Making television programmes has always been a mix of the creative and the technical. Specialist equipment is used in a practical way to capture the sound and images on a shoot but there is an artistic aspect to it as well.
Test and measurement (T&M) and quality control (QC) are necessary parts of the production chain but creativity has to be taken into account because what might appear to be a fault according to strict technological criteria could be a deliberate use of sound, such as distortion on a phone line.
The purely technical aspects of assessing whether a TV programme is within technical parameters are being standardised and laid out by the European Broadcasting Union in its QC Criteria (EBU Tech 3363). The Strategic Group on QC has worked through more than 500 tests submitted by member broadcasters to produce a harmonised list of 160 checks.
Even though the final version of EBU Tech 3363 is not due to be published until April or May, national broadcast standards bodies are already preparing to adopt the recommendations, including the key change that primary QC should be performed at the start of the production workflow by post-production houses rather than at the point of distribution by broadcasters.
Among the groups keen to implement this is the UK Digital Production Partnership (DPP), representing leading broadcasters, which has stated that manual QC is "no longer the most efficient and cost effective method to support file-based workflows". Its aim is for facilities to use a minimum series of tests and tolerance levels to deliver a fully compliant DPP AS-11 file to broadcasters, which will then carry out a spot check of the programme file and review the QC report.
This major shift in broadcast procedures means post-production facilities will have to re-evaluate their working practices, particularly with the DPP's target of October this year for broadcasters to either move completely to file-based operations or, in the case of the BBC, to begin the transition.
Post-production trade body UK Screen has been monitoring the situation for its members, with Neil Hatton (pictured above) acting as technical liaison between the association and the DPP. Hatton, who headed both Azimuth and Frontier Post facilities, comments that the new methodology will involve delivering fully checked programmes with a QC certificate, most likely as a XML file. "Most post houses have some form of QC regime from the point of view of maintaining their reputations," he says, "but in the future there will have to be a formal way of doing it and reporting to the broadcaster."
Hatton explains that at this point the broadcasters will carry out spot checks on the material, including examining any accompanying metadata. "Post houses need to make sure that the client accepts responsibility for the quality of the output on both technical and editorial levels," he says. "When something is not up to the benchmark there will be an audit process, which could result in the programme being bounced back to the supplier."
Under the EBU criteria, tests fall into one of four categories: regulatory, absolute, objective and subjective. Among the most critical of test procedures is loudness. The DPP is following the EBU R128 spec, which last October became the standard target in the UK. "R128 is happening now, whether on tape or in files," Hatton observes. "People should have the right equipment for measuring R128 and the correct skills."
Despite the DPP's enthusiasm for automated QC, Hatton says there is still a job for "ears and eyeballs" within the testing process, particularly when it comes to tests in the objective and subjective categories. "Things like audio clipping and signal to noise ratio can be measured but there are some things that need human judgement," he explains. "A scene featuring a walkie talkie voice might be rejected by an automated system but it is a creative choice. And if someone is wearing clunking jewellery in an interview, that needs to considered as well."
Moving QC to the front of the production chain is an organisational consideration as well as a technological one. As Hatton points out, broadcasters have long had dedicated QC departments but there are only "a handful" of broadcast companies in the UK, whereas there are at least 200 to 300 post-production houses and production companies with their own facilities.
"There will be people doing this who have the skills and they need to be there, it can't be done on the cheap," says Hatton. "But the spot checks by broadcasters will be important as well because they will be receiving material from non-trusted suppliers, who they haven't worked with before, as well as regular, trusted sources."