Help on Quality Please

General questions or discussion about HandBrake, Video and/or audio transcoding, trends etc.
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darthasp
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Joined: Thu Feb 23, 2012 4:59 pm

Help on Quality Please

Post by darthasp » Thu Feb 23, 2012 7:54 pm

Hi there,

Hoping some one could point me in the right direction.....

I am currently using Handbrake 4456svn x86_64 (2012021901)from the Nightly builds on a Mac 10.6.5.

So far I have been very impressed with the speed and quality - I like Handbrake very much. However there are a couple of movies where I would like to improve the quality.

My method if encoding has been as follows:

Rip DVD to Harddrive using fairmount or Mac DVDRipper Pro (As suggested by fairmount) or directly from the DVD drive using Fairmount 'On the Fly'

In handbrake I have just used the 'Normal' settings along with 'Web Optimised' and AAC Core 224.

The output of animated fims like Shrek is excellent especially given the very small file size produced 5GB down to about 1GB, there is only a slight loss of colour depth but this is perfectly acceptable for the usage of this films.

However I am suffering a minor issue when encoding films like Gladiator and Pirates of the Caribbean... Basically whenever there is smoke moving around in the backgound arising from some battle or other - it is very blocky and pixelated and does not look too much like smoke. The rest of the picture, faces for example are all very good quality, much better than xvid and more vivid than DVDShink. Although while DVDShrink is overall more grainy it doesn't suffer from this pixelated effect.

Now I like the speed and size of the encodes I am producing and am looking for a small change that may lessen this effect. I have tried the 'High' profile and while the effect was reduced it did not really warrant the extra time it took to do the encoding, it was about 3 times as long!

I do not really want to go over the 2GB mark for output file size. Pirates of the Carribbean 2 is coming out a 1.8Gb for Normal profile and 1.87GB for High.

Any suggestions please...

Thanks

Phil

TedJ
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Re: Help on Quality Please

Post by TedJ » Fri Feb 24, 2012 12:34 am

Try reducing RF to 19 or 18.5, although this will increase filesize somewhat.

darthasp
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Joined: Thu Feb 23, 2012 4:59 pm

Re: Help on Quality Please

Post by darthasp » Fri Feb 24, 2012 2:54 am

Okay Thanks I'll give that a try

copx
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Joined: Mon Mar 05, 2012 8:56 pm

Re: Help on Quality Please

Post by copx » Mon Mar 05, 2012 9:06 pm

I had the same problem. Smoke and also black areas looked horribly pixelated. I solved that by adding the advanced options:
no-dct-decimate=1
no-fast-pskip=1

I think the encoder simply 'skips' too much fine detail in those areas if these options are on (Default) causing said blocky look. For some reason most people don't seem to notice that / don't have that problem. However, if you see pixelated black/smoke try these options.

mithrandir
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Joined: Sun Nov 30, 2008 2:24 pm

Re: Help on Quality Please

Post by mithrandir » Wed Mar 07, 2012 1:34 am

Also try mbtree=0. This turns off a feature that can produce artifacts (smudginess/blockiness) in images with fine detail, particularly darker ones. It may not be the source of your visual concerns but it is worth a shot.

I discovered the problems with mbtree when I was making encodes at CRF 19 and wondered why some scenes just looked crappy even at that low CRF. A great example is the first two shots on "No Country For Old Men" (00:00:40 - 00:00:55). Encode with mbtree=1 and mbtree=0, dramatic difference.

I turned off mbtree for all of my film encodes. mbtree improves compression efficiency but it's quality is too uneven IMO.

j4mm3r
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Joined: Sun Mar 11, 2012 12:19 am

Re: Help on Quality Please

Post by j4mm3r » Sun Mar 11, 2012 12:38 am

hi, i wonder if anyone can advise/comment?

ive been using hb for a few years but ive always encoded with a 2 pass & set bit rate for example 15000 for 1080p and 6000-7000 for 720p on average this will give me a file size of 12-15gb for 1080p and 6-7.5gb for 720p......

well ive been trying out the one pass constant quality method and wanted to check with others if it sounds right, after reading about on the web for good quality bluray rips it is suggested cq of 18 is the sweet spot for bd although this will produce a large file. anyway i encoded today 'the lincoln lawyer' a 2 hour movie into 720p with dts passthrough mkv on cq setting 18, 6 ref frames, trellis 2, high profile setting as normal for me.

the file size is approx. 2.87gb!! as you will see from above im used to 6-7bg for 720p movies and alot of guides say you will get a big file at cq 18 but 2.87gb seems really small to me. do others get this sort of file size for 720p movies on a high setting, also the average bit rate from memory is something like 3000 possibly lower i cant remember now (on diff pc), this seems low to me for 720p?

watched the 720p movie tonight on my 46" led and to be honest i thought the pq was excellent! lol

this was with the latest hb ive just installed today x64bit, does the hb update improve upon file compression in anyway?

TedJ
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Re: Help on Quality Please

Post by TedJ » Sun Mar 11, 2012 8:17 am

There are some significant improvements in x264 with the latest stable release of HandBrake but the main issue is your average bitrates have been excessively high for the majority of your sources. This is the primary advantage of using constant quality encoding; once you've determined the RF that works for you and your viewing arrangement then all of your encodes will be of the same quality and HandBrake will determine the bitrate required to reach it.

RF18 for a BD encode is also a little excessive... many people look more in a range of 23-21.

j4mm3r
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Joined: Sun Mar 11, 2012 12:19 am

Re: Help on Quality Please

Post by j4mm3r » Sun Mar 11, 2012 10:09 am

ok thanks for that, but if i go up to 23-21 im going to have an even smaller file size, i guess if im using cq ive got to get over my hangup on file size/bite rate right?

its just when i started encoding my collection a few years ago people in forums would frown upon people with small files for hd, infact so did i! heres the info from media info on the film, it was set to cq 18:


Format : Matroska
Format version : Version 2
File size : 2.90 GiB
Duration : 1h 58mn
Overall bit rate : 3 501 Kbps
Writing application : HandBrake 0.9.6
Writing library : libmkv 0.6.5

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L3.1
Format settings, CABAC : Yes
Format settings, ReFrames : 6 frames
Codec ID : V_MPEG4/ISO/AVC
Duration : 1h 58mn
Bit rate : 1 922 Kbps
Width : 1 280 pixels
Height : 544 pixels
Display aspect ratio : 2.35:1
Frame rate : 23.976 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.115
Stream size : 1.59 GiB (55%)
Writing library : x264 core 120
Encoding settings : cabac=1 / ref=6 / deblock=1:0:0 / analyse=0x3:0x113 / me=hex / subme=7 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=12 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=5 / b_pyramid=2 / b_adapt=2 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=2 / keyint=240 / keyint_min=24 / scenecut=40 / intra_refresh=0 / rc_lookahead=50 / rc=crf / mbtree=1 / crf=18.0 / qcomp=0.60 / qpmin=3 / qpmax=69 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00
Language : English
Default : Yes
Forced : No
Color primaries : BT.709-5, BT.1361, IEC 61966-2-4, SMPTE RP177
Transfer characteristics : BT.709-5, BT.1361
Matrix coefficients : BT.709-5, BT.1361, IEC 61966-2-4 709, SMPTE RP177

Smithcraft
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Re: Help on Quality Please

Post by Smithcraft » Sun Mar 11, 2012 12:13 pm

It depends on the image quality of the movie. Some transcode down much lower than others.

Also, since you were putting a fixed amount of bitrate in to each frame, you had big encodes. With a quality based encode rather than a bitrate based encode, the bits are used when needed, and not used when not needed.

SC

Flo
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Re: Help on Quality Please

Post by Flo » Sun Mar 11, 2012 2:28 pm

j4mm3r wrote:i guess if im using cq ive got to get over my hangup on file size/bite rate right?
That's pretty much it. File size just isn't a reliable indicator of quality. I have a number of 720p rips from clean sources that are not only smaller, but look significantly better, than some of my SD TV or DVD rips.

j4mm3r
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Joined: Sun Mar 11, 2012 12:19 am

Re: Help on Quality Please

Post by j4mm3r » Sun Mar 11, 2012 4:11 pm

Ok thanks guys, I've not done much cq encodes so appreciate comments.

On a slightly different note, as you can imagine I've gotta lot of 6-7gb 720p files, if I wanted to re-encode them with cq to reduce size would I be better going back to the original source or can I re-encode the 720p file (would it make any difference to quality)

Thanks

nightstrm
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Re: Help on Quality Please

Post by nightstrm » Sun Mar 11, 2012 6:37 pm

j4mm3r wrote:Ok thanks guys, I've not done much cq encodes so appreciate comments.

On a slightly different note, as you can imagine I've gotta lot of 6-7gb 720p files, if I wanted to re-encode them with cq to reduce size would I be better going back to the original source or can I re-encode the 720p file (would it make any difference to quality)

Thanks
Yes, I'd highly recommend going back to the original source for this.

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