4K HDR conversion

[Drillakilla]

Hi all,

Been a long time, about 15 years since I used any of the tools like Megui, Avisnth

I am looking to shrink a 40gb video file to maybe a 30gb one, whilst retaining the HDR tags in place.

My original file is an untouched H265 HEVC video file.

I managed to do a conversion on Megui (ffmpeg), but no HDR tags

Are there any guides on how to convert using Megui and keep the HDR in place?

[ProWo]

You can try clever FFmpeg-GUI.
Load your 4k HDR video, click main, click encode video stream, click keep size, set x265 as encoder, set crf 20, click various, check HDR/HLG, in the next screen check Keep HDR/HLG, click ok, click to batch.


[Attachment 76369 - Click to enlarge]

Click Batch tasks and click execute.
Since 4k HDR 10bit encoding is slow, the batch way is better because the computer does not switch to standby mode until the end of processing, so complete processing is guaranteed.

After the batch task is finished, click multiplex, the newly generated HDR video stream is displayed in orange.
Check all streams on the left except the original video stream (the blue one) and click multiplex.


[Attachment 76370 - Click to enlarge]

Done.

[Drillakilla]

Thanks for this mate.

I've never used crf for encoding. Am I correct in understanding 0 will be lossless, and should be about the same file size?

Are there 2 pass options within this app, using bitrate?

[ProWo]

Crf 0 is lossless, but will increase the filesize.
CRF 20 with hevc is visually lossless and will decrease the filesize.
crf encoding is the best, no need for 2 pass.
2 pass encoding is not present in the app.

[Drillakilla]

Thanks mate. Really helpful. last question, I'm converting action movies,, do you think crf 20 still works?

[usually_quiet]

Hi all,

Been a long time, about 15 years since I used any of the tools like Megui, Avisnth

I am looking to shrink a 40gb video file to maybe a 30gb one, whilst retaining the HDR tags in place.

My original file is an untouched H265 HEVC video file.

I managed to do a conversion on Megui (ffmpeg), but no HDR tags

Are there any guides on how to convert using Megui and keep the HDR in place?

Even if Megui is capable of HEVC encoding, I haven't seen any indication that Megui has been updated to preserve HDR metadata. However, I did find comments going back a few years indicating that you are not the only one who wants that feature to be added.

Before I came back to this thread and saw ProWo's post, I tried clever FFmpeg-GUI with a UHD video that has HDR10 and was able to produce a significantly smaller file while preserving HDR. Unfortunately, I don't have any action movies samples to try.

[ProWo]

Thanks mate. Really helpful. last question, I'm converting action movies,, do you think crf 20 still works?

You can go down to CRF 16.

[Drillakilla]

Thanks mate

[Drillakilla]

Processing my first full encode, it's taking about 12 hours. Need to upgrade my hardware.

Just wanted to get your thought on this other app I stumbled across, Staxrip, how does it compare to Clever FFMPEG?

[davexnet]

Processing my first full encode, it's taking about 12 hours. Need to upgrade my hardware.

Just wanted to get your thought on this other app I stumbled across, Staxrip, how does it compare to Clever FFMPEG?

They all use x264 for encoding under the covers.
It comes down to features and options in the interface and personal preference.

You can choose a preset for x265/264, fast, medium, slow, etc.
For x265, "fast" is supposed to be the sweet spot

[ProWo]

Processing my first full encode, it's taking about 12 hours. Need to upgrade my hardware.

To speed things up you can use x264 (avc) with CRF 12 instead of x265, limit the resolution to 1920 width and encode with 8 bit instead of 10 bit.

[Drillakilla]

Thanks mate. I don't mind the speed so much, trying to retain the picture quality as I use a projector.

The final output size is 16gb down from 40gb, and this is 16 CRF. I'm actually shocked at how good the picture is, I can't actually tell the difference.

[ProWo]

Thanks mate. I don't mind the speed so much, trying to retain the picture quality as I use a projector.

The final output size is 16gb down from 40gb, and this is 16 CRF. I'm actually shocked at how good the picture is, I can't actually tell the difference.

As i said, visually lossless.

[Drillakilla]

Doing some great encodes now.

Is there any way to estimate the output file size, I've encoded two movies with vastly different file sizes, both action movies, both about two hours, using CRF 14.
One came out 16gb, the other came out 10gb.

If I could estimate the size I would dial up/down the CRF number?

[davexnet]

Doing some great encodes now.

Is there any way to estimate the output file size, I've encoded two movies with vastly different file sizes, both action movies, both about two hours, using CRF 14.
One came out 16gb, the other came out 10gb.

If I could estimate the size I would dial up/down the CRF number?

If you need a specific size use 2-pass VBR.
CRF gives a specific quality, size is indeterminate, depends on the complexity of the source
(movement/still, sharp/soft, noise/clean, grain/flat, etc,etc)