Displaying 20 results from an estimated 4000 matches similar to: "here's the test case, possible solution"
2000 Dec 26
4
Thought for the new year
Some thoughts for the new year:
1) MDCT is good for image coding
2) image coding and audio coding are two very different things
3) combine 1 and 2
4) if a psycho model is good, after leaving out what it tells you
you can without hurting quality, applying the same model should
yield the same results as you got before
5) from 4: decode -> encode -> decode should result in (almost) the
2000 Aug 22
1
optimization progress
Hi all,
The decoder is down 30% execution time, identical bit output.
Didn't get the mdct yet; 1024 point mdct is a bit much to brute-force,
and I'm not going to hand-unroll the whole thing either (the machine-
unrolled version produced a 1.5M executable; understandably, it wasn't
very fast. Still waiting for processors with 1.5M L1 code caches ;-)
Slowest parts now are:
-- mdct
--
2000 Dec 23
1
Look what I found under the Xmas tree!
Hello people,
Looks like Santa Claus thinks I've been a good boy this year.
Here's the third in my performance patch series: d.m.l
Apply after applying d.o.n and d.n.m; I don't know how much of
those got applied to the CVS tree.
What's inside:
Request for help! Look in os.h if you're using a compiler or
processor I don't use (I use gcc on K5, K7, G3).
New MDCT! Now we
2000 Oct 23
4
More mdct questions
Sorry for starting another topic, this is actually a reply to Segher's post
on Sun Oct 22 on the 'mdct question' topic. I wasn't subscribed properly
and so I didn't get email confirmation and thus can't add to that thread.
So Segher, if the equation is indeed what you say it is, then replacing
mdct_backward with this version should work, but it doesn't.
Am I applying
2003 Mar 31
5
Rhubarber (advanced peeler)
Hi all,
[For the uninitiated: a "peeler" is a program that transforms
a Vorbis stream into a smaller, (somewhat) lower quality Vorbis
stream, and does so quickly, by just throwing out some data.]
After having prototyped several peelers that aim to peel
to a certain filesize, or to a certain quality, with mixed
success, I've now taken a different route: a peeler that
aims for the
2003 Mar 31
5
Rhubarber (advanced peeler)
Hi all,
[For the uninitiated: a "peeler" is a program that transforms
a Vorbis stream into a smaller, (somewhat) lower quality Vorbis
stream, and does so quickly, by just throwing out some data.]
After having prototyped several peelers that aim to peel
to a certain filesize, or to a certain quality, with mixed
success, I've now taken a different route: a peeler that
aims for the
2001 May 23
3
optimisation
what are the main fields where optimisation will take place to improve
the CPU use when decoding Ogg Vorbis files?
--
Venlig hilsen/Kind regards
Thomas Kirk
ARKENA
thomas@arkena.com
http://www.arkena.com
"I was drunk last night, crawled home across the lawn. By accident I
put the car key in the door lock. The house started up. So I figured
what the hell, and drove it around the block a
2004 Jun 02
4
Transient coding: AAC vs. Vorbis
Thread-split from the vorbis-mailing list
("Vorbis determined to be as good as MPC at 128 kbps!")
<p>On Sun, 30 May 2004, Segher Boessenkool wrote:
[Steven So]
SS>> If iTunes AAC can encode castanets with much less pre-echo at
SS>> ABR 128 kbps, then hopefully there will be an imaginative
SS>> (and non-patented) way of doing this in Vorbis without the
SS>>
2000 Dec 22
1
Different floor, quality improvement
Hello all,
Please try this "patch". It changes the way the noise floor is used
for quantization in a not-so-subtle way.
At the very end of _vp_compute_mask, add the lines:
for(i=0;i<n;i++)
flr[i]=.01f*sqrt(flr[i]);
The .01 is there to ensure the current codebooks will work. We will
really need different, newly-trained codebooks with this change; then
the
2000 Nov 18
3
beta3 problems
Hiya,
Just downloaded beta3, and I actually got it to compile without
too much hassle. Great job!
Still, some problems:
-- (easy): the -V option to ogg123 is broken, --version works.
-- make profile doesn't work (in vorbis-tools), need to pass in
some -pg -static or something like it (doesn't exactly work,
-static is swallowed by libtool; read some docs, needs to be
-all-static
2001 Jan 23
4
rehuff
Hiya,
Here is the sources to my "rehuff" program.
./rehuff in.ogg out.ogg
does a lossless recoding of a vorbis stream. (It generates optimal
huffman codes for the particular stream).
This code is meant for developers only, until someone is kind
enough to provide good build and configure support for it.
I won't. And no installation help questions please.
There is a little patch
2002 Jul 30
8
rehuff [source attached]
Hi all,
Yes, it's true. A new version of rehuff, the tool that losslessly compresses
Vorbis files: one that is easy to compile, and that works with
newer-than-two-years-ago streams, too!
On 1.0 streams, you get about 3% size reduction, and the headers get _much_
smaller (which helps for fast-start network streams).
Building it should be easy (you might have to add some -I and -L for
2002 Jul 30
8
rehuff [source attached]
Hi all,
Yes, it's true. A new version of rehuff, the tool that losslessly compresses
Vorbis files: one that is easy to compile, and that works with
newer-than-two-years-ago streams, too!
On 1.0 streams, you get about 3% size reduction, and the headers get _much_
smaller (which helps for fast-start network streams).
Building it should be easy (you might have to add some -I and -L for
2003 Apr 08
6
bitpeeler
No offense, Segher, but the output quality of this thing is awful. =)
I'll disregard the fact that, at least with *my* compiler, the source
tarball I downloaded reduces every packet to zero bytes, which isn't
terribly interesting.
I decided to set the byte reduction to something constant: I started
by dividing each packet's size by 2 just to see what would happen.
The resulting ogg
2001 Mar 04
3
Some comments about beta4
Hi,
I've just tried Ogg/Vorbis for the first time, and I'm quite
impressed with the results. I haven't heard any artifacts in my
tests so far, even at -b 112 (but I'm not a trained listener).
Thanks for the great work!
Now, some (mostly minor) points:
When building libvorbis on either a Linux/libc5 or a Solaris system,
both with gcc, it failed with undefined references to logf()
2001 Jul 02
1
ogg vorbis dynamic memory allocation.
I couldn't resist:
izeof(synth_buffs) = sizeof(float)*2*2*0x120 = 4 * 4 * 0x120 = 0x1200 =
4608
-Anish
> -----Original Message-----
> From: Segher Boessenkool [mailto:segher@chello.nl]
> Sent: Monday, July 02, 2001 6:34 PM
> To: vorbis-dev@xiph.org
> Subject: Re: [vorbis-dev] ogg vorbis dynamic memory allocation.
>
>
>
>
> Firelight Multimedia wrote:
>
2004 Sep 18
1
Question about granulepos in packets
On 17-sep-04, at 8:30, Jean-Marc Valin wrote:
> The granulepos is only available on a per-page basis (otherwise it
> would
> take up too much space). You can probably see how to use it by looking
> at speexdec.c
The libogg library _should_ however compute this per *packet*. I know
it doesn't. I know it'll be hard for it to do, esp. as how to compute
it is codec-dependent.
2003 Jul 04
6
Flaming
Greetings,
I thought this was supposed to be a list for educated people to discuss
serious development of the ogg vorbis project. In light of that, it is
amazing to see the level Mr. Segher Boessenkool drops down to in the
last posts. More or less calling people insane and accusing them of
being on crack and what not. I didn't want to post this on the list,
for there is no reason to
2000 Nov 16
1
recent Vorbis, sound quality problems
Hello all,
I'm having some problems with the sound quality of recent Vorbis.
There is some kind of metallic echo/tremolo effect in the lower
frequencies. This is on my iMac; haven't seen this problem on x86.
If you need a sample, I can put one up somewhere, or mail it to
someone with a good ftp server, preferably.
It could be caused by the iMac sound system doing surround sound,
(Dolby
2000 Dec 19
1
Tarkin video codec?
Me again, this time not about patents but about wavelets. I've been
doing some work on an image compression method which uses Haar wavelets
plus VQ and entropy coding, and Segher Boessenkool told me in a private
message that you are also doing a video codec. So I searched the
archives and read a bunch of posts, but I never did find out any web
address. And it's not on xiph.org either. So