[Speex-dev] frame of silence

David Hogan david.hogan at freshtel.net
Wed Feb 14 14:35:52 PST 2007

In what fashion does the encoder 'blowup' when passed a frame of zeroes
to encode?
What version of speex are you using?

From: Chris Cowden [mailto:ccowden at ncsoft.com] 
Sent: Thursday, 15 February 2007 7:57 AM
To: David Hogan; speex-dev at xiph.org
Subject: RE: [Speex-dev] frame of silence

	Okay, you've answered part of my question, which is "What value
equals silence?". I assume then that a (decoded) frame of silence would
be a buffer the size of my frame (320 bytes) full of 0's.


	Passing this frame (a frame of all 0's) through the encoder
causes it to blowup though.. 


	In response to your answer below, I don't think I want to
overwrite the decoded audio output since I don't want to lose any
"voice", I only want to interpolate silence into it. So I would guess
your response to this would be "Why don't you just interpolate a frame
of 0's in between frames of voice after it's been decoded?"... to which
I reply, "that seems sort of hack-ish... I'm looking for a more
programmatic way of generating silence that the speex codec won't choke
on." Is there such a thing?


	I don't mean to have a one-sided conversation, only to make the
best use of the bandwidth of this email.. Thank you for your help and I
look forward to any responses!



	From: David Hogan [mailto:david.hogan at freshtel.net] 
	Sent: Wednesday, February 14, 2007 2:37 PM
	To: Chris Cowden; speex-dev at xiph.org
	Subject: RE: [Speex-dev] frame of silence


	Forgive me if I misunderstood your question, but can't you just
overwrite the decoded audio buffer (either before encoding or after
decoding, depending on what you are trying to do) with zeros?



	David Hogan



		From: speex-dev-bounces at xiph.org
[mailto:speex-dev-bounces at xiph.org] On Behalf Of Chris Cowden
		Sent: Thursday, 15 February 2007 3:43 AM
		To: speex-dev at xiph.org
		Subject: [Speex-dev] frame of silence

		Hi, I'm new to this list. I'm using Speex as the base
codec in a voice chat application (with DirectSound as the audio
playback/capture interface).


		To help me debug some of my network-related issues, I
would really like to insert frames of "silence" into speech. Is there a
convenient function call or API call that takes in a buffer that is the
size of a frame and writes a frame of "silence" to it?


		I'm not sure if I'm wording the question well, so any
feedback would be greatly appreciated!


		Btw, I am really enjoying using this codec and look
forward to getting this working! Thanks!

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