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  1. Banned
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    All right, this will be my absolute final test on the matter. I used XnViewMP to convert my 214 png to an avif and webp file using the default settings. Can you tell the difference?
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  2. Originally Posted by Jay123210599 View Post
    All right, this will be my absolute final test on the matter. I used XnViewMP to convert my 214 png to an avif and webp file using the default settings. Can you tell the difference?
    yes
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    Originally Posted by poisondeathray View Post
    Originally Posted by Jay123210599 View Post
    All right, this will be my absolute final test on the matter. I used XnViewMP to convert my 214 png to an avif and webp file using the default settings. Can you tell the difference?
    yes
    what is it?
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  4. Originally Posted by Jay123210599 View Post
    Originally Posted by poisondeathray View Post
    Originally Posted by Jay123210599 View Post
    All right, this will be my absolute final test on the matter. I used XnViewMP to convert my 214 png to an avif and webp file using the default settings. Can you tell the difference?
    yes
    what is it?

    The webp image is worse everywhere - it has texture loss/softening, dct artifacts, edge artifacts, line noise, blocky color edges , loss of clean color edges

    The avif image is definitely better than the webp - but it has smoothed over textures, including some of the original artifacts in the shadows where people are standing. Some grey ground textures in the foreground have changed from the source - probably also a side effect from the smoothing . Texture shading on the sign have changed . Almost all the more changed areas are from darker textures - e.g. the guy in the dark blue shirt has different artifacts now, the dark grey pants on the bottom left have halo like artifacts. The brighter areas are less negatively impacted. You can probably reduce some of the artifacts by tuning presets and settings, and of course more bitrate. There are presets for still image and AQ setting options to shift bits to darker areas. The lines are much cleaner than the webp . If you look closely you can see changes everywhere, but they are minor compared to the webp. The results are pretty good for the filesize compared to the PNG
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    Originally Posted by poisondeathray View Post
    Originally Posted by Jay123210599 View Post
    Originally Posted by poisondeathray View Post
    Originally Posted by Jay123210599 View Post
    All right, this will be my absolute final test on the matter. I used XnViewMP to convert my 214 png to an avif and webp file using the default settings. Can you tell the difference?
    yes
    what is it?

    The webp image is worse everywhere - it has texture loss/softening, dct artifacts, edge artifacts, line noise, blocky color edges , loss of clean color edges

    The avif image is definitely better than the webp - but it has smoothed over textures, including some of the original artifacts in the shadows where people are standing. Some grey ground textures in the foreground have changed from the source - probably also a side effect from the smoothing . Texture shading on the sign have changed . Almost all the more changed areas are from darker textures - e.g. the guy in the dark blue shirt has different artifacts now, the dark grey pants on the bottom left have halo like artifacts. The brighter areas are less negatively impacted. You can probably reduce some of the artifacts by tuning presets and settings, and of course more bitrate. There are presets for still image and AQ setting options to shift bits to darker areas. The lines are much cleaner than the webp . If you look closely you can see changes everywhere, but they are minor compared to the webp. The results are pretty good for the filesize compared to the PNG
    How about now? I set the quality setting to 100% for both of them and the format is 420 for avif, like the input video.
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  6. Originally Posted by Jay123210599 View Post

    How about now? I set the quality setting to 100% for both of them and the format is 420 for avif, like the input video.

    The webp is improved from the last version, but it still has deteriorated color edge issues - blurring and bleeding . If you did this conversion directly on YUV420 video, possibly there are extra conversions steps going on such as going through RGB then back to YUV420. There is still noticable noise . Lossy webp @ Q100 is not as good as it should be . The upper end scale should extend higher (something like Q200 with the current scale). Lossless webp is good, because it's always better than PNG compression wise, yet still has decent compatibility

    The avif is YUV444, not YUV420, and it looks good - very close. There are differences if you check closely, but the differences are very minor.

    One negative of YUV images is the method used to convert to RGB for display can vary. There are more points of variability - and if you're asking can you see differences compared to 00214.png - an RGB conversion that you did - there can be other little differences due to the method used. For example, some colors might look slightly different if you used Firefox vs. Chrome. Vs. ffplay vs. local media player. An RGB image will take that variability out of the equation (mostly; there are some issues with PNG's with gAMA and cHRM tags - the solution is to have PNGs with no tags - then they display the same everywhere as sRGB). Even the 00214.png image can be slightly different, if someone took the original video and took a screenshot, because the YUV to RGB conversion for that screenshot might be slightly different than the one you used. The chroma upscaling algorithm used from 420 can be different (eg. some might use bicubic, others bilinear for softer results) . For higher bitdepth YUV sources, the downconversion to 8bit can be accompanied by dithering algorithms.
    Last edited by poisondeathray; 8th Feb 2024 at 23:03.
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    Originally Posted by poisondeathray View Post
    Originally Posted by Jay123210599 View Post

    How about now? I set the quality setting to 100% for both of them and the format is 420 for avif, like the input video.

    The webp is improved from the last version, but it still has deteriorated color edge issues - blurring and bleeding . If you did this conversion directly on YUV420 video, possibly there are extra conversions steps going on such as going through RGB then back to YUV420. There is still noticable noise . Lossy webp @ Q100 is not as good as it should be . The upper end scale should extend higher (something like Q200 with the current scale). Lossless webp is good, because it's always better than PNG compression wise, yet still has decent compatibility

    The avif is YUV444, not YUV420, and it looks good - very close. There are differences if you check closely, but the differences are very minor.

    One negative of YUV images is the method used to convert to RGB for display can vary. There are more points of variability - and if you're asking can you see differences compared to 00214.png - an RGB conversion that you did - there can be other little differences due to the method used. For example, some colors might look slightly different if you used Firefox vs. Chrome. Vs. ffplay vs. local media player. An RGB image will take that variability out of the equation (mostly; there are some issues with PNG's with gAMA and cHRM tags - the solution is to have PNGs with no tags - then they display the same everywhere as sRGB). Even the 00214.png image can be slightly different, if someone took the original video and took a screenshot, because the YUV to RGB conversion for that screenshot might be slightly different than the one you used. The chroma upscaling algorithm used from 420 can be different (eg. some might use bicubic, others bilinear for softer results) . For higher bitdepth YUV sources, the downconversion to 8bit can be accompanied by dithering algorithms.
    Are all avif files YUV444? The second one I sent you has these settings.
    Image
    [Attachment 76881 - Click to enlarge]

    By the way, did the first one look better than both webp files?
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  8. Originally Posted by Jay123210599 View Post
    Are all avif files YUV444?
    No

    The second one I sent you has these settings.
    Maybe the program isn't sending the proper commands

    By the way, did the first one look better than both webp files?
    The 1st AVIF definitely looked "better" than the 1st webp in terms of "more similar" to 00214.png; and in many ways better than the 2nd webp . The main negative of the 1st AVIF is smoothing of textures. If you had an anime source style with fine textures, there would be a larger visible difference. It's still pretty good for the filesize. When using lower bitrate ranges smoothing is arguably less bad than edge artifacts - it's a good tradeoff for most people especially on this type of anime style
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    Originally Posted by poisondeathray View Post
    Originally Posted by Jay123210599 View Post
    Are all avif files YUV444?
    No

    The second one I sent you has these settings.
    Maybe the program isn't sending the proper commands

    By the way, did the first one look better than both webp files?
    The 1st AVIF definitely looked "better" than the 1st webp in terms of "more similar" to 00214.png; and in many ways better than the 2nd webp . The main negative of the 1st AVIF is smoothing of textures. If you had an anime source style with fine textures, there would be a larger visible difference. It's still pretty good for the filesize. When using lower bitrate ranges smoothing is arguably less bad than edge artifacts - it's a good tradeoff for most people especially on this type of anime style
    So what should I do for avif files?
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    How about this? I converted the png to jpg using these settings.
    Image
    [Attachment 76890 - Click to enlarge]

    Image
    [Attachment 76893 - Click to enlarge]
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    I also made an JXL file with these settings.
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  12. I wouldn't use xnviewmp for conversion on YUV 420 video to images (YUV or RGB). It assumes the wrong chroma placement - it uses center aligned or "MPEG1" (which is correct for 420 jpeg) . Most common types of video use "left" or "MPEG2" (an exception is UHD BD which uses top left). As a result you get chroma misalignment and less sharp color borders from xnviewmp with YUV420 video input on RGB output images (such as PNG, jpeg-xl - basically most image types)

    Also the xnviewmp YUV exported images are not converted directly (they go through intermediate RGB step) - so all images are lower quality from YUV video than if you used a proper method (part of the reason for color edge issues for the webp images mentioned earlier).

    If you use RGB input, xnviewmp should be ok for RGB output
    Last edited by poisondeathray; 10th Feb 2024 at 11:42.
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    Originally Posted by poisondeathray View Post
    I wouldn't use xnviewmp for conversion on YUV 420 video to images (YUV or RGB). It assumes the wrong chroma placement - it uses center aligned or "MPEG1" (which is correct for 420 jpeg) . Most common types of video use "left" or "MPEG2" (an exception is UHD BD which uses top left). As a result you get chroma misalignment and less sharp color borders from xnviewmp with YUV420 video input on RGB output images (such as PNG, jpeg-xl - basically most image types)

    Also the xnviewmp YUV exported images are not converted directly (they go through intermediate RGB step) - so all images are lower quality from YUV video than if you used a proper method (part of the reason for color edge issues for the webp images mentioned earlier).

    If you use RGB input, xnviewmp should be ok for RGB output
    I used a RGB png for input, which one of these images looked the closest to the original?
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  14. The jpg is not good - typical jpeg artifacts .

    The jpegxl image looks very similar, just some very minor differences. It's the closest out of the bunch. The 2nd avif is next closest
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