ffcli.rs

A ffmpeg cli args builder

Using

``` rust let filtersplit = VideoFilter::new() .input(0) .output("rgb") .output("alpha") .params("format", "rgb32") .params("split", 2); let filterrgb = VideoFilter::new() .input("rgb") .output("out0") .paramsraw( VideoFilterParams::new() .key("lutrgb") .paramsraw(VideoFilterParams::kv("a", "minval")), ) .params("format", "rgb24"); let filteralpha = VideoFilter::new() .input("alpha") .output("out1") .paramskey("alphaextract") .params("format", "gray"); let args = FFmpegArgs::new(Level::Debug) .i("test.png") .vf(filtersplit) .vf(filterrgb) .vf(filteralpha) .buildfilter() .map("[out0]") .raw("rgb.png") .map("[out1]") .raw("alpha.png") .build(); asserteq!("-hidebanner -y -loglevel warning -stats -i test.png -filter_complex [0]format=rgb32,split=2[rgb][alpha];[rgb]lutrgb=a='minval',format=rgb24[out0];[alpha]alphaextract,format=gray[out1] -map [out0] rgb.png -map [out1] alpha.png", args.join(" "));

```