C / C++ / MFC

Re: Killing clicking noises after downsampling 48kHz to 8kHz

17-Oct-08 3:40

No changing the function made the sound worst.

Redeye9217-Oct-08 4:02

Re: Killing clicking noises after downsampling 48kHz to 8kHz

17-Oct-08 4:02

Is the sound a clicking on the edge of the buffers? Does the frequency of the clicks change if you change the buffer size? Or is it just nasty noise over the top of the sound you want?

CrazyDogg17-Oct-08 4:19

Re: Killing clicking noises after downsampling 48kHz to 8kHz

17-Oct-08 4:19

the click sounds like click one´s tongue wtih a bit more frequency.

Redeye9217-Oct-08 4:21

Re: Killing clicking noises after downsampling 48kHz to 8kHz

17-Oct-08 4:21

Is the frequency related to nBytesToReduce?

CrazyDogg17-Oct-08 4:30

Re: Killing clicking noises after downsampling 48kHz to 8kHz

17-Oct-08 4:30

How I can get this out?

Sorry I´m a beginner in programming sound

Redeye9217-Oct-08 4:38

Re: Killing clicking noises after downsampling 48kHz to 8kHz

17-Oct-08 4:38

You haven't given me the information I need to help you. At the moment I can't tell whether you've got discontinuities on the buffer boundries of whether it's something else. I think you've got more than one problem actually - that downsampling routine you posted won't work, but it isn't that that's causing the problem you're describing.

Try using the downsampling routine I posted and vary the size of the buffers you send to the output. Does the frequency of the clicks also vary when you do this?

CrazyDogg17-Oct-08 4:43

Re: Killing clicking noises after downsampling 48kHz to 8kHz

17-Oct-08 4:43

Downsampling with your routine and vary the size of Buffer you can´t understand anything it´s just very nasty noise

Redeye9217-Oct-08 5:01

Re: Killing clicking noises after downsampling 48kHz to 8kHz

17-Oct-08 5:01

Okay, it sounds like you've got several problems that I'm not really going to be able to solve quickly for you, but I'll give you some pointers :

1. It sounds like you've got problems with your buffer start/end points. Check that you can take data in and send it back out to the soundcard at 48kHz without any degradation before you start worrying about downsampling and doing uLaw encoding.
2. You need to low pass filter before you do the decimation. The routine you posted isn't doing this - it's just giving you a weighted average of every 6 samples which is completely different. It's actually best done in two stages - LPF the buffer in place (corner freqency just above 4kHz), then decimate using the routine that I posted. The filtering is probably best done with a biquad IIR filter - you'll probably get away with a 2nd order LPF filter at 5kHz for what you're doing. To implement the IIR filter, do a search on the web - that's a big topic in itself.
3. If I were you I'd do all the intermediate calculation in floating point and only convert back to fixed point at the last minute. There's relatively little performance hit in Windows and it helps avoid some hideous problems that you can encounter with fixed-point IIR filtering.

CrazyDogg17-Oct-08 5:16

17-Oct-08 5:16

Sorry for being late Big Grin | :-D

.

After I tried it with recoding in 8kHz and without any manipulation on the raw data it sounds a bit better.
Someone has graphed my raw data and after downsampling. This both graphs looks really good to us.

But I will try to do your tips.

I had thought if I capture the sound with DirectSound the low pass filtering is still done.
Therefore I don´t do low pass filtering.

ClipBoard

MsmVc17-Oct-08 2:20

MsmVc

17-Oct-08 2:20

Hi All

I am useing ClipBoard.It's working for text.But how can i know file formate.

GetClipboardData(CF_TEXT)

Plz tell me what UINT uFormat is used for file?
Thanks in advance Rose | [Rose]

SandipG 17-Oct-08 2:25

SandipG

17-Oct-08 2:25

Does IsClipboardFormatAvailable() help??

Regards,
Sandip.

David Crow17-Oct-08 3:50

David Crow

17-Oct-08 3:50

MsmVc wrote:
Plz tell me what UINT uFormat is used for file?

What file?

"Love people and use things, not love things and use people." - Unknown

"The brick walls are there for a reason...to stop the people who don't want it badly enough." - Randy Pausch

MsmVc17-Oct-08 18:18

MsmVc

17-Oct-08 18:18

any type of file name.

David Crow18-Oct-08 14:40

David Crow

18-Oct-08 14:40

Filenames are just text. Use GetClipboardData(CF_TEXT).

"Love people and use things, not love things and use people." - Unknown

"The brick walls are there for a reason...to stop the people who don't want it badly enough." - Randy Pausch

MsmVc17-Oct-08 19:06

MsmVc

17-Oct-08 19:06

Hi All

When i am useing this code then i am geting text only which is copy .

HANDLE clip; 
	if (::OpenClipboard(NULL))
	{   
		clip = GetClipboardData(CF_TEXT);   
		CloseClipboard();  
	}  

	CString text;  
	text = (char*)clip;
	
	//AfxMessageBox( (char*)clip );
	AfxMessageBox(text);

Now i want to know File Name Copy.Can any one tell me what i use.

David Crow18-Oct-08 14:38

David Crow

18-Oct-08 14:38

MsmVc wrote:
Now i want to know File Name Copy.

"Love people and use things, not love things and use people." - Unknown

"The brick walls are there for a reason...to stop the people who don't want it badly enough." - Randy Pausch