H.264 4k export is so blocky, it might as well be minecraft

[exclusivemoose]

Guess which one is a screenshot from the program monitor, and guess which is the screenshot from the export?  I couldn't believe my eyes when I watched this back.  I almost uploaded this as the final because I have not had this issue... Original footage from the Sony A7siii, 4k 60p 10bit 422.  Export is scaled down to 1440p resolution, h.264.

I have not noticed THIS insane quality reduction ever, even when exporting using these same settings.  I tried exporting in ProRes, and there is almost no quality loss.  Yes, I know ProRes is more ideal, but when delivering these files to clients, uploading a 5gb final vs a 700mb final makes a big difference.

What can be done?  Maybe switch to final cut since every week there is a new issue I encounter while exporting with my new macbook pro?

[Mike Dziennik]

What preset are you using. Looks like the data-rate isn't high enough. Have you tried 2-pass VBR?

[R Neil Haugen · Accepted solution]

You have a clip there all perfectly designed to mash up the image into blocks, with the type of compression that H.264/5 uses. A bit of understanding of the process is a very good thing. Once you understand how it works, you can tailor your compression settings for the clips you're working with.

H.264/5 achieves incredible file reduction by throwing out 'excess' data. Such things as a block of 4 pixels for a rough example. With numbers of 34/46/22, 35/45/22, 34/47/21, and 33/48/23.

The H.264 compression will look at those and simply say ... naw, we only need to store one data set, we'll go with 34/46/22. For all four pixels. They're now simply a block of one color, no detail, no shading. And blocks can be larger, 9 pixels or so.

Look at that image, all the near-identical color wash over it? Yea, it's gonna mash a ton of those pixels down to a very few values. So the bitrate, especially with any motion from actually dancing, is going to have to go WAY up to keep an H.264 encode from giving you moving blocks.

So that's why you would need to kick the Mbps way, way up on this. You didn't give your Mbps figure, and that's a crucial part here. Now, if size of final file is really an issue, then the colorists I work with ... most of whom work in Resolve of course ... always export a ProRes from Pr or Resolve, then go into ShutterEncoder, HandBrake, or ffmpeg, and take the ProRes to a smaller file in H.264 that way.

Those apps have better, more granular settings for H.264/5 encodes. But they do take a bit of understanding how they work to really use well.

Neil

[exclusivemoose]

Hi Neil, thanks.  It was exported at 25mbps.  It could just be the scene here like you said..  Another file size issue is that I upload the finals to instagram, which won't allow more than a 1GB file... this 4 minute video when exported to prores 422 LT comes in at around 5gb.  I will give handbrake a shot.

[exclusivemoose]

Using handbrake on the 5gb Prores copy, made a huge difference.  Now I'm wondering why this isn't a feature within Premiere.  Surely there must be a way to render h.264 within this software to prevent this the first time around?  Seems silly to export twice just to get a usable image...

[R Neil Haugen]

NLEs and pro-level grading apps are designed for more heavy-lifting things, I guess. They are built for subtlety in their exports it seems.

Because it doesn't make any difference whether it's Premiere, Resolve, Avid, or Baselight, you'll get the best quality especially with files like this from a ProRes/Cineform/DNx export out of your app of choice, with H.264/5 made by HandBrake, ShutterEncoder, or ffmpeg.

So Premiere's got company there.

Neil

[basil1891]

Premiere  build-in h.264 encoder engine is quite mediocre. Standalone Handbrake tool uses much more optimized and flexible x264 library. Some 3rd party Premiere plug-ins have it too: Voukoder (donation-ware) and TMPEnc x264 (paid). Probably there are more, but I just unaware of it. 

One other thing you can try is to use a bit higher bitrate + CBR mode instead of using VBR.

[Andy 1968]

25 mbps is kind of low for 4K at 60P. 

[exclusivemoose]

Thanks but the issue is the H.264 encoder not being able to handle the clips.  Using a ProRes export, and then handbrake to export to an H.264 at the same 25mbps, resulted in a night and day difference.  I can't go much further above 25mbps because of file size limitations.. all of this stated above..

[Andy 1968]

I just noticed you scaled the 4K down to 1440. At 1440 resolution 25 mbps is not bad.