Forums

Video-equivalent of "pitch-shifting."

Started by Radium August 21, 2007
"BobG" <bobgardner@aol.com> wrote in message 
news:1187739471.037333.144590@x40g2000prg.googlegroups.com...
> If you play the tape or record faster, the pitch shifts up. If colors > are analogous to pitch, speeding up would be a shift to the blue, > slowing down would be a red shift. >
This is only true in the domestic experience using a gramophone record or tape but in the world of TV, Film and Music Industries if a producer asks me to speed up some dialog I will do so without affecting the pitch, likewise I can take the pitch up without affecting the tempo. The chipmunk sound is of course achieved by both increasing tempo and pitch. In the analog domain this has been possible and widely used to tighten up commercials etc since 1958 via the EMT Pitch and Tempo Regulator ( a German invention of 8 playback heads in a rotating drum either in the direction or in counter rotation to the linear motion of the tape) and in the modern digital domain with a simple plug-in for programs like Adobe Audition or Wavelab.
Radium wrote:
> On Aug 21, 5:19 pm, "AnthonyR." <nos...@nospam.please.com> wrote: > >> So basically you want software that analyzes each frame the way mpeg coverts >> video and instead of eliminating file size by compressing the images, you >> want to have it eliminate most of the static images and thus reduce file >> duration instead. Is this correct? > > I don't think so. Any thing in the video with a temporal/spatial > frequency component that is too high for a low-bandwidth device to > accept, should have all of its frequencies downshifted until the > highest frequency is low-enough for the low-bandwidth device to accept > without any aliasing or other artifacts associated with a frequency > exceeding the limits.
Visible light extends for less than one octave, nominally from 400 to 700 nanometers. Those are wavelengths more or less centered around 500,000,000,000,000 Hz. You can't shift the band much and still see it.
>> So if a scene has movement and talking you want that left alone but if the >> person is just standing still or not much action going on in the scene have >> it eliminated and blended so it shortens the duration but not affecting the >> movement speed thus making the scene shorter in length. > > No. The length of any parts of the movie should not be affected at > all. > >> DVD player software can speed up movement by say 10% and allow the sound to >> not be effected as far a pitch goes, this is useful for watching say a 2 >> hour and 15 minute movie on a flight that is 2 hours long. >> Is this what you are trying to find? > > Not really. This change in video-frequency has nothing to do with > speeding up a video. The movie should remain exactly the same length. > Two hours should stay two hours.
Describe the action of a person taking a one-mile walk and some stations along the way. Jerry -- Engineering is the art of making what you want from things you can get. &macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;
"Radium" <glucegen1@gmail.com> wrote in message
news:1187738038.538439.164520@i38g2000prf.googlegroups.com...
> Hi: > > I started a new thread because the previous one started to go into > tangent of digital vs. analog but was filled with emotions and > personal vendettas rather than science and logic. So I changed the > thread. >
[ Oh dear how busy you are, making up nonsense trolls! If you were serious, you would give a couple links to youtube showing examples of spatial & temportal "pitch shifting" video equivs
On Aug 21, 9:19 pm, Jerry Avins <j...@ieee.org> wrote:

> Radium wrote:
> > I don't think so. Any thing in the video with a temporal/spatial > > frequency component that is too high for a low-bandwidth device to > > accept, should have all of its frequencies downshifted until the > > highest frequency is low-enough for the low-bandwidth device to accept > > without any aliasing or other artifacts associated with a frequency > > exceeding the limits.
> Visible light extends for less than one octave, nominally from 400 to > 700 nanometers. Those are wavelengths more or less centered around > 500,000,000,000,000 Hz. You can't shift the band much and still see it.
You're talking about color-frequency. Totally irrelevant to my discussion of video-frequency. I am talking about temporal and spatial frequency, not color-frequency. Color-frequencies = frequencies of electromagnetic radiation visible to the human eye, which as you pointed out, corresponds to wavelengths that are at least 400 nm but no more than 700 nm. Once again, by "video frequency", I am referring to the temporal and spatial frequencies of the video signal, not the color-frequencies.
> > Not really. This change in video-frequency has nothing to do with > > speeding up a video. The movie should remain exactly the same length. > > Two hours should stay two hours.
> Describe the action of a person taking a one-mile walk and some stations > along the way.
Huh?
In article <1187738038.538439.164520@i38g2000prf.googlegroups.com>,
 Radium <glucegen1@gmail.com> wrote:

> Hi: > > I started a new thread because the previous one started to go into > tangent of digital vs. analog but was filled with emotions and > personal vendettas rather than science and logic. So I changed the > thread. > > Anyways, Adobe Audition and voice-changers allow the frequencies of an > audio signal to be shifted w/out low-pass filtering or changing the > tempo. There are two video-equivalents of this because, while audio > has only one frequency component [temporal], video has two [temporal > and spatial]. > > The temporal video-equivalent would be changing the rate of back/ > forth, up-down or other repetitive/cyclical movement [such as wing- > flapping or flickering of lights] of the video signal without high/low- > pass-filtering, separating any portion of the video signal, or > changing the speed at which the video-signal -- just as voice-changers > can lower the frequency of audio without changing the speed of the > audio. Using a voice-changer to decrease the pitch your voice will not > cause your speech to slow down. > > The spatial video-equivalent would be changing the "sharpness" of a > still image without high/low-pass-filtering or changing the size of > the image. > > Below is an example of low-pass-filtering in the spatial domain: > > Here is an original picture: > > http://www-dse.doc.ic.ac.uk/~nd/surprise_96/journal/vol4/sab/report.normalimag > e.jpg > > Here is the picture after low-pass filtering: > > http://www-dse.doc.ic.ac.uk/~nd/surprise_96/journal/vol4/sab/report.lopass.jpg > > I obviously do not want this at all. Low-pass filtering involves > removing high-frequency components while preserving the low-frequency > components. Once again, this is not what I want. If a device cannot > handle high-frequencies, then I would like all the frequencies of the > signal to be down-shifted until the highest frequency is low-enough to > be acceptable to the device. This down-shifting should be done w/out > slowing the speed of the signal -- or in the case of spatial > frequency, w/out increasing the size of the image.
I didn't want to post this on the original thread because it would have been lost in the noise. There is a very fundamental difference between a data stream representing audio, and one representing video. Analog or digital; makes no difference. A stream representing audio is a continuous stream of information, with every part of it temporally related to a specific time in the audio. It can be slowed down, sped up, or have pieces cut out or added at will. These last are the basis for the "speed up/slow down without changing the pitch" algorithms. There is absolutely no parallel to this for video, as it is handled today. Unlike audio, video is a series of still images, equally spaced (hopefully) in time -- i.o.w. it is always temporally quantized. It is possible to change the spatial resolution (temporal spacing between successive images) and the spatial resolution (within each individual image) totally independently, and in fact, the two need to bear no particular relation each to the other. You can create high temporal resolution but low spatial resolution -- or the other way around -- easily. You can also increase or reduce the temporal resolution by interpolation/decimation while leaving the spatial resolution totally unaffected, and you can also do the "reverse". The fact that there is essentially no relation between these two entities -- i.e. the data stream is comprised of a sequence of descriptions of a series of still images -- is the reason why what you want to do is almost certainly impossible. If you really want to try, the first step will be to devise a method of recording video that does not quantize the temporal axis; i.e. not using a sequence of still images. Good luck, and great fame awaits. Isaac
 On Aug 21, 4:13 pm, Radium <gluceg...@gmail.com> wrote:
 > Hi:
 >
 > I started a new thread because the previous one started to go into
 > tangent of digital vs. analog but was filled with emotions and
 > personal vendettas rather than science and logic. So I changed the
 > thread.
 >
 > Anyways, Adobe Audition and voice-changers allow the frequencies of
an
 > audio signal to be shifted w/out low-pass filtering or changing the
 > tempo. There are two video-equivalents of this because, while audio
 > has only one frequency component [temporal], video has two
[temporal
 > and spatial].
 >
 > The temporal video-equivalent would be changing the rate of back/
 > forth, up-down or other repetitive/cyclical movement [such as wing-
 > flapping or flickering of lights] of the video signal without high/
low-
 > pass-filtering, separating any portion of the video signal, or
 > changing the speed at which the video-signal -- just as voice-
changers
 > can lower the frequency of audio without changing the speed of the
 > audio. Using a voice-changer to decrease the pitch your voice will
not
 > cause your speech to slow down.
 >
 > The spatial video-equivalent would be changing the "sharpness" of a
 > still image without high/low-pass-filtering or changing the size of
 > the image.
 >
 > Below is an example of low-pass-filtering in the spatial domain:
 >
 > Here is an original picture:
 >
 > http://www-dse.doc.ic.ac.uk/~nd/surprise_96/journal/vol4/sab/report.n...
 >
 > Here is the picture after low-pass filtering:
 >
 > http://www-dse.doc.ic.ac.uk/~nd/surprise_96/journal/vol4/sab/report.l...
 >
 > I obviously do not want this at all. Low-pass filtering involves
 > removing high-frequency components while preserving the low-
frequency
 > components. Once again, this is not what I want. If a device cannot
 > handle high-frequencies, then I would like all the frequencies of
the
 > signal to be down-shifted until the highest frequency is low-enough
to
 > be acceptable to the device. This down-shifting should be done w/
out
 >  slowing the speed of the signal -- or in the case of spatial
 >  frequency, w/out increasing the size of the image.
 >
 > Thanks for your assistance, cooperation, and understanding,
 >
 > Radium

I can't believe I'm jumping into this muck. Totally useless point in
that any changes in frequency leaves you with a signal you can't use.
No recorder can record it and no monitor can display it.  Now if
you're willing to live within the frame/line rate definitions, then
changing frequencies _within the line frame boundaries_ would be
similar to a DVE zoom but there is much more capability than that. 25
years agon the Ampex ADO and Quantel Mirage were literally twisting
pictures into screws, making them into spheres, rolling them up. Tape
machines have been slo-mo and speeding up for over 30 years. Stuff is
way cooler now. Go look it up.

GG

Radium wrote:
..
> >>Describe the action of a person taking a one-mile walk and some stations >>along the way. > > > Huh? >
Wide-screen TV showing whole soccer pitch. Man in middle distance runs from left goal to right goal. Takes 100 paces, 20 seconds. You want to slow this down to (say) 10 paces (pedestrian equivalent to wing-flapping). With no artifacts. Does he still reach the other goal, in 20 seconds? Does it not look like someone running on the moon? Richard Dobson
"Radium" <glucegen1@gmail.com> wrote in message 
news:1187738038.538439.164520@i38g2000prf.googlegroups.com...
> Hi: > > I started a new thread because the previous one started to go into > tangent of digital vs. analog but was filled with emotions and > personal vendettas rather than science and logic. So I changed the > thread. > > Anyways, Adobe Audition and voice-changers allow the frequencies of an > audio signal to be shifted w/out low-pass filtering or changing the > tempo. There are two video-equivalents of this because, while audio > has only one frequency component [temporal], video has two [temporal > and spatial]. > > The temporal video-equivalent would be changing the rate of back/ > forth, up-down or other repetitive/cyclical movement [such as wing- > flapping or flickering of lights] of the video signal without high/low- > pass-filtering, separating any portion of the video signal, or > changing the speed at which the video-signal -- just as voice-changers > can lower the frequency of audio without changing the speed of the > audio. Using a voice-changer to decrease the pitch your voice will not > cause your speech to slow down.
Mainly I don't really believe this whole question, BUT the only thing I can think of that comes close is: Take frames 1 to 4 of someone running for example, replace frames 2 & 3 with a 'tween' of 1 & 4 - and so on through 4-8 etc. That way you keep your sharpness (tween is not motion blur) yet loose half your detail of movement. And would look very strange indeed. Probs need to do all manner of vid tricks to tween certain films of course. Cheers, Dave H
Radium wrote:
> On Aug 21, 9:19 pm, Jerry Avins <j...@ieee.org> wrote: > >> Radium wrote: > >>> I don't think so. Any thing in the video with a temporal/spatial >>> frequency component that is too high for a low-bandwidth device to >>> accept, should have all of its frequencies downshifted until the >>> highest frequency is low-enough for the low-bandwidth device to accept >>> without any aliasing or other artifacts associated with a frequency >>> exceeding the limits. > >> Visible light extends for less than one octave, nominally from 400 to >> 700 nanometers. Those are wavelengths more or less centered around >> 500,000,000,000,000 Hz. You can't shift the band much and still see it. > > You're talking about color-frequency. Totally irrelevant to my > discussion of video-frequency. I am talking about temporal and spatial > frequency, not color-frequency.
Describe what you mean by "video frequency". To me, it means how often the still image that makes up the video is updated. I call it the frame rate.
> Color-frequencies = frequencies of electromagnetic radiation visible > to the human eye, which as you pointed out, corresponds to wavelengths > that are at least 400 nm but no more than 700 nm. > > Once again, by "video frequency", I am referring to the temporal and > spatial frequencies of the video signal, not the color-frequencies.
Video consists of a sequence of still pictures. There are no temporal frequencies. Spatial frequency relates to resolution.
>>> Not really. This change in video-frequency has nothing to do with >>> speeding up a video. The movie should remain exactly the same length. >>> Two hours should stay two hours. > >> Describe the action of a person taking a one-mile walk and some stations >> along the way. > > Huh?
The video is of a person walking leisurely. She covers a mile in 20 minutes. With your magic, we slow her gait to half speed, but she still finishes that same mile in the the same 20 minutes. How? Jerry -- Engineering is the art of making what you want from things you can get. &macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;
isw wrote:

   ...

> Good luck, and great fame awaits.
Isaac, If Radium doesn't take the trouble to understand your clear exposition, he's beyond help. Jerry -- Engineering is the art of making what you want from things you can get. &macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;&macr;