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Old 10th April 2016, 17:36   #952  |  Link
r0lZ
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Yep. I use CRF 18 for the movies where the video quality is very important (like Sin City 2), and CRF 22 when I just want to keep a movie but I want the smallest file size. The default, CRF 23, gives already very good results.

Note also that the CRF mode gives very different file sizes for movies of the same length. For example, CRF 20 may produce a very small file of only 2 or 3 GB if the movie is very easy to compress, like a CGI (Pixar) movie. In the other hand, an old movie with much noise may require 10 GB for the same movie duration. It's absolutely normal, and it's one of the major advantages of the CRF mode over 1 and 2-pass. The quality is maintained in all cases, regardless of the difficulty to compress the movie. (It's different if you use 1 or 2-pass encoding, where the bitrate is specified. And anyway, 2-pass gives always a slightly lower quality than CRF for the same file size.)

The CRF value is not all. You can compress even better without quality loss if you select a slower preset. I use normally the slow or slower preset, to keep a very good quality with a small file size.

And don't forget that in the original BD, two full-size video streams are encoded. In Half-SBS or Half-T&B, the resolution is divided by 2 and therefore the resulting movie requires much less disc space anyway.

Finally, don't be scared by the final size. It may appear too small, but x264 is an excellent encoder, and IMO, the large bitrates used for the commercial BDs are mainly to impress the consumer, and justify the high price for a double-layer BD 50. IMO, it's usually not necessary. Trust your eyes, and watch the small movies encoded with a relatively high CRF without prejudice. I bet that you will not see the difference with the original BD.
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