Hi,
relax, audio isn't so hard to understand at all. At least not the WAV-File
thingy.
Here's a good overview on that:
http://www.borg.com/~jglatt/tech/wave.htm
WAV-Files were designed to carry sample-based codecs like PCM(which isn't
codec just a sample representation), A/u-law (which compresses 12-bit audio to 8
bit via a logarithmic scale) or ADPCM (which uses linear prediction to reduce
data rate). All these formats deliver data on a sample basis (one PCM sample
in-one XY-sample out - no such thing as audio blocks). Vorbis for example, like
other powerful codecs with a high compression rate need to gather data in block,
process them, and put them in a file. Which couldn't be an original
wav-file, because it doesn't support blocks.
The "frame"-concept within wav-files has been introduced for
multichannel storage and comprises (quote)
"..The sample points that are meant to be "played" (ie, sent to
a DAC) simultaneously (. They ) are collectively called a sample frame.."
so for stereo you alternatingly store the samples of left and right channel that
belong to together, for 5.1 audio you have to store groups of 6 samples each
sample clock and so on..
Hope this helped - if you have other questions, feel free to ask.
Maybe not all questions should go over this list, as it was rather established
for vorbis-internal discussions..
Bye,
Hannes
//
// we apologize for the inconvenience
//
// Hannes Guddat
// Fraunhofer IGD - Department Communication and Cooperation
// Fraunhoferstraße 5
// 64283 Darmstadt
// GERMANY
//
// hannes.guddat@igd.fraunhofer.de
// Tel. +49 6151 155-217
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// http://www.igd.fraunhofer.de/~wam
//
----- Original Message -----
From: Nhan Than
To: vorbis-dev@xiph.org
Sent: Sunday, March 09, 2003 9:09 AM
Subject: [vorbis-dev] Please help me!!
<p> Dear Ogg Vorbis,
I'm a senior in Information Technology, and my thesis is on Audio
Watermarking. As a new starter in audio, I really need your help, and
suggestions. I think in order to persue something on Audio I have to know much
details about audio formats. So could you please show me where I can find the
documents about the information I need ? Finally,could you please answer a
confused question in my mind :
What are the differences between frames in file wav?
Thank you so much for your time and consideration.
I'm looking forward to hearing from you soon.
Sincerely,
Nhan Than
<p><p>--- >8 ----
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