Creating a SMIL Playlist

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. The @content is a URL pointing to ISOBMFF file, where the MovieBox (moov) represents desired target profile.

Without setting this, the first clip in the playlist will be used as the target profile.

seq

The <seq> element holds a list of one or more clips to be played consecutively.

isContinuous

New in version 1.12.2.

Boolean attribute seq@isContinuous (default false) indicates that child elements comprise a contiguous sequence. (E.g.: nPVR archive) The segments are merged into one before clipping, conditioning and alignment.

par

The <par> element combines multiple files to be presented simultaneously. This is useful if different tracks are stored in separate source files. (E.g.: CMAF files)

clipBegin / clipEnd

The @clipBegin and @clipEnd attributes can be used to select the time span to be presented rather than whole.

currently only supports using the "wallclock(ISO 8601)" format, not all formats included in SMIL 2.0
clip timing reflects the media timeline of the source

Clip attributes are valid in <audio> and <video> elements as well as <seq> and <par>, but logically the cuts should always be simultaneously across all tracks.

clipMode

The @clipMode attribute specifies how to handle @clipBegin and @clipEnd values that do not match a fragment boundary in the source media. See also: Specifying conditioning info using 'clipMode'.

ConditioningInfo, EventStream, Event

See: Media Conditioning For Ad Insertion and Specifying Timed Metadata in a SMIL playlist.

When using remixing archive segments captured with --remix we recommend creating a sequence <seq isContinuous="true" clipBegin"..."> around the archive segments and ensuring that enough priming media is available in the first archive segment.

This avoids a problem previously caused by Unified Remix not being able to find a sync-sample near the start of the archive.

SMIL Examples 

A SMIL playlist to play a pre-roll bumper and 30 seconds of Tears of Steel looks like this:

<?xml version="1.0" encoding="utf-8"?>
<smil xmlns="http://www.w3.org/2001/SMIL20/Language">
  <head/>
  <body>
    <seq>
      <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)"/>
    </seq>
  </body>
</smil>

A use case with pre- and mid-roll advertisements using Sintel as the main content, targeting Sintel for the output profile:

<?xml version='1.0' encoding='UTF-8'?>
<smil
  xmlns="http://www.w3.org/2001/SMIL20/Language">
  <head>
    <meta name="outputDescription" content="http://storage/main/sintel/sintel_dref.mp4"/>
  </head>
  <body>
    <seq>
      <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)"/>
    </seq>
  </body>
</smil>

An example based on different bitrates in separate MP4s, using <par> to combine these MP4s into a single clip, followed by a single media source that contains the same tracks:

<?xml version="1.0" encoding="utf-8"?>
<smil xmlns="http://www.w3.org/2001/SMIL20/Language">
  <head>
  </head>
  <body>
    <seq>
      <par>
        <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" />
      </par>
      <video src="http://local-storage.unified-streaming.com/demo/tears-of-steel/tears-of-steel-teaser-no-jpg.ism" />
    </seq>
  </body>
</smil>

An nPVR example where multiple 5 minute segments are merged and clipped for re-broadcast.

<?xml version="1.0" ?>
<smil xmlns="http://www.w3.org/2001/SMIL20/Language">
  <head/>
  <body>
    <seq>
      <!-- replay yesterday's match from nPVR archive -->
      <seq clipBegin="wallclock(2022-08-23T06:11:59.60)"
             clipEnd="wallclock(2022-08-23T06:21:04)"
        isContinuous="true">
        <video src="http://storage/blobs/205-1Oqn6U.ismv"/>
        <video src="http://storage/blobs/205-1OqnbK.ismv"/>
        <video src="http://storage/blobs/205-1OqngA.ismv"/>
        <video src="http://storage/blobs/205-1Oqnlq.ismv"/>
      </seq>
    </seq>
  </body>
</smil>

For a more complicated example, here is the same nPVR example, but interrupted by an add break and news break.

nPVR playlist with intermission

<?xml version="1.0"?>
<smil xmlns="http://www.w3.org/2001/SMIL20/Language">
  <head/>
  <body>
    <seq>
      <!-- replay yesterday's match from nPVR archive -->
      <seq clipBegin="wallclock(2022-08-23T06:11:59.60)"
             clipEnd="wallclock(2022-08-23T06:21:04)"
        isContinuous="true">
        <video src="http://storage/blobs/205-1Oqn6U.ismv"/>
        <video src="http://storage/blobs/205-1OqnbK.ismv"/>
        <video src="http://storage/blobs/205-1OqngA.ismv"/>
      </seq>
      <!-- intermission -->
      <video src="local/ads/buy-emergendizer.mp4" />
      <!-- replay nine o'clock news update, but skip the weather -->
      <par clipEnd="wallclock(6:41.28)" clipMode="sample">
        <audio src="http://recorded/latest-news.cmfa"/>
        <video src="http://recorded/latest-news-low.cmfv"/>
        <video src="http://recorded/latest-news-medium.cmfv"/>
        <video src="http://recorded/latest-news-high.cmfv"/>
      </par>
      <!-- pick up nPVR where we left off -->
      <seq clipBegin="wallclock(2022-08-23T06:21:04)"
             clipEnd="wallclock(2022-08-23T06:30:00)"
        isContinuous="true">
        <video src="http://storage/blobs/205-1OqngA.ismv"/>
        <video src="http://storage/blobs/205-1Oqnlq.ismv"/>
      </seq>
    </seq>
  </body>
</smil>

Creating a SMIL Playlist

SMIL Origin

SMIL functionality supported by Remix

SMIL Examples

SMIL Origin 

SMIL functionality supported by Remix 

SMIL Examples 