Remix VOD for Ads


Remix VOD for Ads enables server side mixing of content to produce a single output stream. Clients and playback devices see the stream coming from a single origin and having a timeline without any discontinuities.

In addition to the standard functionality provided by Remix VOD it adds:

  • signalling for advertisement tracking, for example, based on a VAST 4.0 XML which includes events with callback URLs
  • passing or inserting VAST messages to trigger events downstream
  • just-in-time transcoding for mismatched content

The solution makes use of three Unified Streaming Platform products:

  • Remix, to create a single presentation from multiple input sources
  • Origin, for Just-In-Time packaging/transmuxing to all supported streaming formats
  • Transcode, for Just-In-Time transcoding of audio and video to match a desired output profile

Remix VOD for Ads allows for the following use case:


Unified Origin

Playout Origin for content, this takes the remixed MP4 created by Remix and plays out all streaming formats, optionally with DRM applied.

Transcode Origin

If content doesn’t match the non-matching content will be transcoded so that it will match. An obvious example is content with a different resolution, but content needs to match on many other properties as well.

Remix Origin

Based on a SMIL playlist compares the listed sources and produces a single remixed MP4.

Remix Caching Proxy

The Remix process is relatively intensive, but only really needs to be done once for any given presentation. The caching proxy sits between the Unified Origin and Remix Origin to prevent unnecessary repetition of the Remix process.

This can be any HTTP caching proxy, e.g. Apache httpd with mod_cache and mod_proxy, NGINX, Varnish.

SMIL Origin

Creates a playlist based on a request URL.

This is the most important integration point as it provides the mapping of a request URL to the source media that will be used to produce the final presentation.


SMIL Origin

The SMIL Origin must return a SMIL 2.0 (Synchronized Multimedia Integration Language) playlist.

SMIL functionality supported by Remix

  • ‘outputDescription’ meta element in head to point to target profile
    • Without setting this, the first clip in the playlist will be used for the target profile
  • ‘seq’, sequence of clips to playout
  • ‘par’ combine multiple files into a single clip as part of the sequence, e.g. if different bitrates are stored in separate source files
  • ‘clipBegin’, ‘clipEnd’, to select only parts of the clip rather than whole
    • currently only supports using the “wallclock(ISO 8601)” format, not all formats included in SMIL 2.0

SMIL Examples

A SMIL playlist for a simple use case that will play a pre-roll bumper and 30 seconds of Tears of Steel looks like this:

<?xml version="1.0" encoding="utf-8"?>
<smil xmlns="">
      <video src="http://sample-content/logo_5s_dref.mp4"/>
      <video src="http://sample-content/tears-of-steel-dref.mp4" clipEnd="wallclock(1970-01-01T00:00:30.000Z)"/>

An example for a use case with pre- and mid-roll advertisements using Sintel as the main content, targetting Sintel for the output profile:

<?xml version='1.0' encoding='UTF-8'?>
    <meta name="outputDescription" content="http://storage/main/sintel/sintel_dref.mp4"/>
      <video src="http://storage/ads/origin/origin08_x264.mp4"/>
      <video src="http://storage/main/sintel/sintel_dref.mp4" clipEnd="wallclock(1970-01-01T00:00:30.000Z)"/>
      <video src="http://storage/ads/capture/capture10_x264.mp4"/>
      <video src="http://storage/main/sintel/sintel_dref.mp4" clipBegin="wallclock(1970-01-01T00:00:30.000Z)" clipEnd="wallclock(1970-01-01T00:01:00.000Z)"/>

An example based on different bitrates in separate MP4s, using <par> to combine these MP4s into a single item:

<?xml version="1.0" encoding="utf-8"?>
<smil xmlns="">
        <video src="http://storage/path/to/files/file_1280.mp4" />
        <video src="http://storage/path/to/files/file_1024.mp4" />
        <video src="http://storage/path/to/files/file_768.mp4" />
        <video src="http://storage/path/to/files/file_480.mp4" />
      <video src="" />


Storage for Remix VOD for Ads can consist of any form of attached storage (a mount point on the filesystem) or HTTP accessible storage such as S3.

The only requirement is that content must be accessible at the same path from both Remix Origin and Unified Origin, e.g. if using network attached storage mounted to /storage, the mount must be the same on all Remix Origins and Unified Origins.


Remix VOD for Ads is flexible when it comes to deployment options, as both Unified Origin and Remix are stateless and work over HTTP. This means it can easily be deployed on both physical or virtual hosts, or using container technology such as Docker.

Our GitHub Remix Demo has each component running in a separate Docker container, and uses Docker Compose to deploy and configure them to produce a working environment.

Supported OS and software versions

Remix requires Apache 2.4.x.

Recommended OS and web server versions are:

Ubuntu 14.04 Apache/2.4.7
Ubuntu 16.04 Apache/2.4.18
Alpine Linux v3.4 Apache/2.4.27


Remix VOD for Ads can be deployed using various approaches:

  • Bare metal
  • Virtual machines as for instance Amazon EC2
  • Container environments managed by for instance Kubernetes