The proliferation of automation, post-production software, digital file-based media, server technologies, media standards, advanced encoding techniques, enhanced picture resolutions, bundled with a growing media market promises an exciting road ahead for production houses and broadcast studios that aim towards broadcasting pristine quality media to end-users.

Chinks in the Armor

Is the above utopian picture really perfect? Is there any chink in the armor that shadows the goal towards faultless media quality?
The recent years has seen far-reaching changes in the broadcast industry triggered by evolving technologies.

• Media has metamorphosed from analog to digital. And digital has evolved from MPEG-2 to MPEG-4 to H.264. Server technologies are here to stay. Working from a file has speeded up composition, editing, and repurposing.
• There is no dearth of audio / video / system formats to choose from: MPEG-2, H.264, VC-1, MPEG-2 TS, MP4, AAC, AC-3. Each new format has brought with it challenges as well as more than a few headaches: equipment provision and staffing.
• Studios have multiple options to reach to their audience: IPTV, cable, branded channels, satellite, DTH, VOD, SVOD, DVD. Each play-out has it owns requirements of quality, resolutions, bit rate, ratings, security, and more.
• There are challenges of interoperability between heterogeneous equipments and formats: editing tools, codecs, proprietary formats.
• Evolving technologies have increased the demand of skilled professionals and training of existing staff.

Is the broadcast industry, already struggling with the technical advancement, actually doing all that is needed to play-out faultless media quality?

Broadcast professionals have to cope with large volume of file-based ingest media daily - at times between 1000 to 1500 media files a day.

There are manual or script-based QC processes in place in most studios. These QC processes provide a very basic control on the media quality. This may not be enough to stay ahead in today’s competitive landscape.

The problem may be compounded by the fact that there may not be any uniform QC process across the different facilities of the studio. Often, the rules and processes tend to drift from a centrally defined work sheet leading to inconsistencies across centers.

With the advent of HD, consumers’ expectations of the quality of delivered media has sky rocketed. Studios need to upgrade their workflows, quality processes, and infrastructure to deliver this expectation.

It is only a matter of time when well-defined Service Level Agreements (SLAs) and content quality standards will have to be strictly adhered to by the broadcasters. The studios need to gear up to this inevitable challenge.

With evolving technologies, increasing consumer demand for media and entertainment, the broadcast professionals have no choice but to put the QC, at ingest, in the back seat - a strategy that will only make things worse rather than improve the situation.

For content developers and production houses, the problem is slightly different. Each studio facility has its own workflow and QC rule sheet. The content developers have to create content adhering to these rule sheets, keeping in mind that the rule sheets do not interchange even by mistake. For example, a content developer cannot afford to mix up the resolution requirements for two different studios that they are working for.

Therefore, the content developers and production also need automation. QC automation can help them save their not-so-easily-available creative time from the routine and mundane packaging checks before delivering media to the studios. Content developers would ideally want to “qualify” their content as “QCed”, and get a sign-off from the studios. What is needed, is a good and clean hand-off and sign-off between content creators and the studios.

In short, the demands for an automated QC is high from all over – any tool or infrastructure to alleviate this problem is what the broadcast industry needs today.

In this parched QC landscape, we cannot expect an off-the-shelf QC tool to work miracles since studio workflows and requirements vary significantly. The need of the hour is QC technology and infrastructure that can be customized for individual studio needs and gets seamlessly plugged into the current workflow. The ideal solution would be if QC tool providers could augment their QC offerings with custom services to provide a tailor-made solution to the individual studios and content developers. It is heartening to see that companies are beginning to offer custom services over their core QC technology for building custom solutions for existing workflows of individual studios.

The Messy Real World

From creation to broadcast, different resolutions, bit-rates, encoders, devices, and formats create a scenario where maintaining quality and having a quality control mechanism seems rather complex. Unlike other industries, there is no major single vendor of a broadcast studio. Broadcast studios deal with multiple content vendors who work with different formats and equipments. In this heterogeneous landscape, what determines the quality of media that is broadcast?

The ingest process is the gateway between production house and the broadcast studios where adherence to studio-specific requirements determines the acceptance or rejection of media content. Individual broadcasters could have specifications, such as, 800*600 resolution in PAL, 4:3 and 16:9 picture format, audio with a subjective quality at least comparable with NICAM 728, Teletext 708 data, bit-rate of 4.6Mbit/sec, fixed audio tone for first 3 seconds at 300Hz, or a blank video at the beginning of the stream. Thus, determining the quality for a studio means mapping to studio-specific quality checks.

How do production houses ensure that their content meets the acceptance criteria? How do broadcast studios filter inferior quality media from reaching the content servers? The challenge now actually begins.

One of the commonly used methods of quality control is monitoring digital signals. Of course, monitoring requires an experienced person to run the equipments and interpret the display signals. Digital monitoring also covers a limited range of checks and needs to be re-configured for different formats and resolutions.

Production houses and studios even use homegrown scripts to check quality issues. But, homegrown scripts are often not comprehensive enough to cover all the quality issues in a stream. And keeping pace with the changing technology and format landscape is a Herculean task, to say the least, for these homegrown solutions.

Analysis software, such as Interra’s Vega Analyzers are also used to check for media compliance against standards, such as H.264, MPEG-2, VC-1, AAC, AC-3, and MPEG-2 TS.

Manual QC is also a prevalent method, but brings with it a fair amount of disorder in monitoring media quality at ingest. Firstly, manual QC is an expensive proposition requiring highly experienced and knowledgeable professionals to catch errors as a stream plays. And what happens if a manual tester with experience in MPEG-2 formats has to deal with an H.264 or a VC-1 stream? The tester may not know which quality issues to look for in these formats. Further more, today it is not easy to hire an experienced tester in new formats so quickly.

Secondly, manual QC gives way to subjective quality checks and human errors. Human eye is not reliable or consistent over a continuous stretch of time, nor is each human’s interpretation about quality consistent. Interpretation about quality depends on individual’s skills, experience, exposure to work domain, and sincerity. At the most, a tester can only test the visual or audio quality of a stream. With evolving standards, how does the human tester keep track of standard specifications or standard related quality issues? And, what about varying checklists of different studios? How does a human tester keep track of studio-specific requirements? It is very easy to short-circuit studio-specific requirements and label a video as broadcast quality. There could be cascading effects if a studio accepts a content that is not compliant with the broadcast requirements.

Manual QC, besides being subjective, does not produce concrete data. What are the standard-specific syntax elements that have inaccurate values? What are the possible interoperability issues in a video? Have all the optional syntax elements been tested? What is the structural level in a video where an error has occurred? What is the bit-rate? What is the acceptable level of blockiness? Is the fixed tone length just accurate? Are the color bars of the required length? Absence of concrete quality statistics leads to a quality that is shadowed with an element of doubt. Is the media really quality certified?

A nasty situation could occur if the studio’s decoder smoothened an encoding error. Of course, the QC tester missed the error. However, the cable operator’s decoder was unable to smoothen the error resulting in blocky transmission to the customer and subsequent complaints. The broadcaster, in this situation, would take a hit despite ensuring QC at the studio. And, there could be a long process to trace the source of the quality leak.

Consider the following example. It is often not easy to identify small level of blockiness in a video as shown in the picture below. A feature of block-based coding is visible in block structures. Block edges are typically reconstructed with less accuracy than interior pixels and blockiness is generally considered to be one of the most visible artefacts with the present compression methods.

In content provider’s landscape, a QC tester would not only face all the drawbacks just mentioned, but this tester would also have to deal with multiple studio-specific rule sheets. Production houses typically provide content to multiple studios, each with its own specifications of bit-rates, resolutions, and more. Multiple rule sheets means a greater probability of mismanagement and expensive content acceptance cycle.

Removing the Mess

The messy QC mechanism, leaving so much to human eye, creates a quicksand that setbacks all the advantages of evolving technologies leading to inefficient collaboration between media creators and broadcasters, high probability of inferior media in the market, increased content acceptance cycles, ineffective use of human skills, and increased operation costs.

The stage hence is set for a structured automated QC approach – an approach that can be customized and plugged into the existing workflows. Removing the fuzziness of manual QC, an automated QC process brings in concrete quality matrix. Other than reducing content acceptance iterations, concrete data can help identify breaks in content creation process, provide an impetus to evolve quality checks, and provide the much-needed QC audit trail to track and eventually correct the source of inferior video and audio quality.

One of the advantages of an automated QC is its ability to process large number of media files accurately and consistently, each time. This is definitely a boon to the broadcasters who often receive more than 1500 media files a day.

The automated QC could be plugged at the ingest process to accept or reject content received from productions houses. The automated QC could also include a trigger to validate content before a media is ready for play-out.

A greater hue is added, if the automated QC is customized to production house and studio workflow. As already espoused, studios and production houses have their individual workflows and need a QC technology over which a customized solution can be built which is easily plugged in the existing workflow.

Besides being efficient and fast, an automated QC can easily pinpoint errors that are hidden from human eye and probe the inner most structural level for encoding errors or standards non-compliance. The following report from Interra’s Baton shows the discrepancy in the buffer, which manual QC would not have detected.

An automated QC is also more precise with visual errors that are often missed by the human eye. In the sample below, Baton effectively catches a missing data in a picture, which could have been easily missed by a human tester had the tester been just a little careless.

Obviously, an automated QC would bring in complete check for standards conformance, thus leaving the knowledge about media standards and compression parameters to the QC software rather than burdening content creators and studio staff with the need to know details of ever evolving standards. Furthermore, a QC software would abstract the technical details in a quality matrix to easy-to-interpret results, enabling studio/production house staff with little or no knowledge about standards and specifications to schedule test tasks and generate quality reports.

As espoused earlier, multiple studio-specific rule sheets are one of the major reasons for inferior content and this means that automated QC needs to be very flexible and configurable. The automated QC should provide the facility for content creators and studios to register rule checks. This would be the silver lining of automated QC. While the broadcast studios would ingest quality media content that abides by their specifications, the production houses would benefit from having an automated QC done on media against a given studio’s checklist ensuring less probability of rejection. This would mean that the QC is configurable to specifications on the fly. Baton, for example, enables creation of custom rule sheets, as illustrated below. QC tasks can then be scheduled against a given rule sheet making life so much easier for the content providers and the broadcasters.

Automation always provides an impetus to improvement of work processes and flows. With an automated QC process in place, broadcast professionals can concentrate on improving studio workflow and quality check parameters. Further, an automated QC process would ensure a clean hand-off between content providers and broadcasters encouraging a process towards well-defined SLA.

Summary

An automated, configurable QC definitely promises efficient collaboration between content creators and broadcaster based on concrete, quantitative quality assurance. With emerging, QC solutions, the broadcast professionals seem to have opened up to a new dimension in automation. For both, solution developers and broadcasters, the road ahead seems to be exciting and promising.