osxvideo.lua

-- E. Culurciello Oct 2014
-- video file loading in macos
-- a cheap ffmpeg hack / alternative:

require("image")
local lfs = require "lfs"

video = {}

function video:init(args)
   self.ifile = args.ifile or assert(false)
   self.h = args.h or 640
   self.w  = args.w or 360

   -- use ffmpeg to create a dir of images from a video file:
   -- ffmpeg -i video.mp4 -vf scale=640:360 -f image2 scratch/image-%3d.jpeg
   os.execute('mkdir scratch')
   print('ffmpeg -i "'..self.ifile..'" -vf scale='..self.w..':'..self.h..' -f image2 scratch/image-%3d.jpeg')
   os.execute('ffmpeg -i '..self.ifile..' -vf scale='..self.w..':'..self.h..' -f image2 scratch/image-%3d.jpeg')

   -- a table of filenames
   self.frames = {}
   self.idx = 3 -- to skip . and .. files in dir!

   -- load images from the list of files
   for file in lfs.dir('scratch') do
      -- file is the current file or directory name
      table.insert(video.frames,file)
   end

   return self
end

function video:forward()
   local frame = image.load('scratch/'..video.frames[video.idx])
   video.idx=video.idx+1
   return frame
end

return video

use:
video = require("osxvideo"):init{ifile = opt.videoPath,
h = resolutions[opt.camRes].h, w = resolutions[opt.camRes].w}
frame = video:forward()