UK HD TV: Interlace not dead yet
Wednesday, 09 July 2014
From October 1 2014, nearly all UK broadcasters will only accept TV programmes as files - tapes will not be allowed. To help independent TV production companies prepare for 'File Delivery Day,' the UK Digital Production Partnership have agreed on standards for everyone to follow.
The Digital Production Partnership is "funded and led by the BBC, ITV and Channel 4 with representation from Sky, Channel 5, S4/C, UKTV and BT Sport to help producers and broadcasters maximise the potential of digital production."
An important aspect of the technical standard is for those who like to use animated graphics, transitions, titles and credits scrollers: they must be rendered as interlaced. Even if all the video in a programme is 25 frames per second progressive…
moving graphics and effects […] must be generated and added as interlaced to prevent unacceptable judder.
To see YouTube attempt to show the interlaced fields, use the settings control (the cog) to choose 1080p (HD) and then click the full screen button in the bottom-right corner of the player.
In Final Cut Pro X, make sure your projects are 1080i25 and to check that graphics and transitions are properly interlaced, use the 'Show Both Fields' option in the Viewer's pop-up menu.
The UK TV file format specification:
Each high definition programme must be delivered as a single MXF OP1a file which conforms to the AMWA specification AS-11 v1.1. The AS-11 file must use the ‘UK DPP shim specifications’ that describe exactly how the file must be constructed to meet DPP requirements
Final Cut Pro X users will have to turn to third parties to handle the video encoding and required metadata. Currently the only product that is available is Hamburg Media's AS-11 Suite.
The rest of the specifications (including the standard allocation of 16 audio tracks), read the Digital Production Partnership Technical Delievery Standards document.