View Single Post
Old 25th July 2019, 08:42   #1594  |  Link
r0lZ
PgcEdit daemon
 
r0lZ's Avatar
 
Join Date: Jul 2003
Posts: 7,469
Sorry again, for whatever reason, the forum do not send me the notifications for the new posts any more, hence my late replies.
Quote:
Originally Posted by donpoku View Post
Hi yday I did one from 40gig disc to 7gb using this, surely there's a loss in quality? If so what's the best way to get like for like with no loss in quality?

Many thanks
When you re-encode a video file, there is always a loss in quality, except if you use specifically the lossless options. And re-encoding losslessly doesn't make much sense, as usually, the size of the final MKV file is greater than the original M2TS file ! So, the question is : what amount of loss of quality can I accept ? I can't reply for you, but usually, I consider that it's mainly a false problem. Of course, if you compress extremely, the quality loss will also be extreme, and therefore much visible, but most peoples cannot see the difference with the original BD (without using special tools) when the default option (CRF 23) is used. The decrease of the file size is NOT really an evidence of a visible quality loss, and it depends largely of the images of the original movie. Trust your eyes, and do not imagine that you can see a difference because you think that a small size means bad quality.

That being said, you can easily modify the quality (and the size) of the encoding. As noted by tebasuna51, the CRF mode is recommended, because it adapts itself so that you will always obtain more or less the same quality, but the file size may vary, especially for old films with much noise. The CRF parameter can be used to increase the quality and the file size. The default value for x264 (CRF 23) gives good results for a very small file size, but you can decrease it to, say, 20 or even 15 to obtain a much better quality, but take in mind that the file size of the video stream can be doubled when you decrease the CRF value by approximately 3.

BTW, to encode in lossless mode, use CRF 0, but buy a big hard disc, as you will obtain a huge file size !
__________________
r0lZ
PgcEdit homepage (hosted by VideoHelp)
BD3D2MK3D A tool to convert 3D blu-rays to SBS, T&B or FS MKV
r0lZ is offline