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就madvr来看似乎没什么用：http://forum.doom9.org/showthread.php?t=146228
B) FreeSync / G-SYNC
Games create a virtual world in which the player moves around, and for best playing experience, we want to achieve a very high frame rate and lowest possible latency, without any tearing. As a result with FreeSync/G-SYNC the game simply renders as fast as it can and then throws each rendered frame to the display immediately. This results in very smooth motion, low latency and a very good playability.
Video rendering has completely different requirements. Video was recorded at a very specific frame interval, e.g. 23.976 frames per second. When doing video playback, unlike games, we don't actually render a virtual 3D world. Instead we just send the recorded video frames to the display. Because we cannot actually re-render the video frames in a different 3D world view position, it doesn't make sense to send frames to the display as fast as we can render. The movie would play like fast forward, if we did that! For perfect motion smoothness, we want the display to show each video frame for *EXACTLY* the right amount of time, which is usually 1000 / 24.000 * 1.001 = 41.708333333333333333333333333333 milliseconds.
FreeSync/G-SYNC would help with video rendering only if they had an API which allowed madVR to specify which video frame should be displayed for how long. But this is not what FreeSync/G-SYNC were made for, so such an API probably doesn't exist (I'm not 100% sure about that, though). Video renderers do not want a rendered frame to be displayed immediately. Instead they want the frames to be displayed at a specific point in time in the future, which is the opposite of what FreeSync/G-SYNC were made for.
If you believe that using FreeSync/G-SYNC would be beneficial for video playback, you might be able to convince me to implement support for that by fulfilling the following 2 requirements:
1) Show me an API which allows me to define at which time in the future a specific video frame gets displayed, and for how long exactly.
2) Donate a FreeSync/G-SYNC monitor to me, so that I can actually test a possible implementation. Developing blindly without test hardware doesn't make sense. |
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