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1st June 2015, 23:48 | #1 | Link |
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Quality trouble
Hello everyone,
I'm using the x264's Slow preset with MeGUI, but I don't know... there's something bugging me. In the video, the faces or objects that are close to the camera are detailed, clean, looking-good! But when it's in the background, like a person or whatever, then the quality isn't that great, almost grainy, it loses its detail. Beside increasing bitrate, is there a parameter I should try changing for that issue? I don't know if it's because I'm getting used to the video quality I'm watching, but I did not have this problem a few years ago, with an actually faster preset. I don't get it. |
2nd June 2015, 16:31 | #3 | Link |
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I bought the movie from an online french VOD service, and I'm trying to reencode it to the best size/quality ratio because I don't have a lot of space on my HD, so I'm using 950 kbps for the video.
Source: http://i.imgur.com/SKH9BB5.jpg Reencoded: http://i.imgur.com/tagbnwk.jpg Is it just a matter of bitrate, or should I play with... I don't know, the deblocking maybe or something like it? |
2nd June 2015, 16:57 | #4 | Link | |
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Without knowing your entire x264 command line it's difficult to suggest something since I don't know into which command line "Slow preset with MeGUI" translates. Some general hints:
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3rd June 2015, 10:27 | #5 | Link |
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What are you playing back to? If you're using PC only for now, would you be willing to switch to x265 instead? It's much slower, but even on medium preset would look better than x264 at these low bitrates. Otherwise, you're right at the point where reducing the resolution is beneficial, as Groucho said. Chopping the edges off and making it 16:9 would also help without sacrificing too much, relative to the quality gain. Try a scene with a couple different methods to see what you can tolerate best.
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3rd June 2015, 11:44 | #6 | Link |
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I assume the slow x264 preset with MeGUI is literally the default x264 settings with the slow x264 speed preset? If so, that should be fine.
If the video isn't being resized or filtered in any way then it can only be the bitrate if you're not using "odd" encoder settings (noise filtering can blur a little as well as reduce noise so use it if you think it's necessary as that'll help keep the bitrate down but don't apply heavy noise filtering if it's not required). CRF encoding is a better idea because you pick the quality and after a while you'll find a CRF value that gives you an average file size you're happy with and hopefully a quality you can live with. The file sizes will vary quite a bit which is why I say "an average" file size. Maybe start with the default CRF value of 23 (lower values = higher quality) and check the resulting bitrate. If you're happy with the quality that might give you an indication as to whether your current bitrate is realistic. You can encode small sections of video for testing rather than encode it all (although still encode a decent amount) by adding Trim() to the end of a script. For example to encode frames 1000 to 2000 you could use this: Trim(1000,2000) And I assume you're using "automated 2 pass" or "targeting file size" encoding (same thing for MeGUI) and not ABR (average bitrate) encoding in order to specify a bitrate, because especially at low bitrates, 2 pass would probably do a much better job. Last edited by hello_hello; 3rd June 2015 at 11:49. |
3rd June 2015, 14:39 | #7 | Link | |||
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And like I said, I used to do it with my own videos and I was satisfied with it, but not anymore now I got new settings and lost the old ones. Quote:
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Yes, I'm using 2-pass encoding but I think you're right, I think CRF encoding is a better choice than picking bitrate in my case. I just need to find the right value for me. Thank you all for your replies! |
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3rd June 2015, 14:52 | #8 | Link |
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If you're talking about YIFY, your encoding screenshot is what I would expect from them, in fact maybe a little better. I think you've just been spoiled (happens to us all!). A combination of a little crop & resize will help a little, but you can't expect a miracle when you're conserving space either.
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3rd June 2015, 14:56 | #9 | Link | ||
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The encoder configuration lets you select an x264 speed preset. It simply adds something like --preset slow to the command line, but if you show the advanced settings you'll see the appropriate ones are changed accordingly. The deblocking, psy and AQ strength settings are changed when you select an appropriate x264 tuning. For example when Tuning "None" is selected the deblock settings are zero and zero, select Tuning "Film" and they'll change to -1 and -1 under the advanced settings tab as they're the defaults for the film tuning, but you'll just see --tune film in the command line. Last edited by hello_hello; 3rd June 2015 at 15:00. |
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3rd June 2015, 15:21 | #10 | Link | ||
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Also, since you mention the viewing, now I think about, could my player settings be the cause of this? I don't remember using specific settings before, just the K-Lite Codec Pack maybe, but now I'm on a new computer I may not have the same settings. If I use MadRV or whatever (with MPC), could that make my film look better? Edit:Quicky question: I remember a time where the default qmin was 10, now it's 0 and the default qmax was 51, now it's 69. Why has it change so much? And is 0/69/4 really better than 10/51/4 on all occasion? Last edited by Solon8; 3rd June 2015 at 15:24. Reason: question |
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3rd June 2015, 16:46 | #12 | Link | |
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You have to realize that the required bitrate for the same perceived quality depends largely on the nature of the movie/video. For a Cartoon you probably won't need more than 1Mbps for 720p but for a movie like "300" or "Black Swan" which have artificially added noise you need easily 10Mbps. I noticed that your re-encoded screen shot is not only from a different frame than the source, it's also very blurry. Did you add any filters?
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3rd June 2015, 16:52 | #13 | Link | ||
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No filter at all, beside the resize one (Lanczos sharp). This was my encoding settings: "cabac=1 / ref=5 / deblock=1:0:0 / analyse=0x3:0x113 / me=umh / subme=8 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=20 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=12 / lookahead_threads=2 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=2 / b_bias=0 / direct=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=240 / keyint_min=24 / scenecut=40 / intra_refresh=0 / rc_lookahead=50 / rc=2pass / mbtree=1 / bitrate=950 / ratetol=1.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / cplxblur=20.0 / qblur=0.5 / ip_ratio=1.40 / aq=1:1.00" See anything particularly wrong with it? Beside the low bitrate. Last edited by Solon8; 3rd June 2015 at 16:53. Reason: forgot something |
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3rd June 2015, 17:41 | #14 | Link | |
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--ref 16 --subme 10 --me_range 24 --trellis 2 --bframes 8
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4th June 2015, 20:02 | #15 | Link | |
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I don't know if modern video cards have noise or deblocking filters. Mine doesn't, but both can cause blurring. My TV's media player has noise filters but I disable all the video enhancing crap in the TVs settings too. |
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4th June 2015, 22:37 | #16 | Link | |
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But for that specific effect, that's an Adaptive Quant issue where QPs are too high for those flat/smooth slow moving areas. Using a slower preset, and --tune film are both good. But if you're still not getting there, you could try --aq-mode 2. It'd be nice if you could copy the full command line from MeGUI's last Advanced pane here. |
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5th June 2015, 01:19 | #17 | Link | |||
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Should I always use aq-mode 2 for all my files from now on? And if not, in what occasion should I use it? Also, I just encoded the movie with a CRF of 26 and I find the quality acceptable (to my standards). I'll keep playing with the value, but from what I see, I think I'll stick to a range of 24-26. It seems to be the kind of quality/size I want to have. Does anyone disagree? Thank you all for your replies. |
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5th June 2015, 12:08 | #18 | Link |
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Wow, I usually encode with CRF16 ~ CRF18. Anyway, whatever floats your boat.
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5th June 2015, 12:53 | #20 | Link |
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Sure I do. I encoded a bunch of Simpsons and Family Guy DVDs even below that bitrate.
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