Media file input/ Video file input

Video file input supports playback of video clips, looping playback, and automatic startup. 

• Media source - Use the Load button to load a clip into Composer. If a clip has been loaded, but the file has been modified, you can use the Reload button to refresh the clip in Composer. Use the Clear button to unload the clip.
  Note! Only movie clips can be loaded–no image files. Supported media format and codecs.
• Playback state - Current playback state
• Commands
  • Play button - Start playback
  • Pause button - Pause playback
  • Stop button - Stop playback
• Configuration
  • End of file behaviour - Determines the action to perform at the end of the file. The options are Loop/repeat playback, Hold the last frame and Stop.
  • Synchronize playback  - All Movie inputs with this checkbox active will start their playback in sync.
  • Start playing when loaded - Check this option to automatically start playback when the file is loaded (Default).
  • Video decoder thread count - Number of CPU threads used for decoding. 
  • Prefer hardware decoding - (Default enabled) The GPU (NvEnc) will decode the file if enabled.  This will reduce the load on the CPU and is preferred for all h264 and h265 clips. (To enable this feature, the video file must be stopped first)
  • Hardware decoding active - If yes, the GPU is used to decode the file . The video file must have a resolution of a minimum of 48x48px. 
  • Cue points JSON - By adding a JSON array, it is possible to call a connector on a specific frame. This will trigger one or more events.
    In the example below, after 100 framesare played, it will trigger a connector called "TOP". After 200 frames, it will trigger the connector "FRONT".
    Example: [ { "100": "TOP" }, { "200": "FRONT" }]
• Script Engine Functions (optional)
  • On End-of-File - Specify a callback function for the Script Engine. Executed when the video file has ended.
• Performance and properties
  • Message - Info message
  • Avg video decoding time (ms) - average time (in ms) for decoding a video frame.
  • Video buffer memory used (MB) - Used memory for video buffer.
  • Parsed video buffer length (ms) - Video buffer length in milliseconds.
  • Parsed audio buffer length (ms) - Audio buffer length in milliseconds. 
  • Video buffer length (ms) - Number of video frames decoded (buffered) but not rendered. Buffered video might occur depending on how the video is encoded. For example, if the video encoding utilizes b-frames, there will be a longer video buffer than a video encoded without b-frames.
  • Audio buffer length (ms) - Audio buffer length (in ms)
  • Current time - Current playback time (Time code) in hours:minutes:seconds:frames.
  • Number of loops played - Number of loops performed.
  • VideoTrackInfo - Detailed debug information on video track properties.
  • AudioTrackInfo - Detailed debug information on audio track properties.
• Optional TAGS (space separated)
  • TAGS—Add a "tag" for the input smart search function. You can ass multiple tags by separating them with a SPACE-character.
• Resolution
  • Width -  Video width (pixels)
  • Height - Video height (pixels)

* Debug properties. Only visible if "Show debug properties" are enabled in Settings.

Media format and codecs 

Video with audio:
The .mp4 container is preferred for movie files, with an h264/h265 (HEVC) video track and aac audio track. There are multiple compressors for encoding original content or transcoding existing content. Available settings will differ between compressors. The most important settings are: 

• .mp4 container with h264/h265 video and aac audio
• Bitrate depends on resolution, but reasonable bitrates are generally between 3 and 15 mbit/s
• Keyframe (I-frame) distance set to double the move framerate
• AAC 48 kHz stereo, Bitrate 128 kbps or above
• If there are options for pooling or interleaving audio, interleaving should always be chosen

Video/audio with alpha channel:
It is possible to use a video containing an alpha channel. Save the video file as a .mov file with the video codec "Quicktime Animation", in colorspace RGBA (with alpha channel).

Handbrake

An excellent utility for transcoding media files is Handbrake. It is free and works for Windows, Mac, and Linux. These are the recommended key settings in Handbrake:

By default, Handbrake will use the suffix .m4v when saving a file, rename the suffix to .mp4 to make Composer recognize the file.

DaVinci Resolve

Another useful tool for converting video clips is Davinci Resolve: https://www.blackmagicdesign.com/products/davinciresolve

Clips exported from DaVinci Resolve is compatible with Composer. For efficient playback, we recommend the following settings:

• Format: mp4
• Codec: H.264 or H.265
• Network optimization: ON 
• Frame reordering: OFF