Nitrogen example for ffmpeg frontend

ffmpeg.erl

%% -*- mode: nitrogen -*-
-module (index).
-compile(export_all).
-include_lib("nitrogen_core/include/wf.hrl").
-include("video.hrl").

main() -> #template { file="./site/templates/bare.html" }.

title() -> "FFmpeg frontend".

body() ->
    #container_12 { body=[
        #grid_8 { alpha=true, prefix=2, suffix=2, omega=true, body=inner_body() }
    ]}.

inner_body() -> 
    [
        #h1 { text=title() },
        #flash {},
        #p{},
        "
        Upload video and it will be converted here to mp4
        ",
        #p{}, 	
        #upload { tag=myUpload1, button_text="Upload File" },
        #p{},
        "
        Run <b>./bin/dev help</b> to see some useful developer commands.
        ",
        #panel{id= videoPanel, body = ["Here will be video"]}
    ].
  
  
start_upload_event(myUpload1) ->
  wf:flash("Upload started.").


finish_upload_event(myUpload1, FileName, LocalFileData, Node) ->
  FileSize = filelib:file_size(LocalFileData),
  wf:flash(wf:f("Uploaded file: ~s (~p bytes) on node ~s, file: ~p.", [FileName, FileSize, Node, LocalFileData])),
  wf:continue({ffmpeg, FileName}, fun() -> transcode(FileName, LocalFileData) end, infinity),
  ok.

continue({ffmpeg, FileName}, {ok, NewPath}) ->
  Message = wf:f("Converted file '~s' (~p)", [FileName, NewPath]),
  wf:flash(Message),
  % HTML = wf:f("<video src='~s'/>", [NewPath]),
  wf:update(videoPanel, #video{src = NewPath}).

	
event(click) ->
    wf:replace(button, #panel { 
        body="You clicked the button!", 
        actions=#effect { effect=highlight }
    }).

transcode(FileName, Path) ->
  NewPath = filename:basename(FileName, filename:extension(FileName)) ++ ".mp4",
  Cmd = wf:f("ffmpeg -y -i '~s' -vcodec libx264 -preset fast -acodec libfaac 'site/static/~s'", [Path, NewPath]),
  os:cmd(Cmd),
  {ok, NewPath}.