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我反而是没怎么研究过 madVR 是如何处理的，两三年前大概试过，不太清楚现在的情况。
mpv 的话应该就是这么三个东西：
--hdr-compute-peak=<auto|yes|no>
Compute the HDR peak and frame average brightness per-frame instead of relying on tagged metadata. These values are averaged over local regions as well as over several frames to prevent the value from jittering around too much. This option basically gives you dynamic, per-scene tone mapping. Requires compute shaders, which is a fairly recent OpenGL feature, and will probably also perform horribly on some drivers, so enable at your own risk. The special value auto (default) will enable HDR peak computation automatically if compute shaders and SSBOs are supported.
--hdr-peak-decay-rate=<1.0..1000.0>
The decay rate used for the HDR peak detection algorithm (default: 100.0). This is only relevant when --hdr-compute-peak is enabled. Higher values make the peak decay more slowly, leading to more stable values at the cost of more "eye adaptation"-like effects (although this is mitigated somewhat by --hdr-scene-threshold). A value of 1.0 (the lowest possible) disables all averaging, meaning each frame's value is used directly as measured, but doing this is not recommended for "noisy" sources since it may lead to excessive flicker. (In signal theory terms, this controls the time constant "tau" of an IIR low pass filter)
--hdr-scene-threshold-low=<0.0..100.0>, --hdr-scene-threshold-high=<0.0..100.0>
The lower and upper thresholds (in dB) for a brightness difference to be considered a scene change (default: 5.5 low, 10.0 high). This is only relevant when --hdr-compute-peak is enabled. Normally, small fluctuations in the frame brightness are compensated for by the peak averaging mechanism, but for large jumps in the brightness this can result in the frame remaining too bright or too dark for up to several seconds, depending on the value of --hdr-peak-decay-rate. To counteract this, when the brightness between the running average and the current frame exceeds the low threshold, mpv will make the averaging filter more aggressive, up to the limit of the high threshold (at which point the filter becomes instant). |
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