similar to: Fixed Quantizer - Fixed Quality

Hi all, I have to compare the theora codec with MPEG and H264. I was googling and I found that the PSNR is a common used parameter. How can I do this with Theora? Thanks -- Leonardo de Paula Rosa Piga Undergraduate Computer Engineering Student LSC - IC - UNICAMP http://www.students.ic.unicamp.br/~ra033956

a couple points before I look at this too hard: "For VP3, since you can't do a constant quality encode" what? that should not be the case. Could be a QT-specific bug. Theora at any rate is certainly capable of doing constant-quality encode. This probably explains your standard deviation complaint -- VP3 is running a rate control alg, where the other codecs are just shooting for

One thing I have noticed when encoding VCDs is that often videos with complex backgrounds don't compress nearly as well as those with simple ones. Part of the problem is that TV cameras seam to have the focus so that the entire image is clear rather than focusing on the foreground (and blurring the backgrounds). The result is that a good number of bits are wasted trying to perfectly

Hi List, Just batting a few ideas around here, but would it be possible to include in to the codec, estimation for common video artifacts that occur in the analogue world? For example, anything that's gone through a composite stage will likely have dot-crawl and false colour - if we can recognise this effect in the encoder, we can treat it as a special case. Other artifacts that come to

Hi, I guess this is a good time to start putting together a wish list for a video codec. I see that for audio the compression is around 10X for reasonable quality. I am sure this will start its own thread of conversation. For video you can do 40X fairly easily and the big task is to go to 80X or 100X with reasonable picture quality, say, a peak luma SNR of more than 30 dB. Uncompressed

Hello, I'm using the "sem" package to do a confirmatory factor analysis on data collected with a questionnaire. In the model, there is a unique factor G and 23 items. I would like to calculate the standardized residual variance of the observed variables. "Sem" only gives the residual variance with the "summary" function, or the standardized loadings with the

Okay, Not exactly the answer I was looking for. This sounds like a big change. I don't mind re-writing the LSP quantizer but re-training code books and breaking compatibility is not what I want to do. I am working on an optimization for an ARM cortex-A8. It is desirable to process things in 4 element blocks. Is there a simpler approach you could recommend? Vasant Shridhar

Hello, I have finally added 2 lower quality settings for the NHW codec: -l1 (-5Ko) and -l2 (-10Ko).I use a quantization of 0.935 and 0.88 (kind of quantization), and I decrease residual coding on the first order wavelet image. I have updated the demo page: http://nhwcodec.blogspot.com/ . These 2 lower quality settings are still experimental.If you could find time, would be interested in any

I am fairly new to R and would like help with the problem below. I am trying to sum and count several rows in the data frame yy below. All works well as in example 1. When I try to add the columns, with an NA in Q21, I get as NA as mySum. I would like NA to be treated as O, or igored. I wrote a function to try to count an NA element as 0, Example 3 function. It works with a few warnings,

> Also, Kai has been kind enough to send me a copy of his file which > has a > problem only on -8, which I'll be looking into soon. After some intense debugging, I found the problem. One block in the file triggered a very rare bug in the LPC coefficient quantizer caused by insufficient floating point precision. There is a snippet to compute the log(base 2) of a number:

Hi all, First of all a big thank you for your work. I would like to know what is (could be) the best (optimal in a psnr and/or subjectivity sense) maximum distance between keyframes or is theora using a good heuristic change scene detection mecanism? Does it really matter to theora as with mpeg4 part2/10? Thank you and keep up the good work -- Josh

I am forwarding to the list a mail that I send to one of the subscribers, related to codecs comparison. Perhaps the material will be helpful to some of you. <p>Regards, <p> ---- Gabriel Bouvigne www.mp3-tech.org personal page: http://gabriel.mp3-tech.org <strong>attached mail follows:</strong><hr noshade> Hello I just looked at your vp3/mp4 comparison. In

Hi, I think that it would be a good thing to know more about those 2 projects (and also the future patent free format). I think that many people as me know about Lame, but not about Vorbis, and vice-versa. It would be fine that someone (perhaps the maintainer) of every project would introduce to both group of people those projects. 2 things would be interesting (to my mind): - to know about the

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>>

Hi list! I have a strange echo problem. Two days ago I setup * 1.0.6. at a friend of mine. Just an * server and for outbound calls wengo.fr was used to place calls via sip. He had a strange echo on the line I didn't experience on my setup. Today I upgraded my asterisk 1.0.5 to 1.0.6 and suddenly I have an echo too on sip calls thru wengo!! I already verified wengo was not the source of

After reading http://mp3.radified.com/mp3.htm I sent Rad an explanation of some things as I understand them. He liked it and posted it on his site (still unlinked, use the URL below). Can somebody with better understanding of psycho-acoustic terms and the vorbis model check it and comment on it? In particular I didn't know how vorbis handles quantization noise. If you reply with

Hi, Can anyone tell me the significant differences between VP30 and VP31 (or are you allowed to)? Are there different token and quantizer tables? Are there algorithmic differences? I have a VP30-encoded file that plays with the VP3 VfW DLL but not with the open source decoder. Thanks... -- -Mike Melanson --- >8 ---- List archives: http://www.xiph.org/archives/ Ogg project

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Dear Celts, I've become intrigued by the problem of spherical quantizers, so I decided to see if I could come up with something better than PVQ. What I wound up writing is something I call an "octagon quantizer. In two dimensions, PVQ uses a "diamond" (square) shape. An octagon code (OVQ) uses an octagon, which is a much better

Hello, I've found some time to get back to the NHW Project.In fact a Xiph forum member told me that even if I will start a new job, he hopes that I will still continue to develop a little the NHW Project, on my spare time.I told him that I would furthermore spend my spare time on the NHW Project if a community around the project could emerge... and he told me that certainly the best way for

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