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| Unofficial VirtualDub Support Forums > Advanced Video Processing > Decimate Help For Strange Video |
| Posted by: TCmullet Jul 14 2011, 04:05 AM |
| I have a video that is 200fps, but needs to eliminate duplicates which will result in 30 fps (or 29.97). I can't quite grasp what the meaning of Vdub's decimate feature is (what the integer parameter means), though I've read Vdub's help and I've searched this forum. My gut is telling me I may have to use a series of Decimate filters in Avisynth. Can someone please best advise? |
| Posted by: phaeron Jul 16 2011, 03:11 AM |
| The integer parameter is the divisor, i.e. 3 means divide the frame rate by 3. This produces the same result as if you had chosen the conversion option and entered in that frame rate. If your video is compressed and actually has padding frames to push it to 200 fps, you can do this operation quickly in Direct Stream Copy mode, provided that you know the maximum actual frame rate. For instance, if you have a 120 fps file with mixed 24 fps and 30 fps sections, you can convert to 30 fps and VirtualDub will dump the padding frames to make that work. Unlike in full processing mode, though, this is constrained to only work at the highest actual frame rate, and if you go below that you'll get temporary desyncs. This also won't work if the duplicate frames are actually compressed into the stream, in which case you'll have to do it the slower way with recompression. Note that the frame rate options won't do anything based on the actual image itself, i.e. it won't try to intelligently choose frames to drop when the duplication is a bit irregular. I'm not sure that'd be a problem going from 200 fps to 30 fps, though, and the more irregular the drop pattern, the more you'd have to skew the video relative to audio to track it. |