Microsoft Smooth Streaming Client 2.5 with MPEG DASH Support

The PlayReady team, working in conjunction with the Windows Azure Media Services team is pleased to announce the availability of the Microsoft Smooth Streaming Client 2.5 with MPEG DASH support.

This release adds the ability to parse and play MPEG DASH manifests in the Smooth Streaming Media Engine (SSME) to provide a Windows7/Windows8 and MacOS solution using MPEG DASH for On-Demand scenarios.

Developers that wish to move content libraries to DASH have the option of using DASH in places where Silverlight is supported. The existing SSME object model forms the basis of DASH support in the SSME. For example, DASH concepts like Adaptation Sets and Representations have been mapped to their logical counterpart in the SSME.

Also, Adaptation Sets are exposed as Smooth Streams and Representations are exposed as Smooth Tracks. Existing Track selection and restriction APIs can be expected to function identically for Smooth and DASH content.

In most other respects, DASH support is transparent to the user and a programmer who has worked with the SSME APIs can expect the same developer experience when working with DASH content.

Some details on the DASH support compared to Client 2.0:

  • A new value of ‘DASH’ has been added to the ManifestType enum. DASH content that has been mapped into Smooth can be identified by checking this property on the ManifestInfo object. Additionally the ManifestInfo object’s version is set to 4.0 for DASH content.
  • Support has been added for the four DASH Live Profile Addressing modes: Segment List, Segment Timeline, Segment Number, and Byte Range.
  • For byte range addressable content, segments defined in the SIDX box map 1:1 with Chunks for the track.
  • A new property, MinByteRangeChunkLengthSeconds, has been added to Playback Settings to provide SSME with a hint at the desired chunk duration.
  • Multiple movie fragments will be addressed in a single chunk such that all but the last chunk will have a duration greater than or equal to this property. For examples of how to set Playback Settings see the Smooth documentation.

There are some limitations in this DASH release, including:
  • Dynamic MPD types are not supported.
  • Multiple Periods are not supported in an MPD.
  • The EMSG box is not supported.
  • The codec and content limitations that apply to Smooth similarly apply to DASH. (see here)
  • Seeking is supported, but not trick play. Playback rate must be 1.
  • Multiplexed streams are not supported.
If you have feature requests, or want to provide general feedback, please use the Smooth Streaming Client 2.5 forum.

Source: Microsoft