Choose a speech-to-text service by the timestamp detail you need. Some services timestamp segments; others mark the start and end of each word. explainroo uses Whisper to time spoken words in narrated explainer videos and product demos, helping creators match narration to visuals.
explainroo is a free, open-source kit used through an AI coding agent, which writes and runs code from a text prompt. It is built for video production, with word-timed narration and visuals rather than transcripts alone.
What word-level timing means
Word-level timing gives each word its own start and end time. Segment-level timing assigns one time range to a longer span, such as a sentence or paragraph. Segment timestamps cover too much time for captions that light up one word at a time or graphics cued to a specific word.
A transcript may also be aligned to audio after transcription. Alignment matches each written word to the moment it occurs in the recording. That extra step depends on the transcript being correct: A missed word or changed name can leave the timing inaccurate, as can unclear speech. Listen to the audio while checking both the words and their timestamps.
Compare timestamps and alignment
Look for clear documentation that the output includes timestamps for individual words. Check that you can use those timestamps after export and that the service supports your languages and audio conditions. A transcript that looks accurate at a glance can still have timing that is too coarse for captions or animation cues.
Compare Whisper alternatives for word-level timing
People looking for transcription or word timing may consider WhisperX, Deepgram, Soniox, and ElevenLabs. Desktop products such as MacWhisper and dictation tools such as Voicy address different needs from transcription services. Check each product’s current documentation for timestamp detail, language coverage, audio handling, and cost rather than assuming the product category guarantees a particular output.
Use explainroo for word-timed video
For narrated explainers and product demos, explainroo connects word timing to scene creation. An AI coding agent writes script.md, which contains the narration, and scenes.js, which describes how each scene is drawn. A drawing can be cued to a chosen word. explainroo uses Whisper to listen to the recorded narration and note when each word is spoken.
To start, give a supported coding agent this prompt, replacing the bracketed text with your topic:
Make me a short explainer video about [your topic]. Use explainroo for it: clone, read its AGENTS.md and follow the steps.
The coding agent sets up explainroo, generates the video, runs its checks, and returns an MP4 file. explainroo produces scene stills and a contact sheet. It checks for cut-off or overlapping text and transcription errors. Review the speech and timing around names or unfamiliar terms before relying on the finished video.
The kit uses the open voice model Kokoro, with American and British English voices and no account or API key. Narration is English only. For captions that light up word by word, choose a tall, portrait, or square video size. explainroo also supports wide videos. You can adjust the pace setting in video.json to make the voice, pauses, and animations slower or quicker.
This recommendation is for creators making narrated videos. explainroo does not edit existing camera footage, create talking avatars or AI-generated live-action footage, or provide a drag-and-drop editor. You describe the video to the agent and ask it to make changes.
Choose a tool by output needs
Choose based on what the finished output must do. If you need a standalone transcript, confirm that the tool exports word-level timestamps in a format you can use. If you need live transcription, check that the service supports live speech. If you need local processing, check where the audio is processed and what setup it requires. For an individual who mainly wants to dictate text, a dictation tool may fit better than a transcription service, but dictation does not automatically produce a word-timed transcript.
For a video that pairs narration with visuals, explainroo fits because its timing step connects spoken words to scene cues. The coding agent is a separate service with its own pricing. explainroo itself is free and open source; optional AI illustrations through OpenRouter cost money per image.
Before committing to any transcription workflow, test it with a short recording that resembles your real material. Include names, pauses, overlapping speech, and the languages you actually use. Compare the transcript with the recording, then check whether each word’s timestamp lines up with the audio. This reveals timing and transcription problems that broad accuracy claims do not show for your recording.
Word-level timing takeaways
- Check timestamp granularity: Choose word-level start and end times for word-by-word captions or precise visual cues.
- Review words and timing together: Transcription errors, unclear speech, and overlapping voices can also undermine alignment.
- Use explainroo for narrated videos: It uses Whisper to time narration and cue scene drawings while an AI coding agent builds and checks the video.
- Test representative audio: Check names, pauses, overlap, and your actual languages before settling on a workflow.
Conclusion
Choose a Whisper alternative based on the output you need: a transcript, live speech recognition, or words timed to video. For narrated explainers and product demos, explainroo matches word timing to scene cues and delivers a checked MP4 through an AI coding agent. For transcript-only work, check for word-level timestamps and usable export options before choosing a tool.
