I've resolved to start keeping track of helpful information again, so reconfigured access to the ol' blog.
Working on copying down some videos to an old phone for our daughter to watch in airplane mode so the main phones aren't used/abused/reconfigured... There are a few songs that are more bearable at different playback speeds.. Stumbled upon this comment on a thread that gave a good example of modifying both the audio and video playback speeds at the same time with a complex filter in ffmpeg.
https://davidwalsh.name/video-speed#comment-509672
Relevant code snippet, to use the same 'multiplier' even though in one case it's a divisor.
ffmpeg.exe -i input.mp4 -filter_complex "[0:v]setpts=PTS/1.3[v];[0:a]atempo=1.3[a]" -map "[v]" -map "[a]" output.mp4
