BD Ripper (3D Plus) Feature request: CUDA-based h264 CRF-encoding

[Dark$oul71]

Hi there,

I just bought BluRay ripper because I was both conviced from the copy-protection support as well as from the CUDA support for transcoding. What I am somewhat missing in the encoding options is a possibility to choose CRF-based encoding.

Nowaday I think using bitrate / filesized based 1/2-pass encoding is not really required anymore. This is nice if you are really targeting a certain media-size (e.g. DVD-DL) but most peoples I know (including me) either backup their BDs on HDD.

Encoding at a certain bitrate almost always means that you are wasting bitrate or you are spending too less bitrate.

For the latest BD backups I did, I have used x264 under Windows in CRF-based encoding mode. My full 1080p rips show size variations at a CRF of 21 between 5GB and up to 12GB per movie. All this with no cropping applied and dual DTS audio tracks.
This clearly shows to me how less suited a CBR-approach for BD backups.

Personally I like to store as much BD rips on my HTPC as possible without sacrificing quality but also maximizing space usage.

For me the holy grail would be CUDA-based CRF transcoding via BluRay ripper. Right now I get around 22-25 FPS in 1080p on my AMD QuadCore (Phenom 4x3GHz) but 50-55 FPS would be way cool.

CRF provides the benefit of 1pass-based encoding and enables you to always get constant quality out off your rips without wasting space.

Best regards,
D$

[fengtao]

We have plan to support CRF in both software and CUDA way, please give us some time to check it.

[Dark$oul71]

fengtao,

that is great to hear

That being said, I must admit that 1080p stuff in 8 MBit looks great. On my 32" Sony I could tell no difference between the 8 MBit video and the orginial one (MKV passthrough). At least not for Underworld Awakening and Prometheus.

So far I have not seen another CUDA-based encoder with this quality. Thanks for this....

Best regards,
D$

[Dark$oul71]

fengtao,

hopefully I do not sound too demanding but is there any ETA for the CRF-based encoding mode in DVDFab ?

So far I always found the quality that BD Ripper provides in 1 pass-mode with 8-10 MBit sufficient but for Avatar this was clearly too less. i reencoded the full movie software-based (using x264) with a CRF value of 19 and the results make a difference like night and day. The video encoded with BD Rippers 1 pass GPU mode was as big as the CRF-based encoding but the later was visually much crisper and showed no artifacts at all.

Please provide us CRF-based encoding ASAP

Kind regards,
D$

[signals]

Please have some patience, they are working on it.

How much time does it require to encode a movie (Avatar for example) using the CRF settings you mentioned in your post?

[Dark$oul71]

This depends on the x264 presets you use.
Using "normal" usually translates to ~16 - 18 FPS in full 1080p.
Using "faster" means around 22 - 24 FPS in full 1080p.

I usually can not tell a difference between "normal" and "faster" at CRF around of 21.

This is without GPU acceleration for h264 decoding (which would be possible via AVISynth). My system has a AMD Phenom with 4x3 GHz and 8 GB RAM if this is of interest.

With DVDFab and CUDA support for transcoding I get ~ 55 FPS in 1080p.

[3dnut]

This depends on the x264 presets you use.
Using "normal" usually translates to ~16 - 18 FPS in full 1080p.
Using "faster" means around 22 - 24 FPS in full 1080p.

I usually can not tell a difference between "normal" and "faster" at CRF around of 21.

This is without GPU acceleration for h264 decoding (which would be possible via AVISynth). My system has a AMD Phenom with 4x3 GHz and 8 GB RAM if this is of interest.

With DVDFab and CUDA support for transcoding I get ~ 55 FPS in 1080p.

no wonder you struggle to notice any diffrence, 32" screen isnt big enough to compare. i watch on a 46" The current encoder is fast but the quality isnt to good.

do a movie only encode of something like The Avengers, do the same with bdrebuilder x264 2 pass with slow settings, sure it will take 4 times longer but its worth it.

I would like to see dvdfab have options for slower more detailed encodes.

dvdfab is an amazing product, only let down by a poor encoder

[Dark$oul71]

@others: Sorry for short off-topic conversation !

@3dnut,

agreed, on a bigger screen visual artifacts become more visible. You are more than welcomed to pay a few bucks in the just recently founded "Dark$oul needs one of those biggie > 60" displays" fund

Take my words: I am in the video encoding business long enough to know what I have to watch out for.

Even my small 22" 1080p monitor is good enough to look out for compression artifacts and / or loss of details.

I think we both agree that from the perspective of quality versus space any bitrate-based encoding will always be a compromise. Either you spent "too much bitrate" (= video looks identical with a CRF-based encoding but the later is a lot smaller) or you spent "too less bitrate" (= video needs a much smaller CRF value to meet identical target size than what it needs to look good).

Yes, most fast encoders (be it a software encoder with fast presets or GPU-based) will need more bitrate to reach identical quality compared to a slow working software encoder with enough time for a decent analysis. The question is if you notice it !

Previously I used x264 in CRF mode. For my eyes a CRF value of 19-21 is certainly enough to experience great quality of HD content (either 1080p from BD or 720p from HDTV). Above 22 for CRF quality is still nice but it degrades the higher the values get.

For testing I encoded Prometheus and Underworld Awakening with x264 (software based encoder) with a CRF of 20.

Underworld Awakening was 6.3 GB big with two DTS audio tracks.
Prometheus (Non 3D) is 10 GB big with two DTS tracks as well.

I also encoded both movies with the Bluray Rippers CUDA-based 1 Pass-mode and ~ 10 MBit Video Bitrate. The resulting files were pretty identical to those done in CRF.

The resulting movies were really nice in quality and I bet most normal peoples could hardly tell a difference between the 10 MBit CUDA encoding and the software-based CRF 20 encoding. I made a "hand to hand" comparison via my HTPC between a full BD rip (MKV passthrough), the 10 MBit CUDA encoding and my CRF-encoding. I didn't see a difference.

Avatar on the other hand did make quite a difference. Using CUDA-based encoding at 10 MBit showed clear artifacts in high-action scenes but this is no wonder. The CRF-based encoding at factor 20 resulted in a 20 GB big MKV file with dual DTS audio. The CUDA-based encoding was merely 12 GB big (average bitrage much lower). It would have been interesting how a CUDA-encoded copy of Avatar looks like if encoded at 15-20 MBit.

My final point is this:
When the folks from dvdfab get CUDA-based CRF encoding ready and I get an equal quality compared to my current software method by simply lowering the CRF-value by 2, then I am all theirs. Then this will mean constant quality at a bit higher size and encoding at 55 FPS.

As for BD Rebuilder and 2 pass: You should stick to 1 pass CRF if possible. Everything else is a waste of quality, time and/or space (not in a specific order).

Bitrate-based encoding methods have always been sub-optimal in terms of achieving constant quality. Guess why they invented D2SRoBa for DVD backup back then ?

[3dnut]

@Dark$oul71

you must have been around a while to remember the big 3

heres hoping dvdfab can deliver the encoding options especially needed for 3D imo

my [3rd] subscription is about to expire and im swaying towards fengtao's progs. Everything is covered

[fengtao]

We will consider to add more encoding options, please be patient.

[ordman]

If you like the Quality with 264.

Then the Quality & Compression with 265 should be just as good, and Probably better.

[Dark$oul71]

@ordman:
stop high-jacking the threads of other peoples by posting useless information !
The quality and compression ratio of h265 has yet to be seen. Also h264 is well supported by playback devices, recording devices and tool chains out there. h265 does currently neither share this status, nor do I have interest to use it.

@dvdfab staff:
I can only state once again how important CRF-based encoding is for people that want quality rips and recompress by using any DVDFab-based product. Using the bits per pixel value for any bitrate vs. quality considerations is useless. It will not guarantee a reasonable quality for a certain movie at a certain bitrate. In the age of users ripping their BD backups to NAS or HDD is hardly makes a difference if a movie is like 8 or 12 GB big. Even for backing up stuff on optical medias, there are single layer BD-Rs which give you 25GB of storage.

Back in the days when people used tools like Gordian Knot to back up their DVDs as DivX the importance of the Bit per pixel value was quite different though. Mainly because people could either adjust their output duration or bitrate to get reasonable qualities. Unfortunately those values do not count anymore for backing up HD stuff via h264 encoding.

Still using bpp for adjusting the bitrate might also give your transcoder a bad reputation.

During the last few month I have backed up a lot of HD stuff (both 720p and 1080p) and using CRF-based encoding I have seen BIG size variations. Some 1080p videos come out at 5 GB with two DTS audio tracks while others get 12 GB big with only one AC3 track.

There is only one approach that comes to my mind in order to find out what bitrate is required for constant quality:
Encode 1-3 % samples of the video for a CRF value matching your desired quality. Then calculate then final size for 100% of the video and from that calculate the video bitrate used for final 1pass / 2pass encoding.

They used AVISynth SelectRangeEvery back then for the sampling:

http://avisynth.org/mediawiki/Select

Until CRF-mode arrives in BDRipper I will stick to my x264 frontend written in AutoIt.

Simply check out this doom9 thread in regard to using BPP for h264:

http://forum.doom9.org/showthread.php?t=134555

[Dark$oul71]

Any updates on CUDA-based CRF-encoding ?
Is it possible at all ? Can we expect something in the next half year ?
I am not impatient but curious

[fengtao]

Software-based CRF will be added to interface very soon.

CUDA-based CRF will be added next.

[Dark$oul71]

That is great ! I am awaiting the version with CRF-based encoding.