Hybrid QC: a More Complete Approach to Delivering High-Quality Video

Quality control (QC) operations are evolving. A decade ago, QC was strictly a manual-based process. In more recent years, broadcasters have relied on file-based, automated QC workflows to speed up operations and ensure the accuracy of video and audio content.

Today, automated QC solutions are an essential part of file-based workflows. They have the capability to check content for conformance, metadata, and different kinds of audio video quality issues. Some tools are capable of detecting a wide range of base-band audio and video quality issues. Yet, there's more ground to be covered. Significant R&D is still underway to detect an even larger set of checks through automated means.

Every year more capability is added to automated QC, removing the tasks that formerly needed not be handled manually. Companies supporting auto QC realize that there is a need to provide a single platform to support both automated and manual QC for broadcasters’ operations. Besides offering an efficient workflow today, a hybrid platform also enables seamless deployment of checks as they become enabled by new automated QC technology. The result is a hybrid QC platform, which enables broadcast operators to perform automated and manual QC checks within a single platform. This allows the broadcast facility’s entire QC policy to be implemented in a single solution. This article will explain certain scenarios where using a hybrid QC solution is ideal, along with the key requirements that broadcasters should look for in a hybrid QC solution.

The hybrid QC workflow

A broadcaster typically performs several checks before the content can be called “OK”:

  • Chroma Change
  • Blockiness
  • Motion Jerk
  • Subtitle Detection
  • Matching Audio Tracks with Specified Language
  • Video Dropout
  • Lip Sync
  • Aliasing
  • Progressive Rollers
  • Spelling and Punctuation
  • Other Checks

Some of these type of errors still cannot be auto-detected and broadcasters have to rely on manual inspection of the content. 

Figure 1. With an automated QC workflow, there are only two possible outputs for a file. Either it passes or it fails, which often means manual examination.

Figure 1. With an automated QC workflow, there are only two possible outputs for a file. Either it passes or it fails, which often means manual examination.

Typically, after auto QC, the manual QC is performed outside the auto QC platform based on the organization’s policies. The files are either passed or failed. The passed files are then pushed for post QC actions.

With hybrid QC, auto QC is complemented by manual QC checks on the same platform before the files are passed as shown in Figure 2. Hybrid QC ensures that the file needs to be reviewed for manual checks before the rest of the automated workflow kicks in.

Figure 2. In a Hybrid QC workflow, any QC failures are examined while the file remains in the QC system. This is especially effective with special effects content as automated QC may flag such frames as having video artefacts.

Figure 2. In a Hybrid QC workflow, any QC failures are examined while the file remains in the QC system. This is especially effective with special effects content as automated QC may flag such frames as having video artefacts.

When manual checks are necessary

There are a few scenarios where broadcasters may prefer to perform manual QC. One instance is when special effects are added to video. Special effects detected by an automated, file-based QC solution are often identified as artefacts in the video frame, also known as false positives. Manual intervention is necessary to understand the anomalies and take appropriate corrective measures.

False negatives can be another challenge with an automated QC solution. In this instance, errors that need to be reported are ignored by auto QC systems. Without using manual intervention, broadcasters would be unable to address critical issues in the video or audio stream, such as lip sync, which automated QC solutions are incapable of identifying alone.

What to look for in a hybrid QC solution

Given the benefits that manual checks bring to the table, broadcasters may choose a file-based QC solution that includes manual and automated capabilities. The system should offer a comprehensive range of audio/video quality checks, as well as support for a wide range of media formats and codecs, including SD, HD, UHD, 4K, and mixed workflows. A powerful media player will ensure that the broadcast workflow is well-integrated and efficient. Manual intervention can be built into the test plan, allowing users to add necessary errors, as well as mark each manual task as reviewed.

Scalability is another important requirement in a hybrid QC solution. A software-based hybrid QC solution allows a broadcaster to expand the quality control workflow as their needs grow. Seamless integration with media servers, transcoders, MAM archiving, and workflow solutions is also essential, as it assures trouble-free installation and upgrades. Finally, broadcasters will want to select a hybrid QC solution that is built with high availability, continuing to operate even if one of the hardware components is down.

The best of both worlds

By relying on a combination of auto QC and manual intervention, broadcasters can implement QC policies for their facility more effectively. As research advances, and some of the manual checks are increasingly completed through automated means, a facility‘s workflow will not need to change. Benefits include increased efficiency, cost savings, and higher content quality. 

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