A Shotcut user asked about the characteristics of “professional” vs non-professional video.
Over-the-air broadcast video must conform to certain standards enforced by the FCC. If video does not conform to these standards, the broadcaster risks being cited and fined. It is up to the broadcaster to reject video which does not conform to the standards.
Part of the FCC’s job is to guarantee that licensed broadcasters will not cause interference to one another’s signals. Another function is to make sure transmitted signals can be received and viewed on the installed base of millions of TV receivers.
To make things more complicated, various networks and syndicators have their own distribution standards covering such things as pixel formats, bit rates and audio formats.
On the other hand, video services such as YouTube and Vimeo resample video and audio to formats suitable for the web.
The two main video formats used in broadcast and cable are 720p (progressive scan) and 1080i (interlaced scan). Interlacing means that alternate rows of pixels are transmitted every 1/59.94 second. One set of alternate pixel rows is called a field. There are two fields per frame. Together, the two fields comprise one frame. The frame rate is thus 29.97 frames per second for interlaced video.
In this format the frame is 1920 pixels wide and 1080 pixels tall. Alternatively, in 720p, the frame is 1280 pixels wide and 720 pixels tall. Being progressive scan, all 720 rows of pixels are transmitted at a frame rate of 59.94 frames per second. In both formats the picture aspect ratio is 16:9.
For broadcast, the 8-bit video levels are in the range of 16 - 235. The color space is BT.709 YUV and the video codec used for transmission is MPEG-2.
If you want to make a quick and dirty, 720p, broadcastable video in Shotcut, I suggest the XDCAM preset. If you want 1080i video, Follow these steps: Set the resolution to 1920 x 1080, Frames/sec to 29.97003, Scan mode to Interlaced, and Field order to Top Field First.
Always check with your target broadcast or cable service to make sure the format you intend to deliver is acceptable to them. Best to send them a sample video file for them to run through their QC. To check video levels you can use Shotcut’s video waveform scope.
Below is a table of video formats used by various U.S. broadcast and cable services: