> Each frame consists of two interlaced fields: first the odd-numbered lines and then the even-numbered ones<p>Not always. Most† interlaced video is indeed upper/top-field-first, but some is lower/bottom-field-first! DV, for example, is usually BFF.<p>It gets even more complicated with modern GOP codecs that can also be PAFF or MBAFF.<p>[†] Source: Experience — I encode a lot of SD video.
Very briefly mentioned here, but Captain D’s great frame rate take: <a href="https://youtu.be/DyqjTZHRdRs?si=oTzq_5x2-g5gkomY" rel="nofollow">https://youtu.be/DyqjTZHRdRs?si=oTzq_5x2-g5gkomY</a>