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| Unofficial VirtualDub Support Forums > General Discussion > "forced Film" For Fcchandler's Mpeg-2 Plugin |
| Posted by: Miles Dec 15 2010, 10:45 PM |
| Opening MPEG-2 from NTSC DVD, 23.976fps with 3:2 pulldown. I remember the old VirtualDubMod used to give 23.976fps by default (but would occasionally trip over if it encountered an unusual flag pattern). VirtualDub-MPEG2 I think had an option to honor pulldown flags or not. The latest VirtualDub with the MPEG-2 plugin seems to always give 29.97fps. Is there any way to force it to output 23.976fps? |
| Posted by: -SPM-Mad Dec 25 2010, 03:10 PM |
| I am not and expert on the pulldown/conversion topics, but isn't the original footage 29.97fps and the pulldown to 23.976 was calculated? There is the IVTC (Inverse Telecine) filter in the filterdialog now since VirtualDub can change the framerate in the filterchain since version 1.8 or something like this. Maybe that helps, Greetings and merry xmas Michael |
| Posted by: fccHandler Dec 25 2010, 06:27 PM |
| Ideally this type of DVD has 23.976 encoded frames per second, but there are special flags in the stream which instruct the player to reassemble the fields into a 29.97 output video for NTSC television. Those flags are always honored by the plugin so what you see in VirtualDub is what you would see on a real NTSC DVD player. In a perfect world, if we simply ignored the flags then we would expect to see the real frames at 23.976 fps. Unfortunately the reality is not that simple and "forced film" is difficult to do well. There are many cases involving erratic flags and mixed content which have to be worked around. It's been on my TODO list for a long time and I don't know when I will get around to it. |
| Posted by: Miles Jan 2 2011, 11:03 AM |
| Thanks. I only really wanted to use VDub to get a quick preview of the "uncombed" frames. It looks like the best option is to use VirtualDub-MPEG2 and ignore pulldown flags for this purpose. For any editing or video work where forced film is important, I can of course use AviSynth with DGMPGDec. |
| Posted by: ale5000 Jan 2 2011, 12:55 PM |
| @fccHandler: Maybe there can be an options in extended options to ignore the flag for users that need it. |