Video

WATCHOUT can play back videos saved in a Windows Media (DirectShow) or QuickTime-compatible format, such as MOV, WMV, AVI, DV and MPEG-1/2/4 (including H.264/AVC). A progressive – that is, non-interlaced – format is preferable (for example, “30p” or “60p”).

NOTE: WATCHOUT can utilize QuickTime, including all its codecs, if available. However, QuickTime is not required by WATCHOUT. Some popular video formats often stored in MOV files will use native codecs built into WATCHOUT regardless of whether QuickTime is available or not. This includes the H.264 (MPEG-4), Animation, Prores and HAP codecs.

High Resolution Video

WATCHOUT supports high resolution video using MPEG-2, H.264 ,Windows Media 9, Prores and HAP, as well as other codecs capable of high-resolution encoding and playback. Many MPEG-2 encoders have difficulty encoding higher resolution than 1920x1080, while other formats tend to be more flexible, and can support 4k and beyond, depending on hardware resources.

NOTE: H.264/AVC is limited to level 5.2. Videos encoded using a higher level will not be rendered.

NOTE: High-resolution content using H.264, Windows Media and Prores codecs requires a comparatively fast CPU. Likewise, HAP and Prores requires a very fast disk/SSD subsystem. In general MPEG-2 content will play on less powerful computers.

Computer-generated ­Animations

When using computer-generated moving images, you must specify the frame-rate and resolution of the resulting video during rendering. Generally, when combining computer generated and pre-recorded video material, the frame-rate is dictated by the live material. Alternatively, if your playback computer is fast enough, match the rendered frame-rate to the WATCHOUT display frame-rate (see “Display Framerate”); for example, 60 fps progressive.

As computer generated videos are by nature resolution independent, it is also possible to make videos that are much larger than a single display area. Very large videos may need to be pre-split in order to be used in WATCHOUT (see “Pre-splitting a Large Video”), depending on the performance of the display computers.

Using Transparency

Some applications support inclusion of transparency information in the gene­rated video file. Such transparency can either come from the source material (for example, a computer generated animation), or be added afterwards (for example a mask or color key applied to a video clip).

Being able to create arbitrarily shaped videos, or videos with holes in them, means you can combine videos and still images in many creative ways.

In order to include transparency information in the video file, you must choose a codec that supports this, such as the Animation or HAP codecs. If exporting the video, set to use “Millions+” of colors. The “+” at the end stands for the transparency information. This is sometimes called “Millions+Alpha”. You must also use an application that’s capable of reproducing and/or generating transparency information, such as Adobe After Effects.

HINT: In many cases, a clean green or blue background can be used instead of true transparency. Simply apply WATCHOUT’s Key tween track to the video.

Video Compression

Due to the large amount of raw data in a video stream, storing and playing back uncompressed video is usually not feasible. Video compression is based on the concept of codecs. A codec (which stands for compressor/decompressor) is the part of the editing and display technology responsible for storing and playing back compressed digitized video.

There’s a wide variety of codecs available, each optimized for a particular kind of source material and playback requirements. WATCHOUT supports both Apple QuickTime and Microsoft DirectShow codec technologies for playback. Here’s a rundown of some of the more commonly used codecs:

MPEG-2. High quality. Used on DVD video discs. Optimized for camera video at normal frame sizes. Also supports high definition formats with some encoders (see “High Resolution Video” on page <?>). The WATCHOUT MPEG-2 decoder performs de-interlacing automatically when required.

Quicktime Animation. Very low compression. Optimized for computer-­generated material. Supports transparency when set to “Millions+” of colors.

Windows Media 9. High quality. Flexible in terms of frame size (useful for making tall or narrow videos), frame-rate and interlacing/progressive options. Demanding on processor speed when using high resolutions.

H.264/AVC. High quality. Flexible in terms of frame size (varies with encoder). Demanding on processor speed when using high resolutions. H.264/AVC is limited to level 5.2. Videos encoded using a higher level will not be rendered.

Prores. Very high quality and low compression. Due to the high data rate, a fast disk/SSD is required. This codec is mainly designed for use in editing workflows, but given sufficiently powerful hardware it can also be used for playback.

HAP. Medium-to-high quality. Good playback performance. Due to the high data rate, a fast disk/SSD is required. The HAP-Alpha veriant supports transparency when set to “Millions+” of colors during encoding. While HAP is built into WATCHOUT, it’s not available natively in most video encoders. Get the HAP codec here:

https://github.com/vidvox/hap-qt-codec/releases/

Choosing the right codec and codec settings for your source material and playback hardware may require some exper­imentation.

Recommended Compression Formats

Although WATCHOUT supports most video file formats, some formats tend to give better results. As a general guideline, use MPEG-2, H.264 or Windows Media 9. H.264/AVC is limited to level 5.2; videos encoded using a higher level will not be rendered. HAP is often a good choice too – particularly if you need to play numerous videos simultaneously. If you need transparency encoded into the video, choose either the HAP-Alpha or Animation QuickTime codec. WM9 as well as H.264 requires more processor power, but provides greater flexibility then MPEG-2 in terms of supported frame sizes.

Pre-splitting a Large Video

High-end computers are often capable of playing numerous high-definition video files at the same time. As long as what you need to play fits within the realm of your computer’s capabilities, you should generally choose among the recommended formats listed above.

However, for extremely large videos, spanning numerous displays, even modern computers may not be fast enough to handle the required resolution as one large video. This applies in particular to computer generated videos, which can be made at any resolution and frame-rate your animation software is capable of producing. Such very large videos can be played by splitting them into individual pieces, where each piece includes only the portion of the frame that will play on each display.

While this splitter function is built into WATCHOUT for still images, it is not handled automatically for moving images. The primary reason for this difference is that the original, large videos would most likely have to be compressed in order to be stored and distributed to the display computers. To split the video, the display computers would have to decom­press each frame, split it and then re-compress the result again for final playback. This would mean that each video frame will be compressed twice. The end result would be a loss of image quality.

In addition to this quality aspect, there are also storage and bandwidth considerations related to distributing and storing the original (large) video in order to split it, as well as the processing time involved in compressing it twice. The latter would be significant for such a large video, particularly to achieve the best quality.

This can all be avoided by splitting the image using the originating application, prior to compression. Most applications allow you to crop the output to any desired rectangle. In some cases, you can even set up batches to generate all the individual videos files in one go.

As an example, assume that you have two 800 by 600 pixel displays with a 30% overlap, and want to display a video of 1200 by 480 pixels, the split would appear as in the illustration.

NOTE: These figures are only chosen as an example. All modern computers would be able to play such a video as is, without pre-splitting it.

Include the overlap in the split, since the portion of the image in the overlap will have to play on both displays. Likewise, if the displays aren’t overlapping you will have to factor in any gap between the edges of the display areas by speci­fying a corresponding gap when making the split.

Most applications specify cropping relative to the initial image size. This means that the bottom and right edges need to be calculated based on the height and width of the original (large) image.

IMPORTANT: When splitting a large video into smaller pieces like this, avoid using a compressed video as the source. Doing so would introduce an additional de-compression/re-compression step, resulting in lower quality. Thus, whenever possible, start out with the original material, such as individual, computer-generated, image files.

Save the resulting files into a separate folder. Give each file the name of the WATCHOUT display on which it will appear. Select “Pre-split for Multiple Displays” and link the Video Proxy to the folder (see “Pre-split”).

Video Settings

Double-click the name of a video in the Media window to change its specifications. Click the Browse button to link the media item to another file. This updates all cues to show the newly selected image instead.

Transparency
Most video formats do not support transparency. For the few that do (for example, QuickTime Animation and HAP-Alpha), the “Auto Detect” setting is usually sufficient. If you see a light or dark halo around the video content, you may try one of the “Premultiplied” settings instead.

Enable WATCHPAX Hardware Acceleration
Applies only when playing certain video formats, such as H.264, on WATCHPAX. May improve video playback performance when playing high resolution video. This checkbox has no effect when using other display computers.

Apply Frame Blending
This setting often results in smoother video playback, at the possible expense of some loss in image sharpness. This is especially true when the frame-rate of the video is not an even multiple of the display computer’s frame-rate (for instance, when playing 25 fps video on a display computer set to 60 fps). This is accomplished by blending adjacent frames together, weighted by their temporal position.