Audio stuttering while scrolling (C# WebBrowser) - c#

I have a WinForms WebBrowser control in a WPF WindowsFormsHost, but I've verified the problem in straight WinForms as well as several different computers.
What happens is whenever a webpage is playing music and I start scrolling the page the audio freezes and repeats the same short sample over and over again. One of the most pronounced sites that exhibits this is Google Play Music.
Is there anything I can do to mitigate this problem?

Try enabling GPU rendering for your WebBrowser control via FEATURE_GPU_RENDERING feature. Here is how to do it, and there's a bunch of other features to play with.

Related

Sound interaction between two applications

I have built a Windows Phone application with a video player to show a logo animation at startup.
If I launch an external application (like Spotify) with background audio (for example a song) and then switch to my application, the song is stopped (probably because of my logo animation) even though my logo animation doesn't even have audio.
I used a MediaElement for the logo animation :
<MediaElement AutoPlay="False" Name="media" Source="Assets/video.mp4"/>
In the code behind I use media.play(); to start the logo animation.
Is there a way to avoid stopping the sound of other applications?
From the MSDN:
When a MediaElement control plays audio or video content, any
background sounds or media already playing are halted. The app
launches the playback experience when the user taps the control. Only
one MediaElement control can operate at a time.
What this means for you is that you need to redesign the logo to run via XAML animations or some other means besides MediaElement if you want background audio to function properly. Depending on where your animation is coming from, this might be simple for you or it might be outside your scope. You'll have to determine for yourself if the benefits of background audio (Pandora, Spotify, Podcasts, etc) outweighs the work required.
That being said, I've used a large number (probably 20% in my testing) of apps that cancel background audio every time you enter them, and it's extremely frustrating. I think most users would prefer you fixed your application so that background audio is not interrupted.

Play Background Sound and Sound Effect in Windows Phone 8

I have researched a lot on playing sounds for Windows Phone 8 devices and found multiple solutions but they don't quite match my case.
What I need : I'm writing an app (C#+XAML) that uses a file as background sound (must be active while navigating the whole app), and also to be able to play sound effects.
What are the issues :
For background sound I could use the BackgroundAudio Agent, but it doesn't meet my requirements because I want the sound to be played only in the background of my app, and to stop if my app closes or is not active.
For sound effects - I tried MediaElement which is okay, but I couldn't manage to make it somehow play while I am navigating the whole app. Media closes if I leave that page - I guess I could use this for the sound effects trick. Also, there's the SoundEffect which is not quite a good solution since it can play only .wav files... I could use it for sound effects only but not background sound (big sized files).
So, how should I proceed to play background sound (only inside my app) if I choose MediaElement/SoundEffect to play a sound effect in the app. I need a solution that would allow me to play 2 sounds at once (background and sound effect) and the background sound to be played only while the app runs (is active)...
So far I am confused and managed only to solve the sound effects issue.
Any suggestions are greatly appreciated.
The issue you are seeing with your MediaElement is that you are defining it to be part of the application page and it stops playing as soon as it disappears off of the Visual Tree (i.e. after OnNavigatedFrom).
If you define a MediaElement to be "visible" as part of the application frame, audio will keep playing while your app is active (you will need to handle deactivation events, naturally).
If you do this MediaElement should work for your "background audio".
Be aware you can only have one single active MediaElement playing media in your app, however you should be able to use SoundEffect for your sound effects.
Update:
To put your MediaElement in a frame, you will need to create a custom PhoneApplicationFrame class/XAML, add the MediaElement to that XAML, and refer to your custom frame in App.xaml.cs.
// Do not add any additional code to this method
private void InitializePhoneApplication()
{
if (phoneApplicationInitialized)
return;
// Create the frame but don't set it as RootVisual yet; this allows the splash
// screen to remain active until the application is ready to render.
RootFrame = new MyCustomPhoneApplicationFrame();
RootFrame.Navigated += CompleteInitializePhoneApplication;
See this Dzone article for more about Frame/Page in Windows Phone.
In practice, MediaElement is has some gotchas like the visual tree requirement. There are ways to get around it, but they are not optimal. I would suggest scrapping using MediaElement and use XAudio2 instead. It is native so default usage would be in c++, but you can also use SharpDX to access this framework from C#.
The advantage of XAudio2 is that you would not need to worry about sound dropping out when navigating around since it is not dependent on the UI. Another advantage is you could have one SourceVoice for handling your background audio, and other SourceVoices for handling sound effect playback. This all fits well within the model of usage the framework was designed for.

Dynamically increasing/decreasing speed of a video in a windows forms application

I'm building a Windows Forms application in VS 2010 that smoothly increases or decreases the speed of a video playing back based on the speed of the user input.
I've tried several avenues..
1.) Using the AudioVideoPlayback DirectX class - I set the speed of the video, by setting the current position of the video, based on a timer.. and increased or decreased that value based on user input. While this worked on my PC, it lags a lot on our lower end target PC's. Can anyone think of a more efficient way to increase/decrease the speed of playback using this class?
2.) I've tried the Windows Media Player ActiveX control, and tried setting the rate/position dynamically, but this is extremely jumpy and laggy even on my development PC
3.) I've tried the Apple QuickTime Control 2.0 COM Component that comes with VS 2010, and it's also very laggy.
4.) I'm trying to figure out how to set the speed on the Shockwave Flash Object control, but haven't found that out yet
Can anyone suggest other avenues to explore? I just need to be able to increase/decrease the speed of video playback smoothly based on user input without lag. I don't care what format the video needs to be in, all videos can be converted to the required format.
Any help/ideas will be appreciated.
Thanks
The ultimate way is to decode the Bitmaps from videos, and handle the frames yourself.
Try the CaptureNET example from DirectShow.NET. It allows you to capture bitmaps from each frame. After that, write your own playback control to handle the refresh rate.
After trying many different formats/libraries and components I found the VLC Media Player ActiveX control to be the most efficient method to slow down/speed up video without any noticeable lag.

Playing videos in C# application via Windows Media Player. Is there a stable, decently performing solution?

I've written a WPF application (in Visual C# 2010 Express) that has 2 windows. The 1st has a various buttons, the other displays video using the MediaElement control. When a button is pressed, a video associated with it is played or stopped if it's already playing.
On my development machine (Windows 7, good graphics card, lots of memory etc), this runs fine. The only problem I've encountered is that when attached to the debugger it is very unstable but when run normally these issues go away.
Unfortunately when run on a much less powerful XP machine the videos run at 1-2fps. This is despite the fact that the videos run fine in Windows Media Player.
There seem to quite a lot of reports of poor performance for the MediaElement control (not to mention inconsistencies in what it can play) so I decided to look at some alternatives.
I tried a free library call WPF MediaKit (http://wpfmediakit.codeplex.com) that I thought might have some effect, however while I've got it to work on an XP machine, it resolutely refuses to display videos on my development machine despite using exactly the same code. I'm still hoping I can this to work but I'm not confident it will help given it's still using the MediaElement control behind the scenes.
I then tried using wmp.dll COM control (Windows forms rather than WPF) and even with the simplest app (new Windows Form project, WMP control added to form, and 1 line of code to set the URL on load) I get odd behaviour. With the debugger attached, it works across multiple monitors, but sometimes when it starts playing, it just repeatedly stutters over the 1st few frames and the only way to break it out of this seems to be to move it to the other monitor. If I'm not using the debugger, I don't seem to get the stutter issue but the video is only displayed on the main monitor, as soon as I move the window to the secondary monitor, it goes black.
So my question is has anyone experienced anything like the above and/or have a decent solution to it? It would be especially nice to find something that works consistently with and without the debugger attached!
Have you tried this library?
http://directshownet.sourceforge.net/about.html
There's also this .NET interface to VideoLAN media player, but that introduces a dependency to VLC:
http://wiki.videolan.org/.Net_Interface_to_VLC
WPF MediaKit does not use MediaElement behind the scenes, but instead uses the D3DImage interop class to provide high performance video to WPF.
WPF in XP has always been a hit-or-miss in terms of performance. You might want to take a look at the rendering tier to ensure WPF is fully hardware accelerating. Also make sure you have the newest video drivers available and that the GPU is capable.
-Jer

DirectShow EVR resizing window problem

So I've been looking into the world of media playback for windows and I've started making a C# Media Player using DirectShow. I started off using the VRM-7 windowed video renderer and it was brilliant except it had a couple of small problems (multi monitors, fullscreen). But after some research I found that it's deprecated and I should be using VRM9.
So I changed it to use VRM9 windowless then found out that was an old post rofl >_< so finally I'm using Vista/Win7 (or XP .net 3) Enhanced Video Renderer (EVR) which is apparently the most up to date Microsoft video renderer and has all the flashy performance/quality things added to it. (tbh I haven't noticed any difference but maybe I need a blue-ray or HQ video to notice it).
With using EVR everything is working fine except resizing the video. Its really laggy/choppy/teary and probably something to do with its frame queueing mechanism.
To demonstrate my problem
open up windows media player classic.
View -> Options -> Playback -> output
Chose the "EVR" DirectShow Video renderer
Now restart wmp class and play a video, while it's playing click and drag a corner to resize it. You'll notice its horribly laggy. This is the exact same problem i am having.
But if you chose "EVR Custom Pres. **" or EVR Sync **" resizing works beautifully! So i tried googling around for anything about EVR resizing issues and how to fix it but i couldn't believe how little i could find. I'm guessing "Custom Pres." stands for "Custom Presenter" which sounds like they made their own.
Also you'll notice on the right hand size when you swap between EVR and the other EVR's the Resizer drop down on the right greys out.
So basically I wan't to know how I can fix this retarded resizing problem and is there any decent documentation out there? There is a fair bit for VMR7/9 but not much for EVR. I downloaded the DirectX SDK which apparently has samples but it was a waste of 500mb of bandwidth as it had nothing relevant.
Perhaps there is some way to force it not queueing up frames if that is the problem?
If you want code say the word and I'll paste some in. But it's really quite simple and nothing much happens, i'm convinced it's a problem with the EVR renderer.
EDIT: Oh and one other thing, what does VLC use? If you go into vlc options and change the renderer to anything but default, they all suck. So is it using VMR7? Or its own?
I need to write my own Custom Presenter, which from the looks of http://msdn.microsoft.com/en-us/library/bb530107(VS.85).aspx is a relatively big task.
Guess i'll look at the sample and try to go from there

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