Encoding NTSC DVD from Progressive 29.97 Source

[audiohominis]

This one's kind of urgent, my friends.

I'm trying to encode an NTSC DVD off of 29.97 progressive video using AVISynth and HCEnc (2.3) but I absolutely need to ensure standard compliance. Should I interlace, and how? Would simply selecting Digital Video source interlacing option from the Settings 1 tab do the trick? Should I also specify the field order or just leave it at the default BFF. Should I pre-interlace the source in AVISynth prior to serving? If so, would you kindly provide the snippet?

Thank you very much.

[TheSkiller]

Hi there, :)

Should I interlace, and how?
if your video footage is entirely(!) progressive you have three options:

1) encode with zigzag scan and set both progressive flags
2) encode with zigzag scan and set only one of the progressive flags
3) encode with alternate scan and don't set any of the progressive flags at all


Zigzag scan is for progressive video and increases the encoding effiency compared to alternate scan which can be used for anything. Zigzag scan doesn't cause any trouble, so I'd say 3) is out of question.

I personally have never had any trouble at all with 1) but if you really don't want to risk absolutely anything, go for 2). I personally doubt it but apparently some people say the second progressive flag (called "progressive_sequence") is not DVD compliant, hence my recommendation for 2) just to be on the safe side.


For an encoding in HCenc following 2) you

• set "interlacing options" in Settings 1 to progressive
• make sure "progressive sequence" in Settings 2 is unticked
• TFF flag shouldn't matter but I'd set it to false via BFF in Settings 1

That should be playable on anything that calls itself a DVD player (or Blu-ray player).



Should I pre-interlace the source in AVISynth prior to serving?
This is neither needed nor possible because the frames you serve to HCenc for encoding differ only in one thing from interlaced ones and that is the absence of interlacing which doesn't cause any problems. A DVD player really doesn't care if both fields are from the same point in time or not. ;)

[audiohominis]

Thank you so very much for saving the day and sorry that I'm thanking you with a delay. It's just that I've been chasing a production deadline.