An edit often leads to smaller jobs: a viewing copy for a client, stills for discussion or audio for a colleague. Repeating those steps file by file soon becomes tedious.
FFmpeg can transcode and extract media. Its companion ffprobe reads information about formats and streams. See the FFmpeg documentation and ffprobe documentation.
Inspect before converting
An MP4 extension does not tell me everything about a delivery file. I would check its codec, dimensions, frame rate and audio tracks before deciding whether it needs conversion.
Extracted frames help with comparisons. To judge continuity, I would still play the sequence around the cut.
Approve a sample first
For a batch of viewing copies, choose a sample with motion, shadows, small text and speech. Check that output before applying the same settings to everything else.
Keep the originals and write outputs to a separate folder. A smaller file is useful only if the product details remain readable.
Watch the result
A completed command is not a delivery review. Play the beginning, middle and end, checking colour, truncation and sync. Team members who do not use the command line can still specify the intended output and checks clearly.