similar to: mdct as hardware

Hi, as we are trying to implement MDCT in hardware, we are caring now about the "n" (size of input and output vectors to and from MDCT). As I have looked in the code, this "n" is chosen from the Ogg/Vorbis stream data in info.c:_vorbis_unpack_info() which means this "n" can vary aribitrarily (as the power of 2) depending only on the value got from song data? or is

FYI.. ---------- Forwarded message ---------- Date: Thu, 25 Jul 2002 15:41:56 +0200 (CEST) From: Pattara Kiatisevi <ott@linux.thai.net> Reply-To: oggonachip@yahoogroups.com To: oggonachip@yahoogroups.com Subject: [oggonachip] Ogg-on-a-Chip project first phase finished Hi all, Finally our master thesis is finished! Ogg Vorbis player ran with RTEMS operating system on LEON on the FPGA

Hi, I wonder if there is specific requirement or restriction for the decoder in order to be consider "Vorbis" compliant (or let's say, to be a "correct" vorbis decoder). I am experimenting with integerized libvorbis and the decoder delivers the audio data as following, (and compare with the floating point version below). $ tail audioout-int.txt 0290670 025e 085c 02cf 0895

Hi, I'm trying to determine how the frequency data that is passed to the MDCT, and output time domain data obtained from the MDCT, is changed when setting #define MDCT_INTEGERIZED For instance, the trig array, for a size 256 window begins 1.000000 0.000000 0.998795 -0.049068 0.995185 -0.098017 if INTEGERIZED is set, then it begins 16384 0 16364 -803 16305 -1605 which is simply a left shift

I'm considering creating an ogg vorbis decoder chip for my senior project in school. At this point, my idea is to have a program (such as XMMS, ogg123, WinAMP) send the encoded ogg bitstream through a USB port to my project, which is then decoded. My project then returns the raw PCM audio, which is then handled by the player program for final audio output. I'm planning on USB as it

Hi vorbis-dev, I'm investigating the mdct* function in libvorbis and writing a small client program to test it. I found that I have to set ARRAYSIZE when mdct_init(lookup, ARRAYSIZE) to minimum value of 62 otherwise it will segfault with mdct_backward. Is there any lower limit or it is more likely that my code has bug? Thank you very much, Pattara -- Please avoid sending me Word or

Hi all, This is to say hello to all of you as we are starting the project Ogg on a Chip for our master thesis. More information can be found at http://oggonachip.sourceforge.net/. Cut from the homepage: "The Ogg Vorbis Player (http://www.xiph.org/ogg/vorbis/index.html) shall be implemented in form of a system-on-a-chip by using hardware/software co-design techniques. A prototyping board

Hello, I have used "MDCT_INTEGERIZED" version of mdct and the resulting bitstream is absolutely silent. Do I have to make some other changes to the source code to get it working? I mean some int->float or float->int conversion before/after call a mdct function. Thanks Rado --- >8 ---- List archives: http://www.xiph.org/archives/ Ogg project homepage:

Hi Vorbis, Now I get libvorbis-rc3 + integerized mdct_backward + integerized window running. The sound output is ok. Now we have to go further on possible optimization of the code in order to have the music played realtime on our chip (LEON-Sparc). There are 2 possible ways: 1.Make everything integer, remove all floating point usage. Then we can remove FPU and can run the chip at higher

Dear all I'm working on the implementation of the MDCT for the processor ARM-Cortex-M4 I'm trying to replicate the behavior of the MDCT for several overlapped values however I realized that current implementation of the MDCT is very close to the theory only in case in which we have and overlap exactly equal to N/2 where N is the size of the input vector as is shown in the examples for

Dear Experts, Can anybody please direct me to proper MDCT theory reference which will help me understand the code better? I'm trying to optimize MDCT for a embedded platform. So need good understanding about theory behind & implementation. Thanks in advance for your time. Warm Regards, Mahantesh -------------- next part -------------- An HTML attachment was scrubbed... URL:

Hi, Can someone tell me which MDCT and invMDCT equation uses? I implemented the invMDCT one given in eusipco.corrected.ps file (handed out by Monty way back) and it produces different time domain samples. I tried both the FFT method and the slow way directly from the equation and couldn't reproduce the results from the original code. This leads me to believe that the forward MDCT used in

In mdct.c there's some functions including some-point butterfly. In 32-point and 16-point there are calling of smaller-point function everytime twice on each half of data. When I looked on it I found that's just linear algebra. So it can be rewritten to matrix multiplication. Some one can say: there's optimization on in register working. But imagine there's one calling 32-point,

Hi, I have a doubt regarding MDCT window size for OggVorbis decoder. Can the MDCT window size vary from 64 samples to 8192 samples? Specification says that "legal frame sizes are powers of two from 64 to 8192 samples" . Is this same as MDCT window size? Please help me out.. Regards, shikha <p>--- >8 ---- List archives: http://www.xiph.org/archives/ Ogg project homepage:

The Vorbis audio format, uses something called the Modified Discrete Cosine Transform (MDCT). I was interested in how this worked, but did not know where to start. Is this the name of a particular algorithm, or does it just mean something like a cosine transform, but not quite right? So I asked the Vorbis mailing list. Nobody answered. It was not a high priority, so I did other things for

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

I did composition of butterfly8 and butterfly16 and I found, that these functions are well decomposed - decomposition doesn't lower computional speed. On the other hand the same can be done with butterfly8 - decomposition to butterfly4 (further decomposition is not possible) but there's no reason to do this. I think little improvement can be done by inlining them. Compiler and processor

Hello Vorbis folks, I'm one of the FFTW authors (www.fftw.org), and a few days ago I was playing with our codelet generator for fun and modified it to spit out hard-coded MDCTs of small sizes. The code (at jdj.mit.edu/~stevenj/mdct_128nr.c) for 256 samples (128 outputs) seems to be almost twice as fast as the Vorbis MDCT code for that size on my 2.2GHz P-IV (gcc 3.2.2 and flags "-O1

In vorbis/lib/mdct.h the following are defined: for integer: #define TRIGBITS 14 #define cPI3_8 6270 #define cPI2_8 11585 #define cPI1_8 15137 #define FLOAT_CONV(x) ((int)((x)*(1<<TRIGBITS)+.5)) for floats: #define cPI3_8 .38268343236508977175F #define cPI2_8 .70710678118654752441F #define cPI1_8 .92387953251128675613F #define FLOAT_CONV(x) = x Could someone explain where these values

Better late than never :) jack. --- Ogg Traffic for Tuesday, November 13, 2001 Jack Moffitt <[1]jack@xiph.org> _________________________________________________________________ Table of Contents 1. [2]Support The Ogg Project 2. [3]Status Updates 2.1. [4]Stan Seibert 2.2. [5]Chris Wolf 3. [6]New Developments 3.1. [7]Ogg On A Chip