AS-03 was developed in a partnership between AMWA and PBS as part of a sub project of PBS’ Next Generation Interconnection System (NGIS), the Non-Real-Time Program File Delivery Project (NGIS-NRT). AS-03 is a constrained sub-set of the MXF standard and allows interoperability with editing workflows and video playout servers from AMWA members such as Avid, Grass Valley, Omneon and Harris. RadiantGrid was asked to join AMWA to develop a means of transcoding files to AS-03 delivery format.
“AS-03 is a version of MXF which is used for the playback of finished programming in a server environment,” says Brad Gilmer, executive director of the Advanced Media Workflow Association (AMWA). “The specification was driven by PBS, which needed a rock-solid way to distribute programs to PBS-member stations. RadiantGrid's support for AS-03 fits perfectly not only into the workflow envisioned by PBS, but also fulfills the goals of the AMWA in enabling networked media workflows.”
Since RadiantGrid combines multiple isolated processes under one platform, including closed caption management, broadcasters are able to more quickly and efficiently manage their content. PBS is the first to implement RadiantGrid’s AS-03 support into its workflow for its NGIS-NRT initiative. AS-03 MXF files are prepared using the RadiantGridTM Platform to transform the video essence data into MPEG-2, the audio essence data into PCM and AC-3 and ancillary (closed caption) data into SMPTE 334M and SMPTE 436M VANC structures, which are muxed into the AS-03 MXF container format. In the case of PBS, these AS-03 MXF files are then delivered to PBS member stations over satellite.
“With more broadcast outlets looking towards file-based delivery, we felt it was essential that RadiantGrid be one of the first companies whose platform supports AS-03,” says Kirk Marple, president, chief software architect, RadiantGrid Technologies. “Now our users can still have access to the faster-than-real-time transcoding along with multiple concurrent processes that they have come to expect from RadiantGrid with the added option of working in AS-03.”
With RadiantGrid’s Closed Captioning Management Module, broadcasters are able to extract closed captioning from media sources and insert closed captioning back into the transcoded output file. This is done concurrently along with other transcoding functions as opposed to having to put them into another program once complete with other processes.
SMPTE 436M joins the extensive list of closed captioning formats the RadiantGrid Platform can support, including SMPTE 360M within VANC data in a GXF container, ATSC EIA-608 and EIA-708 within user data in an MPEG-2 program stream, ATSC EIA-608 and EIA-708 within VANC data in an MPEG-2 transport stream, bitmapped VBI data in the visible video stream or SAMI and SCC in a textual format.
In addition to providing multiple concurrent processes under one platform, RadiantGrid’s TrueGridTM transcoding technology allows users to transcode files faster than other platforms. RadiantGrid accepts many media archive essence formats and ingestion container formats, such as Avid DNxHD, Avid IMX50, MPEG-2 Long GOP, GXF and MXF Op-Atom and Op1a. From any of these container formats, RadiantGrid can deliver content to broadband, mobile, cable and broadcast formats and standards such as Microsoft Silverlight (VC-1), H.264, CableLabs 1.1 MPEG-2, QuickTime DVCPRO-HD, Flash On2 VP6, 3GPP and the Apple iPhone.