Quality Control

QC for file based media generally means validating that the file is fit for its intended purpose by detecting a variety of possible issues, including:
  • compliance to a specification
  • correct file type
  • correct Time Code
  • correct layout (slate, bars, etc.)
  • video errors (color gamut, artifacts)
  • audio errors (loudness, clicks, silence)

Quality Control can be either automated, with software validating the media. This method while efficient and fast can’t check everything. Manual QC involves human operator reviewing the file. It’s more time consuming but can help detect issues that automated systems have problems with (sync problems or color shifts). Also, artistic and editing decisions are made by humans. An editor might feel the audio dialog is a bit too quiet for a particular scene and choose to make adjustments.

Benefits of QC

Early detection of problems means cost savings. Being able to verify if the content meets specifications before delivery allows to avoid costs related with content rejection. And fixing such problems just before the air date can be even more expensive, and sometimes impossible.

Then there are legal regulations, that in many countries control multiple aspects of broadcasting industry. Issues range from audio loudness, caption quality to photosensitive epilepsy (PSE). Failing to detect them before the delivery can lead to fines and disciplinary measures. DPP (UK) and NABA (North America) are such examples that already are or will become major factors in media delivery.

Last but no least, content recipients often have their own set of specifications they require compliance with. Providers that can’t meet them are facing additional costs for re-submission.

Should I do QC?

If you’re post production studio, content creator or broadcaster - then the answer is most likely “yes”.

If your media files come from various sources you may want to run QC on them before moving on with further processing. Particularly, when time is of essence and finding any issues as soon as content arrives is critical. Making sure the incoming content meets certain parameters - like video/audio bitrate, frame size, aspect ratio, frame rate, video and audio duration, audio loudness, if all the audio tracks are in place or if the channel configuration is correct - should be the first step.

Similarly, when content is ready for delivery or to be aired, running QC is essential to assure compliance with clients’ requirements or legal regulations that broadcasters need to adhere to (facing consequences if they don’t).

What should you be testing?

  • File level testing:

    File level testing checks the container level. For example, is it an MXF or a QT file? If you get the wrong file type, you may not be able to work with it. Simply checking if the file format is fit for purpose is important.

  • Codec, frame rate, and frame size details:

    There are various tests for MXF structure and partition sizes, for example. You may want to look at video bitstream to verify that there aren’t any syntax errors. When recording a satellite feed or transport stream, errors can occur in bitstream syntax, which in turn cause visual artifacts.

  • Metadata testing:

    When checking metadata in the file, you’ll likely want to know if the timecode is right. Is there AFD (active format description) and if so is it the type of AFD you need? Are captions present and valid?

  • Baseband video testing:

    QC systems will also do a low-level test for the actual video, checking GOP structures, chroma subsampling, black levels, encode settings, and color gamut.

  • PSE testing:

    Content can also be tested for Photosensitive Epilepsy (PSE) Flash Pattern. Flashing in the content is known to cause certain people to have epileptic fits, and testing for this is a mandatory requirement to produce a certificate in some markets.

  • Cadence testing:

    QC systems can also detect cadence issues. A check might reveal for example that the content had a 24 to 25 conversion with the bottom field first, or that there is a broken 2:3 cadence resulting from a wrong telecine process.

  • Audio testing:

    You may be concerned about loudness compliance before content goes to air. Other audio QC tests might include checking the bit rate, sample rate, phase correlation, looking for silent channels, or detecting artifacts such as clicks or pops.

We can help you with carrying all these test within Telestream Cloud in an easy and efficient way. Please get in touch with us and let’s start a conversation what we can do for your business.

QC as a service in the cloud?

As more and more media processing moves to the cloud there’s also growing interest in ability to run QC in the cloud with all benefits it offers:

  • getting started within minutes without software installation or hardware setup required
  • bunch of ready to use templates to test for compliance with industry standards (DPP UK, ZDF ARD, Netflix, iTunes, PSE and many more)
  • scalability and optimized media processing by making automated QA part of the ingest and transcoding process if your content already is in the cloud

Cloud based SaaS QC requires minimal setup and is ready to use in minutes. You skip the process of setting up hardware and software needed to run QC in your local facility. It also means you don’t need to maintain and manage it to stay up to date. With cloud based service like Telestream Cloud all it takes is to sign up and pick templates to use.

Speaking of templates. Good QC service includes pre-defined templates for common delivery specifications saving you time needed to create them from scratch. The QC service will compare your media file to a selected template for verification, and in some cases for correction. And when you need to create custom template it takes only couple minutes to do so.

Scalability is another strength of cloud based QC. It makes little sense to buy additional hardware you may not need later if you can use flexibility of the cloud to your advantage. You’re likely to process a number of files simultaneously and scalable system that can seamlessly grow with you to handle 10 or 1000 files is essential. And if it integrates seamlessly with your transcoding and delivery process - your life just got easier.

Easy to use and accessible to your whole team web application allows staff that may not be steeped in video knowledge to identify problems early. That’s a huge benefit as it’s not humanly possible to check for and correct all of the parameters of a file when considering the number of compliance requirements.

On top of that, Telestream Cloud features Lip-Sync which uses deep learning and AI technology to test your media for audio-video synchronization issues. It detects human faces in the media files and matches them to human speech thus allowing to detect errors that are not identified by current automated video quality control systems.

Increased standardization (e.g. DPP, AS-10, ZDF, DPP NABA) means even more compliance verification will be required. More requirements for different regions will cause media companies to rethink how they are meeting QC testing requirements.

Using the capable and robust automated media QC ensures you have the right file for the job, mitigates the risk of content rejection, and lets you deliver content with confidence. And using a cloud based service means less time spent on managing the system and faster time to market, especially if your own or your client’s content is already in the cloud.