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24p in an NTSC DVD
I was told in another forum that regular movie DVDs purchased/rented in stores are actually 24p.
Now that I have 24p footages (with the pull down removed, making them real 24p footages), is it ok to create DVDs with 24fps frame rate? How is this achieved in Encore?
If I put back the pull down before importing the 24p footages in Encore, does that mean I have to create the DVD in 29.97?
We’re in the Philippines so I’ll use NTSC. Thanks!
ut in omnibus glorificetur Deus
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18 Replies
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DVDs are capable of storing the native 24p (actually 23.976 not 24 fps)stream. With NTSC equipment, it’s not possible to display 24p signal directly as the monitors only support the 60i framerate. Hence, pulldown must be added to the 24p(23.976fps) material to be displayed.
On each DVD encoded at 23.976, a flag is inserted within the Mpeg-2 data stream that instructs the player to repeat certain fields to reconstruct the 29.97 NTSC video. It’s the player which will add pulldown for display on interlaced sets. If it’s a progressive scan player displaying a progressive TV, it will only show the 24 frames.
In Encore, you can import a 24p footages or any pre-generated 24p mpeg files and author 24P DVDs. -
Thanks Jeff! Is this the export settings of Premiere or Encore? It looks like Premiere.
ut in omnibus glorificetur Deus
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Nope. It’s Encore (notice the Library menu that’s showing in the Preview panel).
-Jeff
The Focal Easy Guide to Adobe Encore DVD 2.0
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I see. About the GOP Settings where M frames are at 3 and N Frames are at 12, what do those numbers mean? Will I always use 3 and 12 whenever I make a DVD for both 29.97 and 23.976 or is it for 23.976 only?
ut in omnibus glorificetur Deus
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It’s for 23.976 in NTSC-land, and it’s also usable for PAL video. Normally for 29.97 fps video the settings are 3 and 15. What that does is put a new I-frame every half second, which usually works well for MPEG2 DVD video. (15 is half of 30 and 12 is half of 24.)
-Jeff
The Focal Easy Guide to Adobe Encore DVD 2.0
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Thank you very very much Jeff! That’s a tremendous help. I’ll work on the video again tonight. God bless.
ut in omnibus glorificetur Deus
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Thank you Raja. That’s very informative. God bless!
ut in omnibus glorificetur Deus
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Here’s a thread which explains the details of the technology. MPEG 2 does not support 23.98 framrates. The codec was around much sooner than progressive video. DVD only supports 29.97 and 25. 23.98 with the flags sets makes it a 29.97 stream.
https://forums.creativecow.net/thread/155/870715#870887
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Hi Eric,
I can encode a 23.976 fps video to MPEG2, and get a 23.976 MPEG2 video file. When you say MPEG2 doesn’t support 23.976 fps video, are you saying it’s unsupported natively? That is, the 23.976 fps video only exists as a soft- or hard-telecined 29.97 fps stream? If so, I agree because I believe that’s technically accurate.
However, Hollywood soft-telecines their films for DVD, effectively putting that 23.976 fps video in a “virtual” 29.97 fps stream. The extra frames that are needed for 29.97 fps display don’t exist in the stored video file; only flags exist to tell the decoder what frames to duplicate. To my eye, there is a visible difference between a 23.976 fps video that’s been hard-telecined vs. one that’s been soft-telecined.
If your MPEG2 encoder can soft-telecine your 23.976 fps video, then that video can be put on DVD the same way that Hollywood films are, ostensibly increasing the film-like viewing experience of your video.
At least that’s my understanding. If you have different information, then I’d like to hear it because I really, really don’t want to be wrong about this.
-Jeff
The Focal Easy Guide to Adobe Encore DVD 2.0
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