chroma

bin/from-chroma

@@ -0,0 +1,13 @@
+#!/usr/bin/env ruby
+
+if ARGV.length < 1
+  STDERR.puts "Usage: #{__FILE__} [ffmpeg_args] <output> < command"
+  STDERR.puts ARGV.length.to_s
+  exit 1
+end
+
+resolution = STDIN.read(8).unpack("L>L>")
+width = resolution[0]
+height = resolution[1]
+
+exec("ffmpeg", "-v", "error", "-f", "rawvideo", "-pix_fmt", "argb", "-s", "#{width}x#{height}", "-i", "-", *ARGV)

bin/to-chroma

@@ -0,0 +1,16 @@
+#!/usr/bin/env ruby
+
+if ARGV.length != 1
+  STDERR.puts "Usage: #{__FILE__} <input> | command"
+  STDERR.puts ARGV.length.to_s
+  exit 1
+end
+
+
+resolution = IO.popen(["ffprobe", "-v", "error", "-select_streams", "v:0", "-show_entries", "stream=width,height", "-of", "default=noprint_wrappers=1:nokey=1", ARGV[0]]).read.split.map{ |x| x.to_i }
+
+
+STDOUT.write(resolution.pack("L>L>"))
+STDOUT.flush
+
+exec("ffmpeg", "-v", "error", "-i", ARGV[0], "-f", "rawvideo", "-pix_fmt", "argb", "-")

spec

@@ -0,0 +1,11 @@
+filters and generator should accept and produce sequences of images. Each sequence has the following format:
+
+width           unsigned 4 bytes big-endian
+height          unsigned 4 bytes big-endian
+
+followed by one or more arrays of pixels:
+
+pixels          array of 4 byte big-endian ARGB pixels, width * height in length
+                    pixel_index(x, y) = x + y * width
+
+if a filter does not use alpha in any way it's best practice to copy the input alpha to the output.