This causes downconversion artifacts as well as reduced resolution. Relying only on the flags. The result is motion artifacts every now and then. 3-2 Pulldown, Summarized For film source material, the DVD has enough material for 24 complete frames for every second of playing time, matching the original film. Note that for frame 2, the field with even lines comes before the frame with odd lines.
Interlaced output uses the above fields as-is.
This part is for the more technical minded folks. It is presented concisely enough to be printed and used as a checklist when discussing a DVD player you want to buy. Stand alone doubler or doubler built into TV always has 1b and 3b. A progressive scan player with 1b is not true progressive scan. Results can be excellent if either 1a or 2a applies.