DVD framerate bug

[monohouse]

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[neuron2]

Post a link to an unprocessed sample of the VOB. Use DGSPLIT, for example, to cut off the first 50MBytes.

[monohouse]

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[neuron2]

Can't you use mediafire or something with more bandwidth than 1KB/sec?

[monohouse]

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[neuron2]

5MB is not 50MB. :confused:

Anyway, from the tiny sample you provided, it's standard 3:2 soft pulldown. The stream is film with 3:2 pulldown to bring it to a standard 29.97 fps NTSC DVD display rate. Nothing unusual there.

[monohouse]

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[neuron2]

It depends on what the player does with it. If the player honors the soft pulldown, it is 29.97. If the player ignores the soft pulldown, it is 23.976.

If you want to transcode it, then you have the option to honor or ignore the pulldown. If you do the latter, you can encode to 23.976 progressive.

DVD was designed to output 29.97 to an interlaced TV. To encode more efficiently, soft pulldown is used to output 29.97 from 23.976 progressive.

[monohouse]

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[neuron2]

Fields are duplicated. See here:

http://www.dvdfile.com/article/what-the-heck-is-32-pulldown-8799

[monohouse]

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[neuron2]

Actually, for 3:2 pulldown, fields are duplicated not frames. And 2 of every 8 fields are duplicated, so that's 25%.

It's a common mistake to say that frames are duplicated.

The source video stream is still progressive on the DVD. It's only during display that the fields are shown twice. So it's easy to recover the film rate progressive video without "inconsistencies of various types".

[monohouse]

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[neuron2]

The first case is not a bug!

What problem are you having with this second one?

[monohouse]

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[neuron2]

Your second one is the same as the first: soft 3:2 pulldown.

How are you removing the pulldown? The simplest way is to set Forced Film in DGIndex.

[monohouse]

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[neuron2]

The pulldown is removed only for the video served via DGDecode. Video demuxed by DGIndex is not altered from the original.

You can use DGPulldown to remove pulldown from demuxed video. Read the help file; it tells you how:

"Note that if the custom rate conversion is selected, and if the source rate is
specified as equal to the destination rate, then all pulldown is removed and the
stream is flagged as having a rate equal to the specified destination rate."

So, select custom rate and put 23.976 in the source and destination rate boxes.

If you are transcoding there is no reason to demux. Just serve the video into your encoder using DGDecode and an Avisynth script as described in the Quick Start guide.

What are you trying to accomplish?

[monohouse]

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[neuron2]

Then use DGPulldown if you want to remove the 3:2 pulldown. You'll have to demux the video.

[monohouse]

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[neuron2]

strange, I have used "no change" and it speeded the 23.976 to 29.970 (set whatever was in pulldown into the real fps), so I guess no change changes it into whatever is written in the pulldown, im gonna try a custom "23.976 > 23.976" see how that goes, but yhe this program is more effective for this "No change" means no change. Your VOB specifies a rate of 29.97 so it stays that way.

btw can I use DGIndex to determine the real fps with field operation > forced and look at the preview log to give the correct value for DGpulldown ? btw it's not working with "up to 6 decimal places." Please just do what I told you (set custom and put 23.976 in both boxes). You'll find that the result is exactly what you are after.

The output frame rate must be a valid MPEG2 rate. The input rate can vary with the 6 places precision. The output rate cannot, because the valid MPEG2 rates do not have more than three places. You may ask why the input rate can be different from the compliant rates. But I fear you are not equipped yet to understand the answer. Let me just say that sometimes it is useful to lie about the input rate in order to achieve a certain pulldown result.

because when I enter 23.976024 into input, it does not work, only when delete last digit into 23.97602, the question is what kind of effect that has on the video (precision) ? what is there is a problem and the framerate is unknown ? isn't there an option to just remove pulldown without manually specifying framerate ? Your output video must have a specified MPEG2-compliant frame rate. It's not arbitrary. The DGPulldown window even tells you what the valid rates are. The one you want is 23.976. That's it. Period. So you put that in both boxes. As the instructions clearly state, if both boxes are the same, then all pulldown is removed.

It's interesting to answer your question about precision though. If the rate is off by 0.00002 as you ask about, then in order to get off by one frame the movie must be 1/0.00002 seconds long, i.e., about 14 hours. Does that put things into perspective? :)