theibcdaily
QC is key, but how to make it efficient?
Manual Quality Control does not scale in file-based broadcasting facilities
Frans de Jong: “I don’t think we will any time soon see a QC algorithm to correctly interpret green underwater shots”
By Frans de Jong, coordinator of the EBU QC Strategic Programme
In an ideal world a programme’s quality is watched over throughout the production chain, at acquisition, ingest, archive transfer, transcoding, post production, exchange and playout. Until now this has been a human exercise.
‘Golden eyes’ would make
sure no black, blurred or bad- taste frames would pass unnoticed. But with the move to file-based facilities the traditional model has become outdated. Manual Quality Control (QC) does not ‘scale’. It simply would be too expensive to have a pair of eyes check every piece of content existing in a facility. Besides that, the abstract
MXF integrity Quested explains: “We are approaching this problem from two sides. The requirements list is basically a scratch card of possible QC tests. These can be format-related, such as MXF integrity validation or a verification of the compression scheme used, but also baseband checks. “Think for example of
New RockNet expansion card released Riedel
By Monica Heck
Riedel is showcasing its new RockNet SI expansion card for digital Soundcraft SI consoles at this year’s IBC. The
RN.344.SI card, which is expected to ship at the end of the third quarter of 2012, fits into any Soundcraft SI console’s expansion slot. In its first firmware release, the card will support 32 inputs and 32
outputs to the RockNet system. A world clock output is available at the front panel. A rotary switch is provided for device identification and selection of up to 16 programmable routing tables.
The
RN.344.SI enables
the respective Soundcraft product to become a part of the RockNet digital audio network and enables remote control of any RockNet microphone pre- amplifier.
It also supports RockNet’s Independent Gain feature. Independent Gain is described as convenient for multi-console and recording setups. It allows several mixing consoles to operate with the same mic pre-amps without affecting each other. While the master-console is controlling the analogue gain of the pre-amps remotely, all other consoles operate with emulated pre-amps just as if they were also controlling the actual mic input.
nature of audio and video wrapped in files has taken away some of the basic quality assurances that existed in the tape-based world. Cassettes used to fix most of the technical parameters, but a modern file can virtually contain anything, which quickly leads to difficult- to-prevent interoperability problems. Small differences can have large consequences. A simple (bit) error in a file can make it impossible to playout a programme. So it should be no surprise that QC at the forefront of broadcasters’ concerns. In 2011 the EBU made QC into one of its Strategic Programmes. Led by industry veteran Andy Quested (head of Technology, BBC HD & 3D), a group of professionals from broadcasters and QC product providers is creating guidance for setting up QC in file-based facilities. The participants share QC test material and have collected a large list of requirements. Current focus is on specifying exactly how to test each of the listed QC items, including tolerances and thresholds to signal what is a ‘pass’ or a ‘fail’.
blockiness detection or a scan for audio clipping. The idea is that individual broadcasters can pick and choose items from the list and ask vendors for products supporting these. The exact implementation and representation (interface) obviously is up to the manufacturers to decide. There is, and should continue to be, healthy competition between QC product providers. “With the requirements list we just want to make sure we all speak the same QC language. This holds for the reporting part too, which is the second side we’re working on. The lack of a common output format is a big issue hindering integration. Reporting also can mean the difference between a useable or a useless product. We’ve frequently heard the complaint that products report too many problems, swamping the user with QC data to sift through. By defining some minimal reporting features, we hope to improve both the interoperability and usability of QC tools.”
First generation The timing of the EBU’s QC work is deliberate. Quested says: “You could say the QC software market has only just started booting up. We did some tests last year, which showed products that did not even support timecode or simple audio checks! Clearly these were first generation tools. “But from the conversations in our group and the interest in file-
Riedel’s RockNet suite of console interfaces already includes interface cards for Yamaha, Studer and Soundcraft consoles as well as a MADI unit for integrating consoles from additional brands. RockNet allows consoles from various manufacturers to operate simultaneously. RockNet is a digital
realtime audio network that provides up to 160 digital audio channels over a single counter-rotating CAT-5 ring. It offers audio quality with up to 96kHz/24-bit and a dynamic range of up to
Monday 10.09.2012
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based QC in the market, I am convinced the situation will evolve rapidly. We should be careful about our expectations on the human side of the computer, though. I don’t think we will any time soon see a QC algorithm to correctly interpret green underwater shots. The context- awareness of humans is hard to mimic, as anybody who has worked in the Artificial Intelligence field will be able to confirm. “So we can expect to see a combination of automated QC at multiple stages throughout the production chain, complemented with human ‘eyeball’ QC for the more subjective elements. The idea is to design the workflow in such a way that the automated QC rejects material as early on as
“You could say the QC software market has only just started booting up. We did some tests last year which showed products that didn’t even support timecode or simple audio checks!” – Andy Quested
possible, to prevent people unnecessarily checking those files. “This is the approach we are using in the UK, for example, based on the AS-11 shim the Digital Production Partnership has created. We will be demonstrating the basis of this process at the EBU QC Workshop on 7-8 November, together with many QC tools. The IBC exhibition offers a good moment to look at the latest product improvements. Processing speed, in particular, is key, because to make QC efficient, optimised workflows and interoperable products alone are not enough – the QC tool itself must be fast too.”
The RockNet SI expansion card is designed for digital Soundcraft SI consoles
117dB. Based on a redundant ring topology, RockNet is described as forming a self-healing redundant network with no loss of audio in case of a connection fault between two devices. 10.A31
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