Easy-to-follow video tutorials help you learn software, creative, and business skills.Become a member

Providing feedback while recording

From: Windows Phone SDK Essential Training

Video: Providing feedback while recording

So we have set up the basic recording capability, now let's provide some feedback to the user to show them the amplitude of the data that they're seeing. We'll come over and look in the solution and see that we've added an additional image here. Let's take a look at what that image looks like. So this essentially is our amplitude meter, and what we're going to do is we actually have another piece of XAML code that sits on top of that whose size we shrink from the right side to the left in time with the data coming back from the buffer to show how much data is there.

Providing feedback while recording

So we have set up the basic recording capability, now let's provide some feedback to the user to show them the amplitude of the data that they're seeing. We'll come over and look in the solution and see that we've added an additional image here. Let's take a look at what that image looks like. So this essentially is our amplitude meter, and what we're going to do is we actually have another piece of XAML code that sits on top of that whose size we shrink from the right side to the left in time with the data coming back from the buffer to show how much data is there.

So we don't actually render the squares at runtime, we simply shrink the mask that's hiding them at runtime. So let's take a look at the XAML for the main page to see how we set that up. So here is our XAML, and you can see that here we've created an image and filled it with the meter bar, and then inside that we've created a rectangle that is exactly inside the meter bar and at runtime we then shrink that--let's say that we've set this to 400.

But we also adjust the Margin at the same time so that the right-hand end of this rectangle always stays here, and we shrink the size of the rectangle and move it to the right so the right-hand end is always there. Thus, if we do this, this way and shrink it again, the image underneath is more exposed. Let's undo all this stuff and put it back to its original state and go take a look at the code. So our code looks very similar to what we had before. We still have our same four instance variables, the microphone, the buffer, the stream, and our RecordingMode, got the same Xna .FrameworkDispatcher.Update logic.

We've reduced the time span of the buffer duration from half a second to a 10th of a second, and that way our meter on the screen will update more quickly. So how do we do that? Well, we do it all here in the Callback method for the microphone data. So when a buffer of data comes in, we do what we did before, we go get the data buffer, we write it out to the stream, and now we compute the average amplitude of the sound that's inside that buffer so that we know how big or how small to make the rectangle mask, thus deciding how much of the meter image underneath we should expose.

So first we go through all the samples. Now, the samples are two byte samples, so the recording on a Windows phone device is always 16-bit recording, and it's 16-bit raw PCM, so we know that every one is two bytes. So we basically loop through the data, looking at all the samples, we extract one sample from the buffer, then we convert it to a 32-bit int, because we want to Math.Abs, because the data coming from the microphone is either -32768 in that direction, or up to +32767, but all we really care about is the absolute magnitude, because what that data is actually representing is digital samples of the sine wave of the sound.

So even though it might be loud, it might be up in the 10,000s, it could be on the bottom end of the sine wave, so the number coming back might be -10,000, but we don't care about that right here, all we really want to know is what's the magnitude of the wave that's currently being recorded at the moment. So we grab it as an integer, we get its absolute value, we create an absolute number, and then we turn around and just calculate the average so that we get an average volume inside that buffer. Then we have to do a little bit of graphic magic, so we need to scale that, because that number is going to be between 0 and 32,000, and we need to scale it so we can use it with our meter bridge.

We scale it by 10, because in order to get a reasonable response out of the meter, it's very rare that someone is actually going to get a volume that's all the way up into the red, but if you just use the raw values, then you only get just a little bit of the green showing, so we scale it up a little bit, because most recording data is going to be in the middle, and we want to have that meter look reasonable in terms of what the user is expecting, to give them visual feedback. So now we have our CoverSize that says how big should that rectangle be, and now we need to convert that into XAML units so we can adjust the coordinates for that rectangle.

So we first create a Thickness object from the current margin of that rectangle, and then we update the left edge of the rectangle by saying it's 21 plus the meterCoverSize, meaning the size we just calculated. This is what shifts it to the right. And then we update the Width so that it shifts back so it doesn't overflow the right-hand end of the graphic so that the teal border we have around the meter always shows exactly as it should. And then finally, this is the same code we had before. We go get the current position in our current stream and update the recording number in our TimerTextBlock, and that's it.

But we've also added one more thing to the recordbutton_Click, which is when you're in Record mode, and you stop, we want to put the cover back on top of our meter so that it appears that there's no sound coming in, so we want the meter to be completely black now with none of the green, yellow, or red showing. So let's rebuild our solution and give it a whirl. Just like before, we click the Record button, but now as we're recording, you can see that the meter is showing the amplitude of the volume that's actually coming in through the microphone.

So if I say 1-2-3, you can see as the meter goes up, as I'm talking, we've got that visual feedback so that the user knows something is really happening here, and their sound is actually being recorded. So that's great! Now we've got the microphone hooked up, we've got some feedback going on so that your user knows that there's actual sound being recorded. Let's go on now and add something to play that sound back so that we can actually hear what got recorded.

Show transcript

This video is part of

Image for Windows Phone SDK Essential Training
Windows Phone SDK Essential Training

65 video lessons · 2909 viewers

Michael Lehman
Author

 
Expand all | Collapse all
  1. 2m 34s
    1. Welcome
      55s
    2. What you need to know to take this course
      51s
    3. Using the exercise files
      48s
  2. 15m 44s
    1. Downloading and installing the Windows Phone tools
      2m 44s
    2. Creating a Hello World application
      9m 31s
    3. Debugging on a Windows Phone device
      3m 29s
  3. 6m 29s
    1. Exploring device capabilities
      2m 58s
    2. Understanding the Emulator
      3m 31s
  4. 8m 51s
    1. Understanding the SDK
      8m 51s
  5. 41m 32s
    1. Introducing the converter
      3m 36s
    2. Creating the user experience (UX)
      13m 35s
    3. Responding to the Application Bar
      2m 40s
    4. Implementing click handlers
      3m 52s
    5. Saving and loading settings
      8m 18s
    6. Preparing your app for shipment
      9m 31s
  6. 20m 48s
    1. Introducing sonnets
      1m 38s
    2. Data binding with Silverlight
      4m 4s
    3. Exploring the Model-View-ViewModel pattern (MVVM)
      4m 2s
    4. Implementing the Master-Detail pattern using pages
      3m 53s
    5. Loading external data
      7m 11s
  7. 50m 26s
    1. Choosing a multipage controller
      3m 13s
    2. Preparing for persistence
      7m 30s
    3. Updating the data model
      7m 2s
    4. Creating the details page
      4m 30s
    5. Bringing it all together
      3m 58s
    6. Cloning a Windows Phone app
      6m 49s
    7. Using SQL CE
      8m 49s
    8. Updating the data model
      2m 24s
    9. Querying and updating the database
      6m 11s
  8. 14m 19s
    1. Working with the camera
      6m 11s
    2. Exploring GPS
      5m 21s
    3. Exploring the accelerometer
      2m 47s
  9. 29m 34s
    1. Introducing recording and playback with XNA
      45s
    2. Capturing sound
      5m 12s
    3. Providing feedback while recording
      5m 50s
    4. Playing a recording
      4m 34s
    5. Persisting a recording
      2m 58s
    6. Listing recordings
      5m 15s
    7. Managing the recording list
      3m 26s
    8. Recording under the lock screen
      1m 34s
  10. 28m 32s
    1. Building the UX
      3m 54s
    2. Using WebClient
      4m 1s
    3. Determining network connectivity
      2m 9s
    4. Leveraging Internet Explorer
      7m 56s
    5. Adding a live tile
      2m 42s
    6. Building a background agent
      7m 50s
  11. 14m 46s
    1. Hello World in C++
      4m 35s
    2. Libraries
      4m 17s
    3. Managed plus managed
      5m 54s
  12. 26m 35s
    1. Exploring built-in controls
      4m 28s
    2. Windows Phone Toolkit
      2m 42s
    3. Introducing Coding4Fun
      3m 13s
    4. Reminders and notifications
      6m 10s
    5. Wallet and In-App Purchase
      1m 34s
    6. File and protocol associations
      1m 59s
    7. Bluetooth
      44s
    8. Integrating speech
      1m 28s
    9. Near field communication (NFC)
      1m 23s
    10. WinRT and legacy Windows Phone APIs
      2m 54s
  13. 12m 14s
    1. Publishing your apps
      2m 49s
    2. Learning from apps in the Windows Phone Marketplace
      1m 22s
    3. Staying in touch with updates and new information from Microsoft
      2m 34s
    4. Looking at Windows Phone 7 app reviews
      44s
    5. Exploring web sites books and other useful links
      4m 45s
  14. 1m 34s
    1. Farewell
      1m 34s

Start learning today

Get unlimited access to all courses for just $25/month.

Become a member
Sometimes @lynda teaches me how to use a program and sometimes Lynda.com changes my life forever. @JosefShutter
@lynda lynda.com is an absolute life saver when it comes to learning todays software. Definitely recommend it! #higherlearning @Michael_Caraway
@lynda The best thing online! Your database of courses is great! To the mark and very helpful. Thanks! @ru22more
Got to create something yesterday I never thought I could do. #thanks @lynda @Ngventurella
I really do love @lynda as a learning platform. Never stop learning and developing, it’s probably our greatest gift as a species! @soundslikedavid
@lynda just subscribed to lynda.com all I can say its brilliant join now trust me @ButchSamurai
@lynda is an awesome resource. The membership is priceless if you take advantage of it. @diabetic_techie
One of the best decision I made this year. Buy a 1yr subscription to @lynda @cybercaptive
guys lynda.com (@lynda) is the best. So far I’ve learned Java, principles of OO programming, and now learning about MS project @lucasmitchell
Signed back up to @lynda dot com. I’ve missed it!! Proper geeking out right now! #timetolearn #geek @JayGodbold
Share a link to this course

What are exercise files?

Exercise files are the same files the author uses in the course. Save time by downloading the author's files instead of setting up your own files, and learn by following along with the instructor.

Can I take this course without the exercise files?

Yes! If you decide you would like the exercise files later, you can upgrade to a premium account any time.

Become a member Download sample files See plans and pricing

Please wait... please wait ...
Upgrade to get access to exercise files.

Exercise files video

How to use exercise files.

Learn by watching, listening, and doing, Exercise files are the same files the author uses in the course, so you can download them and follow along Premium memberships include access to all exercise files in the library.


Exercise files

Exercise files video

How to use exercise files.

For additional information on downloading and using exercise files, watch our instructional video or read the instructions in the FAQ.

This course includes free exercise files, so you can practice while you watch the course. To access all the exercise files in our library, become a Premium Member.

Are you sure you want to mark all the videos in this course as unwatched?

This will not affect your course history, your reports, or your certificates of completion for this course.


Mark all as unwatched Cancel

Congratulations

You have completed Windows Phone SDK Essential Training.

Return to your organization's learning portal to continue training, or close this page.


OK
Become a member to add this course to a playlist

Join today and get unlimited access to the entire library of video courses—and create as many playlists as you like.

Get started

Already a member?

Become a member to like this course.

Join today and get unlimited access to the entire library of video courses.

Get started

Already a member?

Exercise files

Learn by watching, listening, and doing! Exercise files are the same files the author uses in the course, so you can download them and follow along. Exercise files are available with all Premium memberships. Learn more

Get started

Already a Premium member?

Exercise files video

How to use exercise files.

Ask a question

Thanks for contacting us.
You’ll hear from our Customer Service team within 24 hours.

Please enter the text shown below:

The classic layout automatically defaults to the latest Flash Player.

To choose a different player, hold the cursor over your name at the top right of any lynda.com page and choose Site preferencesfrom the dropdown menu.

Continue to classic layout Stay on new layout
Exercise files

Access exercise files from a button right under the course name.

Mark videos as unwatched

Remove icons showing you already watched videos if you want to start over.

Control your viewing experience

Make the video wide, narrow, full-screen, or pop the player out of the page into its own window.

Interactive transcripts

Click on text in the transcript to jump to that spot in the video. As the video plays, the relevant spot in the transcript will be highlighted.

Are you sure you want to delete this note?

No

Your file was successfully uploaded.

Thanks for signing up.

We’ll send you a confirmation email shortly.


Sign up and receive emails about lynda.com and our online training library:

Here’s our privacy policy with more details about how we handle your information.

Keep up with news, tips, and latest courses with emails from lynda.com.

Sign up and receive emails about lynda.com and our online training library:

Here’s our privacy policy with more details about how we handle your information.

   
submit Lightbox submit clicked
Terms and conditions of use

We've updated our terms and conditions (now called terms of service).Go
Review and accept our updated terms of service.