Deliverables are the TV programs, promotions, advertising and other material that are delivered to broadcasters for distribution on their networks: TV channels, agencies, Web, DVD, mobile phones, etc. The business of making deliverables has hugely expanded with the widening scope of digital media platforms. Today it is a big and complex business.
As industry bodies like the UK’s DPP race ahead with implementation of AS-11 for broadcast TV program delivery, The Advanced Media Workflow Association (AMWA) has released an update to the MXF Commercial Delivery specification, AS-12.
Traditionally deliverables have been made by copying from the edited masters of programs, commercials, and any other material ready for transmission. This process involved copying the edited master to the customer’s required video format and recording medium for delivery to the broadcaster or publisher.
In the UK the industry has avoided dealing with a potentially huge selection of formats by the implementation of the DPP (Digital Production Partnership) standard which all users accept. This is an implementation of the AMWA AS-11 format.
Making deliverables can involve treatments such as pan and scan, color grading and standards conversion. If they are for use on mobile phones then different aspect ratios and sizes may apply, requiring processes such as conversion and image re-framing. Some internet video such as the BBC’s iPlayer catch-up service uses a lower frame rate to help reduce the data rate.
To provide the best quality for all users the original material should be produced in the highest required viewing resolution. Also the frame rate should be high enough to work well with the largest required format. For instance the 1080/24P or 25 HD format can be used to make high quality versions for most television formats. This top-down approach preserves quality as the HD image size means any resizing will be downward, making big pictures smaller, rather than up-res’d blow-ups from smaller pictures. For frame-rate conversion, over half a century of running movies on TV has established straightforward ways to fast play 24 f/s material to at 25 f/s and to map it to 60 Hz vertical rates using 3:2 pull-down for television. However, increases in the size and brightness of consumer displays mean that the resulting motion judder is becoming less acceptable, so that more sophisticated frame rate conversion is becoming necessary.
Combinations of fast replay (24 to 25 f/s), 3:2 pull-down, down-res and ARC are applied to output the required image format, vertical rate and aspect ratio. For example, fast play of 1080/24P at 104.16 percent speed produces 1080/25P. Down-res produces 16:9 images in 576 lines and then the 25 progressive frames are read as 50 interlaced frames to create the 576/50I TV format widely used in Europe and the old ‘PAL’ countries. ARC is applied for 4:3 output. Changing from 24P to 60I vertical scans is achieved using 3:2 pull-down. Increasingly, 104.16% fast play is becoming less acceptable because of the audio pitch shift, so people are demanding high quality 24 to 25 frame rate conversion.
Today a majority of movies are produced in the DCI 4K (4096 x 2160) standard for distribution. This is close in size to the UHDTV-1 4K TV standard and can be re-sized to 2K which is only slightly wider than 1080-line HD (2048 against 1920 pixels per line), and the same 1080 lines. However the sampling of TV is 4:2:2 whereas digital cinema uses 4:4:4, meaning that the TV material will not look quite as sharp as the 2K (or 4K!) made-for-movie content. Also TV and cinema use different colorspaces.
But that material may need further editing, for example, a commercial for showing in a different country may require a new soundtrack and text for pricing. There may be censorship issues so shots need adjusting or replacing. Also the growth of digital media platforms means that more work may be required for a wider deliverables market – with escalating numbers of versions required. Some scenes of a digital film master may need re-grading for domestic TV viewing or further processing to fit the bandwidth and screen limitations of mobile viewing.
This type of work may be best undertaken with the finished program in uncommitted form, where the source material and all the tools and their settings are available, so that any part of the program can be re-accessed, changed and the whole program re-output exactly as required for the target medium and without compromising the quality of other deliverables.