BrightSign players are capable of high-quality video playback at 60 frames per second—without dropped frames, hiccups, or video corruption. However, since the digital A/V landscape includes a diverse array of formats, codecs, connectors, video modes, and resolutions, you can easily degrade the quality of video playback by not configuring your digital signage content properly. This tech note outlines the factors that affect video quality and the steps you can take to ensure that you get the best results.
To achieve optimal video quality, you must minimize the amount of processing that the player and display device must perform on the video:
- Avoid interlaced video modes: Interlaced video modes (e.g. 1920x1080x60i) result in severe performance degradation, which will be especially noticeable if the video displays text. Note that the LS422, HD120, HD220, and HD1020 players automatically use interlaced video modes to display 1080p50, 1080p59.94, and 1080p60 video.
- Match the video frame rate to the native frame rate of the display: The progressive frame rate of the video should be the same as (or a multiple of) the frame rate of the display. For example, if a display accepts a maximum frame rate of 50p or 75p, then a video at 25p will perform well. Video at 59.94p will work with 29.97p output, but every other video frame will be dropped.
- Avoid scaling video unnecessarily: Upscaling or downscaling the video will result in some performance degradation, though the effects may not be noticeable. When practical, match the resolution of the authored content to the native resolution of the display or widget.
- Avoid using overscan when possible: The best solution is to select a video mode that doesn't overscan at the chosen output.
- Use an optimal bitrate: The maximum recommended CBR (constant bit rate) is 25Mbps for HD, LS, XDx30, and XDx32 players, while the recommended CBR for XT, 4K, XDx34, and XDx33 players is 30 to 40 Mbps.
Interlaced video modes (e.g. 1080i) are a legacy of cathode ray tube (CRT) TVs and should be avoided in all circumstances. While CRT TVs show an interlaced signal natively, LED, LCD, and Plasma displays must de-interlace the input prior to displaying it, thereby reducing the video quality. Many displays (especially monitors intended for use with PCs) do not de-interlace video properly, causing video flicker—even with static images.
We do not recommend using interlaced video; however, if you must use interlaced video, you can specify whether the de-interlacing should be handled by the display or the BrightSign player:
- To have the display handle the de-interlacing, select an interlaced video mode in BrightAuthor (e.g. 1920x1080x50i) in the New project window or in the File > Presentation Properties > Main tab.
- To have the player handle the de-interlacing, select a progressive mode with the appropriate resolution (e.g. 1920x1080x50p).
The LS422, HD120, HD220, and HD1020 players automatically use interlaced video modes to display 1080p50, 1080p59.94, and 1080p60 video.
Codecs and Formats
BrightSign players support numerous video codecs and container formats, but some applications require specific video codecs/formats:
- Seamless Looping: For XTx44, XTx43, XDx34, XDx33, HDx23, 4Kx42, and LS423 players, we recommend using an .mp4 or .mov file with H.265 encoded video (though H.264 will work as well). For other models, use an .mp4 or .mov file with H.264 encoded video. If the looping video includes audio, use PCM audio encoded with the SOWT codec.
- BrightWall and Enhanced Synchronization: For XTx44, XTx43, XDx34, XDx33, HDx23, 4Kx42, and LS423 players, we recommend using an .mp4 or .mov file with H.265 encoded video (though H.264 will work as well). For other models, use an .mp4 or .mov file with H.264 encoded video. It is also possible to use a transport stream (.ts file), but the video must begin with a presentation timestamp (PTS) of zero.
- Media Streaming: If you’re using a BrightSign player to stream content to other networked devices, the video must be formatted as a transport stream (.ts) file.
Overscan, which is a type of upscaling, is performed on videos to account for variation in the screen edges of different TV models. The overscan mode on BrightSign players upscales the video by approximately 5%. Most modern TVs have an "exact scan" mode that eliminates the need for overscan entirely. Overscan can be disabled in BrightAuthor by selecting No overscan – use full screen area in the New project window or in the Edit > Layout tab (overscan can also be disabled in BrightScript).
Overscan is only needed for TV modes (e.g. 720p, 1080p), and should never be applicable for VGA modes (e.g. 1370x768, 1600x1200); however, there is some inconsistency in the way that different TVs and monitors deal with overscan settings.
Display manufacturers use different terminology to refer to no overscan:
- Panasonic: “1:1 mode”
- Samsung/LG: "just scan"
- Toshiba: "exact scan"
- Vizio: No overscan settings, but the “wide” display mode will disable overscan.
XTx44 and XDx34 players support a constant bit rate (CBR) between 70 and 80 Mbps. The second video decoder on the can simultaneously support a video up to 70 to 80 Mbps as well.
If the video is encoded using a variable bit rate (VBR), we recommend an average bitrate of 70 to 80 Mbps, which may include peaks at up to 100Mbps.
XTx43, XDx33, 4Kx42
For XTx43, XDx33, and 4Kx42 players, we recommend a constant bit rate (CBR) between 30 and 40 Mbps. The second video decoder can simultaneously support a 1080p video at up to 40 Mbps as well.
If the video is encoded using a variable bit rate (VBR), we recommend an average bitrate of 25 Mbps, which may include peaks at up to 40Mbps.
XDx32, XDx30, HDx23, HDx22, LS423
The recommended constant bit rate (CBR) is 25Mbps maximum. If you are using the video as part of a larger presentation area (with other zones decoding images, graphics, or audio), the CBR should be significantly less than 25Mbps.
If the video is encoded using a variable bit rate (VBR), an average bitrate of 25Mbps may include peaks at up to 40Mbps. The video may experience performance issues at these peaks, so we recommend an average bitrate significantly less than 25Mbps if the video is VBR encoded.
When a BrightSign player displays a rotated video (at 90 degrees, 270 degrees, etc.), it consumes CPU and graphics-processor cycles to transpose the pixels of each video frame before sending it to the display. Compared to standard playback, rotated video places a substantially greater burden on CPU and memory bandwidth in the real-time display pipeline, so video playback can become overloaded and exhibit video glitches more readily than standard video playback. This section provides performance and playback guidelines for portrait video.
When playing portrait video, other real-time system tasks can, depending on the player model, interfere with playback. These tasks include the following:
- 2D graphics operations: Tickers, HTML graphics, and large image files
- Network Traffic: Performing large and/or frequent networked updates (e.g. via the asset pool)
- USB audio
When building presentations, you need to consider these secondary tasks and their interaction with the hardware restrictions on your player model (outlined below). If your portrait video is exhibiting glitchy playback, you may need to reduce or eliminate such tasks or upgrade to a more performant player model.
Guidelines by Player Model
The LS423 can output portrait HD video (1080x1920) at up to 50p. If there are additional system tasks (e.g. a ticker), the display output may need to be reduced to 1080p30 or less.
The framerate of the source video should not exceed 1080p30.
The HDx23 can output portrait HD video (1080x1920) at 60p.
The framerate of the source video should not exceed 30p.
The LS423 and HDx23 can only play a single portrait video at a time.
XTx44, XTx43, XDx34, XDx33
The XTx44, XTx43, XDx34, and XDx33 models can output portrait HD video (1080x1920) at 60p. Multiple portrait video windows are supported (up to 60p for both the source file and the output), but the total area of all video windows should not exceed 1080x1920.
If your HTML page creates
<video> tags dynamically, it can be easy to inadvertently maintain more than one active video player–even if the extra video players are not visible. If videos are displayed in portrait mode, additional video players will quickly exhaust CPU and graphics resources on the player.
To destroy an unused video player, clear the
src attribute and reload the element using
.load. The firmware will then synchronously release the hardware resources assigned to that element.
Mosaic mode does not currently support portrait video.
Portrait video is not supported with interlaced video output modes (e.g. 1080i).