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Aleksoid1978 / VideoRenderer

Внешний видео-рендерер
GNU General Public License v3.0
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Unable to speed up x5 the 4k VP9 video #133

Closed Telezhka-the-First closed 4 months ago

Telezhka-the-First commented 4 months ago

I noticed that if I use this video renderer in MPC-BE, any video with codec vp09 seems impossible to speed up: while time and audio successfully increase in speed, video plays as if it was at x1 speed, so audio outruns video. This doesn't happen with h264 and h265: they speed up as intended.

Aleksoid1978 commented 4 months ago

What player use ?

The video renderer has nothing to do with changing the playback speed. I checked in MPC-BE - everything is fine.

clsid2 commented 4 months ago

Hardware decoder maybe too slow?

v0lt commented 4 months ago

This is a problem with your hardware that you didn't mention.

Also, if you press Ctrl+J, you will get additional information.

Telezhka-the-First commented 4 months ago

What player use ?

The video renderer has nothing to do with changing the playback speed. I checked in MPC-BE - everything is fine.

Not sure what do you mean by player. I use MPC-BE with MPC Video Renderer & MPC Audio Renderer.

Telezhka-the-First commented 4 months ago

Hardware decoder maybe too slow?

Maybe. VLC speeds up vp09 fine though. Maybe some option breaks vp09 in MPC-BE.

Telezhka-the-First commented 4 months ago

This is a problem with your hardware that you didn't mention.

Also, if you press Ctrl+J, you will get additional information.

Thanks, that's test with x5 speed: image

Aleksoid1978 commented 4 months ago

Frame rate 120, working.

Telezhka-the-First commented 4 months ago

It's not x5, i took this speed just to illustrate the problem. Usually this starts happening at about x1.7. What happens is that after some speed Sync offset is no longer dropping towards zero, but increases, increasing difference between audio and video. This means that this program reaches it's maximum framerate (bitrate?) for the video and can't process it any faster, while audio doesn't care and speeds up to any number.

Telezhka-the-First commented 4 months ago

Is it the only solution: to upgrade hardware? Can anything be done via program part?

clsid2 commented 4 months ago

Yes, your hardware is too weak.

v0lt commented 4 months ago

The hardware decoder has a decoding speed limit. This limit is different on different decoders. Also, part of the power is taken by the output to the screen.

In my measurements on an Intel UHD 750, the HEVC 8-bit decoder is faster than the VP9 8-bit decoder. For fast operation of integrated graphics, fast RAM operating in dual-channel mode is required.

Telezhka-the-First commented 4 months ago

It would be better though, that if vp09 video can't reach desired speed it would lag and stutter rather than running video slower than needed. This way desync would be immediately noticable.