search for: perceptually

I quote from "Principles of Digital Audio" by Ken C. Pohlmann: "Because perceptual coders tailor the coded signal to the ear's acuity, they similarly tailor the required response of the playback system itself. Live music does not pass through amplifiers and loudspeakers, it goes directly to the ear. But recorded music must pass through the playback signal chain. Much of the

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

Hi Has anybody done THD or THD-N measurements with the CELT Codec (bext would be on various bit rates) If someone could share results for Mono at 64kBit and Stereo at 128 and 196kBit it would be great. thank you very much Jochen -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.xiph.org/pipermail/opus/attachments/20100817/b1da17cc/attachment-0002.htm

Hi, Does anyone have an idea about the possibility to apply psychoacoustic models as the ones in mp3 or AAC to a CELP coder? Thanks! /Pontus <p>--- >8 ---- List archives: http://www.xiph.org/archives/ Ogg project homepage: http://www.xiph.org/ogg/ To unsubscribe from this list, send a message to 'speex-dev-request@xiph.org' containing only the word 'unsubscribe' in the

(This is almost out of topic but anyway...) It is surprising how little research effort have been put into psy-acou models for CELP. The basic problem lies in that it is not easy to alter the LP model without distroying the minimum-phase property (ie. the stability of the predictor). That leaves us with psy-acou modelling of the noise-part only. However, my own research is in constrained

Hi, I have a newbie question, and a not-so-newbie one. I've just found out about Ogg, and I haven't been able to find a clear answer in the many webpages this proyect has (btw, why not create just one site instead of vorbis.com, ogg-vorbis.com...). The question is, does Ogg use perceptual coding, like mp3 does? And if so, would it be possible to build an encoder in such a way as to

Le mar 11/11/2003 à 05:00, MAL a écrit : > Jean-Marc Valin wrote: > > Hi, > > > > I just released unstable version 1.1.2 that contains more fixed-point > > work. Though it's still not 100% complete, enough have been done to make > > it run in real-time on ARM. In order to do that, compile with > > --enable-fixed-point --enable-arm-asm. All narrowband

Hi Masakazu, I have reproduced the Speex high frequency noise issue on a Blackfin 537 by sending 'silence' into the Speex fixed point encoder. By recording the Speex decoder output and plotting the spectrum using Audacity the following two frequencies. 1596Hz at -31.3dB 3200Hz at -48dB These two frequencies are present in both Narrow Band and Wide Band modes. I've tried a number

Dear R-list members, I need an help with the Multidimensional Scaling analysis (MDS). So far I used the cmdscale() command in R, but I did not get the perceptual map I would love to see, and I would like to know if it is possible to get it using R, and if yes how. I also had a look to the functions isoMDS() and sammoc() but with no luck. I summarize the experiment I performed, and I would ask you

...lot of bits in the LF because of that". > It could also be just the MP3 encoder being silly, or other things. Was the original poster speaking about the SILK or the CELT derived mode? Because at least wrt SILK (and the rest of the LPC derived codecs) there is an additional explanation: perceptually matched synthesis. If you look at things like the GSM/UMTS series codecs, they can seem *really* bad in a naive noise floor comparison, while sounding better at low bitrates and when applied to speech-like signals. That's pretty much the reason LPC derivatives are used in the first place, a...

Hi, I have been using speex version 1.0.5 on a text-to-speech program. Recently I upgraded to version 1.2beta1 and noticed that the waveform the I got after encoding and decoding on the new versions (beta1,beta2) is much more different than the original than on version 1.0.5. I also ran a PESQ comparison test on 700 voice samples and got better results in the older version (I used quality 9, and

[ I'm not in the list because I didn't find a digested version; please move the lists to sourceforge.net, and we would have the digested version. I read the replies from the archive. ] Hello. Would it be possible to allow Vorbis use the same codebook for multiple files? I could keep a 650 MB codebook on CD-R and use that for all my audiofiles. If that is possible, how much the

I was wondering if the developers were using anything to "objectively" test the quality of the speex vocoder. For instance PSQM or one of the many derivatives. Mean Opinion Scoring seems an expensive route. Is there some open source software to use for this? <p>--- >8 ---- List archives: http://www.xiph.org/archives/ Ogg project homepage: http://www.xiph.org/ogg/ To

I was recently talking to a friend of mine who produces what's widely referred to as "techno", music that's heavy on electronically generated loops and effects, samples, and has plenty of bass. He doesn't like ogg for a few reasons - he sent me a rather long email, and I've stripped out the nonsense from it (he has some technically irrelevant reasons for not liking

...resent thousands or tens of thousands of points, but all I read from them are density and distribution --- the gene names cannot be shown. At what point, would a sunflowerplot-like display or a smooth gradient be better? When two data points drawn as 50% gray disks are small and tangent, are they perceptually equivalent to a single, 100% black disk? Or a 50% gray disk with twice the area? What problems are known about plotting with disks --- do viewers use the area or the diameter (or neither) to gauge weight? As you can tell, I'm a non-expert, mixing issues of data interpretation, visual percep...

Hi, I just released unstable version 1.1.2 that contains more fixed-point work. Though it's still not 100% complete, enough have been done to make it run in real-time on ARM. In order to do that, compile with --enable-fixed-point --enable-arm-asm. All narrowband modes work in real-time with complexity 1 (some work with higher complexity) and some wideband modes also work (up to ~20 kbps) at

Which web server does mongrel fair best with? -Ron

Hi all, I'm implementing the opus codec for a proprietary RF link (for fullband audio) and want to make sure I understand something. The link is currently running at 44.1KHz - realtime (i.e. streaming from an A/D at one side, ultimately to a D/A at the other). Rather than muck with all the infrastructure, I'm looking at how to run Opus at 44.1K. I have flexibility in the frame sizes of

All: Attached please find yet another RTP profile revision (v5). You can also find the document at: http://www.herlein.com/downloads/speex/docs/ Changes: - added vbr, cng, ebw, sr optional parameters to MIME - added vbr, cng, ebw a=fmtp options for SDP use - added required document attributes for submission to IETF and IANA (format and author contact information). Note that we

> Does anyone have an idea about the possibility to apply psychoacoustic > models as the ones in mp3 or AAC to a CELP coder? Thanks! > /Pontus This is (sort of) done in the decoder with the optional perceptual filtering. Speex tries to shape the noise so that it sounds more pleasant, I believe. To really use perceptual coding, one would require fine granular control over quantization