StorageFile WriteAsync operation is too slow on large files (WinRT) - windows-runtime

I've found a strange behaviour of a StorageFile WriteAsync operation. When I create large file (approx 4gb) and then try to write at the end of this file Write Async operation takes very long time. Looks like it fills the gap between begin and write positions. Anyway Process Manager shows high disk usage. Is it WinRT problem or am I doing something wrong? How to fix it?
const long FILE_SIZE = 4294967296;
var folderPicker = new FolderPicker();
folderPicker.SuggestedStartLocation = PickerLocationId.DocumentsLibrary;
folderPicker.FileTypeFilter.Add("*");
var folder = await folderPicker.PickSingleFolderAsync();
var file = await folder.CreateFileAsync("1.iso", CreationCollisionOption.ReplaceExisting);
using (var stream = await file.OpenAsync(FileAccessMode.ReadWrite))
{
stream.Size = FILE_SIZE; // size 4 Gb
var buffer = new byte[1]; // create one byte buffer
buffer[0] = 0xFF;
stream.Seek(FILE_SIZE - 10); // seek almost at the and position
await stream.WriteAsync(buffer.AsBuffer()).AsTask(); // write operation takes a lot of time
await stream.FlushAsync();
}

Related

getUserMedia and mediarecorder in html

I record audio via getUserMedia and mediarecorder:
...
navigator.mediaDevices.getUserMedia(constraints).then(mediaStream => {
try {
const mediaRecorder = new MediaRecorder(mediaStream);
mediaRecorder.ondataavailable = vm.mediaDataAvailable;
mediaRecorder.start(1000);
...
When I receive the chucks in the callback, I send them to a web api via websockets, which simply writes the parts one after another to a file:
mediaDataAvailable(e) {
if (!event.data || event.data.size === 0)
{
return;
}
vm.websocket.SendBlob(e.data);
...
The file, which is created on the webserver side in the webapi (lets call it "server.webm"), does not work correct. More exactly: It plays the first n seconds (n is the time I chose for the start command), the it stops. This means, the first chunk is transferred correctly, but it seams that adding the 2nd, 3rd, ... chuck together to a file does not work. If I push the chuncks in the web page on an array and the to a file, the resulting file (lets call it "client.webm") is working the whole recording duration.
Creating file on web client side:
mediaDataAvailable(e) {
if (!event.data || event.data.size === 0)
{
return;
}
vm.chuncks.push(e.data);
...
stopCapturing() {
var blob = new Blob(this.chuncks, {type: 'audio/webm'});
var url = window.URL.createObjectURL(blob);
var a = document.createElement('a');
a.style.display = 'none';
a.href = url;
a.download = 'client.webm';
document.body.appendChild(a);
a.click();
I compared the files client.webm and server.webm. They are quite similar, but there are certain parts in the server.webm which are not in the client.webm.
Anybody any ideas? Server code looks like the following:
private async Task Echo( HttpContext con, WebSocket webSocket)
{
System.IO.BinaryWriter Writer = new System.IO.BinaryWriter(System.IO.File.OpenWrite(#"server.webm"));
var buffer = new byte[1024 * 4];
WebSocketReceiveResult result = await webSocket.ReceiveAsync(new ArraySegment<byte>(buffer), CancellationToken.None);
while (!result.CloseStatus.HasValue)
{
Writer.Write(buffer);
Writer.Flush();
await webSocket.SendAsync(new ArraySegment<byte>(buffer, 0, result.Count), result.MessageType, result.EndOfMessage, CancellationToken.None);
result = await webSocket.ReceiveAsync(new ArraySegment<byte>(buffer), CancellationToken.None);
}
await webSocket.CloseAsync(result.CloseStatus.Value, result.CloseStatusDescription, CancellationToken.None);
Writer.Close();
}
resolved, I write all bytes of the reserved byte array to file in server code, not the count of received bytes.

Writing streamed JSON data to MongoDB using buffers

I'm trying to write streamed JSON data via JSONStream to MongoDB. The stream is needed because the data can get very large (it can go up to tens of GBs), and I would like to use MongoDB's bulk write capability to further make the process faster. To do that, I would need to buffer the data, bulk-writing every 1000 JSON objects or so.
My problem is that when I buffer the writing of the data, it does not write all the data and leaves out the last few thousand objects. That is, if I try to write 100000 JSON objects, my code gets to write only 97000 of them. I have tried buffering both MongoDB bulk write and normal write with similar erroneous results.
My code:
var JSONStream = require('JSONStream');
var mongodb = require('mongodb');
// DB connect boilerplate here
var coll = database.collection('Collection');
var bulk = coll.initializeOrderedBulkOp();
var bufferSizeLimit = 1000;
var recordCount = 0;
var jsonStream = JSONStream.parse(['items', true]);
jsonStream.on('data', (data) => {
bulk.insert(data);
recordCount++;
// Write when bulk commands reach buffer size limit
if (recordCount % bufferSizeLimit == 0) {
bulk.execute((err, result) => {
bulk = coll.initializeOrderedBulkOp();
});
}
});
jsonStream.on('end', () => {
// Flush remaining buffered objects to DB
if (recordCount % bufferSizeLimit != 0) {
bulk.execute((err, result) => {
db.close();
});
}
});
If I substitute the buffered write code with a simple MongoDB insert, the code works properly. Is there anything I am missing here?

How to update a custom image Live Tile every minute in Windows Phone 8.1?

There are quite a few Windows Phone 8.1 apps (e.g. Clock hub, Analog Clock Tile, etc.) which allow you to pin an analog clock on the main screen.
I am trying to do the same by following this sample which shows me how to update an XML document every minute.
But if I am going to create an analog clock tile then it needs to be an image.
I have tried to use XamlRenderingBackgroundTask with RenderTargetBitmap to generate the image, this bit works. What I am not sure is how can I update this image every minute.
Any help wold be greatly appreciated!
I took the sample you provided and modified it to generate a custom image live tile every minute.
I've tested it on my phone and it seems to be working OK. You might need to do more testing such as memory usage testing to make sure it doesn't go over the cap (maybe can reduce planTill to 30 minutes to generate less tiles in the loop?).
The UserControl xml file SquareFrontTile1.xml
<Border Height="360" Width="360" Background="#00b2f0" xmlns='http://schemas.microsoft.com/winfx/2006/xaml/presentation' xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml' xmlns:mc='http://schemas.openxmlformats.org/markup-compatibility/2006'>
<TextBlock Text="{0}" HorizontalAlignment="Left" VerticalAlignment="Top" Foreground="White" FontSize="50.667" />
</Border>
The code
public static async void UpdateAsync(BackgroundTaskDeferral deferral)
{
TileUpdater tileUpdater = TileUpdateManager.CreateTileUpdaterForApplication();
IReadOnlyList<ScheduledTileNotification> plannedUpdated = tileUpdater.GetScheduledTileNotifications();
string language = GlobalizationPreferences.Languages.First();
CultureInfo cultureInfo = new CultureInfo(language);
DateTime now = DateTime.Now;
DateTime planTill = now.AddHours(1);
DateTime updateTime = new DateTime(now.Year, now.Month, now.Day, now.Hour, now.Minute, 0).AddMinutes(1);
if (plannedUpdated.Count > 0)
updateTime = plannedUpdated.Select(x => x.DeliveryTime.DateTime).Union(new[] { updateTime }).Max();
StorageFolder folder = await Windows.ApplicationModel.Package.Current.InstalledLocation.GetFolderAsync("Assets");
StorageFile file = await folder.GetFileAsync("SquareFrontTile1.xml");
string xml = await Windows.Storage.FileIO.ReadTextAsync(file);
string startXml = string.Format(xml, now.ToString(cultureInfo.DateTimeFormat.ShortTimePattern));
XmlDocument tileDocumentNow = await GetTileXmlDocument(startXml);
TileNotification notification = new TileNotification(tileDocumentNow) { ExpirationTime = now.AddMinutes(1) };
tileUpdater.Update(notification);
for (var startPlanning = updateTime; startPlanning < planTill; startPlanning = startPlanning.AddMinutes(1))
{
Debug.WriteLine(startPlanning);
Debug.WriteLine(planTill);
try
{
string updateXml = string.Format(xml, startPlanning.ToString(cultureInfo.DateTimeFormat.ShortTimePattern));
XmlDocument updatedTileDocument = await GetTileXmlDocument(updateXml);
ScheduledTileNotification scheduledNotification = new ScheduledTileNotification(updatedTileDocument, new DateTimeOffset(startPlanning)) { ExpirationTime = startPlanning.AddMinutes(1) };
tileUpdater.AddToSchedule(scheduledNotification);
Debug.WriteLine("schedule for: " + startPlanning);
}
catch (Exception e)
{
Debug.WriteLine("exception: " + e.Message);
}
}
deferral.Complete();
}
private static async Task<XmlDocument> GetTileXmlDocument(string xml)
{
Border tileUIElement = XamlReader.Load(xml) as Border;
string liveTileImageName = string.Format("UpdatedLiveTile_{0}.png", DateTime.Now.Ticks.ToString());
if (tileUIElement != null)
{
RenderTargetBitmap rtb = new RenderTargetBitmap();
await rtb.RenderAsync(tileUIElement, 150, 150);
IBuffer pixels = await rtb.GetPixelsAsync();
DataReader dReader = Windows.Storage.Streams.DataReader.FromBuffer(pixels);
byte[] data = new byte[pixels.Length];
dReader.ReadBytes(data);
var outputFile = await Windows.ApplicationModel.Package.Current.InstalledLocation.CreateFileAsync(liveTileImageName, Windows.Storage.CreationCollisionOption.ReplaceExisting);
var outputStream = await outputFile.OpenAsync(Windows.Storage.FileAccessMode.ReadWrite);
BitmapEncoder enc = await BitmapEncoder.CreateAsync(BitmapEncoder.PngEncoderId, outputStream);
enc.SetPixelData(BitmapPixelFormat.Bgra8, BitmapAlphaMode.Premultiplied, 150, 150, 96, 96, data);
await enc.FlushAsync();
}
var tileDocument = TileUpdateManager.GetTemplateContent(TileTemplateType.TileSquare150x150Image);
var tileImageAttributes = tileDocument.GetElementsByTagName("image");
XmlElement tmp = tileImageAttributes[0] as XmlElement;
tmp.SetAttribute("src", liveTileImageName);
return tileDocument;
}
I am not going to fully answer the question since I am myself trying to get this working at present. However I will set you in right direction. I have done this in past with windows 8.
What you need to do is create Tile Updater and schedule tiles updates every so often.. in this case one every minute. The tile schema chosen can have be image or text or a combination of both.
you can find the TileSchema catalogue here
http://msdn.microsoft.com/en-us/library/windows/apps/hh761491.aspx
and details of Tile Schema here
http://msdn.microsoft.com/en-us/library/windows/apps/br212859.aspx
Here is a Windows 8 sample
http://code.msdn.microsoft.com/windowsapps/scheduled-notifications-da477093
Here is a snippet from my code which isn't working correctly so far.. tile is blank
TileUpdater updater = TileUpdateManager.CreateTileUpdaterForApplication();
XmlDocument document = new XmlDocument();
document.LoadXml(str2);
ScheduledTileNotification notification2 = new ScheduledTileNotification(document, new DateTimeOffset(time4));
notification2.ExpirationTime = (new DateTimeOffset?((DateTimeOffset)time4.AddMinutes(1.0)));
ScheduledTileNotification notification = notification2;
updater.AddToSchedule(notification);
Once I finish this, I will write up a blog post and add a link here
I have created a repro project that tries to do this from within sample app (not background task).
http://1drv.ms/1nai8nn
The sample work for me, I add to Windows Phone Silverlight 8.1. You must change Notification Services from MPN to WNS in WMAppManifest.xml and add Background task, tick System event, Timer in Package.appxmanifest (Declarations tab).
#Justin XL: your code not work for me, error in line
Border tileUIElement = XamlReader.Load(xml) as Border;
Error: The application called an interface that was marshalled for a different thread.

Play part of an audio file

I have to play an audio part out of a big file (300MB+).
This is my code:
// Media source is a local file.
// datName = "sound.dat"
// pointer = position in file
// length = length of the part to play
try
{
file = await StorageFile.GetFileFromApplicationUriAsync
(new Uri(#"ms-appx:///Data/" + datName));
// Get the media source as a stream.
IRandomAccessStream stream =
await file.OpenAsync(FileAccessMode.Read);
stream.Seek((ulong)pointer); // This is working, position changes from 0 to pointer
stream.Size = (ulong)length; // Is not working, Size remains unchanged at total file size
media.SetSource(stream, file.ContentType);
media.Play();
}
catch (Exception ex)
{
if (ex is FormatException || ex is ArgumentException)
{
//ShowFileErrorMsg();
}
}
Please note the comments on stream Seek and Size. The file is played from position zero.
How can I play the sound from pointer to pointer + length?
I've solved my problem by using the binary reader. I read the required area in a byte buffer and convert it to an IRandomAccessStream.
StorageFile file = await StorageFile.GetFileFromApplicationUriAsync(new Uri(#"ms-appx:///Data/" + fileName));
using (Stream stream = (await file.OpenReadAsync()).AsStreamForRead())
using (BinaryReader reader = new BinaryReader(stream))
{
reader.BaseStream.Position = pointer;
byte[] buffer = reader.ReadBytes((int)length);
IRandomAccessStream nstream = new MemoryStream(buffer).AsRandomAccessStream();
media.SetSource(nstream, "");
media.Play();
}
This version is now working.

Get a uri from a LocalStorage in Windows Phone

I write the following code to save some images from internet:
public static async Task SaveImage(string name, string uri)
{
var localfolder = ApplicationData.Current.LocalFolder;
var client = new HttpClient();
var imageStream = await client.GetStreamAsync(uri); //Secuencia de bytes
var storageFile = await localfolder.CreateFileAsync(name, CreationCollisionOption.ReplaceExisting);
using (Stream outputStream = await storageFile.OpenStreamForWriteAsync())
{
await imageStream.CopyToAsync(outputStream);
}
}
My problem is when I try to set these images store in the Local Storage to a CycleTile because this class needs the Uri's, and I don't know how to provide the uri here. This is what I have:
CycleTileData cycleicon = new CycleTileData();
cycleicon.Title = "Fotopantalla";
cycleicon.Count = 0;
cycleicon.SmallBackgroundImage = new Uri("/Assets/Tiles/FlipCycleTileSmall.png", UriKind.RelativeOrAbsolute);
List<Uri> images = new List<Uri>();
for (int i = 0; i < 9; i++)
{
/// tries...
string path1 = "ms-appdata:///local/image" + i + ".jpg";
string path2 = "isostore:/Shared/ShellContent/image" + i + ".jpg";
string path3 = "ms-appdata:///Local/Shared/ShellContent/image" + i + ".jpg";
///
Uri uri = new Uri(path2, UriKind.RelativeOrAbsolute);
images.Add(uri);
}
cycleicon.CycleImages = images;
What am I wrong or what am I missing?
For any ShellTileData related data structures you have to use path2:
"isostore:/Shared/ShellContent/*" if the images are not in the (read only) InstalledLocation folder.
For more details see: http://blogs.msdn.com/b/andy_wigley/archive/2013/04/10/live-apps-creating-custom-tile-and-lock-screen-images.aspx
I have something similar in my code:
var store = IsolatedStorageFile.GetUserStoreForApplication();
if (!store.DirectoryExists("Shared/ShellContent"))
{
store.CreateDirectory("Shared/ShellContent");
}
StorageFolder shellContent = await Windows.Storage.ApplicationData.Current.LocalFolder.CreateFolderAsync("Shared", CreationCollisionOption.OpenIfExists);
shellContent = await shellContent.CreateFolderAsync("ShellContent", CreationCollisionOption.OpenIfExists);
Stream imgin = picture.GetImage();
//Picture read stream from Media Library or other input stream
StorageFile new_img = await shellContent.CreateFileAsync(newPictureName);
Stream imgout = await new_img.OpenStreamForWriteAsync();
imgin.CopyTo(imgout);
imgout.Close(); // <- necessary in your code or not?
imgin.Close(); // <-
I'm not sure, whether you really need the Isostore thing at the beginning, but it works, if I haven't done some stupid mistake while shortening the code. ;-)
Also have a look at "StandardTileData.BackgroundImage Property", "Data for Windows Phone" and "How to use the Isolated Storage Explorer tool for Windows Phone" from Microsoft's Dev Center. (The last one is about how to have a look at the saved image file on your device.)