Downsampling/Upsampling render result to match the screen/cpu limit.

[peerless2012]

Currently the render result match the video size. but sometimes this is not the best way, here are some situations:

1. Video is 4k and above, but screen is 1080p, render a 4k ass is waste cpu and memory.
2. Video is 4k and above, and screen is 4k, render is too slow for some cpu limited device or complex ass anims.
3. Video is 720p/480p, and device is 1080p/4k, render result is not clear.
4. Switch to fullscreen or enter pip mode, or set video clip mode.

[moi15moi]

• ass_set_storage_size() - Set the video size.
• ass_set_frame_size() - Set the screen size.

You only have this problem because you call ass_set_frame_size with the video size. This is an error.

[peerless2012]

I do it on purpose currently now.

At least for legacy mode, the screen size calls after the first few cues created, it will make cues render on error position .