2-hour length, 148.50 Mhz, 1920 x 1080 progressive scan image, 1-bit object data, 193 bits of file s

Discussion in 'Amateur Video Production' started by Radium, Oct 27, 2006.

  1. Radium

    Radium Guest

    I think this is what I am describing. I could be wrong though.
     
    Radium, Oct 28, 2006
    #21
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  2. Radium

    Radium Guest

    Because I dislike aliasing.
    Yes. As long as no aliasing -- at *any* level -- occurs.
    LOL. There needs to be at least one bit. Otherwise the data doesn't
    exist.

    So it is true that 1-bit movie cannot exist. What about a WMV file that
    is 148.50 Mhz sample-rate, 1920 x 1080 progressive scan image, whose
    object data rate is a CBR of 1 bit per second? Could this exist? In 2
    hours or this video, the file size would be 7,200 bits.
    Because I hate pixelation and alaising with a passion. Pixelation and
    aliasing make me make me sick. I don't mind the artifacts -- that I
    think -- are associated with a WMV whose color-depth has been
    compressed even to extremes while the sample-rate and pixel resolution
    are left alone. It looks similar to what a WMA file with a 44.1 khz and
    20 kbps sounds like -- I think.

    What would be to the human eye what 44.1 Khz, 20kbps is to the eye?

    The human ear needs at least 20 hz to hear the sound. The human eye
    needs at least 60 hz for the light to appear solid. E.g. a hummingbird
    wing flap is to high of a video-frequency for the human eye to see,
    much like the sound of a dog-whistle is to high an audio-frequency for
    the human ear to see.

    WMA is my preferred type of perceptual encoding. Both WMAs and MP3s
    will produce artifacts with a too-low bitrate. However, WMA's artifacts
    are rather pleasant, while MP3's are digusting.

    I have Adobe Audition 1.5. I generate a silent file. I save it as WMA
    20 kbps, 44.1 KHz, mono. I convert file this to WAV and then back to
    WMA several times. I make my last conversion to WMA and save it. I then
    open this WMA file. Finally I increase the volume of the audio in the
    WMA file and play. Intrigueing tones result. These tones are typical in
    low bit-rate, high-sample rate WMA files. I believe something analogous
    could be done to WMV video.

    Not really. I've tried doing my Adobe Audition experiment with MP3. How
    sickening MP3's audio artifacts are. Much like non-WMV video
    compression of pixels are. Those pixelations are just nasty.
     
    Radium, Oct 28, 2006
    #22
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  3. Radium

    Bob Myers Guest

    Oh, damn - I hate it when I do that....I really
    need to stop and recheck my head, every so
    often...

    Bob M.
     
    Bob Myers, Oct 28, 2006
    #23
  4. Radium

    Radium Guest

    Please ignore the "not really" in the beginning of the above paragraph.
    It was a f--king
    typo!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
     
    Radium, Oct 28, 2006
    #24
  5. Radium

    Radium Guest

    How about a video whose "object data" bit-rate is a CBR of 1 bit per
    second with a sample-rate of 148.5 mhz and 1920 X 1080 progressive scan
    image resolution? How would this video look like? In 2 hours of this
    video, the file size would be 7,200 bits. Sounds like a good idea for
    internet video streaming -- if it is possible to have a bit-rate of 1
    bit per second.
     
    Radium, Oct 29, 2006
    #25
  6. Radium

    Lionel Guest

    No, it isn't possible. I've already explained why it isn't possible in
    great detail, but you are obviously either too lazy to read it, or too
    stupid to understand the explanation.
     
    Lionel, Oct 30, 2006
    #26
  7. Radium

    Bob Myers Guest

    And hopefully you understand at this point why it's going to take
    a LOT more than one bit, or even one bit per second. Again,
    you REALLY need to look into some basic information theory.
    How much information a given signal actually contains, and how
    far you can compress that (and how) before you start to lose
    some. Then you need to consider how much you can afford to
    lose, and why. Once you do that, you will no longer be asking
    questions like:
    ....to which the answer is still "no way."
    Why do you think that, though? Remember, in the sciences
    - which includes physics, and information theory, and electronics -
    what you FEEL the answer ought to be doesn't count for squat
    until and unless you've got some reasoning and knowledge to
    back it up.

    Bob M.
     
    Bob Myers, Oct 30, 2006
    #27
  8. Radium

    Jim Leonard Guest

    I think the terms you're searching for are frequency and amplitude.
    Like you, I greatly prefer video presented at a very high framerate
    (frequency) and don't care so much about color quality (amplitude). In
    other words, if I had a (low) certain amount of bandwidth available, I
    will take a 60fps video that is 4 colors any day over one that has 256
    colors but runs less than 1fps. Both theoretical videos would have
    exactly the same bitrate, but one would be a slideshow and the other
    would be in motion.

    You are very, very confused about information theory and compression.
    Here's a quick primer: Lossless compression -- where sizes are reduced
    without anything being lost -- involves searching the data for
    redundancy and then recoding the data to eliminate that redundancy. So
    the answer to your question ("how small can a video file get without
    throwing anything away?") depends on how redundant the video is. If
    it's nothing but a black screen, most of it is redundant and the file
    can get compressed very small. If it's complex motion with lots of
    changing elements, hardly any of it is redundant and it won't compress
    hardly at all.

    You are comparing lossless compression with WMV, WMA, etc. which are
    LOSSY techniques. Those compression methods throw information away.
    That is a totally different conversation, so you might need to restate
    your question a bit.
     
    Jim Leonard, Oct 30, 2006
    #28
  9. Hang on. One bit per pixel, means that it can only have one value. Of
    course with a LUT you could determine which value should be displayed.
    --
     
    Martin Heffels, Oct 30, 2006
    #29
  10. Radium

    Bob Myers Guest

    No, again, you're missing that all-important phrase "on average."
    Talking about systems that use an AVERAGE of one bit per
    pixel (or even less!) over the whole data stream doesn't really
    tell you anything about the quality of the video being presented.
    As was already discussed, standard HDTV operates at a data
    rate such that there is, ON AVERAGE, less than one bit in the
    transmitted data stream per pixel of the original X x Y pixel,
    N frames per second video.

    How that is achieved is actually quite clever...;-)

    Bob M.
     
    Bob Myers, Oct 30, 2006
    #30
  11. I see. So what you mean is that of all the original bits, on average, one
    is left, after all the compression is done? Interesting.
    --
     
    Martin Heffels, Oct 31, 2006
    #31
  12. None of the "original bits" is left. A compressor takes in a data
    stream and generates a new, smaller, data stream that can be decoded to
    some approximation of the original image or video sequence.

    The bit rate of the compressed data stream is simply the number of bits
    per unit time (frame, second, hour, whatever you prefer) divided by the
    number of original pixels in that same time period.

    Dave
     
    Dave Martindale, Oct 31, 2006
    #32
  13. Radium

    Pasi Ojala Guest

    If you have some kind of predictor coding, one input bit is
    capable of much more than monochrome.

    And, one bit per pixel _on average_ is capable of much more
    still. Ever heard of arithmetic coding?

    -Pasi
     
    Pasi Ojala, Oct 31, 2006
    #33
  14. That's why I mentioned a LUT, where you can make that bit to display
    anything you want.
    Arithmetic has always been my weak point at school ;-)
    But I'll have a look into it.

    -m-
    --
     
    Martin Heffels, Oct 31, 2006
    #34
  15. Radium

    Ken Maltby Guest

    You mean compression ratio, not bit rate.

    One bit has no meaning until there is some significance applied
    to it's two values. Within a computer, a bit exists as an element of
    a byte. The position of a bit within a byte can be an element of data,
    as well, which can change the significance of the bit's value. Bytes
    are grouped/read as a word.

    You don't have bytes of only one bit, even if the rest of the bits
    have no significance they must be there. So in a computer you
    can't have a bit stored all by itself.

    Now the fact that I can assign any significance to each of a bit's
    two values that I wish, doesn't mean it is carrying any more
    information/data than that it is in one of two possible states.
    There is no difference in the amount of information/data conveyed
    between a bit where one state=0 and the other state=1, and a bit
    where one state=the contents of The Library of Congress and the
    other state=a picture of the moon.

    The library contents nor the image data, are actually contained
    within the bit. If I could somehow store that bit someplace (say
    a file) and examine it outside of a program that assigns it's two
    states a particular significance, it only carries the fact that it is in
    one of its two possible states. The "file" with only one significant
    data bit, would not contain anything more than that.

    Now someone will say we are talking about a bit stream not
    data stored on a computer. ( A bit stream of one bit? )
    That the significance of each bit is established by the order in
    which it is processed, not by a structure of the bits themselves.
    ( No bytes, just packets, that are only there for coordinating
    the transmission of the stream.) But for this to actually mean
    anything, you still need a series of bits to feed the process, one
    bit won't do it.

    If you could write a program to read one bit, and apply a
    significance to one of the states of the bit to be; a "2-hour
    length, 148.50Mhz,1920 x 1080 progressive scan image";
    it would be in the program that the "image" data would have
    to reside.

    This is the state of affairs for any level of abstraction above
    the two states inherent in the bit itself.

    Luck;
    Ken
     
    Ken Maltby, Oct 31, 2006
    #35
  16. Radium

    Bob Myers Guest

    No, let's try this another way.

    Let's say you have an original video stream that consists
    of - gee, I don't know - let's say 1920 x 1080 pixel
    frames that come at you at a rate of 30 per second.

    That would be 1920 x 1080 x 30 pixels per second, right?

    Working out the above, we could say it's 62.2 million pixels
    per second.

    Now let's say that we compress this into a data stream which
    has an average rate of - again, just to pick a number completely
    at random - 19.39 Mbits/second.

    On average, how many bits per pixel of the original
    video stream does that compressed stream give you?

    Bob M.
     
    Bob Myers, Oct 31, 2006
    #36
  17. Radium

    Ken Maltby Guest

    Woah - How many bpp? Is it "1bpp" monochrome? Is it
    2bpp CGA? 4bpp EGA? 8bpp VGA? 16bpp XGA,High Color?
    24bpp True Color? How about the 32 bit I use for my desktop?

    I guess you want to use the monochrome 1 bit per pixel, right?
    That would be for both the original and the compressed, right?
     
    Ken Maltby, Nov 1, 2006
    #37
  18. Radium

    Bob Myers Guest

    Doesn't matter. Again, the compressed stream is delivering data
    at a rate which, relative to the original pixel rate, represents less
    than one bit per pixel on average.

    Now, it turns out that the numbers I picked in my example were
    not (surprise, surprise!) chosen completely at random:

    19.39 Mbit/sec is the actual data rate limit specified in the ATSC
    (U.S. digital/HD TV) broadcast transmission standard.

    1920 x 1080 at 30 frames/second, is, of course, a standard HD
    format and frame rate. As it happens, such material is generally
    originated as RGB data at at least 8 bits/color (24 bits/pixel);
    long before getting to the compressed form of the final data
    stream, it will most likely be re-encoded as YCbCr at something
    less than a 4:4:4 sampling scheme - probably 4:2:2 or even 4:2:0
    (which are systems that effectively reduce the spatial resolution
    of the color components, while preserving the luminance component
    at full resolution - this is itself a form of lossy compression vs. the
    original RGB representation). The result then goes through a goodly
    number of further compression processes, which results in the
    cumulative data-rate reduction (compression ratio) seen in the end
    result - something in the neighborhood of 80:1 vs. the original.

    Bob M.
     
    Bob Myers, Nov 1, 2006
    #38
  19. Radium

    Ken Maltby Guest

    OK, so how many bits of "object data" does that put in Radium's
    WMV file? More than one, I would guess. You have been reading
    this thread, right?

    Luck;
    Ken
     
    Ken Maltby, Nov 1, 2006
    #39
  20. Radium

    Bob Myers Guest

    If you look back through the thread, you'll see that I've
    been contributing rather regularly - and as has been
    said several times before, by myself and others, there
    have to be a LOT more than just one bit. Or even one
    bit per second.

    Bob M.
     
    Bob Myers, Nov 2, 2006
    #40
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