[FFmpeg-devel] New filter: remap?

[F.Sluiter]

I am not considering a format change (yet), maybe I wasn't clear enough on
how this filter would work.
Displace works now with a image stream and two in puts, x_displacement,
y_dispacement. x and y are relative so they are added to the x,y location
of the source pixel.  the pixel x,y currently being copied ends up at
(x+displacement_x,y+displacement_y).
However, my remap filter would do and absolute "displacement" or rather
"remap", ampping from source pixels to target pixels.
so the x,y found in the second and third input would determine which source
pixel is copied to the current location.The filter would be almost similar
code to the displace filter but it would copy the source pixel directly
from the given location in stead of displacing it with a relative value..
pseudo code:

/*displace*/
inputimage source[][];
input displace_x[][];
input displace_y[][];
output target[][];

for (int i; i <max_i;i++){
  for int j; j<max_j;j++){
    target[i+displace_x[i][j]][j+displace_y[i][j]] = source[i][j];
}}

/*remap*/
inputimage source[][];
input remap_x[][];
input remap_y[][];
output target[][];

for (int i; i <max_i;i++){
  for int j; j<max_j;j++){
    target[i][j] = source[remap_x[i][j]][remap_y[i][j]];
}}

It might sound trivial, but with "remap" the target can be for example
bigger or with a different aspect ratio, and remap_x,remap_y would just
tell you were the pixels are coming from. So the same pixel from the source
could be copied multiple times to different locations in the target. With
displace, you can move a pixel only once.... It is "Push" vs "Pull".


2016-02-25 23:06 GMT+01:00 Paul B Mahol <onemda at gmail.com>:

> On 2/25/16, F.Sluiter <fsluiter at gmail.com> wrote:
> > Could you actually be more specific, what would be needed for 16bit
> > support? I was naively thinking to just a binary copy from source pixel
> to
> > target for starters.
>
> For example, first input is 8bit depth and 2nd and 3rd are 16bit depth
> so remap works for > 256 dimensions.
>
> Maybe you want to work with nonsubsampled formats only and not have option
> to remap y/u/v differently from each other?
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel at ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>