Choose a slide-based excerpt only when its spoken explanation and essential visual can both survive a small portrait screen. Keep the full source frame when a diagram is needed, and test the result on a phone. If dense labels remain unreadable, simplify the source externally or choose a self-contained spoken passage instead of cropping away the evidence.
Identify exactly what the viewer must see
Write down the visual information that carries the explanation: one axis label, a comparison between bars, an equation or a setting inside an application. Distinguish that evidence from decorative slide branding. Listen for phrases such as ‘this number’ or ‘the column on the left’. Those references need the relevant image to remain visible, or the selected passage will be confusing even when every spoken word is captioned accurately.
Test the smallest essential label in the final composition
Full-frame layout preserves the slide and presenter but reduces their size inside the 720 × 1280 portrait canvas. A fixed crop can make one stable detail larger while hiding the rest. Review all slide changes and pointer movement in the excerpt before committing. Presenter/whiteboard framing is a limited preview, so build an ordinary workflow around the available fixed crop or full-frame options. Do not assume automatic chart-aware reframing.
Prepare a simpler source when the diagram cannot fit
If you own the teaching material, use another editor to create a clearer video with the required chart or demonstration already composed. Check permissions and remove sensitive names, tabs or data before exporting that source. Keep the slide faithful: do not omit an axis, caveat or legend that changes the claim. CastCuts is not a slide editor, redaction tool or a way to reconstruct details missing from the recording.
Review captions against the diagram and the speech
Select a complete 1–90 second explanation and correct available English captions. Check units, decimal numbers and technical terms against the audio; a chart can help flag a possible error but cannot replace listening. Keep an opening headline concise so it does not compete with the key label. Render, download and watch the MP4 on a phone. Publish manually and save the source and clips before the 24-hour retention window closes.
A fictional webinar chart with three series
Illustrative example. The people, recordings and results described here are fictional.
A speaker explains why a blue line rises after a process change. The full slide fits in the portrait canvas, but its legend is unreadable. A close crop shows the line while losing the date range, which would misrepresent the explanation. The creator chooses a later passage where the speaker states the comparison aloud and the visible chart serves as supporting context rather than the only source of meaning.
Preserve the visual’s meaning, or choose a passage that does not depend on unreadable detail.
Check before you finish
- The one visual detail needed to understand the explanation is identified.
- Labels, pointer movement and slide changes survive the complete excerpt.
- The crop preserves chart conditions and legends; private details are removed.
- The final phone-size MP4 communicates the point with accurate captions.
Practical questions
Should every slide recording use full-frame layout?
Full frame is a useful starting point because it preserves context. Still test the smallest essential label; preserving the slide is not enough if nobody can read the detail.
Can CastCuts redesign my slides for Shorts?
No. Prepare redesigned slides or a recomposed video externally, then upload the finished source. The editor selects excerpts and applies its supported layouts and text tools.
Can captions replace the chart?
They represent speech, not every visual relationship. Choose a spoken explanation that makes sense by itself or retain a chart viewers can actually understand.
Use this workflow in CastCuts
Prepare understandable webinar and slide excerpts
CastCuts selects continuous 1–90 second excerpts and exports 9:16, 720 × 1280 H.264/AAC MP4 files. Automatic transcription and transcript-based suggestions support English and require review. Free exports include CastCuts branding; Pro removes it from new renders for $9 USD/month, with the same processing and storage limits. Episode media is retained for 24 hours. Keep your originals and download finished clips before expiry. Publishing is manual.