/// <summary>
/// Reads the image source and save the extracted images to the specified folder.
/// </summary>
/// <param name="imageSource">Image stream reader.</param>
/// <param name="outputDir">Output directory.</param>
/// <param name="fileNameFormat">Image file name format.</param>
/// <param name="onFrameCompletition">Progress function executed after a frame is saved.</param>
public static void SaveFrames(this ImageStreamReader imageSource, string outputDir,
string fileNameFormat = "img-{0:000}.png",
Action <float> onFrameCompletition = null)
{
if (!Directory.Exists(outputDir))
{
Directory.CreateDirectory(outputDir);
}
if (imageSource.CanSeek)
{
imageSource.Seek(0, SeekOrigin.Begin);
}
var idx = 0;
foreach (var frame in imageSource) //use video stream as IEnumerable<IImage> (must support seek operation)
{
if (frame != null) //some videos skip key frames (discard those frames)
{
var path = Path.Combine(outputDir, String.Format(fileNameFormat, idx));
ImageIO.TrySave(frame, path); //TODO-noncritical: add compression options
}
if (onFrameCompletition != null)
{
onFrameCompletition((float)(idx + 1) / imageSource.Length);
}
idx++;
}
}
/// <summary>
/// Reads an image from the stream.
/// </summary>
/// <param name="image">Read image.</param>
/// <returns>True if the reading operation was successful, false otherwise.</returns>
protected override bool ReadInternal(out IImage image)
{
lock (syncObj)
{
image = default(IImage);
if (this.Position >= this.Length)
{
return(false);
}
image = ImageIO.LoadUnchanged(FileInfos[currentFrame].FullName);
currentFrame++;
}
return(true);
}