Recommended File Specs

Quick Reference

If you only read one thing, read this. The defaults that work for nearly every signage situation:

Photos & Graphics

Resolution

Match the resolution to your screen, not your source file. Almost every TV used for signage is 1080p (1920×1080). A 24-megapixel photo from your phone is roughly 6000×4000 pixels — the TV throws away over 90% of those pixels before you ever see them. Resizing to 1920×1080 before upload cuts file size by 8× or more with zero visible quality loss.

Use 4K (3840×2160) only if the screen is a true 4K display and the source photo was actually shot at that resolution or higher. Upscaling a 720p photo to 4K doesn’t make it sharper — just bigger.

Format

Compression

For JPG, save at quality 85%. This is the sweet spot — above that you’re adding bytes nobody can see; below 75% you start to see blockiness in smooth gradients (skies, skin tones).

For PNG, use a tool like TinyPNG to apply lossy palette compression. A typical 1920×1080 logo PNG goes from 2 MB to ~200 KB with no visible difference.

Aspect Ratio

Screens are 16:9 (landscape). Anything else gets letterboxed (black bars on the sides) or stretched. If your photo is portrait or square, consider cropping to 16:9 before upload, or expect black bars on the playback screen.

File Size Targets

Videos

Format / Codec

Always use MP4 with H.264 video and AAC audio. This is the universal format every device decodes in hardware — smooth playback, low power, no surprises.

Resolution & Frame Rate

• 1920 × 1080 (1080p) at 30 fps — the recommended default for everything. Looks great on any TV up to 75″.
• 3840 × 2160 (4K) at 30 fps — only worth using if the playback device is a 4K-capable player (NUC, Apple TV 4K, Fire TV 4K Max) and the TV itself is 4K. Otherwise the player just downscales it back to 1080p and you wasted file size.
• 60 fps — only needed for sports, gaming, or genuinely high-motion content. Doubles file size for minimal signage benefit.
• 1280 × 720 (720p) — acceptable for cheap Fire TV Sticks with little storage, or content where size matters more than sharpness.

Bitrate

Bitrate controls how much data per second the video uses. Higher = sharper but bigger files. For signage:

Audio

• Embedded in the MP4 (don’t upload separate audio files).
• AAC codec, 128 kbps, stereo, 48 kHz.
• If your video is meant to be silent, you can still leave a silent audio track — it’s tiny and helps with sync.

Length

No strict cap, but long videos take longer to cache and use more storage. Practical ceilings:

• Fire TV Stick: 1-hour at 1080p is the safe ceiling for caching. Longer videos work but stream from the network instead.
• Raspberry Pi / NUC: 2+ hours at 1080p cache without trouble.
• Apple TV / iPad: 2+ hours cache fine; full sermon recordings work great.

Audio

DisplayCache plays audio embedded in videos. We don’t currently support standalone audio playlists (audio-only files like MP3 or WAV).

If you have an announcement that should play with sound, the easiest path is to turn it into a video:

• Open a video editor (iMovie, DaVinci Resolve, Canva).
• Drop in a still image (your logo, a slide, or a graphic).
• Add the audio file as a track over the image.
• Export as MP4 H.264 + AAC.

Common Myths

“I need 300 DPI for sharp images on the screen.”

DPI (dots per inch) is a print concept. Screens use pixels, not dots. A 1920×1080 image looks identical at 72 DPI, 150 DPI, or 300 DPI — the only thing that changes is the file size header. Ignore DPI completely for digital signage.

“Higher resolution is always better.”

Only if the screen can actually show it. A 4K photo on a 1080p TV gets downsampled to 1080p before display — you paid for 4× the storage and bandwidth for zero visible benefit. Match the upload to the display.

“PNG is always sharper than JPG.”

For photographs, JPG at 85% quality is visually indistinguishable from PNG and 5–10× smaller. PNG only wins when you need transparency (logos on top of video, watermarks) or when the image has large flat areas of solid color (text slides).

“I’ll just upload the original and let the system figure it out.”

For small files (under 5 MB), sure. For a 50 MB phone photo or a 4 GB ProRes video, you’ll fight slow uploads, hit storage caps, and risk stuttering on cheap devices. Spend two minutes resizing — the time savings on the upload alone are worth it.

“HEIC files from my iPhone work everywhere.”

iPhone defaults to HEIC for storage savings, but many display platforms don’t support it. Either change your iPhone’s camera setting to Most Compatible (Settings → Camera → Formats) so photos save as JPG, or convert HEIC to JPG before upload.

Free Tools

You don’t need Photoshop or Premiere to get good results. These free tools handle 95% of signage prep:

Image Compression & Resize

• TinyPNG / TinyJPG — Drag, drop, download. Cuts file size 60–80% with no visible quality loss.
• Squoosh (Google) — Side-by-side compare original vs compressed. Great for tuning quality settings.
• macOS Preview — Built in. Open photo → Tools → Adjust Size → set width to 1920. Export as JPG.
• Windows Photos — Open → click ... → Resize image → choose Define custom dimensions.

Video Transcoding

• HandBrake — Free, cross-platform. Use the Fast 1080p30 preset for signage — it’s already tuned to recommended bitrates.
• VideoProc Free — Simpler GUI than HandBrake. Good for quick conversions from MOV or AVI.
• QuickTime (Mac) — File → Export As → 1080p handles most basic re-encoding.
• FFmpeg (advanced) — One-liner for re-encoding any video to signage spec:
  ffmpeg -i input.mov -c:v libx264 -preset medium -b:v 3M -c:a aac -b:a 128k output.mp4

HEIC to JPG

• heictojpg.com — Drag and drop converter.
• iPhone: Settings → Camera → Formats → Most Compatible saves new photos as JPG by default.

Pre-Upload Checklist

Need help prepping a specific file?

Email us at hello@displaycache.com with the file and what device it’s going on — we’ll recommend exact settings.