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28th February 2021, 14:00 | #1 | Link |
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Which picture better simulates the original?
Hi folks, I have three pictures for you:
X: A: B: X is the original, A and B are reencodes. When you have to select between A and B, which one do you prefer with the original in mind? Please note that you have to click on the picture again when you are at the image hoster's page to unlock the uncompressed png. Please do not make assumptions about the codecs unless i revealed them after enough people had participated. Last edited by zweifingerjoe; 28th February 2021 at 21:24. Reason: reversed change because of color correction issues |
28th February 2021, 16:08 | #2 | Link |
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A is more similar in terms of characteristics, preserving more of the original compression artifacts. From a compression standpoint it's "better"
B appears filtered (or the encoder effectively filtered it) , less similar, although general public would probably prefer it subjectively if you don't look at the original |
28th February 2021, 16:16 | #3 | Link |
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Different resolutions make it harder to compare.
I would like to suggest giving a and b in 1920x1080, not 1920x1040 or give the cropped 1920x1040 that was the source. I will go ahead and crop that Original myself. After cropping: At first I go with poisondeathray. P.S. Then after ~20 spot comparisons: Can not decide anymore. Certain parts are kept differently in a vs.b. Video will tell, maybe. P.P.S: And now after ~10 more spot comparisions I think that the knitware and the grain over skin is modeled nicely in B. Curious to see the video and maybe revise myself again ;-)
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1st March 2021, 10:54 | #5 | Link |
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B is sharper and preserves more details IMO than A. But the conclusion depends which parts of the picture I am looking at.
What's the purpose of the comparison? It is very questionable to qualify an encoder based on just a single frame. The conclusion for the next frame may be different. Are all pictures of the same type, i.e. I, B, or P frames? Last edited by Sharc; 1st March 2021 at 10:59. |
1st March 2021, 13:13 | #6 | Link | |
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Quote:
tl;dr I looked at different frames, the one I chose contains all the differences I personally noticed in every frame comparison. This is no scientific experiment. |
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1st March 2021, 19:56 | #8 | Link |
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So, I wouldn't give my opinions as much weight as most anyone else here, but just for the heck of it:
Both seem to have lost some graininess compared to the source. I'd actually say B looks grainier and sharper, but that the grain looks a bit blotchy on the actor's cheeks in particular. There's a big flat area on the actor's right lip in the source that's amplified in A but oddly much less noticeable in B. Both of the images have different hue/lightness than the source-- that color management issue you were talking about, I guess. All of these are subtle enough (to me) that I'm prone to second-guess them. Again, I'm not an expert. Last edited by Greenhorn; 11th March 2021 at 02:30. |
2nd March 2021, 17:13 | #10 | Link |
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The only difference I found that could explain the color mapping issue is that the original is 8bit, but a and b are 16 bit. This is because a and b were encoded with 10bit so ffmpeg used 16bit color depth for the pngs. There is no color profile attached to neither of the images. On my (8-bit) monitor the brightness is the same over all three images.
Code:
======== original.png ExifTool Version Number : 12.08 File Name : original.png Directory : . File Size : 3.8 MB File Modification Date/Time : 2021:02:28 13:31:24+01:00 File Access Date/Time : 2021:02:28 13:31:24+01:00 File Inode Change Date/Time : 2021:02:28 14:01:03+01:00 File Permissions : rw-r--r-- File Type : PNG File Type Extension : png MIME Type : image/png Image Width : 1920 Image Height : 1080 Bit Depth : 8 Color Type : RGB Compression : Deflate/Inflate Filter : Adaptive Interlace : Noninterlaced Pixels Per Unit X : 1 Pixels Per Unit Y : 1 Pixel Units : Unknown White Point X : 0.3127 White Point Y : 0.329 Red X : 0.64 Red Y : 0.33 Green X : 0.3 Green Y : 0.6 Blue X : 0.15 Blue Y : 0.06 Gamma : 1.961 Image Size : 1920x1080 Megapixels : 2.1 ======== a.png ExifTool Version Number : 12.08 File Name : a.png Directory : . File Size : 10 MB File Modification Date/Time : 2021:02:28 13:16:03+01:00 File Access Date/Time : 2021:02:28 13:15:40+01:00 File Inode Change Date/Time : 2021:02:28 14:01:03+01:00 File Permissions : rw-r--r-- File Type : PNG File Type Extension : png MIME Type : image/png Image Width : 1920 Image Height : 1040 Bit Depth : 16 Color Type : RGB Compression : Deflate/Inflate Filter : Adaptive Interlace : Noninterlaced Pixels Per Unit X : 1 Pixels Per Unit Y : 1 Pixel Units : Unknown White Point X : 0.3127 White Point Y : 0.329 Red X : 0.64 Red Y : 0.33 Green X : 0.3 Green Y : 0.6 Blue X : 0.15 Blue Y : 0.06 Gamma : 1.961 Image Size : 1920x1040 Megapixels : 2.0 ======== b.png ExifTool Version Number : 12.08 File Name : b.png Directory : . File Size : 11 MB File Modification Date/Time : 2021:02:28 13:19:12+01:00 File Access Date/Time : 2021:02:28 13:19:12+01:00 File Inode Change Date/Time : 2021:02:28 14:01:03+01:00 File Permissions : rw-r--r-- File Type : PNG File Type Extension : png MIME Type : image/png Image Width : 1920 Image Height : 1040 Bit Depth : 16 Color Type : RGB Compression : Deflate/Inflate Filter : Adaptive Interlace : Noninterlaced Pixels Per Unit X : 1 Pixels Per Unit Y : 1 Pixel Units : Unknown White Point X : 0.3127 White Point Y : 0.329 Red X : 0.64 Red Y : 0.33 Green X : 0.3 Green Y : 0.6 Blue X : 0.15 Blue Y : 0.06 Gamma : 1.961 Image Size : 1920x1040 Megapixels : 2.0 |
3rd March 2021, 14:35 | #12 | Link |
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@zweifingerjoe,
Out of interest... What video format has your source been encoded with? Why do you feel the need to process and generate a new encode?
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10th March 2021, 21:50 | #13 | Link |
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1 frame is not a very good comparison. At least are they the same type: I,P,B?
Few frames in sequence is much better. B looks better, but no one will see those differences during real watching scenario, so pick one which encodes faster. Last edited by kolak; 10th March 2021 at 21:52. |
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