Video encoding guide

To make videos play smoothly on kiosks, the CMS re-encodes the videos you upload. This page covers that setting and the targets to use if you want to prepare videos yourself before uploading.

The CMS re-encodes uploaded videos

When you upload a video, the CMS re-encodes it according to the transcoding settings and sends it to the devices. So videos play even if you don’t match the specs below in advance — but each re-encode loses a little quality, so upload the original at the highest quality you have.

The setting is at Settings → Transcoding, and it is shown only to the master account (other accounts don’t see this tab at all; ask your TreeT contact if a value needs changing). Changed settings apply to videos uploaded from then on; videos already uploaded stay as they are. To change the size of an existing video, change the setting and upload the video again — the CMS does not keep originals, so it doesn’t re-encode them.

Item	Default	Meaning
Size rule	Long edge ≤ 1920	1920 · 3840 · custom (256–16384, even) or keep original. Larger long edges are scaled down, smaller videos are not enlarged, and the aspect ratio is kept
Portrait video	Encoded rotated to landscape (no option to choose)	The player rotates it back. With re-encoding off it is handled differently (below)
Codec	VP9 (file .webm · audio Opus)	AV1 (file .mp4 · audio Opus) can also be chosen. The CMS does not encode to H.264 or AAC — because of patent licensing (below)
Quality	Recommended (VP9 31 · AV1 30)	Chosen by measuring quality and size on many videos. Lower numbers mean higher quality
Frame rate	Keep original	Keep original · up to 60fps · up to 30fps. Above the cap it is first halved (50→25 · 60→30 · 120→60)

Portrait videos and portrait photos play exactly as uploaded

Device video decoders are tuned for landscape video. Some devices could not keep up in real time with a portrait 4K 60fps video played as-is, but managed when the same video was rotated to landscape. So when re-encoding is on, the CMS rotates portrait videos 90° before saving and the player rotates them back — on screen they stay portrait (there is no option to turn this off).

When re-encoding is off:

• Portrait videos shot on a phone are saved untouched; only the “show upright” marker is carried over — they appear upright on the device.
• Portrait videos made in an editing program are saved and played portrait, untouched.

Photos are first turned upright according to the orientation the phone recorded, then scaled (fit to a 1920×1080 box — independent of the encoding settings).

Videos at 4K or above · 60fps or above

• Low-end Android devices and Raspberry Pi cannot play 4K smoothly. At sites with such devices, use “long edge 1920” together with “up to 30fps”.
• With an 8K original on “keep original”, the CMS encodes 8K. Use it only for players that can decode 8K (desktop · high-end devices) — none of the Android devices we tested played 8K.
• 60fps costs twice the playback effort of 30fps. Dropping to 30fps saves only about 20% in size, so keep 60fps for high-motion videos (when the player can handle it).

VP9 · AV1 — check the playing devices first

• VP9 (default) — plays at FHD on desktops and most Android devices. Low-end Android devices stutter on VP9 4K — use it with “long edge 1920” where they are present.
• AV1 — smaller files at the same quality, but use it for desktop players only. Older Android (6.0) cannot decode AV1: you hear sound but the screen stays blank.
• Changing the codec does not change videos already uploaded.

Patent codecs — what is refused · what is removed

Uploaded	Re-encoding on	Re-encoding off
HEVC (H.265) video	Refused — the upload is rejected with the reason	Same
Video with AAC audio	Audio is re-encoded to Opus (sound kept)	The audio track is removed before saving (video untouched) · you are told after upload
iPhone photos (HEIC · HEIF)	Refused	Same

Both are because of patent licensing — these codecs can incur royalties per device that uses them.

• For iPhone videos and photos, set the iPhone to Settings › Camera › Formats › Most Compatible; it then saves H.264 and JPEG, which upload as they are.
• To upload a video that needs sound with re-encoding off, upload it as WebM with the audio converted to Opus (see “Preparing it yourself” below).

With re-encoding off, the uploaded file goes out as is

The codec and content licensing of that file is the customer’s responsibility (the settings screen says so too). And if a device cannot decode that format, it won’t play or will stutter — sites with re-encoding off should upload in the format below.

Preparing it yourself — recommended specs

With re-encoding on, you don’t need to match any format — upload the high-quality original (both H.264 MP4 and WebM are accepted) and the CMS encodes it with the settings above. At a site with re-encoding off, prepare videos like this:

Item	Value
Container	WebM
Video codec	VP9
Audio codec	Opus (128kbps · 48kHz)
Quality (CRF)	around 31 (lower is higher quality)
Size · frame rate	With low-end Android or Raspberry Pi present: long edge 1920 · up to 30fps

One line of the free tool ffmpeg does it:

ffmpeg -i original.mp4 -c:v libvpx-vp9 -crf 31 -b:v 0 -row-mt 1 -c:a libopus -b:a 128k -ar 48000 result.webm

• To scale down add -vf "scale=1920:-2" (landscape video); to drop to 30fps add -r 30.
• If the original’s resolution and frame rate are already within the limits, don’t change them.

Why VP9

We decided by putting together the results of playing the same video with only the codec changed on several devices (low-end to mid/high-end Android, desktop · Raspberry Pi) and the patent licensing assessment (2026-10).

Codec	Playback	Licensing	CMS
VP9	✅ desktop · most Android at FHD · ⚠️ low-end Android stutters at 4K	Royalty-free	Default
AV1	✅ desktop · ❌ older Android	Royalty-free	Can be chosen
H.264	✅ all devices	Patent pool	Not encoded (uploaded originals are accepted)
HEVC (H.265)	❌ many devices lack the codec	Several patent pools	Refused

4K does not work on every device

On low-end devices, 4K sometimes exceeded resolution or decoder limits and failed to play or stuttered. If you don’t know the specs of the devices at a site, long edge 1920 (FHD) is the safe choice.

If you must run 4K, play it once on the actual devices going to that site first.