Displaying 20 results from an estimated 1000 matches similar to: "encoder block diagram"
2003 Mar 12
2
encoder block diagram
I've made a block diagram of the encoder because I tried to find out, how it works
http://stoffke.freeshell.65535.net/ogg/block.html
Although there are specifiation docs, that give very
detailed information about single aspects of the encoding (or decoding) ,
I'm missing documenations that give a more general overview,
about how the encoder works.
(Vorbis Illuminated seems a bit
2002 Nov 26
1
floor curve question (whitening filter)
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<HEAD><META http-equiv=Content-Type content="text/html; charset=iso-8859-1"></HEAD>
<BODY bgColor=#ffffff><FONT face="verdana,arial" size="2">
Hi there,</P>
one step in the encoding process (if I got it right), would becomputing a "floor
2002 Jul 09
1
Vorbis Block Diagram
Hi,
I have looked through the documentation available from the downloads and the
web and haven't yet come across a block diagram which shows exactly how the
process of going from a .wav file to a .ogg file works. I suspect it is the
same as the mp3 process (with a different psychoacoustic model). I found
this document:
2004 Mar 03
1
Matlab implementation
Hello!
I´m just interested if there exists a matlab implementation of the
vorbis encoder / decoder or at least of some parts of it (psychoacoustic model,
MDCT, VQ), would need it for my diploma thesis.
Thanks
Stefan Bayer
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2003 Jan 24
8
just an idea about quality evaluation
Hello
I had an idea about judging the quality of ogg vorbis
(or any other lossy codec)
I took a wave-file and encoded it to ogg.
Then decoded ogg to wav and inverted it's phase. When mixing the original
wav with the phase-inverted decoded ogg-file, any identic parts of compressed and uncompressed audio should be eliminated.
Of course there's always a "rest" of sound because
2002 Oct 22
3
Spectral phase information in residue vectors
I found this sentence in the Ogg format specs:
http://www.xiph.org/ogg/vorbis/doc/vorbis-spec-res.html
"A residue vector may represent spectral lines, spectral magnitude, spectral phase or hybrids as mixed by channel coupling."
But where does the spectral phase information come from ?
AFAIK MDCT doesn't provide any phase information.
And in OGG-encoding, MDCT is taking place a few
1995 Nov 14
1
Vorbis Codebooks
Hello,
Vorbis uses codebooks, for example to do vectorquantization and huffman-encoding.
My question is - are all these codebook dynamicly generated ("trained")
or are there also static codebooks used ?
If yes, what specific tasks are these 2 types used for, during encoding ?
Thanks
Stoffke
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Ogg project
2003 Mar 05
1
Questions about window sizes
Hello,
I have a few questions about the block size in ogg vorbis
1. The allowed blocksizes are powers of two between 64 and 8192 Samples.
As I understood , there are fixed sizes for long and short blocks .
The encoder can pick any allowed value for long blocks and onother value, that must
be smaller or equal to the first one, for short blocks.
On which base does the encoder choose the size for
1999 Aug 15
1
Vorbis transform description
OK, into the nitty-gritty, albeit a high-level version. If it sounds
like I'm glossing important details, you're right. This discusses
only the basic DSP; precise coding, framing, sync, etc, will be in
another mail.
Vorbis is a hybrid transform domain general purpose audio encoder,
like MPEG in some respects (it is rooted in much of the same basic
theory). For the most part, the
2006 Mar 27
2
Speex for sampling freq >48KHz
Hi,
I have one doubt again, that is Vorbis use DCT/MDCT based algorithm and also use psychoacoustic model so this is lossy codec. And I dont think it ca regenerate a better matching waveform than speex.
Then there comes FLAC which is the perfect answer to my question, I suppose. But my concern is this that FLAC use simple prediction algorithm and doesnt use any CELP based algo which could have
2006 Mar 27
0
Speex for sampling freq >48KHz
> I have one doubt again, that is Vorbis use DCT/MDCT based algorithm
> and also use psychoacoustic model so this is lossy codec.
Speex is also a lossy codec.
> And I dont think it ca regenerate a better matching waveform than
> speex.
At bit-rates above 32 kbps, Vorbis tends to produce better results than
Speex, even for speech. The only advantages of Speex over Vorbis at
these
1999 Oct 23
0
State of the code 19991022
Tonight's commit is a round of psychoacoustic improvements and bugfixes.
(Basically, a week spent with plotting tools making sure each and every element
of the process was functioning as expected. Found some nasty little tuning
mistakes in there). Things are currently tuned to approximate 128kbps.
If you find any samples that don't sound good at this point, let me know.
What's
2002 Jul 08
1
Vorbis Block Diagram
Hi,
I have looked through the documentation available from the downloads and the
web and haven't yet come across a block diagram which shows exactly how the
process of going from a .wav file to a .ogg file works. I suspect it is the
same as the mp3 process (with a different psychoacoustic model). I found
this document:
2006 Mar 27
1
Speex for sampling freq >48KHz
Hi,
I chose speex initially because i had some work in VQ on speex i.e. modifying split VQ to GMM based parametric VQ and I thought If I train the GMM based VQ codebooks with audio signal and then do audio coding with speex, I probably get a better(smaller) residual signal even with speex. But I couldnt get that.
I was trying to get a lossless bitstream by MUXing the speex-bitstream and the
2007 Dec 09
1
Experimental release of Ghost/CELT 0.0.1
Hi everyone,
I've just made the first public release of some new *experimental* codec
work I've been doing (part of the vague Ghost project) with help from
Monty and Timothy. This is mainly intended with developers with DSP
knowledge, not for doing anything useful with it (but it does encode and
decode already). Also, the main idea is *not* to replace either Speex or
Vorbis, but to code
2007 Dec 09
1
Experimental release of Ghost/CELT 0.0.1
Hi everyone,
I've just made the first public release of some new *experimental* codec
work I've been doing (part of the vague Ghost project) with help from
Monty and Timothy. This is mainly intended with developers with DSP
knowledge, not for doing anything useful with it (but it does encode and
decode already). Also, the main idea is *not* to replace either Speex or
Vorbis, but to code
2007 Dec 09
1
Experimental release of Ghost/CELT 0.0.1
Hi everyone,
I've just made the first public release of some new *experimental* codec
work I've been doing (part of the vague Ghost project) with help from
Monty and Timothy. This is mainly intended with developers with DSP
knowledge, not for doing anything useful with it (but it does encode and
decode already). Also, the main idea is *not* to replace either Speex or
Vorbis, but to code
2007 Dec 09
1
Experimental release of Ghost/CELT 0.0.1
Hi everyone,
I've just made the first public release of some new *experimental* codec
work I've been doing (part of the vague Ghost project) with help from
Monty and Timothy. This is mainly intended with developers with DSP
knowledge, not for doing anything useful with it (but it does encode and
decode already). Also, the main idea is *not* to replace either Speex or
Vorbis, but to code
2006 Apr 20
1
Ogg Vorbis questions
Hi,
I'm currently working on a paper describing Ogg Vorbis. It is not finished
yet. Mostly the decoder is being described. If you have any comments, please
send them to me. See:
http://www.turbocat.net/~hselasky/math/vorbis/files/
Then I have a question about the function "bark_noise_hybridmp()" which is
used in the encoder. Can someone describe what the function does in
1999 Nov 19
2
Impulses
After playing with the vorbis code for a while and doing tons of hacks and
analysis on it, I've found it to perform very poorly with impulse signals.
The MDCT seems to cause lots of spreading, and it seems to result in much
worse impulse performance then mp3.
What is the current plan on handling this? Will a smart quantizer be able
to avoid it?
I've been looking at various ways of