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

Discussion in 'Windows Media Player' started by Radium, Oct 27, 2006.

  1. Radium

    Bob Myers Guest

    Why are you hung up on sample rate per se? Question:
    if I could decrease the sample rate by eliminating "dead"
    time in the original video signal (for instance, by cutting out
    excess blanking time in which no image information was
    being transmitted), would you find that acceptable?

    Oh, OK - in that case, I can give you an infinitely-degraded
    image in no bits at all! :)

    And why do you think that "color depth" is something
    you can compress the daylights out of, but by Gawd, don't
    touch there OTHER things?

    Bob M.
     
    Bob Myers, Oct 28, 2006
    #21
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  2. Radium

    Bob Myers Guest

    Why are you hung up on sample rate per se? Question:
    if I could decrease the sample rate by eliminating "dead"
    time in the original video signal (for instance, by cutting out
    excess blanking time in which no image information was
    being transmitted), would you find that acceptable?

    Oh, OK - in that case, I can give you an infinitely-degraded
    image in no bits at all! :)

    And why do you think that "color depth" is something
    you can compress the daylights out of, but by Gawd, don't
    touch there OTHER things?

    Bob M.
     
    Bob Myers, Oct 28, 2006
    #22
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  3. Radium

    Bob Myers Guest

    Consider the following - the average data rate of an ATSC
    digital television broadcast cannot exceed about 19.4 Mbits/sec.
    In one second, a 1920 x 1080, 60 Hz (2:1 interlaced) HDTV
    source generates at least:

    1920 x 1080 x 30 = 62.2 million pixels.

    So we have a data stream giving us under 20 million bits
    each second, which we're going to have to turn into over
    60 million pixels. That's under 3 bits/pixel, on average.
    Ain't compression wonderful? (And it often gets down
    to an average rate of around a bit per pixel...)

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

    Bob Myers Guest

    Consider the following - the average data rate of an ATSC
    digital television broadcast cannot exceed about 19.4 Mbits/sec.
    In one second, a 1920 x 1080, 60 Hz (2:1 interlaced) HDTV
    source generates at least:

    1920 x 1080 x 30 = 62.2 million pixels.

    So we have a data stream giving us under 20 million bits
    each second, which we're going to have to turn into over
    60 million pixels. That's under 3 bits/pixel, on average.
    Ain't compression wonderful? (And it often gets down
    to an average rate of around a bit per pixel...)

    Bob M.
     
    Bob Myers, Oct 28, 2006
    #24
  5. Radium

    Pasi Ojala Guest

    Or rather, 0.33 bits/pixel..

    -Pasi
     
    Pasi Ojala, Oct 28, 2006
    #25
  6. Radium

    Pasi Ojala Guest

    Or rather, 0.33 bits/pixel..

    -Pasi
     
    Pasi Ojala, Oct 28, 2006
    #26
  7. Radium

    Radium Guest

    I think this is what I am describing. I could be wrong though.
     
    Radium, Oct 28, 2006
    #27
  8. 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
    #28
  9. 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
    #29
  10. 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
    #30
  11. 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
    #31
  12. 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
    #32
  13. 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
    #33
  14. 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
    #34
  15. 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
    #35
  16. 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
    #36
  17. 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
    #37
  18. 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
    #38
  19. 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
    #39
  20. 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
    #40
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