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exclusivemoose
exclusivemoose
Known Participant
February 5, 2022
Resuelto

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

  • February 5, 2022
  • 2 respuestas
  • 2185 visualizaciones

 

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?

Este tema ha sido cerrado para respuestas.
Mejor respuesta de R Neil Haugen

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

2 respuestas

R Neil Haugen
R Neil HaugenRespuesta
Legend
February 5, 2022

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

Everyone's mileage always varies ...
    exclusivemoose
    exclusivemooseAutor
    Known Participant
    February 5, 2022

    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
    exclusivemooseAutor
    Known Participant
    February 7, 2022

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


    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..

    Mike Dziennik
    Community Expert
    Mike DziennikCommunity Expert
    Community Expert
    February 5, 2022

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

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