50fieldpersecond

50fieldpersecond is a term used in video technology to denote a field rate of 50 fields per second in an interlaced video signal. In interlaced systems, each frame is composed of two fields captured at slightly different moments. Therefore, 50 fields per second corresponds to 25 complete frames per second (50i equals 25p in terms of motion perception). This field rate is characteristic of PAL-based broadcast standards and many regional video workflows that relied on 50 Hz synchronization.

Historically, 50 field per second was adopted to align with the electrical mains frequency in parts of the world that used PAL and SECAM systems. It provides a balance between bandwidth efficiency and acceptable motion rendering for standard-definition and early high-definition broadcasts. Signals described as 50i are often associated with regional broadcasting, camcorders, and capture devices configured for PAL environments. Notation may vary, with 50i or 50i/25 indicating interlaced video with 50 fields per second and 25 frames per second.

In modern workflows, 50fieldpersecond remains relevant for compatibility with legacy content and equipment, even as many broadcasts and productions move toward progressive formats (50p, 25p, or higher). Deinterlacing is a common step when converting 50i material to progressive formats, as improper deinterlacing can produce comb-like artifacts. Understanding the distinction between fields and frames is important for video editing, mastering, and display across different regions and standards.