A video and its separately delivered commentary can have plausible filenames without belonging to the same revision. Before assembling a new output file, audition the pair locally. This workflow uses VLC 3.0 on Windows to compare existing media; keep the supplied originals unchanged.

Prepare a short list of recognisable cues from the intended version: an opening sentence, a visible demonstration in the middle and the final spoken instruction. Note whether the video already has useful sound. You need to distinguish the original track from the companion, not merely hear something after pressing Play.

Open the video with its companion

In VLC, choose Media, Open Multiple Files and add the video. Enable Show more options, then Play another media synchronously. Use Browse to open the additional-file selection, add the companion audio, choose Select and then Play.

Inspect Audio, Audio Track and select the intended companion when multiple choices are present. Identify it by a distinctive spoken cue rather than assuming a particular track number applies to every file. Start with a comfortable listening level and verify that you are hearing the expected speaker or commentary.

For example, a revised demonstration may introduce the replacement part halfway through, while an earlier commentary still names the original part. Hearing the correct introduction alone would miss that mismatch. Compare the middle cue before treating a familiar voice as confirmation.

Check the pair across its duration

At each planned cue, compare the meaning and timing of the narration with the visible action. Record whether a mismatch is the wrong content, a constant timing offset or a difference that grows later. Those observations lead to different corrections; repeatedly restarting the same pair does not resolve an incorrect revision.

Check the ending as well. Determine whether the commentary completes its final instruction before the corresponding visual material finishes. Do not label deliberate silence as missing audio without checking the intended script or deliverable.

This playback selection does not produce a newly combined delivery file. Keep any later editing or export decision separate, with the accepted video revision and companion path recorded together. The useful result is a verified pairing and a precise list of remaining discrepancies, so an editor knows which material to assemble and what still needs attention.

Sources: Official documentation.