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How to improve resolution?

I have a video that I've resized the canvas area to capture a certain part of the screen. It is 2529 x 1322. It looks very clear in SF. I export at 1264 x 661. The export is not as clear. It isn't bad but not at all crisp.

 

Is there something I can do to keep the 1264 x 661 size but get the original better resolution in the final product?

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    • CraigSModerator
    • Telestream Desktop Forum Moderator
    • CraigS
    • 3 yrs ago
    • Reported - view

    Those are very odd frame sizes. Also scaling will always have an impact on quality (except with vector graphics) and encoding always involves quality loss.
    With rare exception, codecs tend to work best in blocks which means dimension divisible by 16, 8 or 4 in that order. It's hard to make suggestions because I know of no delivery goal that would use the dimensions you're using. Typical is 16x9, 4x3 or 1x1 or some of the cinematic resolutions such as 1:85x1 or 2:35x1.

    Generally, avoid scaling and stick to the divisible dimensions.

    Even when scaling you want the math to be no more complex than divisible by units of 2.

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    • brett r
    • brett_r
    • 3 yrs ago
    • Reported - view

    Thanks!

    In my case where I'm using 2529 x 1322 and want an end size near 1264 x 661, should I instead use 2529/16 = 158.06...then 158 x 16 = 2528. For a 16x9 that means 2528 x 1314?

    If I understand what you are saying, when I scale down to a small video window, in this case 1264 x 657, I should have much clearer video because I followed the correct ratios?

    I did try the above. The exported 1264x657 video does not look any more crisp than the 1264x661 video. Do you know what is wrong?

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    • CraigSModerator
    • Telestream Desktop Forum Moderator
    • CraigS
    • 3 yrs ago
    • Reported - view

    brett r The problem is that the frame size is inevitably going to have issues because it's not evenly divisible by at least 4. And the scaling should be evenly divisible by 2. Fractional pixel and fractional blocks really don't work so there's going to be interpolation and, therefore, softening or artifacting.

    The best you can do is push the bitrate higher. Encoding to H.265, which is less dependent on standard macroblocks can help. None of this is ideal though.

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    • brett r
    • brett_r
    • 3 yrs ago
    • Reported - view

    Can you give an example of what you are talking about?

    Why do you believe 16 is not divisible by 4.

     

    The only way I've found to make this work is to export at full size, which is currently 2560x1440 and a standard ratio. If I go to to 720 or 1080, I can see the details are blurry. Shouldn't it be HD?

    If I take the 2560x1440 and just resize the viewing window to 720 or 1080, I get the size I want and of course the resolution is retained. Otherwise, nothing works.

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    • CraigSModerator
    • Telestream Desktop Forum Moderator
    • CraigS
    • 3 yrs ago
    • Reported - view

    brett r 16 is divisible by 4 of course. 

    Your odd number dimensions are not divisible by 4 and your scaling involves odd numbers not divisible by 2.

    The fundumental problem is that 2529x1322 is not a combination either scaling or codecs can work with optimally. 

    brett r said:
    2529/16 = 158.06

     That's a problem.

    brett r said:
    1264

     is not 1/2 of 2529 

    Anything other than whole numbers won't be handled well.

    brett r said:
    661

     This is not divisible by 4 so encoders won't handle this well (except maybe H.265 and that may not be a certainty)

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    • CraigSModerator
    • Telestream Desktop Forum Moderator
    • CraigS
    • 3 yrs ago
    • Reported - view
    brett r said:
    2560x1440

     This is 16x9 but the nature of scaling to 720 or 1080 will still involve some loss but just not as bad as with odd numbers.

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    • brett r
    • brett_r
    • 3 yrs ago
    • Reported - view

    720 or 1080 from 2560x1440 still look bad. Should I just resize the player window to 720 and leave the video at 2560x1440 to solve this issue?

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    • brett r
    • brett_r
    • 3 yrs ago
    • Reported - view

    I thought resizing my entire screen and recording at the same resolution would fix this but it didn't. Here's a sample recording at 1280x800, which is one of the mac screen defaults: https://www.dropbox.com/s/owydkwwpt2f20qj/test1280x800.mp4?dl=0.

    Here's the SF file: https://www.dropbox.com/s/sy34ahhdhcwkah3/test1280x800.screenflow.zip?dl=0.

    You can see that in the SF source file, text is very clear but in the MP4, it's blurry. What is the difference there?

    It exported at h.264 and 2500 kbits/sec.

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    • CraigSModerator
    • Telestream Desktop Forum Moderator
    • CraigS
    • 3 yrs ago
    • Reported - view

    brett r What monitor and how are you resizing? Resizing generally doesn't work with Retina displays.

    The best results is 1:1 from Screen Capture to Canvas to Output with no scaling.
    Any change in any resolution after capturing can cause loss.

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    • CraigSModerator
    • Telestream Desktop Forum Moderator
    • CraigS
    • 3 yrs ago
    • Reported - view

    brett r 

    Your canvas shows 2560x1600 so scaling to 1080 or 720 is still losing resolution.
    Your output looks OK when not in motion. The nature of motion is going to be an issue.

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    • brett r
    • brett_r
    • 3 yrs ago
    • Reported - view

    I tried a new test by resizing my screen to 1920 x 1080. I then recorded and tried exporting at 720 and 1080. It still isn't quite as good as what I see in SF. Do you know why?

    The only way I've found to get high resolution is to export at full size then resize the player window on the webpage. I don't know why that works but it does. Do you have some idea about that?

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    • CraigSModerator
    • Telestream Desktop Forum Moderator
    • CraigS
    • 3 yrs ago
    • Reported - view

    brett r If you're not scaling at all then the only variable is the data rate on export. Higher data rate is higher resolution. 

    brett r said:
    export at full size then resize the player window on the webpage.

     Because you're playing the higher resolution file even though the player window is smaller.

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    • brett r
    • brett_r
    • 3 yrs ago
    • Reported - view

    I tried one of the first files and exported at 50% using 6000 kbits/sec data rate. This is an increase over the 3000 rate I was using. I didn't notice any difference in quality. If you are saying a higher data rate will result in better quality, why didn't anything change?

    It's seems the best option is to export at full size (no scaling down) and just resize the player window so you don't have a huge video window right?

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    • CraigSModerator
    • Telestream Desktop Forum Moderator
    • CraigS
    • 3 yrs ago
    • Reported - view
    brett r said:
    didn't notice any difference in quality. If you are saying a higher data rate will result in better quality, why didn't anything change?

     There are diminishing returns as you near the best possible resolution. Encoding always involves some resolution lost short of a good all I frame encoder like Apple ProRes.

     

    brett r said:
    It's seems the best option is to export at full size (no scaling down) and just resize the player window so you don't have a huge video window right?

     If that works best. Some viewers may have bandwidth limits which would mean lower data rate files might work better for them (but would be lower quality). This is why players in YouTube offer mutliple resolution.

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    • brett r
    • brett_r
    • 3 yrs ago
    • Reported - view

    Apple ProRes is only available as a .mov right? Think I'll stick with mp4 since it is more compatible and portable.

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    • CraigSModerator
    • Telestream Desktop Forum Moderator
    • CraigS
    • 3 yrs ago
    • Reported - view

    brett r ProRes is really meant as a post-production codec rather than delivery.

    YouTube recommends at least mp4 at 8mbps for a 1080 file as a source to encode to smaller sizes. 

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    • brett r
    • brett_r
    • 3 yrs ago
    • Reported - view

    Does that mean instead of the default 3000, I need to be at 8000?

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    • CraigSModerator
    • Telestream Desktop Forum Moderator
    • CraigS
    • 3 yrs ago
    • Reported - view

    brett r If you're going to YouTube or a service that re-encodes the video. That bitrate is also good for very high-quality desktop playback.

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    • brett r
    • brett_r
    • 3 yrs ago
    • Reported - view

    Which bitrate are you referring to?

    If I'm not going to use Youtube, then I should stick with 3000 bitrate and lower quality videos? That doesn't make any sense. If 8000 is the bitrate needed to retain quality on lower resolution videos (1080, 720), then why not stay at a higher bitrate and keep the quality?

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    • CraigSModerator
    • Telestream Desktop Forum Moderator
    • CraigS
    • 3 yrs ago
    • Reported - view

    brett r Basically you should push the bitrate as high as you need for best quality given your frame size and viewers' internet connections. Improvements may be incremental and improvement diminishes as you push the data rate up but you may want to go above 3000 to 5000 or so. If 8000 looks even better then do go that high.

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