Editing with h.264 lossless? Someone tried it?

[Bauzi]

Hey there,

I read the guide about the new version of zarxGUI and it mentions a lossless mode for h.264 which turns it in theory into an editing codec like Lagarith or HuffYUV. Sadly I don't have the time to test this function so I would like to ask you:

Did somebody of you tried it before? What are the (dis)advantages of editing with h.264 lossless?

[mirkosp]

Here's the thing: premiere can take mp4 directly, but even if it's with a 1.0 par, it fucks the resolution. So in my experience, you save the lossless x264 and then load it through avisynth. It's still all keyframes so it will be fast (if you have a pc fast enough, otherwise the editing speed compared with huffyuv and lagarith might be noticeable), but you'll have to go through the avisynth step to make sure the AR will be correct. Aside from that, I'd say go for it.

One thing though: lossless x264 is only when the crf (or qp) is set to 0. The option in the zarxgui just makes all frames key-frames, so my suggestion is lowering the constant quality value to 10 or less, to make sure that the quality loss due to the compression won't be there.

[Bauzi]

I think I'll try it.

I use this script:

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"C:\Program Files (x86)\Zarx264gui\x264.exe" [b]--crf 0[/b] --ref 12 --mixed-refs --b-adapt 2 --bframes 5 --b-pyramid --weightb --direct auto --subme 9 --trellis 1 --8x8dct --me umh --progress --aq-strength 1 --psy-rd 0:0 --threads auto --fps 25/1 --output "D:\Videos\Anime\Berserk\Berserk #01-temp.264" "D:\Videos\Anime\Berserk\Berserk #01.avs"
"C:\Program Files (x86)\Zarx264gui\MP4Box.exe" -fps 25 -add "D:\Videos\Anime\Berserk\Berserk #01-temp.264" -new "D:\Videos\Anime\Berserk\Berserk #01.mp4"

So this should result in a lossless edit-friendly file?

[Kionon]

I've done it on mac. I don't notice any difference, so I stick with HUFFYUV.

[Bauzi]

I've done it on mac. I don't notice any difference, so I stick with HUFFYUV.

eh... and why do you exactly stick with HUFFYUV? I mean h.264 has lower filesizes, right?
I know that compatibility can be a good reason, though.

[mirkosp]

I did some more experiments. Crf or qp 0 will results in less than a gigabyte saved compared to the lagarith YV12. HOWEVER! crf 10 with keyint 1 will result in a fifth of the filesize of the YV12 lagarith without any quality loss. I actually didn't check the SSIM of the output but it does look like a perfect copy of the original to me.

So I guess that --crf 10 --keyint 1 is what you need to get an effective gain. However it will *technically* not be lossless anymore, albeit I'd say the difference is really unnoticeable, if existing.

[Bauzi]

So I guess I will stick with 1 or 5 for now.... but I guess I will stay with 1, because there might be a lot of post-processing for my current project.

[Qyot27]

I think I'll try it.

I use this script:

Code: Select all

"C:\Program Files (x86)\Zarx264gui\x264.exe" [b]--crf 0[/b] --ref 12 --mixed-refs --b-adapt 2 --bframes 5 --b-pyramid --weightb --direct auto --subme 9 --trellis 1 --8x8dct --me umh --progress --aq-strength 1 --psy-rd 0:0 --threads auto --fps 25/1 --output "D:\Videos\Anime\Berserk\Berserk #01-temp.264" "D:\Videos\Anime\Berserk\Berserk #01.avs"
"C:\Program Files (x86)\Zarx264gui\MP4Box.exe" -fps 25 -add "D:\Videos\Anime\Berserk\Berserk #01-temp.264" -new "D:\Videos\Anime\Berserk\Berserk #01.mp4"

So this should result in a lossless edit-friendly file?

No it won't - B-frames (especially B-pyramid), and maybe even reference frames (surely mixed-refs would) will mess with accuracy. And I don't think it matters what container it's in, and whether the container properly handles those features - those options are for distribution, and should remain for distribution copies, even if NLEs have improved support for such streams nowadays.

To me, speed (as in, during editing - not the conversion process) matters over size. And as far as that goes, you'll probably be hard pressed to find something faster than HuffYUV or ffvhuff or Lagarith (it depends on multithreading). Or FFV1, if you prefer to avoid some of Lagarith's rendering problems.


You might want to update x264, though - some of those options are no longer even used.