// Get the bitmap representing a video file
// Note that displayIntent is ignored as it's specific to interaction with WCF's bitmap cache, which doesn't occur in rendering video preview frames
public static BitmapSource GetBitmapFromVideoFile(string filePath, Nullable <int> desiredWidthOrHeight, ImageDisplayIntentEnum displayIntent, ImageDimensionEnum imageDimension, out bool isCorruptOrMissing)
{
if (!System.IO.File.Exists(filePath))
{
isCorruptOrMissing = true;
return(Constant.ImageValues.FileNoLongerAvailable.Value);
}
// Our FFMPEG installation is the 64 bit version. In case someone is using a 32 bit machine, we use the MediaEncoder instead.
if (Environment.Is64BitOperatingSystem == false)
{
// System.Diagnostics.Debug.Print("Can't use ffmpeg as this is a 32 bit machine. Using MediaEncoder instead");
return(BitmapUtilities.GetVideoBitmapFromFileUsingMediaEncoder(filePath, desiredWidthOrHeight, displayIntent, imageDimension, out isCorruptOrMissing));
}
try
{
//Saul TO DO:
// Note: not sure of the cost of creating a new converter every time. May be better to reuse it?
Stream outputBitmapAsStream = new MemoryStream();
FFMpegConverter ffMpeg = new NReco.VideoConverter.FFMpegConverter();
ffMpeg.GetVideoThumbnail(filePath, outputBitmapAsStream);
// Scale the video to the desired dimension
outputBitmapAsStream.Position = 0;
BitmapImage bitmap = new BitmapImage();
bitmap.BeginInit();
if (desiredWidthOrHeight != null)
{
if (imageDimension == ImageDimensionEnum.UseWidth)
{
bitmap.DecodePixelWidth = desiredWidthOrHeight.Value;
}
else
{
bitmap.DecodePixelHeight = desiredWidthOrHeight.Value;
}
}
bitmap.CacheOption = BitmapCacheOption.None;
bitmap.StreamSource = outputBitmapAsStream;
bitmap.EndInit();
bitmap.Freeze();
isCorruptOrMissing = false;
return(bitmap);
}
catch // (FFMpegException e)
{
// Couldn't get the thumbnail using FFMPEG. Fallback to try getting it using the MediaEncoder
return(GetVideoBitmapFromFileUsingMediaEncoder(filePath, desiredWidthOrHeight, displayIntent, imageDimension, out isCorruptOrMissing));
// We don't print the exception // (Exception exception)
// TraceDebug.PrintMessage(String.Format("VideoRow/LoadBitmap: Loading of {0} failed in Video - LoadBitmap. {0}", imageFolderPath));
}
}
// All bitmap laoding eventually invokes this static function
public static BitmapSource GetBitmapFromImageFile(string filePath, Nullable <int> desiredWidthOrHeight, ImageDisplayIntentEnum displayIntent, ImageDimensionEnum imageDimension, out bool isCorruptOrMissing)
{
isCorruptOrMissing = true;
// BitmapCacheOption.None is significantly faster than other options.
// However, it locks the file as it is being accessed (rather than a memory copy being created when using a cache)
// This means we cannot do any file operations on it (such as deleting the currently displayed image) as it will produce an access violation.
// This is ok for TransientLoading, which just temporarily displays the image
BitmapCacheOption bitmapCacheOption = (displayIntent == ImageDisplayIntentEnum.Ephemeral) ? BitmapCacheOption.None : BitmapCacheOption.OnLoad;
if (!System.IO.File.Exists(filePath))
{
return(Constant.ImageValues.FileNoLongerAvailable.Value);
}
try
{
// Exception workarounds to consider: see http://faithlife.codes/blog/2010/07/exceptions_thrown_by_bitmapimage_and_bitmapframe/
if (desiredWidthOrHeight.HasValue == false)
{
// returns the full size bitmap
BitmapFrame frame = BitmapFrame.Create(new Uri(filePath), BitmapCreateOptions.None, bitmapCacheOption);
frame.Freeze();
isCorruptOrMissing = false;
return(frame);
}
BitmapImage bitmap = new BitmapImage();
bitmap.BeginInit();
if (imageDimension == ImageDimensionEnum.UseWidth)
{
bitmap.DecodePixelWidth = desiredWidthOrHeight.Value;
}
else
{
bitmap.DecodePixelHeight = desiredWidthOrHeight.Value;
}
bitmap.CacheOption = bitmapCacheOption;
bitmap.UriSource = new Uri(filePath);
bitmap.EndInit();
bitmap.Freeze();
isCorruptOrMissing = false;
return(bitmap);
}
catch (Exception exception)
{
// Optional messages for eventual debugging of catch errors,
if (exception is InsufficientMemoryException)
{
TracePrint.PrintMessage(String.Format("ImageRow/LoadBitmap: exception getting bitmap from file: {0}\n.** Insufficient Memory Exception: {1}.\n--------------\n**StackTrace: {2}.\nXXXXXXXXXXXXXX\n\n", filePath, exception.Message, exception.StackTrace));
}
else
{
// TraceDebug.PrintMessage(String.Format("ImageRow/LoadBitmap: General exception: {0}\n.**Unkonwn exception getting bitmap from file: {1}.\n--------------\n**StackTrace: {2}.\nXXXXXXXXXXXXXX\n\n", filePath, exception.Message, exception.StackTrace));
}
isCorruptOrMissing = true;
return(Constant.ImageValues.Corrupt.Value);
}
}
/// <summary>
//// Load: Full form
/// Get a bitmap of the desired width. If its not there or something is wrong it will return a placeholder bitmap displaying the 'error'.
/// Also sets a flag (isCorruptOrMissing) indicating if the bitmap wasn't retrieved (signalling a placeholder bitmap was returned)
/// </summary>
public virtual BitmapSource LoadBitmap(string rootFolderPath, Nullable <int> desiredWidthOrHeight, ImageDisplayIntentEnum displayIntent, ImageDimensionEnum imageDimension, out bool isCorruptOrMissing)
{
// Invoke the static version. The only change is that we get the full file path and pass that as a parameter
return(BitmapUtilities.GetBitmapFromImageFile(this.GetFilePath(rootFolderPath), desiredWidthOrHeight, displayIntent, imageDimension, out isCorruptOrMissing));
}
// This alternate way to get an image from a video file used the media encoder.
// While it works, its ~twice as slow as using NRECO FFMPeg.
// We do include it as a fallback for the odd case where ffmpeg doesn't work (I had that with a single video).
public static BitmapSource GetVideoBitmapFromFileUsingMediaEncoder(string filePath, Nullable <int> desiredWidth, ImageDisplayIntentEnum displayIntent, ImageDimensionEnum _, out bool isCorruptOrMissing)
{
isCorruptOrMissing = true;
// System.Diagnostics.Debug.Print("FFMPEG failed for some reason, so using MediaEncoder Instead on " + filePath);
if (!System.IO.File.Exists(filePath))
{
return(Constant.ImageValues.FileNoLongerAvailable.Value);
}
MediaPlayer mediaPlayer = new MediaPlayer
{
Volume = 0.0
};
try
{
// In this method, we open mediaplayer and play it until we actually get a video frame.
// Unfortunately, its very time inefficient...
mediaPlayer.Open(new Uri(filePath));
mediaPlayer.Play();
// MediaPlayer is not actually synchronous despite exposing synchronous APIs, so wait for it get the video loaded. Otherwise
// the width and height properties are zero and only black pixels are drawn. The properties will populate with just a call to
// Open() call but without also Play() only black is rendered
// TODO Rapidly show videos as it is too slow now, where:
// - ONLOAD It currently loads a blank video image when scouring thorugh the videos
// - Rapid navigation: loads a blank video image in the background, then the video on pause
// - Multiview: very slow as only loads the video.
// This will be fixed when we pre-process thumbnails
int timesTried = (displayIntent == ImageDisplayIntentEnum.Persistent) ? 1000 : 0;
while ((mediaPlayer.NaturalVideoWidth < 1) || (mediaPlayer.NaturalVideoHeight < 1))
{
// back off briefly to let MediaPlayer do its loading, which typically takes perhaps 75ms
// a brief Sleep() is used rather than Yield() to reduce overhead as 500k to 1M+ yields typically occur
Thread.Sleep(Constant.ThrottleValues.PollIntervalForVideoLoad);
if (timesTried-- <= 0)
{
isCorruptOrMissing = false;
mediaPlayer.Stop();
return(BitmapUtilities.GetBitmapFromFileWithPlayButton("pack://application:,,,/Resources/BlankVideo.jpg", desiredWidth));
}
}
// sleep one more time as MediaPlayer has a tendency to still return black frames for a moment after the width and height have populated
Thread.Sleep(Constant.ThrottleValues.PollIntervalForVideoLoad);
int pixelWidth = mediaPlayer.NaturalVideoWidth;
int pixelHeight = mediaPlayer.NaturalVideoHeight;
if (desiredWidth.HasValue)
{
double scaling = desiredWidth.Value / (double)pixelWidth;
pixelWidth = (int)(scaling * pixelWidth);
pixelHeight = (int)(scaling * pixelHeight);
}
// set up to render frame from the video
mediaPlayer.Pause();
mediaPlayer.Position = TimeSpan.FromMilliseconds(1.0);
DrawingVisual drawingVisual = new DrawingVisual();
using (DrawingContext drawingContext = drawingVisual.RenderOpen())
{
drawingContext.DrawVideo(mediaPlayer, new Rect(0, 0, pixelWidth, pixelHeight));
}
// render and check for black frame
// it's assumed the camera doesn't yield all black frames
for (int renderAttempt = 1; renderAttempt <= Constant.ThrottleValues.MaximumRenderAttempts; ++renderAttempt)
{
// try render
RenderTargetBitmap renderBitmap = new RenderTargetBitmap(pixelWidth, pixelHeight, 96, 96, PixelFormats.Default);
renderBitmap.Render(drawingVisual);
renderBitmap.Freeze();
// check if render succeeded
// hopefully it did and most of the overhead here is WriteableBitmap conversion though, at 2-3ms for a 1280x720 frame, this
// is not an especially expensive operation relative to the O(175ms) cost of this function
WriteableBitmap writeableBitmap = renderBitmap.AsWriteable();
if (writeableBitmap.IsBlack() == false)
{
// if the media player is closed before Render() only black is rendered
// TraceDebug.PrintMessage(String.Format("Video render returned a non-black frame after {0} times.", renderAttempt - 1));
mediaPlayer.Close();
isCorruptOrMissing = false;
mediaPlayer.Stop();
return(writeableBitmap);
}
// black frame was rendered; backoff slightly to try again
Thread.Sleep(TimeSpan.FromMilliseconds(Constant.ThrottleValues.VideoRenderingBackoffTime.TotalMilliseconds));
}
// We failed, so just return a blank video.
mediaPlayer.Stop();
return(BitmapUtilities.GetBitmapFromFileWithPlayButton("pack://application:,,,/Resources/BlankVideo.jpg", desiredWidth));
//throw new ApplicationException(String.Format("Limit of {0} render attempts was reached.", Constant.ThrottleValues.MaximumRenderAttempts));
}
catch
{
// We don't print the exception // (Exception exception)
// TraceDebug.PrintMessage(String.Format("VideoRow/LoadBitmap: Loading of {0} failed in Video - LoadBitmap. {0}", imageFolderPath));
mediaPlayer.Stop();
return(BitmapUtilities.GetBitmapFromFileWithPlayButton("pack://application:,,,/Resources/BlankVideo.jpg", desiredWidth));
}
}
/// <summary>
/// Async Wrapper for LoadBitmap
/// </summary>
/// <returns>Tuple of the BitmapSource and boolean isCorruptOrMissing output of the underlying load logic</returns>
public virtual Task <Tuple <BitmapSource, bool> > LoadBitmapAsync(string baseFolderPath, ImageDisplayIntentEnum imageExpectedUsage, ImageDimensionEnum imageDimension)
{
// 'out' arguments not allowed in tasks, so it returns a tuple containg the bitmap and the isCorruptOrMissingflag flag indicating bitmap retrieval state
return(Task.Run(() =>
{
BitmapSource bitmap = this.LoadBitmap(baseFolderPath, imageExpectedUsage == ImageDisplayIntentEnum.Ephemeral ? (int?)Constant.ImageValues.PreviewWidth128 : null,
imageExpectedUsage,
ImageDimensionEnum.UseWidth,
out bool isCorruptOrMissing);
return Tuple.Create(bitmap, isCorruptOrMissing);
}));
}
