search for: 5khz

Hi I used R for the first time yesterday. I wanted to plot the aliasing effect of sampling a 5.5KHz sinusoid at only 8KHz (below the Nyquist limit). So I wrote a small R script that a) plots 1msec worth of a 5.5KHz sin wave b) plots 1msec of the resulting 2.5KHz alias and c) plots the 8 sampling points on the 5.5KHz source wave. I think I have found a bug. The script is as follows: #truesampling...

...on follows... ENCODER=opusenc from opus-tools 0.2-3-gf5f571b ENCODER_OPTIONS=--bitrate 56 --vbr --comp 5 ALBUM=Test-Sweeps ARTIST=Audacity COMMENT=60s logarithmic sweep (0-20kHz): 5s=10Hz, 10s=20Hz, 15s=39Hz, 20 s=78Hz, 25s=156Hz, 30s=312Hz, 35s=625Hz, 40s=1.25kHz, 45s=2.5kHz, 50s=5kHz, 55s= 10kHz, 60s=20kHz COMMENTS=60s logarithmisch DATE=2016 TITLE=Sweep (0-20kHz at 96kHz) log TRACKNUMBER=2 Opus stream 1: Pre-skip: 312 Playback gain: 0 dB Channels: 1 Original sample rate: 96000 Hz Pack...

...seem to be gone (though they were small in beta2). Good job there! :-) - Velvet.wav also sounds better, but transparent quality is reached at -b256+. - Horn.wav still sounds very sucky, mode -b256 gives ~100kbps (this is understandable because in this sample practically there are no sounds above 5kHz) but the artifacts can be easily heard. Mode -b350 gives ~310kbps but still there is a difference (subtle though). I also noticed that you get similar artifacts when you encode simple tones (like 440Hz or 1kHz), no matter what bitrate is used. - The most occurring artifact in -b128,160,192 modes i...

...not sure what Audacity means by a logarithmisch sweep. Is that a fixed number of Hertz per second (SoX calls that linear)? Or a fixed number of semitones per second (SoX calls that exponantional)? (The ogg comment says 5s=10Hz, 10s=20Hz, 15s=39Hz, 20s=78Hz, 25s=156Hz, 30s=312Hz, 35s=625Hz, 40s=1.25kHz, 45s=2.5kHz, 50s=5kHz, 55s=10kHz, 60s=20kHz so it seems the frequency rises logarithmically.) $ sox -c 1 -r 96k -b 16 -n /tmp/sweep.wav synth 60 sin create 1-20 gain -3 > With Opus I noticed that the file size for 48kHz and 48 kbps > compared to 96kHz Vorbis at 31kbps is about double the si...

...not sure what Audacity means by a logarithmisch sweep. Is that a fixed number of Hertz per second (SoX calls that linear)? Or a fixed number of semitones per second (SoX calls that exponantional)? (The ogg comment says 5s=10Hz, 10s=20Hz, 15s=39Hz, 20s=78Hz, 25s=156Hz, 30s=312Hz, 35s=625Hz, 40s=1.25kHz, 45s=2.5kHz, 50s=5kHz, 55s=10kHz, 60s=20kHz so it seems the frequency rises logarithmically.) $ sox -c 1 -r 96k -b 16 -n /tmp/sweep.wav synth 60 sin create 1-20 gain -3 > With Opus I noticed that the file size for 48kHz and 48 kbps > compared to 96kHz Vorbis at 31kbps is about double the si...

...signals are : ( assuming that the formulas are M = (L+R)/sqrt(2) , S = (L-R)/sqrt(2), saw this in a message on the LAME list ) M : 5 kHz with A = 7.07 + 5.2 kHz at A = 4.24 S : 5 kHz with A = 7.07 + 5.2 kHz at A = -4.24 now if this channels are processed the same way as L/R then the louder signal (5kHz) might mask the quieter one ( 5.2 kHz ) in both M and S channels ( provided there is a bitrate pressure ), thereby eliminating the 5.2 kHz signal. In short : M/S mode might consider parts of music masked, that would not be masked in regular stereo mode. This seems wrong to me, alltough is is poss...

Hi! I have some MP3 audio material which is basically speech with some background noises, essentially > 120Hz and < 5kHz. I had the idea to reduce the file size by recoding the material to Opus at 56kbps. Unfortunately the result is a file sampled at 48kHz much larger than the original. I hope you agree that it does not make sense to create a file larger than the original (MP3). Of course the encoder sees just WAV (R...

...y gurus could tell me if it is possible to stream Ogg on very low bandwidth links (for example satellite phone) where the expected bandwidth would almost certainly be less than 19Kbps, and probably more like 10Kbps. I am not after great audio at this bitrate, mono with an audio bandwidth less than 5KHz. I have done some testing (not streaming though) listening to 8Kbps MP3 - it's pretty bad, but sufferable. Is this possible? Can anyone direct me to some tools that I can test this with? (ie: a server app & a client) I am running Wintel. PS: I can't use speech codecs (such as speex)...

...>> >> > Playing with Opus 1.3 I converted a tone sweep with a sample rate of 96kHz > >> > (just for fun). Before I had converted that from WAV to FLAC, and to Vorbis > >> > without problems. >> >> >> >> 30s=312Hz, 35s=625Hz, 40s=1.25kHz, 45s=2.5kHz, 50s=5kHz, 55s=10kHz, >> > 60s=20kHz >> >> so it seems the frequency rises logarithmically.) >> >> >> >> $ sox ‑c 1 ‑r 96k ‑b 16 ‑n /tmp/sweep.wav synth 60 sin create 1‑20 gain ‑3 >> >> >> >> > With Opus I notice...