#Avisynth decimate manual#

If you aim for a good encode, do not aim for quantity over quality, do not be lazy, take the time out of your day and use a manual decimation alternative. This is why I don't recommend using it, it's way too inaccurate and way too linked to guesswork to be accurate. If you look at the dryrun=True test footage against its VDecimateDrop prop you will see it will often not decimate a frame in that cycle instantly breaking the actual frame rate and frame count.Д®ven if you check for both of these problems and believe this hasn't happened I guarantee you that you have not checked the entire file and realized it does happen later on, and even if you have checked and can confirm it hasn't happened, you surely have wasted a lot of time at this point. Not only that but very often you will get an incorrect amount of frames returned to you. If you test it by using dryrun=True argument, you will see now and then there will be an incorrect frame decimated, like a frame with new data instead of a duplicate, or it will delete a duplicate that is less compressed and keep the frame with more compression because metrically the compression caused it to be seen as a frame with new data. Most people tend to just check a couple of seconds of the footage to see if it decimated correctly if they bother to check at all. If we use TDecimate with a cycle of 5 this will seem to work when you play it back, it actually won't be. Now let's say after deinterlacing that footage has a duplicate frame every 5th frame (which would be hardcoded Pulldown 2:3 in this specific scenario). Let's say every single frame in the file is an NTSC frame (2 fields = 1 frame, interlaced). To give you some examples, let's pretend we have an NTSC DVD MPEG-2 footage, which has a common need to be decimated.

Simply put, it's far too inaccurate and it is ruining a lot of encodes. Time and time again I see people using this function to decimate for inverse-telecine purposes but I implore you to continue reading this and use an alternative decimation method.

I need to clarify when I refer to TDecimate I'm referring to both TDecimate and VDecimate (which is a port of it to VapourSynth)