Give video files a quality grade based on various mediainfos?
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AbedlaPaille
- Posts: 107
- Joined: 12 Apr 2020, 04:02
Give video files a quality grade based on various mediainfos?
Anyone with ideas about this? Lots of values could be taken into account, mbps, vf, vc, ac, af.. Question is how to weight them to have a rather realistic grade.
Re: Give video files a quality grade based on various mediainfos?
You could start by setting minimum settings, anything MKV is better than other formats, anything x264/x265 is better than other stuff.
If audio is 5.1 or above AC3 or DTS as preferred formats for 1080p, AC3 640 for 720p, AC3 448 for standard def.
If audio has fewer channels, FLAC or AAC are acceptable.
If x264 you should check DXVA compatibility, stuff like me, merange, subme settings from x264 should meet some minimum threshold.
You may also want to compare color matrices and color spaces used for HDR, or bit depth, in these cases there's a fairly clear order.
After that you'd probably want to consider other, non numerical comparison methods.
Unfortunately no number or codec will be able to tell you how good a video looks.
Higher resolution may not directly correlate with higher picture quality if bitrate is too low, similar reasoning can be applied to bitrate, which could be the result of wrong encoding parameters and result in a bloated file with no improvement in picture quality. Viceversa there are amazing encodes at fairly low bitrate, maybe the movie has a lot of still shots for example.
Visual comparison (literally comparing screenshots) is unfortunately your best hope (it's still one of the tools used to this day in drug manufacturing to check for impurities in the final product).
You should probably aim for scenes with high contrast, motion sequences, wide static shots and stuff like that.
If you wanted to attempt an automated visual comparison >> https://github.com/Netflix/vmaf could come in handy, but it's not a simple tool to use.
If audio is 5.1 or above AC3 or DTS as preferred formats for 1080p, AC3 640 for 720p, AC3 448 for standard def.
If audio has fewer channels, FLAC or AAC are acceptable.
If x264 you should check DXVA compatibility, stuff like me, merange, subme settings from x264 should meet some minimum threshold.
You may also want to compare color matrices and color spaces used for HDR, or bit depth, in these cases there's a fairly clear order.
After that you'd probably want to consider other, non numerical comparison methods.
Unfortunately no number or codec will be able to tell you how good a video looks.
Higher resolution may not directly correlate with higher picture quality if bitrate is too low, similar reasoning can be applied to bitrate, which could be the result of wrong encoding parameters and result in a bloated file with no improvement in picture quality. Viceversa there are amazing encodes at fairly low bitrate, maybe the movie has a lot of still shots for example.
Visual comparison (literally comparing screenshots) is unfortunately your best hope (it's still one of the tools used to this day in drug manufacturing to check for impurities in the final product).
You should probably aim for scenes with high contrast, motion sequences, wide static shots and stuff like that.
If you wanted to attempt an automated visual comparison >> https://github.com/Netflix/vmaf could come in handy, but it's not a simple tool to use.
I only work in black and sometimes very, very dark grey. (Batman)
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AbedlaPaille
- Posts: 107
- Joined: 12 Apr 2020, 04:02
Re: Give video files a quality grade based on various mediainfos?
Excellent pointers, thank you very much.