What is the Common Intermediate Format?
Common Intermediate Format (CIF) is a picture format defined for interoperable videoconferencing. It uses 352 × 288 luma samples, 4:2:0 chroma sampling, and supports a maximum picture rate of approximately 29.97 frames per second.
How the Common Intermediate Format works
CIF emerged from early video-conferencing standardization as a compromise that equipment built around different television systems could exchange. Its frame is 352 by 288 luminance samples, paired with 4:2:0 chroma and a maximum picture rate of 30000/1001 frames per second. The spatial dimensions align conveniently with the 625-line family, while the timing follows the roughly 29.97-frame convention. Modern workflows mainly encounter it when decoding, normalizing, or preserving legacy communications material.
Key facts
- CIF and QCIF were specified in the December 1990 p × 64 kbit/s revision of H.261. CIF describes picture geometry and sampling rather than a video codec or file container.
- The 4:2:0 representation stores chroma at lower horizontal and vertical resolution than luma; converters must use the correct chroma geometry to prevent color shifts.
- Square-pixel display of 352 by 288 is about 11:9, not 4:3; legacy systems may attach display-aspect assumptions that must be interpreted rather than inferred from dimensions alone.
When the Common Intermediate Format matters
Expect CIF when importing footage from legacy conferencing, surveillance, or communications equipment. Preserve its intended aspect and frame timing during conversion or the result may appear stretched or uneven.