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Brief for a designer

You can give this section to a designer as a technical brief for Stellar screen content. Prepare one video for the body’s LED panels; create a separate file for the built-in monitor.

Canvas and file format

  • Frame size: exactly 960 × 1600 px, with no borders or cropping; a vertical 3:5 layout, square pixels and SAR 1:1.
  • Container: a regular, non-fragmented MP4. Place moov before mdat and enable Fast Start.
  • Frame rate and codec: 29.97 fps CFR (30000/1001) or 59.94 fps CFR (60000/1001). Both modes use H.265 / HEVC, Main, 8-bit.
  • Colour: SDR Rec.709, 8-bit YUV 4:2:0 (yuv420p), with no HDR. No audio by default.
  • Maximum HEVC bitrate: 100 Mbit/s. This is a limit, not the required working bitrate.

Create the composition at 960 × 1600 from the start. Do not stretch material with a different aspect ratio. Remove guide lines, coordinates and diagram labels from the finished video.

Video size and physical LED resolution

960 × 1600 is the video file size and the designer’s canvas. The physical LED resolution is lower: the controller scales video to the installed screen. Do not reduce the export to the panels’ resolution or change the LED grid settings to match the video. All coordinates in this brief refer to the 960 × 1600 canvas.

Use HEVC for both 29.97 and 59.94 frames per second. Stellar Video Maker encodes only in HEVC. “30 FPS” is the rounded lower-rate name; the current higher-rate profile is “59.94 FPS”: the exact rates are 30000/1001 and 60000/1001. Export settings are described in section 16.

Content dimensions for each side

Dimensions below are width × height, in canvas pixels. Each side is one continuous vertical area from top to bottom; the horizontal join does not divide it into separate designs.

  • Front — 320 × 960 px: the visible area below the blind zone. In the full layout: X 480–800, Y 640–1600.
  • Back (door) — 320 × 1600 px: the full height of the back face. In the full layout: X 0–320, Y 0–1600.
  • Left — 160 × 1600 px: the full height of the left side, with no top/bottom split.
  • Right — 160 × 1600 px: the full height of the right side, with no top/bottom split.

The complete front face is 320 × 1600 px. Its upper 320 × 640 px are covered by the camera, monitor and lighting: X 480–800, Y 0–640. Keep key content out of this area. If preparing the front separately, use 320 × 960 px and place it below the blind zone; do not stretch it to the full face height.

The finished video remains one 960 × 1600 px canvas. The side strips occupy X 320–480 and X 800–960, Y 0–1600. The origin is the top-left corner: X increases rightwards and Y downwards; right and bottom range limits are excluded.

Margins, readability and QR codes

Keep at least 16 px from face edges and the hidden area. The front safe area is X 496–784, Y 656–1584. The Y = 960 horizontal join needs no inset and does not divide the content: text and graphics may cross it. Use colour, patterns and motion on the narrow side faces; do not split long words across a body corner.

Start with letters 32–48 px high. Avoid small text, thin lines and low contrast; check readability at the intended viewing distance. A QR code must not cross a body corner or enter the hidden area. Keep it stationary and test scanning on the LED panel.

Camera and screen outlines in diagrams show equipment locations; they are not cut-out drawings. Remove guide labels and lines from the video.

Exporting from another editor

For Stellar content, use H.265 / HEVC at 29.97 or 59.94 fps CFR. The HD-A3L maximum HEVC bitrate is 100 Mbit/s. The settings below do not require using the maximum bitrate.

Standard mode

  • Codec and profile: H.265 / HEVC, Main, 8-bit.
  • Frame rate and size: 29.97 fps CFR (30000/1001), 960 × 1600 px.
  • Working bitrate: 8–12 Mbit/s. Keyframes every 1–2 seconds.

Smooth animation

  • Codec and profile: H.265 / HEVC, Main, 8-bit.
  • Frame rate and size: 59.94 fps CFR (60000/1001), 960 × 1600 px.
  • Working bitrate: 12–20 Mbit/s. Keyframes every 1–2 seconds.

Working bitrates and keyframe intervals are content-preparation recommendations, not hardware limits. The 100 Mbit/s maximum is stated in the HD-A3L specification, page 8. The H.265 decoding range is 64 × 64 to 4096 × 2304. This brief uses the Main, 8-bit profile; Main10 is not required.

Do not create 59.94 fps by simply duplicating frames from 29.97 fps video: this adds no new motion phases. Prepare animation or source footage at the appropriate frame rate for 59.94 fps.

MP4 checks and monitor content

Place moov at the start

The moov atom contains the MP4 index and metadata. Place it before the mdat media data, usually just after ftyp. This allows the index to be read before the main video; any startup speed improvement depends on the controller player. Enable Fast Start / Web optimized when exporting. If the editor has no such option, process the finished MP4 with FFmpeg without re-encoding:

ffmpeg -i input.mp4 -map 0:v:0 -map "0:a?" -c copy -movflags +faststart output.mp4

Before handing over content

  • Check 960 × 1600, SAR 1:1, HEVC, a constant 29.97 or 59.94 fps frame rate and 8-bit YUV 4:2:0.
  • Make sure all guide lines and labels are removed and no key elements enter the hidden area.
  • Test playback and looping on the device, with no stuttering, errors or black frame at the loop boundary.
  • Check face mapping and the Y = 960 join position on the installed system.

Built-in 16-inch monitor

Prepare a separate portrait file for the monitor: 1200 × 1920 px, 10:16 aspect ratio and 29.97 or 59.94 fps CFR. These settings apply to the 16-inch monitor, not the body’s LED layout. Create the design at 10:16 from the start; do not stretch content or add borders. Prepare the monitor file separately from the 960 × 1600 LED content.

DZEN TECH