Video Out section

The video drivers are used for video playback in the compositor and the viewer. These determine how you will see video on the timeline.

Play every frame

this causes every frame of video to be displayed even if it means that the playback of the video tracks fall behind. Most likely you will want this enabled because, after all, in order to edit you want to see each frame. However, if you are just watching a big video, you can switch to not play every frame so that you can at least not be distracted by slowness.

Framerate achieved

the number of frames per second being displayed during playback. This is updated during playback only. The goal is to get as close to the frame rate as possible, even if Play every frame is not enabled.

Scaling equation

Enlarge / Reduce – this algorithm is used when video playback involves scaling or translation (only X11 video driver). This does not affect 1 : 1 playback. Choices available are:

Nearest Neighbor / Nearest Neighbor

low quality output with fast playback. Often produces jagged edges and uneven motion.

Bicubic / Bicubic

Bicubic interpolation is used for both enlarging and reducing, enlarging blurs slightly but does not show stair step artifacts.

Bicubic / Bilinear

High quality output with slow playback. Bicubic interpolation is used for enlarging, which blurs slightly but does not show stair step artifacts. A bilinear interpolation is used for reduction, which produces very sharp images and reduces noise. Bilinear reduced images can be sharpened with a sharpen effect with less noise side effects than a normal sized image.

Bilinear / Bilinear

when slight enlargement is needed, a bilinear enlargement looks better than a bicubic enlargement. Bilinear uses less CPU than either Bicubic or Lanczos.

Lanczos / Lanczos

is not necessarily a general purpose upscaler, but is intended for low resolution sources. However many people like the sharpening effects. More quality from Lanczos does take more CPU.

DVD subtitle to display

DVD IFO files usually contain subtitle tracks. These must be decoded with the MPEG decoder. Select Enable subtitles to enable subtitle decoding. There are usually multiple subtitle tracks indexed by number and starting from 0. Enter the index number of the subtitle track to be decoded in the DVD Subtitle to display text box or use the tumbler to increase the index value. Go to the asset corresponding to the MPEG file in the Resources window and right click. Click on Info. The number of subtitle tracks is shown at the bottom.

Enable subtitles/captioning

for broadcast TV ??

Label cells

??

TOC Program No

Table of Contents program number used in DVB ??

Interpolate CR2 images

enables interpolation of CR2 images. Interpolation is required since the raw image in a CR2 file is a Bayer pattern. The interpolation uses dcraw's built-in interpolation and is very slow. This operation can be disabled and the Interpolate Pixels effect used instead for faster previewing

White balance CR2 images

this enables white balancing for CR2 images if interpolation is also enabled. This is because proper white balancing needs a blending of all 3 primary colors. White balance uses the camera's matrix which is contained in the CR2 file. Disabling white balancing is useful for operations involving dark frame subtraction. The dark frame and the long exposure need to have the same color matrix. If you disable Interpolate CR2 Images and use the Interpolate Pixels effect, be aware the Interpolate Pixels effect always does both interpolation and white balancing using the camera's matrix, regardless of the settings in Preferences. Dark frame subtraction needs to be performed before Interpolate Pixels.

Video driver

normally video on the timeline goes to the compositor window during both continuous playback and when the insertion point is repositioned. Instead of sending video to the Compositor window, the video driver can be set to send video to another output device during continuous playback. However, this does not affect where video is routed when the insertion point is repositioned. Options are listed next.

X11

this was the first method of graphical display on Unix systems. It just writes the RGB triplet for each pixel directly to the window. It is useful when graphics hardware can not handle very large frames. And when X11 is used with the associated checkbox enabled of use direct x11 render if possible it can be a really good playback method to speed up playback for large frames.

X11-XV

this was an enhancement to X11 in 1999. It converts YUV to RGB in hardware with scaling. In some cases it may be the preferred playback method, but it can not handle large frame sizes. Maximum video size for XV is usually 1920×1080.

X11-OpenGL

the most powerful video playback method is OpenGL. With this driver, most effects are done in hardware with the graphics board installed in the computer. OpenGL allows video sizes up to the maximum texture size, which is usually larger than what XV supports, depending on the graphics driver. OpenGL relies on PBuffers and shaders to do video rendering. Plugins or transitions that do not have handle OpenGL in the code will use software instead of hardware and this will slow down playback. OpenGL does not affect rendering. It just accelerates playback. X11-OpenGL processes everything in 8 bit color models, although the difference between YUV and RGB is retained. The scaling equation set in the preferences window is ignored by OpenGL – it always uses linear scaling. Camera and projector operations use OpenGL, but some of the effects may not support OpenGL acceleration.

Raw 1394, DV 1394, and IEC 61883

are for old camcorders.

Default A/B Display

the interface is intended for dual monitor displays. Depending on the value of Display, the Compositor window will appear on a different monitor from the rest of the windows.