CRF doesn't work on mkv untouched files

Locutus2k

Since i've never been happy with the old 2-pass high quality encoding, i've ripped mst of my bluray on my nas using direct stream copy.
Now CRF is exactly what i was waitin' for and i've started to downsize my files using a re-encoding with CRF 18 or 20.
If i rip directly from disc everything works fine and i actually have a smaller file with high quality video. I i rip from the exhisting mkv files (UNTOUCHED direct stream copies) the final size doesn't change a lot. Example: a 22gb mkv file re-encoded with the same audio otpions and CRF 18 measure at the end something like 20/21gb - BUT if i rip the same file from the disc, same options, the final file is 12/13gb.

Obviously i would like to re-encode from files, so i can start a long batch overnight encoding of everything i've already ripped in direct stream copy without changin' disc every time.

glenns

MKV uses a smaller frame size thus smaller file output even if uncompressed.The disk is not using MKV so the frame is bigger to start with.Looks like your going to have to go from disk to get the best results.You could make iso's from the disks and do batch iso's overnight.If you ever plan on projection or 60-80 inch tv screens don't use mkv use m2ts same frame size as most video on disks.MKV is touched even if uncompressed as it uses smaller frame size to get file size down that's fine on smaller screens.

Chetwood

I don't see how this can make a difference visually when the streams are untouched.

glenns

Ok I suppose if uncompressed your correct but compressed you need to be careful to not over compress as the results are more apparent on larger screen sizes and with fast motion,rain and dark scenes and film grain on older films.The same goe's for any format.

GregiBoy

Glenn, you are using incorrect terminology here and I hope you don't mind if I correct you for the record in simplistic terms.

Frame Size = Resolution of the image eg. 1920 x 1080
Frame Rate = The number of frames displayed per second eg. 25fps (PAL)
Bit Rate = The speed at which the data is transferred eg. 4295 Kbps

MKV Passthrough changes NONE of these. These parameters will only be changed if you use different encoding profiles and can be adjusted to suit the users requirements.

To achieve smaller file sizes, the title must be compressed and this is can be done by reducing the "Frame Size" (which obviously does have an effect on visual clarity) AND/OR by reducing the "Bit Rate" by compressing the video stream with a more efficient CODEC than the title was authored with. eg DVD MPEG 2 vs H264.

I remember doing objective tests years ago and reporting them on this forum where less than one in ten could tell the difference between an original DVD and a 1.4 Gb X264 encode of the same title on very high end equipment and I am sure that the same still applies.

In the end, it really comes down to what YOU are happy with.

Hope this helps clarify the above terminology.

Regards
Greg
[QUOTE=glenns;152055]MKV uses a smaller frame size thus smaller file output even if uncompressed.The disk is not using MKV so the frame is bigger to start with.Looks like your going to have to go from disk to get the best results.You could make iso's from the disks and do batch iso's overnight.If you ever plan on projection or 60-80 inch tv screens don't use mkv use m2ts same frame size as most video on disks.MKV is touched even if uncompressed as it uses smaller frame size to get file size down that's fine on smaller screens.[/QUOTE]

glenns

I don't mind being corrected at all I welcome it my point is smaller frame size = less clear video on large screen's.Now correct me if I am wrong here but using pass through with Fab the frame size is smaller than the blu ray frame size if no then why is the file size smaller than the blu ray when your not using a different codex just pass though? MKV just being a container.Dvd's look like junk on big screens from the disks so I am only talking about blu rays into MKV.

For me it's easily seen on front projection screens mine is 100" dia considered a smaller screen for front projection.When you go larger even less clear of a picture this is using good equipment with the gray scale at d6500 the video standard and all settings adjusted by ISF to be the same as the director intended.I also have a 60 inch plasma also adjusted the same way with professional equipment.For me it's easy to see on fast motion,rain,movies with a lot of blacks shadow detail and color detail just not the same.

Now lets get back to the poster who started this thread he made Mkv's with the fab encoder uncompressed why if frame size is the same as blu ray does his conversions of MKV on his drive using the CRF decoder do little to increase clearness and give him only a little smaller file size but when he use's the CRF decoder from the blu ray disk the file size is a lot smaller and the video clearer? He said all audio tracks and settings for subs were the same.

GregiBoy

I don't know why you are getting smaller file sizes with passthrough as nothing should be touched at all.

I suggest as a test you give MakeMKV a go and compare it against the Fab result.

With the OP, He should be using the "Converter" module, not the "Ripper" module so I am at a bit of a loss here what to suggest or using "Ripper" module using ISO's or the original disk as the source as you said.

glenns

Pass through is in the ripper but not in the converter so I guess you must rip from disk to get MKV passthrough.I am doing a test file with converter and it's converting to mkv but with no passthrough it looks like it's compressing or using the smaller frame by default.

Locutus2k

[QUOTE=GregiBoy;152111]I don't know why you are getting smaller file sizes with passthrough as nothing should be touched at all.

I suggest as a test you give MakeMKV a go and compare it against the Fab result.

With the OP, He should be using the "Converter" module, not the "Ripper" module so I am at a bit of a loss here what to suggest or using "Ripper" module using ISO's or the original disk as the source as you said.[/QUOTE]

Obviously i've used the "Ripper" module to rip untouched mkv files from bluray discs to my nas and now i'm using (well, tryin' to) the "Converter" module to downsize the very same files to smaller mkv's.

P.S. if i'm not wrong with the latest dvdfab version Pass through is in the "Converter" module, too, for both video and audio.