Ah ok thanks! I'm surprised no one has need a linear algebra library. I guess there's OpenCV and people use it to do the heavy lifting?
Will look into the API more. Thanks matthew On Thu, Aug 2, 2018 at 3:31 PM Paul B Mahol <one...@gmail.com> wrote: > On 8/2/18, Matthew Lai <matthewlai-at-google....@ffmpeg.org> wrote: > > Hello! > > > > I want to write a more advanced video stabilizer for libavfilter (*), > > implementing the algorithm described here - > > > https://static.googleusercontent.com/media/research.google.com/en//pubs/archive/37744.pdf > > The focus of the paper is rolling shutter removal, but it builds on top > of > > another algorithm that does full frame stabilization, and the new > algorithm > > does that as well. > > > > This is the algorithm used in YouTube's stabilizing filter, and is state > of > > the art. Adobe calls it Warp Stabilizer (it's the same thing as far as I > > can tell from public information anyways). > > > > 3 questions: > > 1. Is there a linear algebra library already in use? I didn't see > anything > > in configure, but would be surprised if none of the existing filters work > > with matrices? > > There is no such library here used. There are indeed video/audio > filters that work with matrices. > > > 2. Is there anything to watch out for re. a high frame delay (say a few > > hundred frames)? Looking at the API, I don't see a callback to flush out > > remaining frames when input frames are finished? Is doing it in two > passes > > the only option? > > It is handled internally, there are two internal APIs, activate one and > legacy. > With legacy you can flush frames when you receive last frame from input. > With newer, activate API, its similar. > > > 3. doc/writing_filters.txt says only slice threading is available. That's > > not really possible with this filter, but frame threading is. Can I just > > buffer frames internally (which I need to do anyways to smooth out > motion), > > and do my own threading? > > You could do it. > > > > > * vid.stab is good for what it does, but it only does rotation and > > translation, and doesn't handle zoom, perspective distortion, or rolling > > shutter. This means it's limited when it comes to things like scuba > diving > > videos, where the camera is filming the seabed at a small distance and at > > an angle. > > > > Thanks! > > Matthew > > _______________________________________________ > > ffmpeg-devel mailing list > > ffmpeg-devel@ffmpeg.org > > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel > _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
