Why a modern production facility needs Automated Quality Control (AQC) in 2019
QC is a technical nightmare that can catch everyone out. Automatic Quality Control of content is an important aspect of file-based workflows and one that should not be taken lightly. Content that does not match broadcast or on-demand delivery specifications can have a detrimental impact on your media business. Content can be rejected by a service provider and sent back to the content maker for rework, which in some instances can include, re-grade, a new audio mix or a retake of an entire scene. This can lead to a great expense for the content maker and a significant hit on the bottom line. With tight margins and very compressed deadlines, nobody wants to affect the bottom line.
There is a common misconception that the implementation of an AQC solution is complicated and expensive. Firstly when you take a look at what AQC is good at, the return on investment is measured in days rather than months. Automation results in significant cost savings for a media business. Let’s remember that AQC systems are better at maths than most humans! Not all AQC systems are created equal and a key factor determining effectiveness is the quality of the user interface. Through a minimal number of mouse clicks, users can achieve compliance. QScan’s unique timeline overview allows users to quickly understand where the problem arises with their content. The single-pass technology allows adjustments to be made (e.g. video levels) without the need for any retesting - saving considerable time, effort and money on the QC process. Today’s AQC software makes the setup process much easier: It is a set and forget solution. With built-in templates or profiles set up to the delivery specification required, users can sit back and relax and let the software do the testing. If users are constantly changing parameters and fiddling with templates then perhaps something is fundamentally wrong with their workflow or worse, their business.
AQC can be divided into two key areas - Container checks and Baseband checks:
The most basic aspect anyone wants to know about file delivery - Is the file what it says it is? How do you know that you have received an MXF Op1a file and not a QuickTime file? Well, surely you just look at the file extension? Right? After all, why would anyone change the file extension from .mov to .mxf. Odd as it may seem, it’s been done.
Obviously this is the part of the file that includes technical and descriptive metadata, which might be simple things like how many audio tracks there are and what language they are etc. What can possibly go wrong with that? The answer is quite a lot. The good news is that AQC is very efficient and reliable at spotting inconsistencies between the ‘wrapper’ (container) and the ‘essence’ (the video and audio within). For example, it can check that there are two physical audio tracks as described in the container’s metadata.
More importantly though, with more complex containers like MXF, AQC systems can check the whole file integrity very quickly. This is something a human simply cannot do. Just playing the file with VLC is not good enough, because many players like VLC only look at the essence for playback and not the whole file. Broadcast and OTT systems, however, rely on information in the wrapper for transcode information as well as audio track mapping and EPG data
Typically this is the video and audio essence within the file container or wrapper. There are many things that can wrong here.
Typical Video errors that may appear:
- These types of checks often start with the codec, is it what it says it is? Are the bitrates and frame rates correct? Is the aspect ratio correct?
- Once the above have been tested and verified, users can move on and check the actual levels of the video - this includes black level, chrominance and luminance.
- Are there any freeze frames present?
- Is the field order correct?
- Are there any macro block errors (caused in transcode and bit rate reduction processes).
Typical Audio errors:
- Are there the correct number of audio tracks?
- Is there even audio present, is it muted?
- Are they true stereo or just dual mono?
- Are the levels correct? All broadcast standards for file-based audio loudness are derived from ITU-R BS.1770-3. This defines the Broadcast Loudness and True Peak measured in LUFS (Loudness Units relative to Full Scale)*. Any AQC system of repute should be able to test audio levels against this.
Additionally, there are regional standards that make use of this:
- EBU-R128 - Europe
- ATSC A/85 US standard that focuses on the AC3 codec In the US the Commercial Advertisement Loudness Mitigation (CALM) Act took effect in 2011. This mandated that commercial content could not be broadcast with louder audio than that of the program content. It’s called TR-B32 in Japan and OP-59 in Australia
Published Delivery Specifications
Perhaps the most well known global delivery standards are Netflix/iTunes and Amazon Prime Video. These standards are widely available in the public domain. Other well known delivery specifications are the AS-11 UK DPP, ARD/ZDF for Germany and AS-10 in France.
Multiple checks are made by the built-in AQC template, including some of the following: audio peaking, EBU R128 Loudness, Black frames, double frames, PSE checking, checking that the MXF wrapper complies with new standards such as AS 11 (UK DPP) or whichever format is required around the globe. The AQC template confirms audio channel configuration is correct, detects error blocking and confirms letterbox is the same size throughout the film.
Detailed workflow integration with Media Asset Management
In many cases AQC systems are controlled by a more complex Media Asset Management system or workflow automation tools. In all of these cases, the level of integration is limited by the AQC’s Application Programming Interface (API). Often this is limited to simple functions such as starting/stopping a job and selecting the AQC template. EditShare is developing this several steps further by integrating QScan QC into the EditShare Flow ecosystem. Not only can Flow start/stop AQC jobs but it can also provide the user with the results of the AQC process at every phase of the production cycle. Furthermore, it can use the AQC results to trigger specific automated actions by an autonomous workflow manager and utilise any MAM system or workflow manager to a new level of intelligence. The Flow UI provides users with a timeline view of where any issues may have been detected.
What 2019 holds for Flow and QScan
A first for the media and entertainment industry is that a single vendor will offer fully integrated Automated QC and Media Asset Management - EditShare is achieving this through combined development within Flow MAM and QScan QC product lines. This unification will deliver significant user benefits, not least the ability to better understand more about your content sooner in the production process, and take corrective actions when needed.
The QScan QC Solution is available now for a global network of EditShare resellers. Interested in testing QScan? QScan has a free 14 day no obligation trial available from the QScan website.
*With the introduction of ITU BS.1770-2 in 2011 the European LKFS (Loudness K-weighted to Full Scale) standard and the ITU standard of LUFS have become the same thing. Some people may still refer to the unit of measure using by ITU BS.1770 as LKFS.