HitFilm export issue - blur & gamma/color change?

edited November 2018 in HitFilm Express Support

I'm wondering what is going on in HitFilm Express when exporting a PNG.

Here is what I have done:

- I import a single PNG image 'original.png' into HF

- I add that image into a composite shot and export it as 'comp.png' (no effects added)

- I add the composite shot into an editor timeline and export it as 'editor.png' (no effects added)

I compare the original PNG image with exported ones and the exported ones look different (seems like gamma and colors are a bit different). There also seems to be a small amount of blur applied to the exported images and I have not added any effect in HF. To verify that the images are really different, I do a difference blend and it shows the differences indeed are there. 

Even HF's own two exported images are different - 'comp.png' is different to 'editor.png' meaning that HF is doing something different even when exporting from the comp shot comparing to when exporting the same comp shot from the editor tab.

I think I have noticed this issue not only when exporting to PNG, but also to some other formats, but now I decided to really test it for the PNG format.

This bothers me because it prevents me from using HF on some parts of the project I'm working on and I'd really like to use HF. I cannot have my original PNG images be blurred and their gamma/color changed when they are imported into and then exported from the HF...

Does anyone know what is happening here and how to circumvent the issue?

Comments

  • edited November 2018

    I just tested and the very same issue is occurring when exporting to BMP, another lossless format.

    As I mentioned earlier, I remember experiencing the same problem in HF with some other lossless or intermediate formats. As it stands now, I'm inclined to think the issue is not even related to some specific export format itself, but to HF internal rendering pipeline or something like that.

    How is it possible that an imported image is altered when exporting (blurred with gamma/color change) if one does NOT do any modifications?

  • Don't know about the gamma change but if you cranked up the anti-alias setting to 16/32x then that can/will add softness.

  • Triem23Triem23 Moderator
    edited November 2018

    Even leaving anti-aliasing at 4x can goof the edges a bit. Hitfilm always anti-aliases on final renders. I believe (but devs have never confirmed, but also not denied) every photo/video track/layer is actually a textured OPENGL polygon... 

    Even leaving anti-aliasing at 4x can goof the edges a bit. Hitfilm always anti-aliases on final renders. I believe (but devs have never confirmed, but also not denied) every photo/video track/layer is actually a textured OPENGL polygon...

    Hitfilm always exports 0-255 levels. Some software aims for 16-235 (notably Vegas Pro). Tell your other software to interpret to Computer levels, not broadcast. 

  • edited November 2018

    Thank you both for your responses and the insights provided.

    I tried AA with the 4x setting and the image is exported with the same blur as with the 32x setting. Actually, the 4x export is pixel identical to the 32x one, probably because I have not used any effects so it is just the original image being rendered out. I assume that if I used some effects, I would see a difference between the 4x and 32x exports.

    The export straight from the comp shot ('comp.png') is less blurred than the editor export ('editor.png'), which indicates that HF renders the comp shot first (and blurs it) and then renders the comp shot again within the editor timeline (2nd blur), without realizing that the whole operation is just a null transform. This also leads to the conclusion that the more nested comp shots one has, the more the image quality is degraded. 

    It is a shame if HF really works that way and it cannot be 'fixed'. I think this is a deal breaker for any professional use. As I'm aware, no professional compositing software (Nuke, Fusion) would ever do such a thing. On the contrary, the transforms there are concatenated as much as possible to not degrade the image quality if not absolutely necessary.

    Seems there is no gamma shift for PNG format though, my test images just appear a bit brighter/darker when looked one after the other because of the blur, I guess. Checking it with the difference blend I think the only issue is the blurring, but it is one hell of an issue, if you ask me.

     Regarding the gamma shift, I do remember having this issue before when rendering in HF in some other formats (Cineform codec maybe) and it was not fixed by having my software interpret HF render in full/data and video levels...

  • Are you on Windows or Mac? I'm on the latter, and haven't seen the kind of blurring you mention of any content I throw into HitFilm (I'm guessing you're talking about blurring the main content, not the edges with antialiasing), nor have I seen any gamma differences. If this were a flaw in the software, I'd think more users would be in an uproar about this, but this is the first time I've heard of this issue, so something tells me the problem lies elsewhere.

  • I'm on Windows and I have not seen any blurring. Beyond an excessive AA setting as previously mentioned.

    About the "gamma shift", I had wondered if that could have been a reference to a levels issue. Hitfilm can be a little peculiar here (last checked a while ago with various codecs in constructed test).

    Proclamations have been made and they are off base as to how things actually work. e.g. The global GL AA setting. What is does and does not do. 

     

  • edited November 2018

    I'm on Windows. I have done the tests several times more in the last couple of days with the 32x and 4x AA. The blurring was present with the 32x setting, but not present with the 4xAA setting, which was surprising because I have done several tests in the first day when I reported this and 4x always had the same blur as 32x.

     

    The only difference with my system is that before doing the tests in the second day I upgraded my Nvidia drivers to the latest version, but I do not think that should really affect how the 4x AA is rendered in HF (my drivers were not old and I had no Nvidia profile for HF anyway and the new driver was installed with preserved settings and profiles).

     

    Now I'm puzzled why 4xAA is rendering without the blur, but at least that solves the issue for me...

  • I posted a reply that I edited a few times and then it disappeared with a notification saying that it needs to be approved. I guess editing it quickly got it flagged as a bot or something. The comment is still not visible after several days though...

  • @Marach when did this occur? I believe the web guys have the automatic spam filters cranked up pretty high, so it might have been flagged accidentally. Mods don't get any notice on that (we're just users who can delete or move comments), so I'll tag @rikkiloades 

    It's the weekend  so it's possible Staff won't re-approve the comment until Monday. If you remember what you wrote, consider a retype.

  • @Triem23

    It was like 3 days ago I believe. I'll give it a little more time and if the comment does not appear, then I'll retype as you suggested. It was not a lot of text anyway.

  • I'm on Windows. I have done the tests several times more in the last couple of days with the 32x and 4x AA. The blurring was present with the 32x setting, but not present with the 4xAA setting, which was surprising because I have done several tests in the first day when I reported this and 4x always had the same blur as 32x.

     

    The only difference with my system is that before doing the tests in the second day I upgraded my Nvidia drivers to the latest version, but I do not think that should really affect how the 4x AA is rendered in HF (my drivers were not old and I had no Nvidia profile for HF anyway and the new driver was installed with preserved settings and profiles).

     

    Now I'm puzzled why 4xAA is rendering without the blur, but at least that solves the issue for me...

  • @Marach Looks like your post was approved...multiple times. Tagging @Triem23 to see about nixing the duplicates.

Sign In or Register to comment.