News and events

“You shall not pass!” - stop video defects before going on the air

A video file has been edited, meticulously reviewed and seems good to go. If this ends with a simple visual inspection, there is a good chance some video defects might go on the air unnoticed. On many occasions problems don’t manifest themselves unless the video is played on a different device or in a different player.

What are the red flags that are not to be missed during post-production? In this blog post, we’re breaking down the trickiest defects for manual detection and things you should watch out for.

Signs of interlacing

Interlacing is a way of displaying video in which each frame consists of two fields - top and bottom. When watching a video, these fields merge together and create an illusion of smooth movement. In reality, an interlaced display often prompts the emergence of motion artifacts and image fuzziness.

Things to watch out for: check your video player settings and make sure to turn off the deinterlacing filter. Some applications automatically remove any signs of interlacing from the video during playback. However, the problem remains in the file and pops up whenever the video is played via another program.

Black and white level

The standard implies that in the digital representation of the YUV color space, the luminance Y-component (luma) is limited to specific values (for example, 16 to 235 for the 8-bit color depth). From a technical perspective, values outside the specified range are not “forbidden”. However, it’s highly probable that they won’t be displayed correctly during a broadcast and, therefore, have to be reset to the nearest “allowed” values.

What could help: make sure to consult the Waveform tool.

Gamut errors

Each pixel of a frame is represented by a set of numbers that must be within a range specified in the standard. If these numbers are off, it could lead to an inaccurate display of the colors in the frame (Gamut errors). Examples of such errors could be that some of the colors look too saturated or faded, or the same color is displayed differently on different devices.

What could help: if you don't have an expert on your team, you‘re going to have a hard time locating Gamut errors on your own. Trying a special filter in Adobe Premiere could be a temporary solution. 

If you need a quick yet comprehensive check of your video content for hidden defects try ORBOX. Run a set of tests and get a report detailing what frames had what issues. 

_________

The ORBOX media file quality control system is Tecom Group’s proprietary product. The software automatically checks media files for compliance with the technical requirements of broadcasters, content makers and providers.

Back to list