Accurate Player - Product Specification


Known limitations

If a file contains both audio and video the following restrictions apply:

  • The audio track and the video track should have the same duration.
  • All tracks must be aligned. No track may start ahead of another track.

The files may not contain a complex edit list because that will cause most browsers to misbehave. If an edit list is included it must have exactly one segment which spans the entire duration of the video stream. Edit lists are sometimes embedded in the video file by editing software if the file has been edited.

Progressive download

The ProgressivePlayer can detect most types of common encoding errors and compensate for them to always maintain frame accuracy.

  • Supported video formats: MP4 & MOV (AVC/h264 & HEVC/h265 (*) )
  • Supported audio formats: AAC/MP4, PCM/WAV, MP3/MP3, AAC/ADTS, Vorbis/OGG, Opus/Ogg, Opus/WebM, FLAC/FLAC, FLAC/Ogg (*)
  • Playback of segments from one or more videos via CutlistPlayer API

General recommendations

Although Accurate Player supports all of the formats listed above, these are the general guidelines that we usually recommend for best performance.

  • Video: MP4 (H.264)
  • Audio: AAC
  • Shorter GOP size improves the scrub and seek time, around 30 frames can be considered short.

When it comes to resolution, bit rate and frame rate it's more important to think about the individual use case and the limitations for the container format.

Variable Frame Rate

Accurate Player supports frame accurate playback of variable frame rate videos for progressive download, the same video formats are supported as for constant frame rate videos.

DASH features

  • VOD, Live, and In-Progress Recordings (dynamic VOD content)
  • Multi-period content (static and dynamic)
  • Multi-codec/multi-container manifests
  • Encrypted content
  • Key rotation
  • WebVTT (both text and embedded) and TTML (both XML and embedded)
  • AbrPlayer API Documentation

HLS features

  • VOD, Live, and Event types
  • Encrypted content
  • MPEG-2 TS support
  • WebVTT (both text and embedded) and TTML (both XML and embedded)
  • AbrPlayer API Documentation

DRM support

DRM encryption will make it impossible to compensate for encoding errors within the stream, therefore correctly packaged material is key to guarantee frame accuracy.


  • Multiple simultaneous discrete audio tracks for progressive playback of audio files via DiscreteAudioPlugin
  • Toggle mute per audio track
  • Individual audio channel toggle and routing within an audio track

Subtitles & Closed Captions

  • Playback multiple simultaneous subtitle/CC tracks using the TimedTextPlugin, it supports;
    • WebVTT
    • IMSC
    • SCC
    • SRT
    • STL
    • PAC
  • See DASH & HLS for supported alternatives


A set of default hotkeys can be activated by enabling the HotkeyPlugin.

  • Rebindable hotkeys
  • Sensible default hotkeys
  • JKL support


The core player is extendable with plugins to activate more advanced features. A few examples is:

  • ChannelControlPlugin - enables muting and routing of individual audio channels within a track.
  • DiscreteAudioPlugin - allows playback of discrete audio tracks in sync with the video.
  • PointPlugin - allows the user to create frame accurate in- and out points.

The complete list of plugins and API documentation can be found here.

Browsers and operating systems

Accurate Player is built primarily for professional users working in a desktop environment. The list below is what we officially support, although the player might be partially compatible with other platforms as well.

Latest stable version and the previous version of the following browsers:

  • Chrome (recommended)
  • Firefox

Operating systems might affect the browsers native behavior, which is why we recommend always using the latest stable version of Windows or OS X.

AbrPlayer is based on Shaka Player, see their Browser support matrix for more information.

Known issues

* In supported browsers

Document Index

    System Overview pages

    Product features
    • Accurate Player - Product Specification
    Accurate Video System Overview