Thank you for your insightful response, John.
JohnAStebbins wrote: ↑
Sat Aug 03, 2019 6:32 pm
Can you define hard telecined?
Hard telecine simply lacks the flags in the data stream to tell the software how to reconstruct progressive frames. Telecine content has a detectable pattern of combing in some frames.
I've seen that pattern form in my architectural models (and in actual video of course). Hmm... "hard telecine". I get it. Thanks! I'll add "hard telecine" to my documentation.
The detelecine filter finds a few combed frames, locks to the pattern and reverses the telecine to create progressive frames.
You know, I thought that HB must be doing that. Thanks for the confirmation.
Aside: It's unfortunate that some processes, for example, telecine, are called "filters". I was taught (a long time ago) that filters are static whereas processes are dynamic. Now I read expressions like "dynamic filter" that actually refer to processes -- I initially found that confusing.
Well, I architected a 2-3 pull-down scheme that does some field blending ... and I'd love to be able to test it to see whether it defeats motion object combing
If the source is telecined, there is no motion object combing, period, full stop.
Correct me, please. I've always thought that "2-3 pull-down" is synonymous with "NTSC telecine".
Before telecine: p24 = frame[ A/a ] frame[ B/b ] frame[ C/c ] frame[ D/d ].
After telecine: p30 = frame[ A/a ] frame[ B/b ] frame[ B/c ] frame[ C/d ] frame[ D/d ].
Aside: It's the
[ B/c ] & [ C/d ] frames (and fields) that produce the motion-object combing. It's especially the temporal proximity of field
[ B ] immediately followed by field
[ d ] that produces the perceived comb.
Or do I have that wrong?
... telecined content *is* progressive once the telecine is reversed. ...
Again, correct me, please. I thought that once an i30 is detelecined (aka IVTC) to p24, it's no longer telecined. Um... Now that I think on it, I guess "detelecined" makes sense: As referring to a formerly telecined video.
... There is *no* combing. If you are seeing combing, then either detelcine failed, or the source is not telecined.
Yes, of course, p24 can't exhibit combing. I was referring to the p24-to-i30 (telecine) process.
... If you require i30 output, HandBrake isn't the right tool.
Hmmm... It seems to do the job. What would be better?
HandBrake can be coaxed into creating interlaced output with special flags passed to the encoder, but HandBrake's pipeline is designed to produce progressive output.
Well, that's good information. Thanks.
If the source is soft telecined, HandBrake will always convert it to progressive frames and the original telecine pattern is lost. HandBrake has no filter to re-telecine it.
Well, i30-to-p24 followed by p24-to-i30 seemed to work for me. Can you illuminate to me why it worked?