private string ConstructArguments()
{
string template = "{1} -i \"{0}\" -f image2 -vframes 1 -y \"{2}\"";
//{0} is input video
//{1} is -ss TIME or blank (inaccurate but fast because it's before -i)
//{2} is output image
string input = _owner.textBoxIn.Text;
if (string.IsNullOrWhiteSpace(input))
{
_message = "No input file!";
return(null);
}
if (!File.Exists(input))
{
_message = "Input file doesn't exist";
return(null);
}
float time = 0.0f;
try
{
time = MainForm.ParseTime(_owner.boxCropFrom.Text);
}
catch (Exception)
{
//ParseTime will throw if the time is invalid, in this case we just set the time to zero if that happens
}
_message = string.Format("Previewing video at {0}", TimeSpan.FromSeconds(time));
if (time == 0.0f)
{
_message += "\nTo preview at a different time, input a valid trim start time";
}
//We can actually allow invalid times here: we just use the preview from the very start of the video (0.0) in that case
return(string.Format(template, input, "-ss " + time, _previewFile));
}