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I want to archive a .mp4 file by 7z but after archiving the size of the file is approximately the original file.

7z config:

img

Result: img2

I'm using win 11 and 7z ver 22.01

win 7z

So do you know how to compress this file to a smaller size? (I also try with compression method LZMA but the size is ~ 20MB, but in another PC with window 10 and 7z ver 21.06 the size is reduced by 50% as I expect)

P/S: Here is the config and result when i compress mp4 file in another PC. config_pc2 result_pc2

Also I have to try compress another type file (pdf) and 7z still not reduce the size 1

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    mp4 is already heavily compressed so there is very little 7z can gain over it. – Mokubai Jan 02 '23 at 14:13
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    One possible way is to reduce the resolution of the video. – Rishon_JR Jan 02 '23 at 14:35
  • Hi @Mokubai, I don't think it's because the mp4 file is already compressed, so 7z can't compress the size anymore. Because I also tested with another PC and the mp4 file is reduced quite a bit. – Nguyễn Tri Mẫn Jan 02 '23 at 14:57
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    Rule of thumb. You cannot compress something that is already compressed - this includes movies & pictures. – Tetsujin Jan 02 '23 at 14:58
  • @NguyễnTriMẫn None of that evidence is in your question, and you don't show what settings you have used so we can only judge what you have shown us. At a guess I'd suspect that you either added two copies of the same file, or the file on the second machine was not the same. It may have been corrupted or otherwise incomplete. – Mokubai Jan 02 '23 at 15:05
  • Hi @Tetsujin, I have try with another file type and still not work, you can see in the newest my post. – Nguyễn Tri Mẫn Jan 02 '23 at 15:29
  • Hi @Mokubai, I have upload result and config in another PC, you can see the image in my post – Nguyễn Tri Mẫn Jan 02 '23 at 15:30
  • @NguyễnTriMẫn that is a completely different file, probably using some other codec which has worse compression and thus has some scope for extra compression. If the file came from some network camera it might have some very poor compression level which leaves a lot of compressible data. Not all mp4 videos are created equal. After that you then compressed a 7.5MB `pdf` which has the same problem because the PDF likely contains already compressed JPEG images which again cannot be compressed further. – Mokubai Jan 02 '23 at 15:41
  • yah, makes a sense. Thanks @Mokubai – Nguyễn Tri Mẫn Jan 02 '23 at 15:48

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