lighttroupe/luz

begin
    require_relative "ffmpeg.#{RbConfig::CONFIG['DLEXT']}"
rescue LoadError => e
end

#
# Provides caching and a cleaner interface on top of the basic read and seek C backend
#
module FFmpeg
    class File
        def with_frame(index=0)
            @image ||= Image.new
            @index ||= 0

            # loop index around on both sides
            index = index % self.frame_count if self.frame_count > 0        # sometimes it's 0?!

            delta = (index - @index)
            #puts "delta = #{delta}"
            if index == 0 || delta < 0 || delta > 10
                seek_to_frame(index) or puts 'video-file: seek failed'
            else
                # Reading and decoding multiple frames-- is there a more effecient way?
                delta.times { read_next_frame_into_image(@image) }        # (possibly 0)
            end
            @index = index

            @image.using {
                yield
            }
        end

        def read_next_frame_into_image(image)
            #puts "reading next frame"
            new_data = read_next_frame
            #puts "video-file: read_next_frame failed" unless new_data
            image.from_rgb8(new_data, self.width, self.height) if new_data
        end
    end
end