FFMpegSource prides “itself” on being able to load, understand and handle VFR clips and it does that job very well indeed (I’ve read the source code), as long as you don’t muck around with its FPS settings. Where as Directshowsource might be excused as not being a very accurate filter, nor necessarily designed to handle or understand VFR clips, ffmpegsource should not be. The other (generally better alternative than directshowsource) FFmpegSource has another problem with its VFR->CFR conversion in that it in order to achieve CFR seems to “willy-nilly” destroy frames and insert duplicate frames at the wrong positions, causing jerky motion.
Avisynth code#
I haven’t studied its source code so I don’t really understand the theory behind its operation, however my observation of *using* it on my clips is that it produces very jerky video and still does not make the video sync up with the audio. When this procedure is done correctly, the video syncs up with the audio, something which directshowsource did not do (for me).ĭirectshowsource with convertfps seems to take another route. So given that the plugin has this knowledge, it *understands* where the *right place* to insert duplicate frames are, in order to achieve the constant target frame rate you’ve specified. Vfrtocfr is guided by a file that describes *exactly* (down to the millisecond) when a given frame should be shown and ensures that each frame from the source video will show up on the screen (or be processed by other avisynth filters) exactly at the intended time. However the ways the two plugins achieve that goal differ, and the sole reason I created the plugin was that neither ffmpegsource nor directshowsource handled the frame rate conversions as expected. I agree, its documentation reads like it should do the same thing as my plugin “ensure the frame rate becomes what you specify it to be”. That’s the main practical point of this plugin I’d say.Īs to your question on Directshowsource’s convertfps parameter. Sorry I digress, but I recall the feeling when I once started using avisynth and discovered the forum around it.Ī succinct and simplified answer to your question about the difference between this plugin and directshowsource would be “this one doesn’t screw up the audio sync for VFR clips” when converting to CFR, which the other alternatives in the avisynth ecosystem tend to do.
Avisynth how to#
a plugin named “Convolution filter 0.9” with mp-teen numeric arguments, each with “greek” descriptions doesn’t really communicate what the plugin does, what it is good for nor how to use it, unless you have a certain level of mathematical knowledge and preferably signal processing as well.
If you happened to have chosen another field of study in school and / or haven’t been lurking around doom9 long enough, then it can take a while to “get to know” and get comfortable with avisynth, the idea around it, where to find plugins, what those plugins really do etc. The language in this case tend to be that of mathematics and signal processing theory, merged with an assumed total recall of everything that has ever been posted, hinted or discussed on. It can at times be like listening in on a discussion in a foreign language you’re not versed in. These guys have a certain lingo and assume everyone understand their jargon and concepts used in their field.
Avisynth professional#
Hi, Jason, this response is going to be a lot longer than the post itself, so you’d better strap in.Īvisynth can be a bit “involved” to get started with, as the atmosphere and sub culture surrounding it is akin to a playground for academic or professional researchers, where they try out new image and video algorithms, critique each others work and spur new ideas etc.
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