It’s zipping a zip file. E

no it isn’t, zipping is lossless. encoding is lossy.

No, the specific file size is irrelevant, he’s wanting smaller file sizes. CRF is a waste of data on more than 70% of scenes in hollywood movies. You set a bitrate and let it go. This is also why virtually all music now is VBR

just fyi x264 and x265 are programs, written by VideoLAN organization. h264 and h265 are the codecs

And no doing that is no guarantee in visibly worse quality. Depends entirely on the video in that scenario. Plenty of them will look almost the same (though h265 is a lot blurrier than 264, I’d say h264 to h264 you’re likely to barely notice)

There are no lossless copies of any movie that have ever been released to the public

Delivery formats (h265, h264, h263 etc) are compressed and lossy.

You need to do 2 pass encoding. You should also not use CRF. You should pick a bitrate for the file size you want. Do a first pass which analyzes the video to see which sections require more data, and then run a second pass which will give high bitrate to more action scenes and lower bitrate to the credits and slower talking scenes.

Some action scenes require 5 times more data to look as good as a talking dinner scene, you couldn’t even notice the quality difference but the bitrate requirement is literally 5 times more.

You also need to use the slow preset and use x265 if you’re doing this to archive the stuff forever. Do it once and do it right.

Lossy to lossy generally doesn’t matter, that is why people transcode over the web on their media players and the video seems fine, they are doing lossy to lossy on the fly there. What is actually stupid is saving media that is 100gb that you ALWAYS have to transcode to play, so no matter what you’re ramping up your wattage use to play a file. This is also why 99.9999% of consumed media is compressed, you can’t play it otherwise. Internet would explode too.

Likewise can size a jpeg down from 4000kb to 1000kb and it’ll likely be almost identical and good enough for most cases. There are certainly zero handheld devices you’d be able to notice it on.** If you size the 4000kb to 40kb now there will be an actual noticeable difference. There are different levels to all of this. **

Similarly a 100mb wav file should be a 10mb mp3 and you can’t tell the difference. You couldn’t even tell the difference with a 3mb mp3 file.

it will result in visible and audible distortion

This is completely wrong, it “might” be visible is accurate. The actual answer is “that depends”

If a file is 5000kbps and you use 3000kbps you now have 25-50% savings like he just said. Nothing is overestimated, you can encode to w/e you want. This is how lossy encoding works, for everything.

you can re-encode something at literally any bitrate, this isn’t relatable at all to “zipping a zip file” this is “opening a zip file, opening the document inside, removing data you don’t need, resaving it and rezipping it”