search for: spectrogram

I know that there is a function, (spectro3D), that produces the Power Spectrogram. Are there R functions that produce the Frequency Spectrogram and the Phase Spectrogram? Thank you for your time. [[alternative HTML version deleted]]

Hi, I need to plot spectrogram of a waveform.What package offers this? -- Rajesh.J [[alternative HTML version deleted]]

...nges than MP3 has? The spontaneous suspect that lower frequency artefacts may be more noticeably than higher frequency artefacts seems plausible, also. Is it a matter of energy (which is higher for higher frequencies)? When your own ears are no longer in their best possible condition, you may try a spectrogram, just to make sure you don't miss anything. Regards, Ulrich >>> Jean-Marc Valin <jmvalin at jmvalin.ca> 31.10.17 3.09 Uhr >>> Just to be clear, my goal here wasn't to make fun of anyone, but to drive the point that spectrograms should *never* be used to demonstrate...

...9;s also artefact at 15kHz which wasn't in the original audio. Visible with Spek program. Download FLAC and Opus both files, new link: http://www.filedropper.com/example_3 FLAC full: 1084 kbps; FLAC solo: 465 kbps. with --bitrate 160: Opus full: 158 kbps; Opus solo: 190 kbps. Included also Spek spectrogram PNG file for Opus solo to see the artefacts. Music is copyrighted but we using it for testing purposes, ok? -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.xiph.org/pipermail/opus/attachments/20181117/17cea3d4/attachment.html>

Jean-Mark sarkasm. Jean-Markasm. (Bonus points for providing an actual noisy WAV! ^_^) On 30/10/2017 20:28, Jean-Marc Valin wrote: Hi, Before I comment on the graphics you posted to visualize the difference between two audio signals, I'd like to ask for your help in evaluating my JPEG encoder. I've encoded an image with JPEG and then computed the difference with the original. I then

...;,'perfect','block','filter'} for k=1:length(fnames) fn=fnames{k}; myfile=fopen([fn, '.fl'], 'r', 'ieee-le'); x=fread(myfile, Inf, 'float32', 0, 'ieee-le'); fclose(myfile); X=specgram(x,2048,1,kaiser(2048,14)); spectrogram_floor=-96; pcolor(max(spectrogram_floor,20*log10(abs(X(end:-1:1,:))))); shading flat colorbar print('-dpng','-r300', [fn, '.png']) end ['Done'] I've posted the output for the filter-based and block-based resampler at different qualities at http:...

...eating sweeps. > After around 50s, there is silence. > The resulting wav file too then, obviously. That's because originally the second sweep was in inverse mono. Therefore, after the mixdown, the sweep got actually subtracted from itself. > As far as I can tell (see the attached spectrograms), > the sound dies out around the point the freq reaches 12kHz. You're probably talking about the other frequency that came in, the one I called the undesired or unwanted frequency. The spectrogram is one thing, but switching to 1/2 or 1/4 or the playback rate and pressing Play is anot...

...(which is higher for higher > frequencies)? Most signals have more LF energy than HF, so it's normal for the noise to look like that as well. If the noise is flat, then you have too much HF noise and you're wasting bits in the LF. In fact, that's exactly what I'm noticing in the spectrograms that are posted. > When your own ears are no longer in their best possible condition, you may try > a spectrogram, just to make sure you don't miss anything. Actually, that's the wrong way. Especially when the spectrogram is computed on a signal difference. For example, some codecs...

...ginal frequency then > quickly disappears while the unwanted new frequency is never completely > filtered out, keeps falling and falling and at the exact time spot where the > original frequency would reach 16 kHz, the undesired frequency goes down to > zero. Yes, I think I see that in spectrogram-opus.png too. And then it goes back up to 8k. And the original frequency keeps rising to around 12k AFAICS. > > As far as I can tell (see the attached spectrograms), > > the sound dies out around the point the freq reaches 12kHz. > > You're probably talking about the other...

Just to be clear, my goal here wasn't to make fun of anyone, but to drive the point that spectrograms should *never* be used to demonstrate quality. The only case where they can sometimes be useful is for diagnostic purposes. If you hear something and you're not sure what you're hearing exactly, then sometimes a spectrogram can help you figure out what it is. That's pretty much it. If...

...tivity side of things. > Most signals have more LF energy than HF, so it's normal for the noise > to look like that as well. If the noise is flat, then you have too > much HF noise and you're wasting bits in the LF. In fact, that's > exactly what I'm noticing in the spectrograms that are posted. Yes. And of course many of the fundamentals live in the LF range. It'd be more useful to post spectrograms which normalized any residual noise by the utility signal reconstructed by the codec; i.e. time-varying S/N ratios per band. Of course that's still rather naïve...

...reached 16 kHz, the frequency in the output file practically fell down to > > zero. The intermediate opus file already contains only the first of the two repeating sweeps. After around 50s, there is silence. The resulting wav file too then, obviously. As far as I can tell (see the attached spectrograms), the sound dies out around the point the freq reaches 12kHz. Also see the transcript below. > > ????Unfortunately, it seems that the lowpass filtering is somehow a part of > > the actual resampling algorithm. What resampling? > > Why do I think so? Opus normally doesn't...

...t bother with what you > "hear" outside of the audible spectrum. > > My current bet is that the very low frequencies are correctly > represented in the Opus file, but your speaker/headphones > are not capable to play them properly (which is no wonder). Attached I send the spectrogram (vic SoX) of the first 20 seconds for the wav file and the opus file. Indeed, there is extra noise for the low frequencies, but somewhere around -100 dB. Jan -------------- next part -------------- A non-text attachment was scrubbed... Name: spectrogram-wav.png Type: image/png Size: 34311 bytes...

...at it's the same song has nothing to do with it. Why would a recording of a solo piano necessarily use a smaller bitrate than a recording of a band? > And there's also artefact at 15kHz > which wasn't in the original audio. > Visible with Spek program. > Included also Spek spectrogram PNG file > for Opus solo to see the artefacts. It is already present in the FLAC file (see attached spectrogram, obtained with SoX). -------------- next part -------------- A non-text attachment was scrubbed... Name: spectrogram.png Type: image/png Size: 365525 bytes Desc: not available URL: &...

On Nov 05 11:32:49, hans at stare.cz wrote: > On Nov 05 11:05:34, hans at stare.cz wrote: > > > Did you also try to listen at the beginning, shortly before the real tone appears in the audible spectrum? While significantly larger, Opus had produced significant ghost noise (much less than Vorbis did)... I experience the "same" low level noise even in a wav file, even on

...to use R to formulate and evaluate specific models. So I would like to ask R people for their recommendations for a program which would a) Take as input a sound file in one of the common formats (".wav", ".au") b) perform at least basic phonetic analysis (formants, F0, spectrograms, ... ) b) Save to file a representation of the basic phonetic analysis which it has done, in a form which R can readily import and use. I've come across 'praat': http://www.praat.org which seems to offer a spohisticated range of analyses, though it's not too clear from...

On Aug 07 00:41:52, petrparizek2000 at yahoo.com wrote: > ????#1. To test encoding at low bitrates, I encoded a sine sweep at 12 kbps > with Opusenc and then decoded the resulting file with Opusdec. What sine sweep exactly? How did you obtain it, and how exactly did you encode and decode it? Jan > The strange > thing was that even though the output wave file was at 48 kHz, it

...original audio. > Visible with Spek program. > Download FLAC and Opus both files, > new link: > http://www.filedropper.com/example_3 > FLAC full: 1084 kbps; > FLAC solo: 465 kbps. > with --bitrate 160: > Opus full: 158 kbps; > Opus solo: 190 kbps. > Included also Spek spectrogram PNG file > for Opus solo to see the artefacts. > Music is copyrighted but we using it > for testing purposes, ok? > There's no point in even looking at it. A spectrogram isn't going to tell you anything useful about whether an audible artifact exists, and is mostly useless exce...

On Aug 07 10:08:43, petrparizek2000 at yahoo.com wrote: > > What sine sweep exactly? > > An exponential sweep. It started slightly below 24 Hz and ended almost at 24 > kHz. And it was 50 seconds long. > > > How did you obtain it, > > I used Angelo Farina's "Aurora" modules. One of them is called "Generate > sine sweep". Can you please

This is not the same as the recent thread on a waterfall graph. I'm thinking about the rolling FFT display used in acoustics and other spectrum analysis tasks. Here's an example of a very fancy 3-D waterfall display: http://www.ultimaserial.com/UltimaWaterfall.html I was just wondering if there are any simple hidden-line tools in R that I could use to draw simple waterfall displays.