I have an album thats a bit more than 200MB, converted to just an audio only M4a or MP4 its still under 80MB
Is that 120+MB all chaff or is there another way to prevent losing all muh damn wheat
CONSTRAINT/NON-CONSTRAINTS
FILE SIZE DOES NOT MATTER AT ALL TO ME. JUST TO BE CLEAR
MUST BE AN MP4 “video” file. I get that MP4 is a container or whatever but that is a hard constraint—Please respect that
M4A/AAC are not acceptable. It must be within the container that is MP4, non-negotiable


if your ‘conversion’ reduced the file size by that much (over 200mb to under 80mb), it likely converted the audio from the source lossless flac to lossy aac.
if you desire lossless, and need the m4a container, use alac (apple lossless, it’s what they use). for broader compatibility outside of apple’s ecosystem, just keep the files as-is, as flac.
It needs to be MP4, m4a is only recognized for seperate added audio tracks but not the main one
For the most part .mp4 / .m4a are interchangeable, you can go lossless --> lossless by going FLAC to ALAC like the earlier comment mentioned e.g. using ffmpeg
In fact, now that umt@lemmynsfw.com mentioned it, you can create a out-of-spec .mp4 with a flac codec inside it if you really wanted. again using ffmpeg
You’d have to test that whatever player you’re using can actually play them, I suspect a lot of players won’t know what to do with a .mp4 containing a FLAC codec unless the player already supports FLAC anyway.
PS - The files actually come out a tad bit bigger FYI, I guess there’s more padding and metadata in a .mp4 container.