Squares showing after export

ianganderton
ianganderton Posts: 6 Just Starting Out

I'm trying to work out if I'm doing something wrong or its just the way it is

When I'm exporting the video and then playing it back through VLC I'm seeing the big square pixels shown in the picture below

The video was shot on a GoPro hero 8 and has .png gauges overlaid as discussed in this thread earlier.

I'm exporting using the YouTube 1080p HD preset

I'm working on the assumption the video should be as good as it can be before setting YouTube's compression demons on it

Thanks in advance for any help/tips/tricks

Ian

Best Answers

  • Triem23
    Triem23 Posts: 20,517 Ambassador
    edited February 2021 Answer ✓

    Ok, so JPEG and MPEG compression both compress in "macroblocks." These are 8x8 or 16x16 groups of pixels. These compression schemes also tend to "combine" low-contrast areas. The blocks you're seeing are where the low contrast areas of cloud are being crunched. You're seeing macroblock "compression artifacts."

    The "default" YouTube 1080p preset is set up for up to 30fps video (that info is in the description line for the preset). Your video is 60 fps.

    Basically, the bit rate of the 1080p preset is too low.

    Two options: First, try using the YouTube 4k preset. Oh, it should still create a 1080p output, but the bitrate will be much higher, so it should smooth out the artifacts. If that doesn't work...

    I recommend right clicking the preset and selecting "Duplicate." Then right click the duplicate and select "Edit." When the profile options open up change the Target Bitrate and Max Bitrate. (Max Bitrate is usually supposed to be 1.5 to 2x the Target. There has been a bit of debate about FXHOME's choice to make them the same.) Change Target to something like 50/60mbps and Max to 75/90mbps. Save your preset.

    Note raising bitrate obviously increases file size. The YouTube 1080p preset is about 16mbps, so raising to 60 Target, 90 Max will create files more than 4 times larger, but, with MP4 compression, the smaller you cram the file, the more compression artifacts you introduce. As you said, you want the highest quality file possible before YouTube mangles it. For reference 100mbps is a common bitrate for cameras recording 4k 60p (GoPro/Drone), so a 60mbps Target, 90mbps Max bitrate export of 1080p 60p is quite healthy.

    Another possibility is exporting ProRes (MAC) or Cineform (Windows). These codecs render very large files, but much higher quality. You could then use an external program like Handbrake to transcode to mp4 for YouTube upload.

    Now, there are several different mp4 encoders. Hitfilm Express uses the one built into your OS. Hitfilm Pro uses Mainconcept. Handbrake uses x264. The main thing here is Handbrake offers more fine control over mp4 settings than Hitfilm - and you can set things like the "fast load" flag in Handbrake you can't in Hitfilm (this isn't a huge deal... That's a flag Hitfilm writes at the end of a file Handbrake puts at the start. It's not a "quality" setting, but it lets YouTube start processing the file as it's uploading so YouTube finishes faster). Don't worry about the additional options for now, just know you can get a better encode exporting Cineform/ProRes and transcoding in Handbrake if you're willing to spend the extra time and steps. See what the Hitfilm 4k preset or your custom preset does first.

    Oh, while tweaking presets, don't render your whole video. Set in/out points around a problem area (the clouds you've shown) and do short 10-20 second renders until you have a quality you're happy with. THEN commit to a full render.

  • ianganderton
    ianganderton Posts: 6 Just Starting Out
    edited February 2021 Answer ✓

    I dont seem to be able to edit a duplicated preset. I can see it as an option when I right click on the new user preset but its grayed out. Is this something I need to pay for?

    Edit - just creating a new one seems the easiest option


Answers

  • ianganderton
    ianganderton Posts: 6 Just Starting Out

    Awesome answer, thank you!!!

    I'll try the UHD YouTube preset first and see if that gives me something good enough

  • Triem23
    Triem23 Posts: 20,517 Ambassador

    I wouldn't think editing Export presets is an add on option. Not on my PC to look.

    Yeah, making a new one works too. I just figure editing a duplicate should be easiest as one just needs to alter the bitrate without worrying about other settings. What you have looks good. You should have a much cleaner render now. 👍