
| Price model | $0.006/min flat, all features | Est. $0.006 / $0.003; successors $0.0045 file / $0.017 live |
| Delivery | Managed WebSocket, preview→final | /v1/audio/transcriptions (+ Realtime on non-diarize SKUs) |
| Live text translation | Any two of 60, same socket | Not on gpt-4o-transcribe; migrate to realtime-translate (~$0.034/min) |
| Speakers | Speaker on every final (speakers: true) | File: gpt-4o-transcribe-diarize; not in Realtime transcription sessions |
| Live minutes / digest | digest: true | Not on these transcription SKUs |
| Languages | 60, auto-detected | Whisper list ~98 for whisper-1; gpt-transcribe uses languages hints |
| Status | GA managed API | gpt-4o-* deprecated; shutdown 2027-02-26 |
| File size | Stream PCM (session-based) | ≤25 MB per upload on Transcriptions API |
| Regions | 7 gateway regions; 2 s backlog cap | OpenAI cloud |
What 1,000 hours cost (Calculated)
| Workload, 1,000 hours a month | LecSync | OpenAI path |
|---|---|---|
| Same-language file STT | N/A as primary product (live API) | gpt-4o-transcribe ~$360; mini ~$180; gpt-transcribe ~$270 |
| Same-language live captions | $360 | gpt-live-transcribe ~$1,020 (recommended) |
| Translated live captions (arbitrary pair) | $360 | Separate realtime-translate ~$2,040/target + STT path |
| Speakers with timestamps during a live session | Included | File diarize SKU only; live sessions: not on gpt-4o-transcribe-diarize |
| Live minutes | Included | Build separately |
| Predictable all-in minute for captions + MT + speakers | Yes | Multiple SKUs / sessions |
OpenAI wins on cheap same-language file STT (mini and gpt-transcribe undercut LecSync’s minute price). LecSync wins when the product is a live bilingual caption feed with speakers and minutes at one flat $0.006. For flat-vs-add-on math, see what 1,000 hours cost once translation, speakers and summaries are added. For stitching your own STT + MT, see built-in translation vs a DIY pipeline.
When OpenAI gpt-4o-transcribe (or successors) is the better pick
- Completed recordings up to 25 MB where you want OpenAI’s file Transcriptions API and Estimated $0.003–$0.006/min STT.
- Cost-sensitive same-language batch — gpt-4o-mini-transcribe (Estimated $0.003/min) or recommended gpt-transcribe ($0.0045/min).
- File speaker labels on the deprecated diarize model (
diarized_json, known-speaker refs) until the 2027 shutdown, if that format still matches your app. - OpenAI platform adjacency — same account as Chat Completions, Realtime agents, and the broader model catalog.
- New integrations that follow OpenAI’s current guidance: gpt-transcribe for files, gpt-live-transcribe for live audio (accepting the higher live $/min).
When LecSync fits better
- Translated live captions on one socket — any pair of 60 languages, each translation tied to its segment.
- Speakers and recording-aligned timestamps during the live stream — meeting client with speakers and timestamps.
- Live minutes while the session runs (
digest: true) — live digest vs post-call summarization. - Predictable minute billing at $0.36 an hour with translation, speakers and digest included — no $0.017 live STT row and no $0.034 translate session.
- Classroom / mixed-language lecture feeds where captions must keep up as the speaker switches languages, without migrating off deprecated gpt-4o SKUs.
Category winners
| Category | Winner | Why |
|---|---|---|
| Cheapest listed same-language file STT | OpenAI mini / gpt-transcribe | Est. $0.003 or $0.0045/min vs LecSync $0.006 |
| File speaker diarization SKU | OpenAI gpt-4o-transcribe-diarize | Dedicated diarized_json until 2027-02-26 |
| Live any-to-any captions | LecSync | 60 languages, MT on the same socket |
| Flat all-in $/min for live captions + MT + speakers + digest | LecSync | $0.006 includes the bundle |
| Recommended OpenAI live mic STT | gpt-live-transcribe | Current docs path; Est. $0.017/min |
| Managed first-word latency story for captions | LecSync | Public ~0.28 s / +~88 ms MT |
FAQ
Is gpt-4o-transcribe still the model OpenAI recommends?
No. OpenAI’s transcription guide recommends gpt-transcribe for file workflows and gpt-live-transcribe for realtime mic/call audio. gpt-4o-transcribe, gpt-4o-mini-transcribe, gpt-4o-transcribe-diarize, whisper-1, and /v1/audio/translations are deprecated and scheduled to shut down on February 26, 2027.
Does gpt-4o-transcribe include live translation?
No. The model card lists Realtime translation and /v1/audio/translations as not supported for gpt-4o-transcribe. OpenAI directs translation migrations to a Realtime translation session (gpt-realtime-translate, Estimated $0.034/min on the pricing table).
How does OpenAI’s Estimated $0.006/min compare to LecSync?
At the Estimated rate, gpt-4o-transcribe matches LecSync’s $0.006/min for same-language transcription math (1,000 hours ≈ $360 either way). LecSync’s minute also includes live translation, speakers and digest on one connection. OpenAI’s recommended live path (gpt-live-transcribe) is Estimated $0.017/min before any separate translate session.
Can I get speaker labels on an OpenAI Realtime transcription session with gpt-4o-transcribe-diarize?
OpenAI’s file transcription guide states speaker labeling is available through /v1/audio/transcriptions and is not supported in Realtime transcription sessions. The diarize model card shows Transcription support only.
When should a live-caption product still use OpenAI transcription?
When the workload is mostly finished files or you already standardize on OpenAI’s API surface and can accept gpt-live-transcribe pricing for live audio. If the product needs bilingual captions, speakers and minutes with a single $0.006 minute, start from the LecSync Realtime Speech API.
Final verdict
OpenAI’s gpt-4o-transcribe family (and its gpt-transcribe / gpt-live-transcribe successors) wins for same-language file STT and for teams already on the OpenAI platform — especially at mini’s Estimated $0.003/min or gpt-transcribe’s $0.0045/min. LecSync wins when you want a managed realtime speech API at $0.006/min all-in with live translation, speakers and digest on one connection.
Next step: open the LecSync developers page, create a connect session, and stream three seconds of PCM to see preview→final captions on one bill.