Checklist for Smooth Video Playback
Creating smooth video playback is a challenging task, where many performance factors interact. Video is a data flow and every component in the chain must be able to match the current stream and do its task.
The footage itself is important, too. You cannot smoothly playback a jerky video file. With 'objects' we mean visible objects in the video frames like eg. text letters.
- Constant object motion
- Slow object motion ( Without blur: max. 1-2 pixels per frame. This is very important for text scrolling. )
- Objects with soft edges ( This is very important for text scrolling. )
- Motion blur
- Downscaling the footage in the output. Movements look smoother when they are minimized.
- Jerky object movement
- Fast object movement with hard edges and no motion blur
- Upscaling the footage in the output. Movements look jerkier when they are maximized.
- Use of too much lossless video media like eg. lossless image sequences?
- Oversized footage resolution: do not use a resolution larger than visible
The settings are project-specific, so there is not general 'good' or 'bad'. But these settings and media facts have an influence on the video framerate
- Does the framerate match the footage framerate? Check this article Video Codecs
- Is an audio input device active? Without audio input device, the software uses the system clock, which has a much lower precision.
- Does the framerate match the footage framerate during playback? Check the framerate by moving the mouse to the left of the UI window, the current framerate will be visible in the bottom left of the window
- Is the vertical sync active? Check for vertical sync in drivers, too. Turn it off for more motion smoothnes.
- Does the output window have the correct size? Sometimes setting 'unusual' sizes solves stuttering issues, please see Windows 7 + ATI + Stuttering Output or Windows 7 + ATI + Output Window On Wrong Screen
- Is non-internal feedback active?
- Lower the footage resolution ( Resolution is important. File size and clip length does not matter )
- Lower the rendering size (Settings->Output Window->Rendering Size)
- Is the correct GPU in use? Many systems have more than one GPU. The onboard graphics usually offers the least performance. Using the onboard connector involves and restricts to the onboard GPU.
- Unintended use of multiple GPUs? Be sure you use only one GPU for maximum performance.
- Do all monitors and projectors share a common framerate?