On Sun, Oct 27, 2013 at 12:41 PM, Net Keenest <thenetkeen...@gmail.com> wrote: > Hi, I use melt (0.9) because of the videostab2 filter. Transcode is > practically unusable and there aren't any ffmpeg binaries available > yet with vid.stab enabled (as far as I know). > > It is sad that the included version (0.75) is older than 3 years. The > developer was quite active in the meantime. > > There is also an ugly bug in the melt version: it seems to ignore the > interpolation setting. The only way it gets reported (with -debug) > correctly, is to set "rescaler=name" for the consumer like: > melt -debug test.mlt -consumer avformat f=yuv4mpegpipe > rescale=bicublin | ffmpeg -i - image%02d.png
This is by design. It is typical in MLT to set a global interpolation level on the consumer and then the filters pick that up. That way one can easily set fast, draft quality levels for preview in a GUI and get higher quality when rendering for finish without having to set parameters on each filter and transition instance. The SDL and audio-only consumers default themselves to nearest and avformat consumer defaults to bilinear. > This outputs (along other lines): > Image Transformation/Stabilization Settings: > smoothing = 10 > maxshift = -1 > maxangle = -1.000000 > crop = Keep > relative = True > invert = False > zoom = 0.000000 > optzoom = On > interpol = Bi-Cubic (4) <== OK! > sharpen = 0.800000 > Final zoom: 0.000000 > > Corresponding code section: > https://github.com/mltframework/mlt/blob/2308a7/src/modules/videostab/filter_videostab2.c#L168 yep, that is fine except for some of the mapping seems incorrect, for example bicubic, which is easy enough to fix. > However, no matter what interpolation setting is used, the image > always looks uninterpolated. Here is a sample with default settings > and the vectors: > 1=0/0:0.02x0;2=0/0:-0.01x0;3=0/0:-0.014x0;4=0/0:0.0265x0;5=0/0:0.0123x0;6=0/0:-0.0178x0;7=0/0:-0.02044x0;8=0/0:0.01276x0;9=0/0:0.01111x0 > Frames: http://imgur.com/a/q3khB#0 > Original: https://en.wikipedia.org/wiki/File:Pm5544_ntsc-1.png > > The code looks right, though: > https://github.com/mltframework/mlt/blob/2308a7/src/modules/videostab/transform_image.c#L674 > > For a normal video, this results in wobbling blocks. > > Can this be fixed? I did some tests, and I definitely see it going into the interpolation functions, and I definitely see differences in the results when looking under a screen magnifier. However, the results are definitely nowhere what I see compared with: melt Pm5544_ntsc-1.png -filter affine transition.rotate_x=0.1 -consumer sdl real_time=0 rescale=bilinear I will look into it further this week. -- +-DRD-+ ------------------------------------------------------------------------------ October Webinars: Code for Performance Free Intel webinars can help you accelerate application performance. Explore tips for MPI, OpenMP, advanced profiling, and more. Get the most from the latest Intel processors and coprocessors. See abstracts and register > http://pubads.g.doubleclick.net/gampad/clk?id=60135991&iu=/4140/ostg.clktrk _______________________________________________ Mlt-devel mailing list Mlt-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mlt-devel
