Recording with lossless setting of AV1 encoder deteriorates

[Deleted member 485476]

When comparing images recorded with the AV1 encoder's lossless setting and CQ level 10, the image with the lossless setting appears to be degraded.

The images are not of exactly the same conditions.
The top is lossless and the bottom is CQ.

Configuring Lossless Settings

• Resolution: 2560x1440
• Frame rate: 60
• Recording Format: Hybrid MP4
• Video Encoder: NVIDIA NVENC AV1
• Audio Encoder: FFmpeg FLAC
• Rescale: OFF
• Rate Control: Lossless
• Keyframe Interval: Auto
• Multipass Mode: 2 Pass(Full resolution)
• Profile: main
• Look-ahead: OFF
• Psychovisual Tuning: ON
• B-frame: 0

Configuring CQ level 10 Settings

• Resolution: 2560x1440
• Frame rate: 60
• Recording Format: Hybrid MP4
• Video Encoder: NVIDIA NVENC AV1
• Audio Encoder: FFmpeg FLAC
• Rescale: OFF
• Rate Control: CQP
• CQ level: 10
• Keyframe Interval: Auto
• Preset: P7: Slowest
• Tuning: High Quality
• Multipass Mode: 2 Pass(Full resolution)
• Profile: main
• Look-ahead: OFF
• Psychovisual Tuning: ON
• B-frame: 0

If you know anything about this please let me know.

Here is the log file.

 

[koala]

How did you determine the lossless image is "degraded"? The human eye cannot usually perceive a difference between cq 10 and original. Additinally, due to the water drops all over the images in different locations in each image, it's just impossible to do any comparison. If you feel you're able to see a degradation with your eyes, you're probably just mislead by the blurring effect of the water drops.

The images are also downscaled from their original size. This makes it impossible to do any comparison on our side here, since any compression artifacts distort/vanish during downscale.

 

[Deleted member 485476]

How did you determine the lossless image is "degraded"? The human eye cannot usually perceive a difference between cq 10 and original. Additinally, due to the water drops all over the images in different locations in each image, it's just impossible to do any comparison. If you feel you're able to see a degradation with your eyes, you're probably just mislead by the blurring effect of the water drops.

The images are also downscaled from their original size. This makes it impossible to do any comparison on our side here, since any compression artifacts distort/vanish during downscale.

The reason why I enlarged the image and uploaded it was because the file size was too large to upload. The thing that bothered me the most was that even with the lossless setting, the E in UNITE on the right side of the image became blurry. No matter how many times I compare it to footage recorded with Output Mode set to Simple and Recording Quality set to Lossless Quality, Tremendously Large File Size, it appears to be degraded. When using video encoders such as AV1 or HEVC, is degradation unavoidable even with lossless settings?

 

[koala]

May be the blurriness is the original, and encoders will accidentally sharpen it as compression artifact as consequence of their removal of detail.
I trust the AV1 creators that if they define a lossless mode, this mode is actually lossless. May perhaps still be subject to color transformation for more efficient processing and storage, for example from rgb to hsv, but no removal of detail.

 

[Deleted member 485476]

I was able to prepare a screenshot, AVI format, and AV1 lossless image for another scene, but the file size exceeds 5MB and I can't use imgur. If there is another site where it is easy to upload, I will upload it there. In the screenshot and original video, the text was clearly visible (though not sharp), but in the AVI format image, the text was degraded, and in the AV1 lossless image, the text was blurred.