Oh any help how to get the maximum compression out winrar or a step by step guide would be appreciated. Thank you in advance.

  • freamon@preferred.social
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    5 months ago

    TV shows and movies are already compressed. If you try to compress something that’s already compressed, it typically ends up bigger if anything.

    • EveryMuffinIsNowEncrypted@lemmy.blahaj.zone
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      5 months ago

      Why does it get bigger? I’ve wondered that for a while now.

      I would think that compressing something that’s already compressed would still compress it further but at diminishing returns.

      • MrNesser@lemmy.world
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        5 months ago

        Once the files are added to the zip folder your also adding information about the files so they can be removed.

          • cam_i_am@lemmy.world
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            5 months ago

            There’s more to it than that. Firstly, at a theoretical level you dealing with the concepts of entropy and information density. A given file has a certain level of information in it. Compressing it is sort of like distilling the file down to its purest form. Once you reached that point, there’s nothing left to “boil away” without losing information.

            Secondly, from a more practical point of view, compression algorithms are designed to work nicely with “normal” real world data. For example as a programmer you might notice that your data often contains repeated digits. So say you have this data: “11188885555555”. That’s easy to compress by describing the runs. There are three 1s, four 8s, and seven 5s. So we can compress it to this: “314875”. This is called “Run Length Encoding” and it just compressed our data by more than half!

            But look what happens if we try to apply the same compression to our already compressed data. There are no repeated digits, there’s just one 3, then one 1, and so on: “131114181715”. It doubled the size of our data, almost back to the original size.

            This is a contrived example but it illustrates the point. If you apply an algorithm to data that it wasn’t designed for, it will perform badly.

              • Num10ck@lemmy.world
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                5 months ago

                it was crucial back in the dial-up internet days or even earlier trying to fit games on a floppy disk. mp3 and mpeg4 came from this quest of course too.

            • EveryMuffinIsNowEncrypted@lemmy.blahaj.zone
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              5 months ago

              I think this example just confused me honestly. Sorry.

              Put another way, though, is it basically like a sock being pushed so far inward that it goes inside-out and gets bigger again?

  • Libra00@lemmy.world
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    5 months ago

    No, movies and music files are already compressed, so compressing them further won’t gain anything. In fact it will actually increase the file size because compressed files require some overhead. So even winrar won’t help, though it might be convenient to have one big file with everything in it (you can even break it up into multiple part files.)

  • make -j8@lemmy.world
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    5 months ago

    just throw away every second frame. repeat for more compression. at some point you ll be left with a couple of pictures to remember the story and replay it faithfully in your head.

    you welcome !

  • jimmux@programming.dev
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    5 months ago

    As most have said, doubling up compression won’t usually get you much.

    However, video compression is usually designed to facilitate performance of sequential reads because videos are typically played beginning to end, so theoretically there may be ways to compress them more if you’re willing to make sacrifices there.

    I doubt RAR is the way to do it, though. It just hasn’t been designed for this kind of data.

    Maybe there’s a video compression format out there designed specifically for archival storage, but I’m not aware of it.

    ISO won’t get you any further compression, that’s for sure.

    You could certainly test this out yourself and let us know if you get any space savings.

  • Otherbarry@lemmy.frozeninferno.xyz
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    5 months ago

    If I use winrar to compress 80gb of tv and movies.

    You haven’t gained anything by doing so since video is already compressed. Compressing data that is already compressed will usually make it slightly larger - or if you’re lucky maybe you’ll save like 1 megabyte space, not really anything worth the trouble.

    Then can I compress it further by making it an iso?

    ISO is not compression.

  • Em Adespoton@lemmy.ca
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    5 months ago

    Iso is a container format; it’s a 1:1 mapping to how the bits are stored on disk with a header at the start describing the structure. Bin/cue separates the header into a separate file and can include data structured in ways that don’t comply with the ISO-9660 standard.

    WinRAR is a compression/decompression program. It supports multiple archive types and compression formats.

    Depending on the type of data you are compressing and whether you want lossless or lossy compression, you’ll want to select a different compression algorithm.

    Depending on how you plan to use the files, you’ll want to use a different archive format.

    Assuming you use the rar archive format, you still have a lot of options to consider. Should the data be encrypted or not? Should the directory structure be encrypted or not? Do you want parity files and segmented archives, so that if one of the parts gets corrupted (or goes missing), you can still extract the original data in a lossless way?

    Beyond all that and selecting the compression algorithm that best compresses the type of structured data you’re storing, the general rule is that if you’ve got lots of data, using the largest dictionary and the largest compression window you can will result in the best compression.

    So the dictionary is essentially a code book that says “when I see data x, represent it with data y in the file”. The compression window is how much of your original data is loaded into memory at any given time for the dictionary to look at and compress.

    [edit] if you’ve got video, the best compression format commonly available today is H.265. This is a lossy compression format, meaning you’ll never be able to precisely recreate the original file. But it’s close enough not to matter at the right compression settings.

    And if you’re using H.265, the best container format to stick it in is an MPEG-4 archive (typically with a .mp4 extension).

    The result is a highly compressed and structured file. Loading chunks into memory for rar compression will usually result in a larger file, because the data is already compressed in a structured manner that a general compression algorithm can’t match… meaning that you’d get the input of xxxxx resulting in output of yyyyyy.

  • bamboo@lemmy.blahaj.zone
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    5 months ago

    If you can sacrifice quality, you can encode the videos at a lower bitrate, but that is lossy compression, not lossless. Also, if your videos are in h.264 codec, then transcoding them to h.265 and preserving the quality may be a way to get the files smaller. You would use a tool meant for video, like Handbrake for this, and not winrar or other generic compression tool.

  • TheFANUM @lemmy.world
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    5 months ago

    No. And that’s a bad plan. Uncompressed them, and then reencode them to h256/x265 with handbrake (use the SuperHQ 1080p setting). That’s as compressed as they’ll get and you can still watch them without having to unzip them first

  • 58008@lemmy.world
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    5 months ago

    If you want to compress video files, you’ll need to reencode them. Maybe using something like HEVC (High Efficiency Video Codec). But for 80GB of videos, you’ll be there for a while and probably won’t shrink them enough to be worth it. It would likely take less time to simply re-download the files later, even with a mediocre internet connection. In practical terms, you won’t get that 80GB to be any smaller.

    ISOs don’t compress anything, as far as I know, or at least not by default. I think they’re basically just a container.

    To reencode your videos, you can use the free HandBrake.

  • doodledup@lemmy.world
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    5 months ago

    80 gb is not a lot for movies. My average 4K movie is between 60 and 80 gb per movie. If you start encoding and compressing them you start seing compression artifacts and reduction in quality very quickly.

    My advice: don’t compress movies if you can. Just get more storage. Storage is relatively cheap these days.

    • notarobot@lemm.ee
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      5 months ago

      What. If you compress them to zip, 7zip, rar, etc. You will never get any artifacts

      • Comtief@lemm.ee
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        5 months ago

        I guess they are talking about re-encoding because video files are already compressed.

        • notarobot@lemm.ee
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          5 months ago

          You can compress with the method above to save more space. But you have to uncompress before watching

  • HappyTimeHarry@lemm.ee
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    5 months ago

    To get the maximum compression out of video you should use a video codec like av1 or hevc. WinRAR wont compress video well at all and making it an ISO is also pointless.

    I would suggest checking out handbrake for a good user friendly video compression tool.

    For lossless compression, things other then video/audio, you should movr to 7zip over winRAR.

    • doodledup@lemmy.world
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      5 months ago

      I gave up encoding movies with Handbrake. I can always see the difference in the resulting picture quality and if I don’t, the file is probably only reduced from 80gb to 70gb and it’s not worth it.

      I usually just rip the blu-rays, strip out the unnecessary languages and leave the rest as it is.

  • Octospider@lemm.ee
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    5 months ago

    Well, it’s sort of possible to compress large things into small sizes. But I don’t think it would work for this situation.

    There are things called “.zip bombs”. Where an otherwise small file, when unpacked, can take up a large amount of space.

    A famous example of a zip bomb is titled 42.zip, which is a zip file of unknown authorship consisting of 42 kilobytes of compressed data, containing five layers of nested zip files in sets of 16, each bottom-layer archive containing a 4.3-gigabyte file for a total of 4.5 petabytes of uncompressed data.