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  1. I need to upconvert an 854x480 MP4 to 1280x720. When I do this with some cheap video converter tools, visual artifacts are being introduced and the video quality is going down quite a bit. What are the best tools/methods for doing such an upconversion? Obviously I am not going to get higher resolution quality in the video. I am simply looking to minimize the number of bad visual artifacts that appear when a lower resolution video is placed onto a larger video bitmap.
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  2. Best video filters without specifying border criteria is contradictory - best in objective or subjective way? In objective way point resize is lossless from mathematical perspective IF upsampling factor is integer and even number. Best in subjective way there is newcoming class of resizers based on pre-trained neural networks.
    Good thread with some comparison https://forum.doom9.org/showthread.php?t=175200
    Yes i know - this is not the answer you wish to receive but your question is way to general.
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  3. Originally Posted by pandy View Post
    Best video filters without specifying border criteria is contradictory - best in objective or subjective way? In objective way point resize is lossless from mathematical perspective IF upsampling factor is integer and even number. Best in subjective way there is newcoming class of resizers based on pre-trained neural networks.
    Good thread with some comparison https://forum.doom9.org/showthread.php?t=175200
    Yes i know - this is not the answer you wish to receive but your question is way to general.
    I do not know how to specify all the relevant border conditions. But in something like Photoshop, if I start with a small image and resize to a large one, it looks awful unless I apply any relevant filter that was designed to handle enlargement. I have been using Bicubic Smooth in that situation with okay results.

    I think I would get at least a better result using any filter designed to enlarge a video. I am willing to try a few. How do I do that?

    Do I have access to the neural network you referenced? If not, how is it helping me solve the problem I have today? I need to apply a better filter this week, not this year.
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  4. Are you sure the artifacts are coming from the upscale filter and not the lossy video encoder? If it's the latter increase bitrate.
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  5. Try nnedi3 in AviSynth (there are some examples in the doom9 link Pandy gave). But if your source video is blurry upscaling it will give a blurry result. You need to sharpen before upscaling to get a sharp result. You may have to downscale to get a sharp image, then upscale from there. In the end you may get a large image with sharp edges and little aliasing -- but nobody will mistake it for real high definition video.
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  6. Member azmoth's Avatar
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    Super Simple Converter which is freeware will do it very well or use Wonderfox HD Converter which has a lossless mode apparently keeping 99.5% of source quality when upscaling. The souce must be of a high quality it is stated to utilize the unique pixel algorithm.

    There's a freeware version and a pro version of Wonderfox. Easy to get a demo/giveway key to unlock the pro features of more formats, but the freeware should be enough. Upscaling is a waste of time, but let your own eyes be the judge.
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  7. Originally Posted by azmoth View Post
    Super Simple Converter which is freeware will do it very well or use Wonderfox HD Converter which has a lossless mode apparently keeping 99.5% of source quality when upscaling. The souce must be of a high quality it is stated to utilize the unique pixel algorithm.

    There's a freeware version and a pro version of Wonderfox. Easy to get a demo/giveway key to unlock the pro features of more formats, but the freeware should be enough. Upscaling is a waste of time, but let your own eyes be the judge.
    Wonderfox HD Converter did a great job with this, even limiting the bandwidth. Going from 480P to 720P I limited to 1500 kbps and the result had all of the artifacts that I saw from my other converter removed. That file was about 7 MB. I tried the vbr highest quality mode and that resulted in a ridiculous high bandwidth and a 200 MB file, and the result was not better.

    I don't suppose this application can do anything to fix a bad upconversion after the fact?
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  8. Member azmoth's Avatar
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    Re.Wonderfox: I don't think that will fix it nor repair as you are reliant upon codec settings as well as the converter. After the fact-already encoded files- you must post process but if they are dud, then some data must be damaged/missing and that would be very difficult to repair, if at all? Below might work.

    https://www.yodot.com/mov-repair/how-to-fix-bad-mp4-files.html
    Last edited by azmoth; 14th Jun 2019 at 09:10.
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