Questions about progressive/interlaced 480i/576i/1080i MPEG2 encoding

[Mandaman]

I’m currently researching the basics of how progressive and interlaced material is stored in MPEG2. I already figured out the difference between frame pictures and field pictures, the different flags including the progressive_sequence flag, the progressive_frame flags, etc. I still have some rather technical questions about this, though. I’d really appreciate some answers from an expert! Thanks in advance.

- Is encoding to MPEG frame pictures much more prevalent than encoding to MPEG field pictures? Expressed in percentages?

- When encoding a progressive source (e.g. 25p or 30p) to frame pictures for DVD, the only thing that makes a standard DVD player (with a CRT TV) play this material as interlaced is the progressive_sequence flag that is set to False, right? So theoretically in this case the interlacing is really done by the player?

- AIUI the TFF flags set to True is much more common than bottom field first, right? Are all commercial movie DVDs / HDTV top field first?

- Do flag-reading progressive players/decoders solely rely on the progressive_frame flag in MPEG2 to determine whether they’re dealing with field-based material or frame-based material? So split the frame picture into fields and send these to the player’s deinterlacer (when progressive_frame flag is set to False) or display the full stored picture progressively (when progressive_frame flag is set to True)?

- Will flag-reading decoders in progressive players (e.g. a software player) always decode a DVD/TS-file to 48i/50i prior to weaving when dealing with frame pictures from progressive frames (progressive_frame flag set to True)? We call it a weave, but since the MPEG2 is stored as frame pictures, the decoder would really simply be displaying the full stored picture; there’s really no reinterleaving/weave going on, right? Or is the weaving always done after the decoding part and will a decoder (even in software) always output interlaced sequences as interlaced?

- Will flag-reading progressive players always treat MPEG2 that consists of field pictures as field-based -> deinterlace?

- Flagged 2-2 pulldown is basically just the progressive_frame flag set to True, right?

- Do progressive sequences contain progressive_frame flags or are they omitted (or maybe required to be 1)?

Thanks.

[Baldrick]

one topic is enough.
https://forum.videohelp.com/viewtopic.php?t=293797&highlight=