Ambassador Video Output Recommendations i.e. file limit, file type, orientation – Vepple

Ambassador Video Output Recommendations

You’ll need to export a separate video file for each Ambassador clip.

Here are the recommended specifications for the files:

MP4

Setting	Recommended Value	Notes
Format / Container	MP4 (H.264)	Broadest browser and device support
Resolution	512×512	Cropped square from source footage
Frame Rate	25 or 30 fps	Match source if possible
Video Bitrate Mode	VBR, 1-pass	Efficient for short clips
Target Video Bitrate	300–350 kbps	Good balance for quality and size
Max Video Bitrate	450–500 kbps	Prevents spikes in file size
Audio Codec	AAC	Standard, compatible audio format
Audio Bitrate	96 kbps	Clear enough for speech
Audio Sample Rate	44.1 or 48 kHz	Use 48 kHz if unsure
Audio Channels	Stereo or Mono	Mono is slightly more efficient
Keyframe Distance	Every 2 seconds (e.g. 60 at 30fps)	Helps with scrubbing and streaming
H.264 Profile	High	Better compression than Main/Baseline
Streaming Optimization	Enabled (Web Optimized / Fast Start)	Ensures video plays before fully loaded

WebM

Setting	Recommended Value	Notes
Format / Container	WebM	Efficient, open format for web
Video Codec	VP9 (libvpx-vp9)	Excellent quality at lower bitrates
Resolution	512×512	Square crop, same as MP4 version
Frame Rate	25 or 30 fps	Match source
Bitrate Mode	CRF + maxrate	CRF handles quality, maxrate keeps size in check
CRF	32	Equivalent to ~300–350 kbps VBR
Max Bitrate	450–500 kbps	Prevents spikes in bandwidth usage
Audio Codec	Opus (libopus)	Modern, efficient speech codec
Audio Bitrate	96 kbps	Great clarity for voice
Audio Sample Rate	48 kHz	Standard for web audio
Audio Channels	Mono or Stereo	Mono saves a bit more space
Keyframe Interval	Every 2 seconds (e.g. 60 at 30fps)	For consistent streaming/scrubbing
Row-MT (multi-threading)	Enabled (-row-mt 1)	Speeds up VP9 encoding
Streaming Optimization	N/A (WebM streams progressively)	No faststart flag needed

Helpful Scripts for Video Processing (Using FFmpeg)

Below, you’ll find scripts that are pre-configured to take a portrait input video (for example shot on a mobile phone) and turn it into a web-optimised square video for use in Ambassador bubbles.

FFmpeg is a free, open-source command-line tool used to process video and audio. It's widely supported, highly flexible, and ideal for automating tasks like cropping, resizing, compressing, and converting videos into web-optimized formats.

What You Need

Download FFmpeg and install it (available for macOS, Windows, and Linux)
Open your terminal (or command prompt)
Run the commands below by replacing input.mp4 with your actual file name

Script 1: Export Square MP4 (H.264) with Audio for Web

On Mac/Linux:


ffmpeg -i input.mp4 \
-filter:v "crop=in_w:in_w:0:in_h/5,scale=512:512" \
-c:v libx264 -preset slow -crf 30 \
-c:a aac -b:a 96k \
-movflags +faststart \
output-512x512.mp4

On Windows:

ffmpeg -i input.mp4 -filter:v "crop=in_w:in_w:0:in_h/5,scale=512:512" -c:v libx264 -preset slow -crf 30 -c:a aac -b:a 96k -movflags +faststart output-512x512.mp4

What it does:

Crops to a square, starting just above the vertical center - (in_h/5) starts cropping one-fifth of the way down the video — this places the square slightly above vertical center, which often frames a person more naturally (e.g. head and shoulders)
Resizes to 512×512
Compresses video using H.264 at high quality (CRF 30)
Keeps clear speech with AAC audio at 96 kbps
Enables fast web playback with +faststart

Script 2: Export Square WebM (VP9 + Opus) with Audio for Web

Mac/Linux:

ffmpeg -i input.mp4 \

-filter:v "crop=in_w:in_w:0:in_h/5,scale=512:512" \

-c:v libvpx-vp9 -crf 32 -b:v 0 -row-mt 1 -threads 4 \

-c:a libopus -b:a 96k \

output-512x512.webm

Windows:

ffmpeg -i input.mp4 -filter:v "crop=in_w:in_w:0:in_h/5,scale=512:512" -c:v libvpx-vp9 -crf 32 -b:v 0 -row-mt 1 -threads 4 -c:a libopus -b:a 96k output-512x512.webm

What it does:

Same crop & resize as the MP4 version
Uses the VP9 codec for better compression at smaller sizes
Includes Opus audio, designed for high-quality speech
-crf 32 provides a great balance of quality and file size (~1–1.5MB for 30s)