Question: Intel Quick Sync + constant QP + vbv-maxrate

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JustEncode
Posts: 14
Joined: Wed Aug 11, 2021 9:59 am

Question: Intel Quick Sync + constant QP + vbv-maxrate

Post by JustEncode »

Description of problem or question:

Hello Community,

i have a question about enconding with Intel Quick Sync and constant QP.
Is it technically possible to choose a constant quality in the future, but to limit the maximum bit rate? The problem, regardless of whether it's 1080p or 2160p is that in some situations there are "outliers" that drive up the bit rate.

The calculation works in 90% of the situation and a good bit rate / quality is selected depending on the source. But especially with intros in some series where only a logo is animated, it can happen that the bit rate goes up to 120Mbits. The average bit rate is, for example, 4000-5000 kbits for 1080p sources, but sometimes there are scenes where the bit rate is much higher than even the bit rate in the source. If you convert via CPU, you can define "vbv-maxrate" and "vbv-bufsize", it can fit. With Intel Quick Sync, this option is not possible with constant quality.

My only option is to use an average bit rate, however in many situations the bit rate will be either too high or too low.


Thanks for the support and thanks to all developers.

Additionally: I noticed that "target-usage (or tu)" doesn't work. No matter what value you use, only 7 or 4 are possible. Even using the 3 presets, tu = 4 is the lowest.
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