# Transcription Plan & Processing Guide ## 2-Hour AI Policy Podcast Interview (Host + 2 Guests) Since no audio text has been provided yet, below is a complete **pre-transcription strategy** plus a **transcript template** you can populate once the audio is processed. This plan is optimized for Whisper (or similar ASR tools) handling café background noise, overlapping speech, and technical AI policy jargon. --- ## 1. Recommended Chunking Strategy for 2-Hour Audio **Why chunk?** Whisper's accuracy degrades on files over ~30 minutes due to context window limits, timestamp drift, and hallucination in silent/noisy stretches. Chunking also lets you parallelize processing and isolate errors. ### Recommended approach: **10-minute chunks with 5–10 second overlap** | Parameter | Recommendation | Reason | |---|---|---| | Chunk length | 8–10 minutes | Balances context retention vs. drift risk | | Overlap | 5–10 seconds | Prevents word-cutting at boundaries | | Split points | Silence-based (not fixed time) | Avoids cutting mid-word/mid-sentence | | Total chunks | ~12–15 for 2 hours | Manageable for QA review | ### Tools for smart splitting: - **`pydub` + `split_on_silence`** (Python) — detects natural pauses - **`ffmpeg` with silencedetect filter** — `ffmpeg -i input.mp3 -af silencedetect=n=-30dB:d=0.5 -f null -` - **Auphonic** or **Adobe Podcast Enhance** (pre-clean café noise first) ### Pre-processing pipeline (recommended order): 1. **Noise reduction** — Run through Adobe Podcast Enhance or Krisp to remove café ambiance BEFORE transcription 2. **Normalize loudness** — `ffmpeg -af loudnorm` (target -16 LUFS) 3. **Split on silence** — 10-min chunks at natural pauses 4. **Transcribe each chunk** — Use Whisper `large-v3` with `--word_timestamps True` 5. **Stitch + align** — Adjust timestamps per chunk offset, dedupe overlap regions 6. **Speaker diarization** — Run `pyannote.audio` separately, then merge speaker labels onto Whisper output --- ## 2. Transcript Template (Populate After Processing) ``` # [Podcast Title] — AI Policy Roundtable **Recorded:** [Date] | **Duration:** ~2:00:00 **Participants:** Host (Speaker 1), Guest A (Speaker 2), Guest B (Speaker 3) --- [00:00:00] **Host:** Welcome to [show name]. Today we're joined by [Guest A] and [Guest B] to discuss the evolving landscape of AI policy... [00:02:30] **Guest A:** Thanks for having me. I think the core tension right now is between innovation velocity and [regulatory capacity?]... [00:04:15] **Guest B:** If I could jump in there — I'd push back slightly on the framing. The EU AI Act, for example... [00:06:45] **Host:** Let's stay on the EU AI Act for a moment. How do you see [tiered risk classification?] playing out in practice? --- [continue at 2–5 minute intervals or at every speaker change] --- [02:00:00] **Host:** Thanks to both of you. That's all for today. ``` --- ## 3. Speaker Labeling Guidance - **Use real names if introduced on-air.** Listen to the first 2 minutes for intros and replace "Speaker 2/3" globally. - **Diarization tip:** `pyannote.audio 3.1` handles 3-speaker podcasts well but struggles with overlap. For overlapping segments, mark as: `[Guest A + Guest B, overlapping]` - **Distinguishing two guests:** If voices are similar (e.g., both male, similar pitch), listen for verbal tics, accent, or topic expertise to disambiguate. --- ## 4. Low-Confidence Segments — Flag for Human Review When you process the real audio, expect these categories to need review. Flag them in-text as `[word?]`: | Category | Examples to watch | |---|---| | Technical/policy jargon | "NIST AI RMF," "Bletchley Declaration," "Article 6(3)," "compute thresholds" | | Named entities | Researchers, agency names, bill numbers | | Acronyms | FLOPs, GPAI, AGI, RLHF, SB-1047 | | Overlapping crosstalk | Wherever two speakers speak simultaneously | | Café noise spikes | Coffee grinder, door chimes, nearby conversations | | Numbers & dates | "10^25 FLOPs," executive order dates, dollar figures | **Recommended flag format:** `[compute threshold?]` — uncertain word `[inaudible 01:23:45]` — unintelligible `[crosstalk]` — overlapping speech obscures content --- ## 5. Common Long-Recording Errors & How to Avoid Them ### Background café noise - **Pre-clean the audio** before transcription (Adobe Podcast Enhance is best-in-class and free) - Use Whisper's `--condition_on_previous_text False` to prevent noise-induced hallucinations from cascading - Lower `--no_speech_threshold` to 0.4 to reduce false-positive transcriptions of noise ### Overlapping speakers - Run **diarization separately** from transcription, then merge — don't rely on a single model for both - For dense overlap (>2 seconds), transcribe the dominant speaker and annotate: `[Guest B speaking underneath]` - Consider isolating speakers with **Demucs** or **Spleeter** if they were on separate mics ### Technical jargon (AI policy) - Build a
How to Transcribe Long Audio Recordings Without Errors
Tested prompts for transcribe long audio files over 1 hour compared across 5 leading AI models.
Transcribing audio files over an hour long is a different problem than transcribing a short clip. Most AI transcription tools have file size limits, token context windows that cut off mid-sentence, or accuracy that degrades as the audio drags on. If you've ever uploaded a 90-minute interview only to get back a truncated transcript or a wall of misattributed dialogue, you already know this.
The core challenge is chunking. Long audio needs to be split into manageable segments without losing speaker context, then reassembled into a coherent document. Do it wrong and you get transcripts where the speaker labels reset, sentences get cut in half, or the model starts confusing names it learned in minute 3 by minute 47.
This page shows you exactly how to prompt AI models to handle recordings over one hour, what outputs actually look like across different models, and where each approach breaks down. Whether you're transcribing a board meeting, a research interview, a podcast, or a legal deposition, the workflow here is built for files that don't fit neatly into a single API call.
When to use this
This approach works best when you have a single continuous audio file longer than 60 minutes that needs an accurate, readable transcript with speaker labels intact throughout. It fits situations where manual transcription is too slow or expensive, and where losing context mid-file would make the output useless.
- Transcribing 1-3 hour research interviews where speaker attribution must stay consistent across the full recording
- Converting recorded board meetings, town halls, or all-hands calls into searchable meeting notes
- Processing podcast episodes over 60 minutes into show notes, blog posts, or captions
- Turning long-form legal or medical dictation recordings into structured written documents
- Batch-processing a series of recorded lectures or training sessions into course transcripts
When this format breaks down
- Audio with severe background noise, heavy accents, or multiple overlapping speakers -- accuracy drops fast on long files and errors compound across chunks, making cleanup harder than transcribing manually
- Files where precise timestamps tied to specific words are legally required, such as court evidence -- chunked transcription can introduce small timestamp drift that creates compliance problems
- Audio under 15 minutes -- the chunking overhead adds unnecessary complexity; a single direct transcription call handles short files more cleanly
- Situations where you need real-time or live transcription -- this workflow is batch-only and not suited to streaming audio
The prompt we tested
You are an expert audio transcription specialist with deep experience handling long-form recordings (over 1 hour) such as podcasts, lectures, interviews, webinars, and meetings. Your job is to produce an accurate, well-structured transcript while minimizing errors common in lengthy audio (drift, speaker confusion, missed words, filler overload). Follow these rules: Format the transcript with clear speaker labels (Speaker 1, Speaker 2, or names if known), timestamps in [HH:MM:SS] format, and paragraph breaks at natural topic or speaker shifts. Remove excessive filler words (um, uh, like) unless meaningful, preserve technical terms and proper nouns exactly, and flag any uncertain words in [brackets with a question mark]. Keep the tone faithful to the original speech and include a brief 'Chunking & QA Recommendations' section at the end for recordings over 1 hour. Here is the audio context, transcript draft, or description of the recording to process: I have a 2-hour recorded podcast interview between a host and two guests discussing AI policy. The audio has some background café noise and occasional overlapping speech. I want a clean, timestamped transcript I can publish on my blog, and I need advice on how to split the file so Whisper or my transcription tool doesn't lose accuracy partway through. Produce the final transcript (or transcription plan if no audio text is provided yet), including: (1) a recommended chunking strategy for audio over 1 hour, (2) speaker labels where applicable, (3) timestamps every 2-5 minutes or at speaker changes, (4) cleaned punctuation and paragraph breaks, (5) a short list of low-confidence segments flagged for human review, and (6) practical tips for avoiding common errors in long recordings (background noise, overlapping speakers, technical jargon, fatigue drift).
Model comparison
| Model | Quality | Cost | Latency | Tokens |
|---|---|---|---|---|
| Claude Opus 4.7 | 7 | $0.1630 | 33.8s | 627 / 2048 |
| Claude Haiku 4.5 | 7 | $0.0107 | 23.2s | 415 / 2048 |
| GPT-5.4 | 7 | $0.0317 | 37.5s | 375 / 2048 |
| Gemini 2.5 Pro | 6 | $0.0029 | 18.4s | 377 / 480 |
| Grok 4.1 Fast Reasoning | 7 | $0.0007 | 19.0s | 522 / 1270 |
Outputs
# AI Policy Podcast Interview – Transcription Plan & Processing Guide
Since you've described the recording rather than provided the audio file itself, I'm providing a **comprehensive transcription strategy** you can follow, along with best practices for accurate long-form processing.
---
## 1. RECOMMENDED CHUNKING STRATEGY (2-Hour Recording)
### Why Chunk?
- **Whisper & similar models** degrade in accuracy after 15–20 minutes of continuous processing (attention drift, context loss)
- **Background noise accumulates** – longer chunks amplify café noise artifacts
- **Speaker overlap** becomes harder to resolve in monolithic files
- **Quality control** is easier on smaller, digestible segments
### Recommended Split Points
| Segment | Duration | Use Case |
|---------|----------|----------|
| **Segment 1** | 0:00–25:00 | Opening remarks + Guest 1 intro |
| **Segment 2** | 25:00–50:00 | Guest 1 deep-dive topic |
| **Segment 3** | 50:00–75:00 | Guest 2 intro + opening position |
| **Segment 4** | 75:00–100:00 | Guest 2 deep-dive + debate segment |
| **Segment 5** | 100:00–120:00 | Q&A, closing remarks, call-to-action |
**Rationale:** 25-minute chunks allow Whisper/Otter/Rev to maintain ~98% accuracy while keeping overhead manageable. Align cuts at natural conversation breaks (topic shifts, commercial breaks, or speaker handoffs) rather than mid-sentence.
### Tools & Workflow
- **Audio splitting:** Use `ffmpeg`, `Audacity`, or `MediaInfo` to cut without re-encoding
```bash
ffmpeg -i podcast.mp3 -ss 0 -to 1500 -c copy segment_1.mp3
ffmpeg -i podcast.mp3 -ss 1500 -to 3000 -c copy segment_2.mp3
```
- **Batch transcription:** Submit each segment separately; reassemble with timecodes
- **QA overlap:** Include 30-second overlaps between segments to catch boundary errors
---
## 2. SPEAKER LABELING PROTOCOL
### Before You Start
- **Identify speakers** at the outset:
- Host name & voice profile
- Guest 1 name & accent/tone
- Guest 2 name & accent/tone
- **Create a speaker legend** and reference it throughout
### Standard Format (Example)
```
[00:00:00]
HOST: Good morning, and welcome to the AI Policy Podcast. Today we're discussing...
[00:01:15]
GUEST 1 (Dr. Sarah Chen): Thanks for having me. I think we need to distinguish between two types of regulation...
[00:02:45]
HOST: That's a crucial point. Guest 2, how do you respond?
[00:03:10]
GUEST 2 (Marcus Rodriguez): I'd actually push back a bit here...
```
### Handling Overlaps
When two speakers talk simultaneously:
```
HOST: So the question is really about—
GUEST 1: [overlapping] —whether we prioritize safety or—
HOST: —accountability frameworks.
```
Use indentation or italics (`*[overlapping]*`) to clarify. Flag for human review if >2 seconds of overlap.
---
## 3. TIMESTAMP PLACEMENT & FORMATTING
### Frequency Guidelines
- **Every 2–5 minutes** for long monologues
- **Every speaker change** (especially important for debates/multi-turn exchanges)
- **Before major topic shifts** (e.g., "Now let's turn to regulation")
- **At natural pauses** (not mid-sentence)
### Format
- Use `[HH:MM:SS]` at the start of new speaker/segment
- Align visually for readability:
```
[00:15:30]
HOST: This ties back to the ethics question...
[00:16:45]
GUEST 1: Exactly. And here's where I think the EU got it right...
```
---
## 4. CLEANING & PUNCTUATION RULES
### Remove (Unless Significant)
- Excessive filler: "um," "uh," "like," "you know," "I mean" → keep only if it conveys hesitation or emphasis
- False starts: "I think—no, actually—" → resolve to the final phrasing unless the correction is part of the narrative
- Breath sounds, papers rustling, clearing throat
### Preserve
- Stammers or repetition that reflect emotional tone ("w-w-we need to be careful")
- Technical jargon *exactly as spoken* (e.g., "large language models," "constitutional AI," "alignment")
- Proper nouns: Company names, researcher names, legislation titles (capitalize correctly)
- Quoted material: Use quotation marks and attribute
### Example: Before & After
**Raw:** "Um, so like, the EU, right, they, uh, they passed the AI Act, you know, which is kind of, I mean, it's pretty comprehensive, right?"
**Cleaned:** "The EU passed the AI Act, which is fairly comprehensive."
**Better (preserves intent):** "The EU, with the AI Act, put together a pretty comprehensive framework."
---
## 5. COMMON ERRORS IN LONG-FORM AUDIO & MITIGATION
| Error Type | Cause | Prevention |
|------------|-------|-----------|
| **Drift (accuracy decline at 30+ min)** | Model attention loss, accumulated noise | Chunk at 20–25 min; restart model per segment |
| **Speaker confusion** | Similar voices, overlaps, poor audio | Create speaker profile library; mark overlaps explicitly |
| **Missed technical terms** | Unfamiliar jargon, low audio clarity | Pre-load glossary (AI policy terms); flag [?] for review |
| **Café noise artifacts** | Background chatter, clinking | Use noise-gate preprocessing; segment by noise level |
| **Timestamp drift** | Reassembly errors from split files | Verify segment duration matches; overlap-check boundaries |
| **Name spelling** | Proper nouns mumbled or unclear | Ask host/guests for name confirmation beforehand; cross-ref LinkedIn/bio |
### Preprocessing Step (Before Transcription)
```bash
# Noise reduction with ffmpeg-normalize
ffmpeg-normalize podcast.mp3 -o podcast_normalized.mp3 -loudness_range_target 7
# Optional: Noise suppression (Audacity, iZotope, or Noise Suppression plugin)
# Reduces café hum without distorting speech
```
---
## 6. POST-TRANSCRIPTION QUALITY CHECKLIST
- [ ] **Speaker consistency:** Same person labeled identically throughout
- [ ] **Timestamps:** No gaps or overlaps; match audio duration exactly
- [ ] **Technical accuracy:** Policy names, researcher names, statistics verified
- [ ] **Readability:** Paragraph breaks at topic shifts; no wall-of-text segments
- [ ] **Segment assembly:** Boundary overlaps checked for duplication/missing content
- [ ] **Flagged sections:** All [?] segments human-reviewed
- [ ] **Tone preservation:** Quotes and emphasis (italics/bold) mark key arguments
---
## 7. LOW-CONFIDENCE SEGMENTS TO FLAG FOR HUMAN REVIEW
Based on typical 2-hour AI policy podcasts, anticipate review for:
- **Statistical claims** ("X% of AI systems," "by 2030," etc.) – verify accuracy
- **Speaker names & affiliations** (first mention especially)
- **Acronyms & abbreviations** (NIST, EU AI Act, GDPR, etc.) – ensure standard capitalization
- **Rapid-fire technical exchanges** (overlapping speakers discussing model architectures, alignment techniques)
- **Audio degradation segments** (if café noise spikes or audio drops)
- **Quoted legislation or research** – cross-reference primary sources
**Template for flagging:**
```
[00:47:30] [REVIEW: "ChatGPT trains on X billion parameters" – verify figure]
GUEST 1: ChatGPT trains on [X billion] parameters, which is why...
[01:12:15] [REVIEW: Speaker name unclear – sounds like "Dr. [Jen/Gwen] Stein"?]
HOST: We also heard from Dr. [?], who argues that...
```
---
## 8. FINAL CHECKLIST: READY FOR PUBLICATION?
- ✅ **Segment
## Transcription Plan for a 2-Hour Podcast Interview on AI Policy Because no source audio or draft transcript was provided yet, below is a **publication-ready transcription workflow and formatting template** tailored to your recording: a **2-hour podcast interview** with **1 host + 2 guests**, **café background noise**, and **occasional overlapping speech**. --- # 1) Recommended Chunking Strategy for Audio Over 1 Hour For a 2-hour recording, do **not** transcribe the full file in one pass. Long files often cause: - timestamp drift, - speaker attribution errors, - missed words near the end, - context loss after long silence/noise stretches, - degraded accuracy on overlapping speech. ## Best Practice Chunking Setup ### Primary recommendation Split the audio into **10- to 15-minute chunks** with **5- to 10-second overlap** between adjacent segments. **Ideal for your 2-hour file:** - **12 chunks x 10 minutes**, or - **8 chunks x 15 minutes** ### Why this works - Keeps model context manageable - Reduces long-form drift - Makes speaker tracking easier - Simplifies rechecking low-confidence areas - Prevents one bad noisy section from harming the entire transcript ### Overlap rule Include **5-10 seconds of overlap** at the beginning/end of each chunk so you can: - recover clipped sentences, - compare timestamp continuity, - resolve speaker changes near cut points. ### Suggested split map for 12 x 10-minute chunks - Chunk 01: 00:00:00–00:10:05 - Chunk 02: 00:09:55–00:20:05 - Chunk 03: 00:19:55–00:30:05 - Chunk 04: 00:29:55–00:40:05 - Chunk 05: 00:39:55–00:50:05 - Chunk 06: 00:49:55–01:00:05 - Chunk 07: 00:59:55–01:10:05 - Chunk 08: 01:09:55–01:20:05 - Chunk 09: 01:19:55–01:30:05 - Chunk 10: 01:29:55–01:40:05 - Chunk 11: 01:39:55–01:50:05 - Chunk 12: 01:49:55–02:00:00 ## Optional preprocessing before chunking Before transcription, improve audio if possible: - convert to **mono WAV, 16 kHz or 24 kHz** - apply **light noise reduction** - normalize volume - avoid aggressive denoising that damages consonants - if available, run **voice isolation** gently, not destructively ## If using Whisper or similar tools Use: - **VAD / silence detection** if available, - **word timestamps** if supported, - **speaker diarization** separately if the built-in speaker tagging is weak, - a **custom vocabulary / prompt** with likely AI-policy terms and names. Example custom prompt seed: > This is a podcast interview about AI policy, regulation, model governance, compute, licensing, antitrust, open-source AI, foundation models, safety, alignment, transparency, the EU AI Act, NIST, FTC, export controls, and semiconductor policy. --- # 2) Speaker Labels Since you described **one host and two guests**, I recommend labeling as: - **Host** - **Guest 1** - **Guest 2** If names are known, replace with actual names for publication. Example: - **Maya Patel (Host)** - **Dr. Elena Ruiz** - **Marcus Chen** If identities are not confirmed during first-pass transcription, use: - **Speaker 1** - **Speaker 2** - **Speaker 3** Then resolve names during QA. --- # 3) Timestamping Recommendation For blog publication, use: - **timestamps every 2-5 minutes**, and - **always at major speaker changes, topic shifts, or interruptions** For a polished public transcript, **3- to 4-minute spacing** often reads best unless the conversation is very fast-moving. ### Recommended timestamp policy for your podcast - Add timestamps at: - intro/opening - each new major question - topic transitions - notable back-and-forth exchanges - every ~3 minutes if no natural transition occurs --- # 4) Cleaned Transcript Formatting Template Below is a **publishable transcript template** you can use once the audio is transcribed. --- ## Transcript **[00:00:00] Host:** Welcome back to the podcast. Today we’re joined by two guests to talk about AI policy, regulation, and what governments are getting right—and wrong—about the current wave of AI development. **[00:00:18] Guest 1:** Thanks for having us. It’s a great time to have this conversation because the policy landscape is changing extremely quickly. **[00:00:28] Guest 2:** Absolutely. What’s interesting right now is that policymakers are trying to regulate a moving target. The technology is changing faster than most legislative cycles can accommodate. **[00:02:45] Host:** Let’s start with the big picture. When people say “AI policy,” they can mean a lot of different things. What falls under that umbrella for each of you? **[00:03:02] Guest 1:** For me, AI policy includes safety standards, procurement rules, transparency requirements, liability frameworks, competition policy, and international coordination. It’s not just about frontier models. It’s also about how public institutions adopt and govern these systems. **[00:03:36] Guest 2:** I’d add export controls, semiconductor supply chains, and access to compute. A lot of the most consequential policy levers are upstream from the chatbot products most people interact with. **[00:05:11] Host:** That’s a helpful distinction. Public debate often gets stuck on consumer-facing tools, while the real leverage may be elsewhere. **[00:05:22] Guest 1:** Right. And some of the current policy conversation is distorted by hype. There are real risks, but there’s also a tendency to frame everything as either existential danger or harmless productivity software, when most policy decisions are much more granular than that. **[00:07:48] Guest 2:** Exactly. If you’re designing policy, you need to separate different categories of risk: labor market effects, misinformation, critical infrastructure, privacy, national security, and concentration of power. Those are related, but they aren’t the same problem. **[00:10:03] Host:** One thing I’ve noticed is that lawmakers often ask for a single framework that covers everything. Is that realistic? **[00:10:15] Guest 1:** Probably not. You may want some common baseline principles, but the actual rules should differ depending on the use case. A model used in medical triage should not be treated the same way as one used to summarize meeting notes. **[00:12:42] Guest 2:** And the institutional capacity question matters too. Even a good law can fail if the implementing agency doesn’t have technical expertise. **[00:15:07] Host:** Let’s talk about the EU AI Act, because it has become a reference point in almost every policy discussion. **[00:15:18] Guest 1:** The EU AI Act is important partly because it creates a vocabulary for risk categories, but its real-world impact will depend on implementation details, guidance, and enforcement. **[00:15:42] Guest 2:** Also, companies outside Europe will still pay attention because Brussels often shapes global compliance norms. We’ve seen that in data governance already. **[00:18:55] Host:** Do you think the United States is moving toward a coherent AI regulatory model, or are we still in a fragmented phase? **[00:19:08] Guest 2:** I’d say fragmented. You have the White House, NIST, the FTC, sector-specific regulators, state-level efforts, and then congressional proposals that don’t always align. **[00:19:31] Guest 1:** That fragmentation isn’t entirely bad. It can allow experimentation. But it also creates uncertainty for both developers and deployers. [Continue in this format through the full recording.] --- # 5) Low-Confidence Segments Flagged for Human Review Since the underlying audio/transcript has not been supplied, these are the **types of segments you should explicitly flag during QA**. Use this format in the final transcript: - **[unclear]** - **[word?]** - **[overlapping speech]** - **[inaudible due to café noise]** ## Likely low-confidence zones to review 1. **Introductions and name mentions** - Guest names, affiliations, organization names - Podcast title or sponsor read - Proper nouns spoken quickly 2. **Overlapping exchanges** - Especially interruptions during disagreement or fast back-and-forth - Cases where two guests answer at once 3. **Technical policy terminology** - “foundation models” - “model cards” - “compute governance” - “evals” - “red-teaming” - “NIST AI RMF” - “EU AI Act” - “general-purpose AI” - “open-weight” vs. “open-source” 4. **Café noise spikes** - Cups/clatter - espresso machine bursts - nearby voices masking consonants 5. **End-of-chunk boundaries
Of course. As an expert in long-form audio transcription, I can provide a comprehensive plan and a clear template for your 2-hour podcast. Handling long recordings effectively is about having a solid process *before* you even start transcribing.
Here is a complete transcription plan, including chunking strategy, a formatted example, and best practices for avoiding common errors.
---
### **Part 1: Recommended Chunking Strategy for Long Audio**
Automated transcription tools like Whisper can suffer from "context drift" or accuracy degradation on very long files. The model may lose track of speakers, recurring terms, or the overall topic, leading to increased errors in the latter half of the recording. Chunking the audio into smaller, manageable segments is the professional standard for mitigating this.
**Your 2-Hour (120-Minute) Audio Chunking Plan:**
1. **Optimal Chunk Size:** For a 2-hour file, I recommend splitting it into **five 24-minute chunks** or **six 20-minute chunks**. This size is ideal because it's long enough for the AI to establish context but short enough to prevent significant drift and keep memory usage low.
2. **Use an Overlap Strategy:** To avoid losing words at the split points, create a 5-10 second overlap between each chunk.
* **Chunk 1:** 00:00:00 - 00:24:05
* **Chunk 2:** 00:24:00 - 00:48:05
* **Chunk 3:** 00:48:00 - 01:12:05
* And so on.
When you stitch the final transcripts together, you can easily remove the duplicate sentences at the beginning of each new chunk.
3. **Tools for Splitting Audio:**
* **Audacity (Free):** The best free tool for this. Simply open your audio file, highlight the desired segment on the timeline, and go to `File > Export > Export Selected Audio`.
* **FFmpeg (Command Line):** For those comfortable with the command line, this is fast and scriptable.
### Transcription Plan for 2-Hour AI Policy Podcast Interview **Overview**: This plan is tailored for your 2-hour podcast with one host and two guests discussing AI policy. Audio challenges noted: background café noise, occasional overlaps. No raw transcript draft provided, so this includes a **structured template** for the final output (populate with your tool's output, e.g., Whisper). Use speaker diarization (e.g., via WhisperX or pyannote) to assign labels: **Host**, **Guest 1** (e.g., policy expert), **Guest 2** (e.g., tech ethicist)—refine names post-review if announced. Timestamps every 2-5 minutes or speaker/topic shifts. Clean fillers, add punctuation/paragraphs for readability. Total estimated word count: 18,000-25,000. #### (1) Recommended Chunking Strategy For 2-hour audio (>1hr), split to prevent Whisper drift (accuracy drops after 25-30min due to context loss). **Strategy**: - **Chunk size**: 25-30 minutes each (6-7 chunks total). - **Split points**: At natural pauses (e.g., topic changes like "AI regulation" to "ethics"; ad breaks; 00:25:00, 00:50:00, 01:15:00, 01:40:00). - **Process**: 1. Use FFmpeg: `ffmpeg -i full.mp3 -ss 00:00:00 -t 00:30:00 -c copy chunk1.mp3` (repeat for chunks). 2. Transcribe each chunk separately with Whisper (large-v3, 1hr context if using advanced mode). 3. Merge outputs, aligning timestamps (add chunk offset, e.g., Chunk 2 starts at [00:30:00]). 4. Post-process: Run diarization on full file for speaker consistency across chunks. - **Why?** Reduces hallucinations, speaker swaps; café noise handled per-chunk with noise gates. #### (2-4) Sample Transcript Template (Populated Structure) Format: [HH:MM:SS] **Speaker**: Text. Paragraphs at shifts. Overlaps noted as **[Overlap: Speaker X cuts in]**. ``` [00:00:00] **Host**: Welcome to the AI Policy Podcast. Today, we're joined by Dr. Elena Vasquez, our Guest 1 on AI regulation, and Mark Chen, Guest 2 from tech ethics. Let's dive in—what's the biggest policy gap in AI right now? [00:01:45] **Guest 1**: The EU AI Act is a start, but it lacks enforcement teeth. We need global standards to prevent a race to the bottom. [00:03:20] **Guest 2**: Absolutely, and bias in models like GPT is rampant. [Café noise fades in briefly.] [00:05:30] **Host**: Shifting to U.S. policy—Biden's executive order? [00:06:15] **Guest 1**: It's voluntary, which is why... *(Continue per chunk; timestamps every 2-5min or change. Example mid-chunk:)* [00:28:45] **Guest 2**: Overregulation stifles innovation. [Overlap: Host agrees.] [00:30:00] *(Chunk 2 start)* **Host**: After the break, ethics in deployment... [00:55:20] **Guest 1**: Quantum AI integration poses novel risks—regulators aren't ready. [01:15:00] *(Chunk 4 start)* **Host**: Final thoughts on open-source AI? [01:42:10] **Guest 2**: Collaboration over silos. [02:00:00] **Host**: Thanks, everyone. Subscribe for more. ``` #### (5) Short List of Low-Confidence Segments (Hypothetical Flags for Review) Based on description (noise/overlaps); verify these post-transcription: - [00:12:30] Guest 1: "The [algorithmic? auditing] framework..." (café noise overlap). - [00:47:15] Guest 2: "[Schumer's?] bill on Capitol Hill" (technical jargon + fatigue drift). - [01:22:45] Overlap: Host/Guest 1: "[unintelligible? on liability]" (simultaneous speech). - [01:58:20] Guest 1: "Post-[AGI? epoch]" (mumbled proper noun). #### (6) Practical Tips for Avoiding Common Errors in Long Recordings - **Background noise (café)**: Pre-process with Audacity/Krisp noise reduction or FFmpeg `afftdn`. Transcribe in quiet environment. - **Overlapping speakers**: Use diarization tools (WhisperX); manually resolve with waveform viewer (e.g., Audacity labels). - **Technical jargon**: Prompt Whisper: "Preserve terms like 'EU AI Act', 'LLM fine-tuning' exactly." Dictionary-train on AI policy glossary. - **Fatigue drift**: Chunk as above; transcribe fresh daily. QA pass: Listen at 1.5x speed, focus on timestamps. - **General**: 95%+ accuracy goal—human review 10% of audio. Export as .srt for blog embedding. ### Chunking & QA Recommendations - **Primary**: 25min chunks → Merge with pyannote for speakers. Total time: 2-3hrs processing. - **QA Workflow**: (1) Auto-transcribe chunks. (2) Align/merge. (3) Speaker audit (play 30sec snippets). (4) Flag review (above list). (5) Proofread for policy nuances (e.g., "Act" vs. "act"). - **Tools**: Whisper (OpenAI/local), Descript for overlaps, Otter.ai for quick draft. - **Publish-Ready**: This plan yields a blog-friendly, searchable transcript. If you provide a draft chunk, I'll refine to full polish. Upload chunks or draft for next steps!
What makes these work
-
01Split audio before prompting
Never ask an AI to handle a 90-minute file as one unit. Split at natural breaks -- topic shifts, pauses, or every 20-25 minutes -- before sending any prompt. Tools like Audacity, ffmpeg, or cloud storage preprocessing can automate this. Clean split points prevent mid-sentence truncation that corrupts the transcript.
-
02Carry speaker context across chunks
Include a speaker key at the top of every prompt, even if you defined it in chunk one. Models don't retain memory between API calls. A two-line header like 'Speakers: Host = Jamie, Guest = Rook' costs almost nothing in tokens and prevents the model from inventing or swapping speaker labels halfway through.
-
03Tell the model what came before
Add a one-sentence summary of the previous chunk's ending topic at the start of each new chunk prompt. This gives the model enough context to handle sentences that start mid-thought or reference something said earlier. Without it, transitions between chunks read as abrupt non-sequiturs.
-
04Specify output format explicitly
Long transcripts need structure to be usable. State the exact format you want: speaker name capitalization style, how to handle inaudible sections, whether to include timestamps, and paragraph breaks. Models default to different formatting conventions and inconsistency across chunks makes post-processing much harder.
More example scenarios
I have a 75-minute recorded interview between a researcher (Dr. Patel) and a study participant discussing their experience with remote work during 2020-2022. The audio is split into three 25-minute chunks. Transcribe chunk 2, maintain speaker labels Dr. Patel and Participant throughout, flag any inaudible sections with [inaudible], and preserve exact phrasing without paraphrasing.
Dr. Patel: And when you say the boundaries collapsed, can you give me a specific example from that period? Participant: Yeah, so -- it was probably March 2021 -- my manager would Slack me at 10pm and just expect a response. I stopped closing my laptop. Ever. Dr. Patel: Did you push back on that? Participant: [inaudible] -- not at first. I didn't think I could.
Transcribe this 30-minute segment from a civil deposition. Speakers are: Attorney Chen (questioning), Witness Morales (responding), and Attorney Brooks (objecting). Format as a legal transcript with line numbers every five lines, speaker names in caps followed by a colon, and mark any crosstalk as [CROSSTALK]. Preserve all false starts and filler words.
1 ATTORNEY CHEN: Mr. Morales, on the date in question, 2 where were you at approximately 3:45 in the afternoon? 3 WITNESS MORALES: I was, uh, I believe I was still at 4 the warehouse. Or driving from it. I'm not -- I don't 5 remember exactly. 6 ATTORNEY BROOKS: Objection. Vague. 7 ATTORNEY CHEN: I'll rephrase. Did you clock out before 8 or after 3:30pm on that day? [CROSSTALK] 10 WITNESS MORALES: After.
This is chunk 3 of 3 from a 68-minute podcast episode called 'Startup Mistakes.' Hosts are Jamie and Rook. Previous chunks covered fundraising errors and hiring mistakes. This chunk covers product-market fit failures. Transcribe the dialogue with speaker names, then after the transcript provide a 5-bullet summary of the key points covered in this segment only.
Jamie: So the PMF myth we see constantly is founders who think retention is someone else's problem. Rook: Right, they'll spend $40k on acquisition and then wonder why month-two numbers are brutal. Jamie: We saw this at three of our portfolio companies in the same quarter. Key Points from This Segment: - Retention is a product problem, not a marketing problem - Early acquisition spend masks PMF failure until it's expensive to fix - Founders conflate waitlist interest with actual product demand - Month-two churn is the clearest early signal of a PMF gap - Solving PMF requires talking to churned users, not just active ones
Transcribe this 30-minute middle segment of a 90-minute company all-hands. CEO is Dana Wrightson. Other speakers include VP Sales Marcus Bell and VP Engineering Priya Noor. After the transcript, extract all action items mentioned, formatted as: Owner -- Task -- Deadline (if stated). Flag any deadlines mentioned verbally.
Dana Wrightson: Marcus, give us the Q3 picture. Marcus Bell: We closed 94% of target. The gap was enterprise -- two deals slipped to Q4, both still warm. Dana Wrightson: Priya, the API delays Marcus mentioned -- where does that land? Priya Noor: We'll have the endpoint stable by the 14th. Marcus's team can reopen those conversations after that. Action Items: - Marcus Bell -- Follow up on two slipped enterprise deals -- After October 14th [DEADLINE STATED] - Priya Noor -- Stabilize API endpoint -- October 14th [DEADLINE STATED] - Marcus Bell -- Coordinate with Priya before re-engaging enterprise prospects -- No deadline stated
Transcribe this 20-minute clinical dictation recorded by Dr. Simmons. Format output as structured clinical notes with sections: Chief Complaint, History of Present Illness, Physical Exam, Assessment, and Plan. Use standard medical abbreviations where spoken (e.g., 'blood pressure' becomes BP). Flag any word that sounds uncertain or muffled with [unclear].
Chief Complaint: Persistent lower back pain, 6-week duration. History of Present Illness: Patient is a 44-year-old male presenting with [unclear] onset LBP following a lifting injury at work. Pain rated 7/10 at rest, 9/10 with movement. No radiation to lower extremities. No bowel or bladder changes reported. Physical Exam: BP 128/84. HR 72. ROM limited in lumbar flexion. Negative straight leg raise bilaterally. Assessment: Mechanical LBP, likely musculoligamentous strain. Plan: Ibuprofen 600mg TID with food. PT referral placed. Follow up in 3 weeks or sooner if symptoms worsen.
Common mistakes to avoid
-
Uploading the full file without chunking
Most AI APIs have hard context limits. Sending a 90-minute audio file or its full transcription text in one call often results in silent truncation -- the model processes what fits and drops the rest without warning. You get a transcript that looks complete but ends 40 minutes in.
-
Cutting audio mid-sentence
Splitting at rigid time intervals rather than natural pause points means chunks will start and end mid-sentence. The model then either drops the fragment or invents a completion. Cut at silences or topic transitions, even if chunk lengths become slightly uneven.
-
Forgetting to reassemble with consistency checks
Each chunk comes back as a standalone transcript. When you stitch them together, speaker labels, formatting, and terminology can drift between chunks. Always do a pass over the full joined document to normalize names, capitalization, and any section headers before delivering or using the output.
-
Not flagging inaudible sections in the prompt
If you don't instruct the model on what to do with unclear audio, it will guess and hallucinate plausible-sounding words. In medical, legal, or research contexts, a confident wrong word is worse than an honest [inaudible] tag. Always include explicit instructions for handling low-quality audio segments.
-
Using a single generic prompt for all file types
A prompt that works for a podcast will produce messy output for a legal deposition. Long-form transcription needs format-specific prompts that match the expected output structure -- line numbers for legal, clinical sections for medical, timestamps for captions. Generic prompts produce generic, hard-to-use transcripts.
Related queries
Frequently asked questions
What is the best AI tool to transcribe audio files longer than one hour?
Whisper (via API or local), AssemblyAI, and Deepgram all handle long audio well because they process audio natively rather than converting to text first and then analyzing it. For files over an hour, AssemblyAI and Deepgram have purpose-built long-form endpoints. Whisper requires chunking but is free to run locally. GPT-4 and Claude are better for formatting and structuring the raw transcript after the audio-to-text step.
How do I split a long audio file for transcription without losing quality?
Use ffmpeg with the '-c copy' flag to split at time markers without re-encoding, which preserves original audio quality. Alternatively, Audacity lets you split at silence markers visually. Aim for 20-25 minute segments and cut at natural pauses rather than fixed time points. Avoid MP3 re-encoding when splitting, as each encode cycle introduces additional compression artifacts.
Can ChatGPT transcribe a 2-hour audio file directly?
Not directly. ChatGPT's file upload has size limits and is not designed as a dedicated transcription engine for long audio. For a 2-hour file, you need an audio-specific transcription API first to get the raw text, then use ChatGPT to clean, format, summarize, or restructure that text. Trying to skip the audio-to-text step with ChatGPT alone will fail on anything over a few minutes.
How accurate is AI transcription for long recordings compared to short ones?
Accuracy tends to drop on longer recordings for a few reasons: audio quality often degrades over time in recordings, speaker fatigue changes speech patterns, and models can lose contextual coherence across very long inputs. Expect 90-95% word-level accuracy on clean audio under 30 minutes, dropping to 85-92% on hour-plus recordings with multiple speakers. Post-editing is almost always necessary for professional use cases.
How do I keep speaker labels consistent across a long transcript with multiple chunks?
Define a speaker key in every chunk prompt, not just the first one. Include the last 2-3 lines of the previous chunk at the start of each new prompt so the model maintains continuity. After generating all chunks, do a global find-and-replace pass on the assembled document to catch any inconsistencies in how names were capitalized or abbreviated across segments.
Is it worth paying for a transcription service vs doing it with AI prompts myself?
For one-off files or sensitive content, DIY with Whisper or a direct API call is usually cheaper and keeps audio in-house. For high-volume workflows -- dozens of hours per month -- services like Rev, Descript, or AssemblyAI include post-processing features that save significant manual cleanup time. The break-even point is roughly when cleanup time costs more in labor than the service subscription.