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Are movie and show file sizes more efficient than they were years ago? (lemm.ee)

submitted 1 year ago* (last edited 1 year ago) by lemonlemonlemon@lemm.ee to c/piracy@lemmy.dbzer0.com

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This may be a stupid question, but I just got back into pirating some shows and movies and realize that many of the QxR files are much smaller than what I downloaded in the past. Is it likely that I am sacrificing a noticeable amount of quality if I replace my files with the smaller QxR ones?

For example, I have Spirited Away from 2017 at 9.83 GB, but I see the QxR is only 6.1 GB. I also have the office from 2019 and the entire show (no bonus content) is about 442 GB, while the QxR version is only 165.7 GB. Dates are what they are dated on my hard drive, can't speak to their actual origin, but they would've been from RARBG. (Edit to add: I also can't really speak to the quality of the downloads, back then I was just grabbing whatever was available at a reasonable size, so I wasn't deliberately seeking out high quality movies and shows - a simple 1080p in the listing was enough for me).

I did some side by side on episodes of the Office (on my PC with headphones, nothing substantial), and I don't notice any differences between the two.

Thoughts on this? Are people better at ripping/compressing/whatever now that they can do so at a smaller size without sacrificing noticeable quality?

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[-] stifle867@programming.dev 15 points 1 year ago

Also it's common for anime to be encoded in 10-bit color rather than 8-bit which can also be used to encode files more efficiently.

[-] huginn@feddit.it 10 points 1 year ago

Compression and encodings are not my forte at all: why is 10bit color more efficient to encode than 8?

[-] stifle867@programming.dev 10 points 1 year ago* (last edited 1 year ago)

I'm no expert either, this is just what I know from experience and through people smarter than me on the internet. I've put together some resources below for you. Apologies for the reddit links, it's just where this content lives.

encoding 10bit reduces the amount of truncation errors during the encoding, which leads to a much smaller filesize despite the two additional bits. To the point where, despite it storing more information, there being less truncation errors offsets the filesize gain to the point where you get similar or even smaller sizes than 8bit encodes.

source: https://www.reddit.com/r/animepiracy/comments/m98u30/comment/grm8uq9/

https://yukisubs.files.wordpress.com/2016/10/why_does_10bit_save_bandwidth_-_ateme.pdf

https://www.reddit.com/r/x265/comments/e08tfu/ultimate_encoding_test_results_for_animation/

[-] huginn@feddit.it 4 points 1 year ago

Counterintuitive but very interesting. Thanks for the explanation!

[-] MonkderZweite@feddit.ch -3 points 1 year ago

10-bit color is HDR and has a bigger file size. You probably mean something different.

[-] stifle867@programming.dev 6 points 1 year ago

My understanding is that HDR formats utilise 10-bit color formats rather than being strictly equivalent.

From Wikipedia:

HDR video refers to a video encoded in an HDR format. Thoses HDR video have a greater bit depth, luminance and color volume than standard dynamic range (SDR) video which uses a conventional gamma curve.

As it alludes, HDR is more than just a 10-bit color space. Encoding anime in 10-bit doesn't take advantage of the greater luminance or dynamic range. It does take advantage of the color space to minimise banding.