Test card

Test cards are images, often accompanied by tones, with known properties that are broadcast to test the functionality of each stage of a broadcast chain or network, and to check how each piece of equipment alters the signal, in desirable or undesirable ways.

YSTV's ystvtest VT is composed of four different static 1080p test cards followed by 4:3 SMPTE bars on a 50% grey background, with 5s white noise, 5s pink noise then a 20 second 20Hz - 20kHz logarithmic sine sweep at -6 dBFS, in a 1050x576 progressive-scan PAL (square pixel) H.264 MP4-contained video at 10Mbps VBR with 48kHz 320kbps AAC stereo audio. The test card can be played out over the vision path to check, at various stages: chroma rendering, luma rendering, cropping, scaling, distortion (whether the image is stretched or squashed along one axis, using the circles), contrast, combing and interference. The audio tones can be used to calibrate volume to known levels, and to compared the frequency response of equipment.