59fps to 23fps, what's wrong?

[askiplop]

Hi!! It's me, again!

I have a video running at 59fps, I'm currently converting it to lagarith using VDub with an AviSynth script.

The VDub window (the one that popup when you click File > Save as AVI) shows 101 744 frames.

101744/23fps = 4423 seconds.../60 = 73 minutes (The avg. length of the movie)

So, I don't understand exactly where are the other ~146 056 frames..

The movie was telecined so maybe it's why my calculations are not accurate. Anyone can help me understanding this?

[jagabo]

Your AviSynth script probably decimated the source.

[manono]

I have a video running at 59fps, I'm currently converting it to lagarith using VDub with an AviSynth script.

First, if it's from a DVD (an M2V or a VOB), it's not 59.94 frames per second (fields per second, maybe).
Second, it's 23.976fps, not 23fps.

Third:

So, I don't understand exactly where are the other ~146 056 frames..

What other 146056 frames? What was the original frame count and how did you come up with that figure? Surely you're not claiming the source had 146056 + 101744 = 247800 frames? As jagabo said, if you IVTC'd it normally, 20% of the frames get removed. They're the duplicates removed when going from 29.97fps back to 23.976fps.

Fourth: As is usual with questions of your type, you should post your script.

[askiplop]

jagabo:Thanks for answering me I double checked the original vs the m2v file.

The original video is in 29.97fps, the m2v file is 59.94fps (Forced Film as manono suggested).



I know it's 23.976fps, it's why I put ~ in from of numbers, sorry, but I don't think it change the facts much for this question. Next time I'll write all the decimals for all my numbers.

First, if it's from a DVD (an M2V or a VOB), it's not 59.94 frames per second

If I ask the question, it's because I'm not sure, that's mean: maybe I'm wrong. I know DVD are not in 59.94 but this is what I saw, it's why I double checked.

Did the Force Film thing put more frames? (It sounds stupid, but I'm a newbie so it's okay )

[jagabo]

If you used Force Film in DgIndex the output of DgDecode will be 23.976 fps.

[manono]

I double checked the original vs the m2v file.

Both the original VOB/MPG and the M2V will have the same framerate. How did you check to confirm it had changed to 59.94fps? Maybe you misread it and it's really 59.94 fields per second.

The original video is in 29.97fps, the m2v file is 59.94fps (Forced Film as manono suggested).

If you saved out the M2V while making the D2V project file (Save Project and Demux Video), the M2V is the same as the source. The TFF/RFF flags don't get stripped out. It's still 29.97fps. It's the D2V file that's 23.976fps and when opened in a script with DGDecode.dll and MPEG2Source will also show as 23.976fps.

[Cornucopia]

Yeah, unfortunately lots of users (mainly newbies) and even many apps play fast and loose with the terms "frames per second" and "fields per second". You could do us a favor if you ONLY used "fps" to refer to fields and "FPS" to only refer to frames (in fact, that would help if everyone here did that). No, I'm not being anal about it, the engineer in me knows that confusion arises because of inaccuracy, and that's happened a LOT on this site. (Like the whole "ripping" vs. "ripping + converting" business).

Your original is 23.976FPS, encoded into a DVD VOB stream as 29.97FPS (or more truly as 59.94fps). That's because when the DVD came out, Analog SD video standards still ruled, and that meant that ONLY 59.94fps (for NTSC) and 50fps (for PAL) were usable. Since that time, progressive has become greatly more viable and HD is available (with its inherent 720p ability), and even VFR has become noticeable.

Running your VOB through DGIndex restores the original data to its 23.976 format when viewed using the .D2V.

23.976 / 29.97 = .8

101744 (frames) * 2 fields/frame = 203488 (fields). If your estimate of total frames was ~247800 (but maybe they were fields), then
203488 / 247800 = .821 (which difference could be explained by your "~")

Scott