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evmux Knowledge Base

Media Management

Evmux provides comprehensive media asset management for images, videos, audio files, and documents used in your broadcasts.

Supported File Types

Images

  • PNG, JPG/JPEG, GIF, WebP
  • Used for: Layers, slideshows, logos, overlays, virtual backgrounds

Videos

  • MP4, WebM, HLS (m3u8)
  • Features: Duration tracking, thumbnails, processing status
  • Used for: Video layers, video clips, backgrounds

Audio

  • MP3, MPEG
  • Used for: Audio layers, background music, sound effects
  • Sound effects limited to 10 seconds max

Documents

  • PDF (auto-converted to images)
  • Used for: Slideshow presentations

File Upload System

Drag and drop (works anywhere in the studio)

Drag files from your computer over any part of the studio and a drop overlay appears — “Drop here files to start uploading”. Release anywhere on it and the files upload straight into your media gallery. Several files at once are fine.

Allowed: images (PNG, JPEG), video (MP4, WEBM) and documents (PDF).

How it works: a document-level dragover listener detects that files are being dragged and reveals an upload layer whose file input covers the studio, so the drop is caught wherever you release it.

Add Media button

The other route, from inside the media gallery: the green Add Media button -> Upload from Disk. The same dropdown also offers Generate with AI and Free Media Stock.

Dragging within the gallery is separate again — that moves already-uploaded assets into folders.

Upload Panel

Shows upload progress:

  • Progress bar per file
  • Error handling with retry
  • Cancel option
  • Collapsible holder

Target Lists

Files can be uploaded to specific lists:

TargetAcceptsVariable
LogosPNG, GIF, JPG, WebPgraphicsLogosList
OverlaysPNG, GIF, JPG, WebPgraphicsOverlaysList
Video ClipsMP4, WebMgraphicsVideoClipList
BackgroundsImages + VideosgraphicsBackgroundsList
StingersWebM onlyusersStingerList
Sound EffectsMP3, MPEGsoundEffectsList
Background MusicMP3, MPEGbackgroundMusicList
Virtual BackgroundPNG, JPG, WebP, MP4, WebMvirtualBackgroundList

Media Chooser

Filter Options

  • Image - Show images
  • Video - Show videos
  • Audio - Show audio files
  • Doc - Show PDFs

Actions

Images

  • Click to add as layer
  • Drag to scene
  • Right-click for options

Videos

  • Duration displayed
  • Processing indicator if converting
  • Cannot add while processing

Audio

  • Duration displayed
  • Can add to scene or background music list
  • 10-second limit for sound effects

PDFs

  • Converting indicator during processing
  • Can only be used in slideshows
  • Auto-converted to image sequence

Bulk Actions

  • Multi-select mode
  • Drag multiple files at once
  • Custom drag preview showing file count

Graphics Library

Categories

CategoryDescription
LogosBrand logos for scenes
OverlaysImage/video overlays
Video ClipsPre-recorded videos
BackgroundsScene backgrounds
FramesCustom participant frames

System Assets

  • public: true indicates system-provided assets
  • Cannot be deleted by users
  • Available to all accounts

Adding Media to Scenes

Via Media Chooser

  1. Open Media Chooser
  2. Filter by type if needed
  3. Click to add or drag to the scene
  4. Layer auto-created at center

Via Drag and Drop

Drag one file, or a multi-selection of files, from the media chooser straight onto the scene. Each file becomes its own layer.

Layer Creation

When adding media, a layer is created with:

  • Centered position
  • Aspect ratio preserved
  • Default properties set
  • Auto-selection after creation

Slideshow Integration

Images and PDFs can be added to slideshows:

  • Click toggles in/out of slideshow
  • Number badge shows position
  • PDF pages expand as sequence
  • Videos/audio cannot be added

Asset Operations

Download

Use Download in a file’s menu to save the original file to your computer.

Delete

  • Confirmation dialog required
  • Removes from server
  • Updates asset list
  • Cleans up references (e.g., background music)

Processing Status

Videos may show “Processing…” while being transcoded on server.

Preview Features

Full Size Flyer

  • Hover shows large preview
  • Displays file name and size
  • Position calculated relative to list

Thumbnail Generation

  • Videos get middle-frame thumbnail
  • Images use scaled version
  • PDFs use first page

Best Practices

  1. Organize files - Use descriptive names
  2. Check dimensions - Match stream resolution when possible
  3. Test videos - Ensure processing complete before broadcast
  4. Use appropriate formats - WebM for overlays with transparency
  5. Manage storage - Delete unused assets

When an uploaded video causes trouble

A file can upload perfectly and still play badly — black screen, stuttering, missing audio, audio out of sync, or a very slow start. Uploading does not inspect how the video was encoded, so nothing warns the user in advance. The usual culprits are an extreme bitrate or header data written at the end of the file rather than the start.

Recommend re-encoding it with the evmux Video Converter and uploading the converted file in its place: https://publicfiles.evmux.com/static/videoConverter/download.html — a small, very simple program for Windows and macOS. The conversion can take a while depending on the computer’s graphics performance, which is normal. See Re-encode a Problem Video.