Mirv sample exposure
From HLAEwiki
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Syntax
mirv_sample_exposure <0.0 - 1.0>
- Default
- 1.0
- Type
- floating point, 0.0 - 1.0 (recommended range)
Description
Controls the frame exposure time. That is the fraction of time a frame is exposed to incoming samples (from the beginning of the frame). A higher value mean longer exposure than a lower value. If you want cross-frame motion-blur see __mirv_sample_frame_strength instead.
This is similar to a Rotary disc shutter where
mirv_sample_exposure = shutter_angle / 360°
Of course HLAE does not simulate a rotating disc, instead the whole frame is closed or opened ideally at once (electronic shutter).
A lower exposure time results in less samples being used, so you might want to compensate with a higher mirv_sample_sps value:
HLAE tries to optimize the processing of the samples and speeds things a bit up when it determines samples can be skipped due to the shutter being closed (the actual amount depends on the sampling method set).
Consequently if you use a lower exposure value you can set mirv_sample_sps higher in order to get about the same amount of samples during the shorter exposure time. (As a rule of thumb use mirv_sample_sps = (mirv_movie_fps / mirv_sample_exposure) * number_of_samples_you_want_during_exposure)
Examples
The examples bellow are available as test video: http://www.youtube.com/watch?v=Tk0EX0RqJ0E
360° shutter angle, 10 samples per exposure, 30 fps output
mirv_movie_fps 30 mirv_sample_enable 1 mirv_sample_exposure 1.0 mirv_sample_sps 300
180° shutter angle, 10 samples per exposure, 30 fps output
mirv_movie_fps 30 mirv_sample_enable 1 mirv_sample_exposure 0.5 mirv_sample_sps 600
90° shutter angle, 10 samples per exposure, 30 fps output
mirv_movie_fps 30 mirv_sample_enable 1 mirv_sample_exposure 0.25 mirv_sample_sps 1200
Speed considerations
Lower values are faster.