Very good results : Compress H.264 to H.265 via ffmpeg, vmaf score 99.836

[Gloster]

Currently used Kubuntu 24.04. Wayland, ffmpeg 8.0

Did compress the video :

Video: h264, yuv420p(tv, bt709, progressive), 1280x720 [SAR 1:1 DAR 16:9], 11343 kb/s, 50 fps, 50 tbr, 90k tbn

to :
Video: hevc, yuv420p(tv, bt709, progressive), 1280x720 [SAR 1:1 DAR 16:9], 5075 kb/s, 50 fps, 50 tbr, 16k tbn

h.264 video-file size= 9GB. h.265 video-file size 3.7GB

VMAF score: 99.836461

the respective ffmpeg command as a script :

#!/bin/sh

for f in *.ts; do ffmpeg -y -i "$f" -map 0:v -map 0:a -vcodec libx265 -crf 16 -preset slow -vf nlmeans="1.6:7:5:3:3",unsharp="3:3:1.0" -c:a copy "$(basename "$f" .ts).mkv";done

A short description :
crf 16 = quality, less value higher quality
nlmeans = filter to reduce grain
unsharp = increase sharpness

Without the filter unsharp. I got a file size of 2.4GB (same video) and a vmaf score 95.6 .

For your information vmaf score of 100. no difference can be seen. 95.6, a good value.

Never reached this high vmaf score without "unsharp". I did decrease crf until I got a compressed file size < 1/2 source file, but the vmaf score max was 96-97.

Also I did compress with "unsharp" other videos with very equal results (vmaf score > 99.9)

I have a restriction : If I can not reduce the file size with crf 16, unsharp as given above to 1/2 of the source file-size. I decide for no compression.

Only to share my results.

Others who would like to share their results ?

[dannyboy48888]

Ah yes the fun metrics rabbit hole. Take them as a guide not concrete. I've gotten hight scores before but the background gradients etc were gone. And I've had home with a lower score (92) look fine visually as the gradients got preserved, just not exactly like the original.

[Gloster]

@dannyboy48888, yes and no. I got bad vmaf scores e.g. 55 but acceptable results checked by vivictpp or via TV.

But this case I can confirm e.g. by vivictpp, I did not see any differences in the pictures, frame by frame.
And it does not depend on the background/foreground.

And also as given by my example, I could see differences with vivictpp and the vmaf score 95, but not with a vmaf score of 99.

[Gloster]

But we have the possibility to check the "subjective" results with a respective upload :

https://we.tl/t-R2sLFzDOX9ypuf2c

The link will be for 3 days available.

From my side of view, the given webpage should be checked before to download my files.

[Gloster]

An additional hint : vmaf developed by Netflix engineers + some US-Universities + ffmpeg community to get a metric for its own, the Netflix encoding results. And if a vmaf score of > 99 would be indicate not an on top result, the logic leads to : Neither Netflix engineers nor some US-Universities nor the ffmpeg community does not know what they speak about, I must confess, I can not believe it.

[rgr]

https://www.diffchecker.com/image-compare/prDVu1tq/

And you can see "cheap" sharpening.
https://imgur.com/onscei2

[Gloster]

@rgr. I must confess, I have no eyes for cheap sharpening, did you see the context of the picture ?
Better it would be, to send 2 pictures, the first you did send and the second, the cursor a bit to the right, then you can compare source/target, the context you have to accept all ways.
But every body can do it, it does not depend on you (vivictpp a tool for free, WIN +Linux).

But I must also confess, to indicate "sheap" sharpening, at a position where the light is totally different (left, right), has to explain its choice.

Obviously you are also the opposite of Netflix engineers + some US-Universities + ffmpeg community ?!

Are you also the opposite of tools for free ?

[Gloster]

And further results with vivictpp : https://we.tl/t-StWaSjJp3RkPmpYo
Two pictures left and right of totally different light.
But @rgr, if it is not the correct timestamp, give me the timestamp, I can give also for further investigations the respective pictures (refer to vivictpp : https://github.com/vivictorg/vivictpp).

[Bencuri]

Currently used Kubuntu 24.04. Wayland, ffmpeg 8.0

Did compress the video :

Video: h264, yuv420p(tv, bt709, progressive), 1280x720 [SAR 1:1 DAR 16:9], 11343 kb/s, 50 fps, 50 tbr, 90k tbn

to :
Video: hevc, yuv420p(tv, bt709, progressive), 1280x720 [SAR 1:1 DAR 16:9], 5075 kb/s, 50 fps, 50 tbr, 16k tbn

h.264 video-file size= 9GB. h.265 video-file size 3.7GB

VMAF score: 99.836461

the respective ffmpeg command as a script :

#!/bin/sh

for f in *.ts; do ffmpeg -y -i "$f" -map 0:v -map 0:a -vcodec libx265 -crf 16 -preset slow -vf nlmeans="1.6:7:5:3:3",unsharp="3:3:1.0" -c:a copy "$(basename "$f" .ts).mkv";done

A short description :
crf 16 = quality, less value higher quality
nlmeans = filter to reduce grain
unsharp = increase sharpness

Without the filter unsharp. I got a file size of 2.4GB (same video) and a vmaf score 95.6 .

For your information vmaf score of 100. no difference can be seen. 95.6, a good value.

Never reached this high vmaf score without "unsharp". I did decrease crf until I got a compressed file size < 1/2 source file, but the vmaf score max was 96-97.

Also I did compress with "unsharp" other videos with very equal results (vmaf score > 99.9)

I have a restriction : If I can not reduce the file size with crf 16, unsharp as given above to 1/2 of the source file-size. I decide for no compression.

Only to share my results.

Others who would like to share their results ?

Can I use ffmpeg 8.0 on Windows 7 running your script?

[cholla]

I usually do not use scripts.
I used the code necessary for the command line in ffmpeg.

ffmpeg -y -i "input.mp4" -map 0:v -map 0:a -vcodec libx265 -crf 16 -preset slow -vf nlmeans="1.6:7:5:3:3",unsharp="3:3:1.0" -c:a copy "output.mkv"

I'm using:
ffmpeg version 8.1.2-WIN7 Copyright (c) 2000-2026 the FFmpeg developers built with gcc 16.1.0 (Rev5, Built by MSYS2 project)
It is one of the ffmpeg that was posted in this thread:
https://forum.videohelp.com/threads/414767-ffmpeg-7-0-1-and-Windows-7/page6
The current version being posted is a version 9.
A version 7 may still be posted but I'm not sure.
autodidact the member creating the versions for Windows 7 is real cooperative & may be able to post a ffmpeg version you want.

I have the 7zip for the version 8.1 still but it is for Windows 7 32-bit.

[Gloster]

given by @cholla :

ffmpeg -y -i "input.mp4" -map 0:v -map 0:a -vcodec libx265 -crf 16 -preset slow -vf nlmeans="1.6:7:5:3:3",unsharp="3:3:1.0" -c:a copy "output.mkv"

additional hints :

The map parameter can be deleted, if only one audio stream will be present :

ffmpeg -y -i "input.mp4" -vcodec libx265 -crf 16 -preset slow -vf nlmeans="1.6:7:5:3:3",unsharp="3:3:1.0" -c:a copy "output.mkv"

the value of nlmeans="1.6:7:5:3:3"
"1.6", first entry can be increased, it depends on the video resolution :

"1.0 to 1.8 for 720p video and 1.0 to 4.0 for 1080p". I does not find the respective link, from where the values I have.

With crf increased up to "crf 19", I also get vmaf values > 99 (sometimes >98), file size decreased to 1/3 - 1/2.

But I must confess, the sources are all ways fps=50.

[Bencuri]

I usually do not use scripts.
I used the code necessary for the command line in ffmpeg.

ffmpeg -y -i "input.mp4" -map 0:v -map 0:a -vcodec libx265 -crf 16 -preset slow -vf nlmeans="1.6:7:5:3:3",unsharp="3:3:1.0" -c:a copy "output.mkv"

I'm using:
ffmpeg version 8.1.2-WIN7 Copyright (c) 2000-2026 the FFmpeg developers built with gcc 16.1.0 (Rev5, Built by MSYS2 project)
It is one of the ffmpeg that was posted in this thread:
https://forum.videohelp.com/threads/414767-ffmpeg-7-0-1-and-Windows-7/page6
The current version being posted is a version 9.
A version 7 may still be posted but I'm not sure.
autodidact the member creating the versions for Windows 7 is real cooperative & may be able to post a ffmpeg version you want.

I have the 7zip for the version 8.1 still but it is for Windows 7 32-bit.

The code that you provided, it works like that with version 9 a well? No need for mods to the code?

[hello_hello]

Is the VMAF score that reliable?
I just gave it a test run on two identical videos (I made a copy of a video and used it for the comparison) and the VMAF score was only around 98.24. It was animation, and 10 bit HEVC (1080p) if that makes a difference, but I fully expected the score to be 100.

I used the following command line. Admittedly it was an older version of ffmpeg (version 7 something) because there was an error when I tried to build the latest version and I was too lazy to work out how to resolve it, so I downloaded a pre-built executable for linux, but I used the latest VMAF models.

/media/Drive1/Programs/VMAF/ffmpeg -i /media/Drive1/VideoA.mkv -an -sn -i /media/Drive1/VideoB.mkv -an -sn -lavfi libvmaf=log_path=/media/Drive1/Programs/VMAF/logs/output.xml:log_fmt=xml:n_threads=12 -f null -

[Gloster]

@hello_hello, obviously you have detect an vmaf error of -1.76. I can agree it for 8Bit : -1.31, one test.

I can live with this error.

Obviously there are a lot of numerical algorithms implemented, what else.