What is the format of the Qpdeltamap used for ROI in NVENC?

Question

I am trying to get started with ROI encoding with the Nvidia Encoder NVENC. As a first step I am trying to get the Nvidia demos to encode using ROI. I know that the switch -qpDeltaMapFile enables the flag enableExtQPDeltaMap. This allows me to send a file with a qp map that the encoder uses to tweak the values obtained by the rate control algorithm.

However there is absolutely no documentation on the format of this file. I tried to use one value per byte, and one byte per value assuming fixed size macroblocks of 16x16. It doesn't seem to work as I would expect.

Any guidance or references would help a lot.

Answer 1

我的代码中存在错误。它实际上几乎像我描述的那样工作。 假设您的屏幕在16x16块中平均分配，则每个值将添加到速率控制算法选择的qp中。传递的每个值都是有符号整数，因此负值将提高质量，而正值将减少它。无论速率控制算法决定什么，值都将保持不变。