How do you assemble visuals and narration into a video?

How do you assemble visuals and narration into a video?

Assembly places visual and audio assets on a shared timeline. The pipeline must decide what appears while the narration plays and how the final output ends.

Build a timing plan

Use the measured narration duration rather than estimating solely from word count. Assign visual segments to time ranges and decide how to handle a visual that is shorter than its required range. Normalize incompatible dimensions or frame rates before combining clips. Keep the planned timeline associated with the job’s input version.

Check the rendered result

Inspect transitions, blank frames, cropping, and the final audio tail. Concatenation is not always equivalent to joining file bytes: the correct method depends on the streams and whether re-encoding is needed. Render a short fixture first, then watch the complete output. Confirm that the final frame and narration end as intended rather than using an automatic trimming option without checking what it removes.

Further reading: FFmpeg concatenation guidance.