Extract images from large AVI movies (50-100 GB)

Question

I will get large RGB AVI files (35 Hz, 1600$\times$1200 pixels) of up to 100 GB size. All three channels contain the same grayscale image. I want to extract each AVI file into one channel png images. To do that I wanted to use the following code snippet:

nImages = Length@Import[aviFileName, "Frames"];

ParallelDo
[
  image = ColorConvert[Import[aviFileName, {"Frames", i}], "Grayscale"]; 
  imageName = ToString@PaddedForm[i, 6, NumberPadding -> {"0", ""}];
  Image`ImportExportDump`ImageWritePNG[StringJoin[imageName, ".png"], image];
  , {i, 1, nImages}
];

Questions:

1. Can such large files be read this way?

2. How can the performance be improved?

Answer 1

Here is an update where I compared the image extraction (8bit, 1 channel) from two AVI files:

My computer (Mathematica 11.0.1, Win 10 Pro, Intel i7 7490-MX, 3.1GHz, 4 cores) has 16 GB RAM and it never used in total more than 5 GB RAM, all running processes included.

The code can be used for multiple AVIs in different subdirectories in a certain base directory:

(* Read in folder which is base dir to search for avi files in all subdirs *)

ChoiceDialog[{FileNameSetter[Dynamic[baseDir], "Directory"], Dynamic[baseDir]}];

SetDirectory[baseDir];

aviNames = FileNames["*.avi", baseDir, Infinity];

numberAVIFiles = Length[aviNames];

aviDirs = DirectoryName[#] & /@ aviNames;

pngBaseDirs = FileBaseName[#] & /@ aviNames;

pngFullDirs = Transpose@{aviDirs, pngBaseDirs} /. {a_, p_} :> StringJoin[a, p];


(* Create a new directory for pngs if it does not exist otherwise delete it and create a new one *)
(If[DirectoryQ[#], DeleteDirectory[#, DeleteContents -> True]; CreateDirectory[#], CreateDirectory[#]]) & /@ 
  pngFullDirs;

Do[
   numberImages = Length@Import[aviNames[[j]], "Frames"];

   ParallelDo[

    image = ColorConvert[Import[StringJoin[aviNames[[j]]], {"Frames", i}], "Grayscale"];

    fileNameCounter = ToString@PaddedForm[i, 6, NumberPadding -> {"0", ""}];

    Image`ImportExportDump`ImageWritePNG[
     StringJoin[pngFullDirs[[j]], "\\", pngBaseDirs[[j]], "_", fileNameCounter, ".png"], image];

    fileName = StringJoin[pngBaseDirs[[j]], "_", fileNameCounter, ".png"];


    , {i, 1, numberImages}
    ];

   , {j, 1, numberAVIFiles}
   ];