Audio Recording echo in Windows Phone 7

Question

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Hye,

I m working on WP7,
and i have created a audio recording app.

when i click on record button,
the code executed is -

microphone.BufferDuration = TimeSpan.FromMilliseconds(1000);
buffer = new byte[microphone.GetSampleSizeInBytes(microphone.BufferDuration)];

microphone.BufferReady += new EventHandler<eventargs>(microphone_BufferReady);

microphone.Start();</eventargs>

(where buffer is byte[], microphone is Microsoft.Xna.Framework.Audio.Microphone object)

now when i overwrite this recording, i clear the byte[] buffer as

for(int i= 0;i< buffer.Length; i++)
{
    buffer[i] =0;
}

and then again this code is executed -

microphone.BufferDuration = TimeSpan.FromMilliseconds(1000);
buffer = new byte[microphone.GetSampleSizeInBytes(microphone.BufferDuration)];

microphone.BufferReady += new EventHandler<eventargs>(microphone_BufferReady);

microphone.Start();</eventargs>

but buffer gets initialized by some bytes, before any recording gets started.

why is it happening.?
due to this, the new recording gets append to the previous one, n it echo while playing (repeat some parts).

thanks in advance.

Posted 22-Feb-11 2:06am

DeepsMann

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3 solutions

Solution 1

Hye,

record append problem is solved by clearing the MemoryStream object- stream before overwriting the previous record.

stream.flush;
and 
stream.SetLength(0);

but the echo problem is still there.
its like when my applications starts and i record for the first time say-
"one two three four" and play the recording,
it sounds correct as- "one two three four".

now when i overwrite it by -"five six seven eight"
and play it, some of the parts of the recording gets repeated like-
"five six.. five six seven eight.. seven eight"

why this happens..??
is it because the SoundEffect object or the Microphone.?

also, there is something strange happening.

if i starts my app and record for the first time,
it records well. (echo problem is still there if u overwrite).

now i save the recording and navigate to some other page and perform some other stuffs..,

and then if i navigate to the page for recording
and starts recording, it records something, as the byte[] have some values.

but when i play it using the SoundEffect object,
there is nothing i can hear.

there is no error or exception.

why this happens?

is there something i m missing, or is it something with the microphone.???

thanks in advance.

Posted 25-Feb-11 2:36am

DeepsMann

Solution 2

Hye everyone,

i came to know that the reason of sound echo in recording is
when i tap on record button in my Application and call the function to record which is -

private void record()
        {
            counter = 1;
            Microphone microphone = Microphone.Default;

            TimeSpan tt = new TimeSpan();
            tt = TimeSpan.FromMilliseconds(1000);
            microphone.BufferDuration = new TimeSpan(0, 0, 1);
            microphone.BufferDuration = tt;

            buffer = null;
            buffer = new byte[microphone.GetSampleSizeInBytes(microphone.BufferDuration)];
            stream.SetLength(0);
            
            microphone.BufferReady += new EventHandler<EventArgs>(microphone_BufferReady);
            microphone.Start();
        }



        void microphone_BufferReady(object sender, EventArgs e)
        {
            microphone.GetData(buffer);
            stream.Write(buffer, 0, buffer.Length);
        }

Now when i tap on the record button the method

VB

record()

is called and
microphone_BufferReady is called in every 1 second.

Now, if i again tap on record button and overwrite my previous recording (i m on the same page)
the microphone_BufferReady is called in every 2 second.

if i tap third time it will be 3 sec and so on.

it can be easily noticed by increamenting a counter in microphone_BufferReady and display it in a textblock.

i m not getting why this is happening.?

thanks in advance.

Posted 15-Mar-11 3:43am

DeepsMann

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DeepsMann · Accepted Answer · 2011-11-14T23:19:00

Solution 3

Making a Voice Recorder on Windows Phone[^]

Posted 14-Nov-11 23:19pm

DeepsMann