rigaya / NVEnc

NVENCによる高速エンコードの性能実験
https://rigaya34589.blog.fc2.com/blog-category-17.html
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Parameters to obtain more grain #552

Open Einst1969 opened 5 months ago

Einst1969 commented 5 months ago

Hi, I'm new here. I'm using this encoder on staxrip 2.35. I have a video that has a certain bitrate and I need to re-encode it to permanently add forced subtitles. I tried CQP and QVBR mode, H.265 codec, Preset p7, output depth 8 and 10, both with and without AQ 0. Example paramenters :"--cqp 21 --codec h265 --preset P7 --output-depth 10 --aq" .I made sure to have the same bitrate as the source but the resulting file is a bit "blurry" which means it removes some grain. Are there any parameters that can help me? Thanks

rigaya commented 5 months ago

Unfortunately, I found it difficult to keep the grains in NVENC encoding. --aq-temporal or simply increasing size might change but very difficult to avoid getting blurry.

Einst1969 commented 4 months ago

Hi, I found a solution. Much grain is kept with AQ spatial + AQ Strengh 15 for the same used bitrate. 15 is the maximum? Then another thing: I tried QVBR, and compared to QCP creates images with more blur. I had already noticed before but with the old version. It seems that even with this version QVBR it creates images with more blur than QCP. I tried to use more bitrate, from 5200 to 7700 but there is still a little blur in QVBR mode (7700b/sec) compared to CPQ (5200b/sec). It's normal or there is a problem? Thank you

rigaya commented 4 months ago

Yes, --aq-strength 15 is the strongest possible.

I'm not sure with qvbr vs cqp, but generally cqp allows to follow temporal changes better, however bitrate spikes can occur and there is no control over the maximum bitrate.