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Old 25th July 2019, 09:02   #1595  |  Link
r0lZ
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Join Date: Jul 2003
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Quote:
Originally Posted by TVI View Post
Dear r0lZ. First of all thank you for your program it's fantastic. I do have a question.

I use BD3D2MK3D to convert ripped 3D Blu-Rays to watch on the Ocolus Go and it works a treat. I'm not particularly tech-savvy...I download the ripped MKV and don't change any of the settings.

The files will vary in size and quality. For example -
Terminator 2 - 7.22GB - Great picture
Gravity - 3.72GB - decent picture
Bladerunner 2049 - 1.63GB - okay picture but more "screen door" effect

I just wondered if there was a simple reason why the files vary in size/quality?

Thanks.
Thanks for your kind words.

As explained by tebasuna51, when you use the CRF encoding mode, the quality doesn't vary much, but the file size can vary, due to the difficulty to compress the images of the original movie. A CGI film like an animated Pixar movie can be compressed extremely well, because the image is very clean and without artifacts. In the other hand, old movies with much noise are very difficult to compress, because each frame is different from the previous one. So, differences in file size are not unusual, and you should not worry about them.

BTW, many peoples think that a specific bitrate is important to encode correctly, and prefer to encode in 2-pass mode for that reason, but it's totally wrong. Specifying the bitrate (in ABR or even 2-pass modes) imposes a constraint that the encoder must obey, and therefore, the quality is ALWAYS less good than the encoding in CRF mode (when it gives finally approximately the same file size, of course). The ONLY interest of 2-pass mode is therefore to control precisely the size of the final MKV file. That may be important if you need to copy it on a physical media like a DVD, but you should always avoid that mode if you don't care of the final file size.

See also my previous reply, just above this one.
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