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Re: Feeding video data to Imager

by tonyc (Pilgrim)
on Mar 27, 2006 at 00:01 UTC ( #539327=note: print w/replies, xml ) Need Help??

in reply to Feeding video data to Imager

There's a few ways you could do it:

  • format the data as PPM as above, or perhaps raw would be better.
  • use the setscanline() method to write data a scanline at a time to the image. Unfortunately this expects data in a particular format, so you'll still need to adjust the data a bit.
  • # untested my $im = Imager->new(xsize=>$width, ysize=>$height); my $per_line = $width * 4; # adjust the data to the format setscanline() takes $nfr =~ s/(.)(.)(.)/$3$2$1\xFF/gs; # paint it for my $y (0..$height-1) { $im->setscanline(y=>$y, pixels => substr($nfr, $y * per_line, $per_line)); }
  • if performance is an issue you could use Inline::C or an XS module to reformat the data and draw it using i_plin() at the C level. Here's some Inline C code to do the job:
  • use Imager 0.48; # this assumes you've created an image of the right # size first. # if you call it with too large an image for the data # supplied then it will crash use Inline C => <<'EOS' => WITH => 'Imager'; void capture2image(Imager::ImgRaw out, unsigned char *data) { i_color *line_buf = mymalloc(sizeof(i_color) * out->xsize); i_color *pixelp; int x, y; for (y = 0; y < out->ysize; ++y) { pixelp = line_buf; for (x = 0; x < out->xsize; ++x) { pixelp->rgba.b = *data++; pixelp->rgba.g = *data++; pixelp->rgba.r = *data++; ++pixelp; } i_plin(out, 0, out->xsize, y, line_buf); } myfree(line_buf); } EOS

Perhaps Imager needs a more general data to image method, but I haven't had much feedback on setscanline() and friends yet.

Edit: added the Inline C code, hard to test without video capture data though.

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