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Currently-Available Highest-Quality Linear PCM Video?

Discussion in 'Electronic Basics' started by Radium, Oct 18, 2006.

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  1. Radium

    Radium Guest


    What are the sample rates and picture resolution [in pixels X pixels]
    of the professional progressive [non-interlaced] linear-PCM video
    format used today? I beleive linear-PCM video signals are used in
    professional studios.


  2. Guest

    Start here

    and here

    and here

    There are MANY more.

  3. Bob Myers

    Bob Myers Guest

    If you're talking about standard-definition television, and
    the case of standard sampling formats for the conversion
    and storage of "analog" video into digital form, the most
    common international standard today is probably CCIR-601,
    which uses a common 13.5 MHz sampling rate for both
    525/60 and 625/50 video systems; this results in image
    formats (not "resolutions," please) of 720 pixels x 480 lines
    for the former and 720 x 576 for the latter. I don't know
    what you mean by bringing "linear-PCM" into a question of
    sampling rates and image formats.

    Bob M.
  4. Radium

    Radium Guest

    What equation did you use to get the numbers 720, 480, and 576?
    Linear PCM is uncompressed PCM. Thats what I am talking about. Sampling
    rate must be at least twice the highest frequency in the signal. Due to
    physical conditions, it is safe to makes the sample rate at least 2.5x
    the highest frequency signal.

    In NTSC, the horizontal frequency is 15.734 kHz, the vertical frequency
    is 60 Hz, and the color subcarrier frequency is 3.579545 MHz. The means
    that the horizontal sample rate must be 39.335 khz or higher, the
    vertical sample rate must be at least 150 hz, and the color subcarrier
    sample rate must be no less than 8.9488625 mhz.

    What is the pixel X pixel resolution -- or "format" if you wish -- of
    today's first-class video signal? Surely it would have to be more than
    720 X 576. My monitor is displaying a pixel X pixel -- or "screen area"
    -- of 1280 X 1024 with 32-bit color. I am not sure of the frequencies
    of my monitor.

    Also, is there supposed to be a special difference between the first
    number and the second number [such as 1280 X 1024 or 720 X 576]?


  5. Radium

    Radium Guest

    CCIR-601 uses interlaced -- not progressive -- signals. I like
    progressive and dislike interlaced.
  6. Guest

    You really need to go look things up and not argue about things you
    apparently know little to nothing about. Bob Myers told you exactly
    right about SD TV. You can go look this up- the sample rate is 858 x h
    rate = 13.5MHz for luma. The 720 is the active number of samples out of
    the 858. That 'dead' time is to allow the CRT based monitors time to
    retrace the Horizontal. The 480 line is computer talk for 525 line
    system of which 483 are active. The remaining lines are to allow
    Vertical retrace of a CRT monitor. If you think about it, LCD and
    Plasma do not require retrace since there is no scanning, just counting
    off samples. HDTV works in a similar fashion but the numbers are all
    different. Try ATSC.ORG. The monitor pixel ratios are often 4:3 or 16:9
    to make square pixels but none of that is etched in stone. Rectangular
    pixels are often used and just re-map the square into rectangular. Now
    go study.

  7. Radium

    Radium Guest

    SDTV is not "first class"
    What about the color subcarrier sample rate? The horizontal frequency
    sample rate?
    That is why plasma and LCD are better than CRT. In addition, plasma is
    better than LCD.
    IIRC, HDTV is a tad closer to "first class" than SDTV. Again, I could
    be wrong.
  8. Guest

    Radium wrote:
    You might be surprised if you saw a serial digital feed on a broadcast
    monitor. Many folks would find it to be totally satisfactory -- if they
    ever got to see it.
    There is no subcarrier for component digital. You didn't look it up.
    The subcarrier is introduced when the component is encoded into
    composite. This does not happen with DVD or SD Digital TV. The
    horizontal 'sample rate' is a continuous 13.5 MHz with a new line
    starting on every 858th sample and the vertical 262.5 X 858 samples.
    The 2 chroma difference channels are each sampled 429 x H for another
    858 time periods for a total data rate of 27MHz sample rate. Bump those
    numbers up to 150MHz for HD.
    That has nothing to do with why LCD or Plasma is 'better' than a CRT.
    You will find a good number people who think the CRT is a better image
    even in HD. Much of what is 'bad' about the CRT is the support
    electonics, mainly poor power supply regulation.
    GG again
  9. Radium

    Radium Guest

    AFAIK, it maybe "satisfactory" but it is not the best quality currently
    Is HD is best quality currently available? How much is the pixel X
    pixel screen area in HD? My LCD computer screen is 1280 X 1024 pixels.

    I prefer "first class" uncompressed linear-PCM video signal viewed
    through a "first class" plasma screen.
    Both LCD and plasma are more resistant to EMI/RFI than CRTs. Plamsa
    offers better clarity than LCD or CRT.
  10. Guest

    Quite simply put, you're not going to get it now or in the near future.
    The best you can get today is MPEG2 HDTV over the air with an ATSC
    receiver delivering 19.34 mega BITS/second. That's compressed between
    75 and 80:1 and that's the BEST available. Remember HDTV pushes out 150
    Mbytes/second and those are not 8 bit but 10 bit so your 1.5Gbits gets
    dropped to 19.34Mbits. But, I just got done watching NCIS in HD and it
    really looked quite good. So go spend some money on a 1920x1080 native
    resolution set with ATSC, put up an antenna and have at it. I've been
    watching HD for nearly 3 years and have 2 computers to record HD OTA
    feeds. They work very well and you don't need the latest whiz-bang
    computer to do it. A Sempron 2500 will do just fine.
    More of the support electronics issues but I agree that the CRT is not
    what I want. Non-CRT sets all suffer from math rounding error noise
    when converting the digital values to PWM to get variable brightness.
    CRTs with all their faults do not have that issue.


  11. Bob Myers

    Bob Myers Guest

    No equation; that's what the standard defines. The 720
    is the number of active samples per line; if you divide the period
    of one horizontal scan line up using a 13.5 MHz sampling rate,
    you will get 858 samples per line (in the case of the standard
    "NTSC" line rate, 15.73426 kHz). Of these, 720 are "active"
    (contain information corresponding to the actual displayed
    image). The 525/60 scan format also has about 484 lines per
    frame of active video (i.e., what's left - 525 minus 484 lines -
    is used in vertical blanking), and CCIR-601 decided to use a
    standard format of 480 lines just to round it to a convenient
    number. Similarly, there are about 576 active lines in the
    625/50 scan formats.
    Which has absolutely nothing to do with how the data is
    encoded, which is what "PCM" is all about - hence I have no
    idea why you are bringing that term up in a question regarding
    sampling rates. Note that the 13.5 MHz rate easily meets the
    Nyquist requirement of being >2X the bandwidth (technically,
    it's bandwidth, not "the highest frequency in the signal) of the
    video (note that U.S.-standard video occupies roughly
    5 MHz of a 6 MHz channel).
    Standard definition video - i.e., anything other than high-definition
    TV, which has different standard formats - is never any better
    than about 720 x 480 pixels/lines for the U.S. 525/60 standard
    format, or 720 x 576 for the "European" 625/50 format. The
    actual effective resolution, in the proper sense of that term (the
    degree to which detail can actually be resolved in the displayed
    image) is generally a good deal less than this. Yes, computer
    formats contain considerably more pixels than anything SDTV is
    capable of.

    Standard HDTV formats are 1280 x 720 pixels and 1920 x 1080
    The way it's normally stated in PC usage, the first number is the
    number of pixels per line, while the second is the number of lines
    per frame. Traditional TV practice has been just the opposite -
    give the number of lines first, then the number of "pixels" - but
    actually, until the advent of digital television there really wasn't any
    such thing as "pixels" in the TV engineer's vocabulary.

    Bob M.
  12. Bob Myers

    Bob Myers Guest

    In that case, what do you think "first class" means? You asked
    about video as it appears in professional studios - unless you're
    talking about HDTV broadcast, SDTV is all there is.
    Those phrases are nonsense. There can be different sample rates
    used for the "chrominance" components vs. the luminance (i.e.,
    go look up "4:2:2" and "4:2:0" sampling as opposed to "4:4:4"),
    but you would never refer to this as the "color subcarrier sample
    Actually, this has very little to do with the relative performance of
    these technologies. And before we start talking about which is
    "better," you'd have to ask what "better" means. "Better" in what

    Since you have yet to tell anyone just what you are thinking of
    when you say "first class," it's impossible to respond any further.
    Do you mean the digital cinema standards?

    Bob M.
  13. Bob Myers

    Bob Myers Guest

    Yes, it IS, in terms of entertainment video. Any "television"
    type programming you are going to encounter is either SDTV
    or HDTV; the vast majority is SDTV, and you would be
    surprised at just how good a 720 x 480 image can look on
    the right display.
    You still don't seem to have any clue at all how "linear PCM"
    plays into all this...

    No, those technologies are more resistant to MAGNETIC
    interference than the CRT; this is not "EMI" or "RFI." It is
    also impossible that either plasma or the LCD would be superior
    vs. the other in terms of "clarity," if by that you mean delivered
    image resolution. Both are fixed-format technologies, so when
    driven at their native format, each pixel of the image is as clear
    as it's ever going to get.

    Bob M.
  14. Bob Myers

    Bob Myers Guest

    Correct, but not relevant to the question you asked, which
    concerned standard sampling rates and the resulting image
    formats. If you're talking about sampling video, you are talking
    about converting an analog video signal to digital form - and
    ALL analog standard-definition broadcast video standards use
    interlaced scanning.

    There are similar standards for progressive-scanned video,
    but since your question clearly was with respect to broadcast
    studio practice, they were also not relevant to the question.

    Since you seem to be able to find Wikipedia, why aren't you
    looking into your questions THERE before asking them here?

    Bob M.

  15. He can't troll the wiki.

    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
  16. Radium

    Radium Guest

    I asked a question about linear PCM video 3 years ago. Here was my

    Quotes from the above link:

    "There is uncompressed PCM for video. The data rate is 270 Mbit/sec for

    standard definition, 525 line, 60 field interlaced. The computer folks
    refer to this as 480i. For Hi def, the data rate bumps up to 1.5
    Gbit/sec for 1920x1080 interlaced. Looks danged fine,too. This stuff
    is only seen in studios and post production facilities. It makes going
    to work fun. "

    My question is what are the sample rate and color-resolution for the
    "Hi def" mentioned above with 1920 X 1080? And why is it interlaced? I
    want it progressive.

    Linear-PCM is uncompressed digital info. If linear-pcm is used for
    audio [e.g. WAV files], then why not for video??

    Here is my insane type of premium video:

    Linear PCM video [with at least 320-bit color resolution, at least
    109,200x100,800 pixel progressive [non-interlaced] picture resolution,
    with a sample rate of at least 1,350 THz sampling rate viewed via a
    plasma screen with at least 1,000x the capabilities of the
    aforementioned values.
  17. Bob Myers

    Bob Myers Guest

    Note that the sentence "there is uncompressed PCM for video"
    does not equate to "all digital video is PCM" or "PCM is required
    for high-quality digital video." PCM is simply one possible encoding
    and transmission scheme, nothing more - and it is not the one used
    in most digital video systems.
    The sample rate can be determined from the pixel format (in
    this case, 1920 x 1080), the frame or field rate (60 Hz, typically,
    in the U.S.), and the amount of overhead time required for
    horizontal and vertical blanking. If you didn't need ANY
    blanking time, then the minimum sample rate is simply

    1920 pixels/line x 1080 lines/frame x 30 frames/sec (it's interlaced)

    Note that if you work the units out as well, it comes out in terms
    of pixels/second, exactly as it should.

    It can be; it simply doesn't HAVE to be, so there is no need
    to be dragging that question in at this point.
    You've got that right - it's insane. Here's why:
    OK, now I see what you mean by "color resolution" - you
    are talking about what's more commonly referred to as
    "color depth" or "dynamic range." 320 bits/pixel (presumably,
    something over 100 bits/color) is absurd; there is no display
    device that can provide this range, nor can the human eye
    deal with it. Somewhere around 10-12 bits/color, properly
    encoded, is about the maximum required, and most systems
    reduce the effective data rate by limiting the spatial resolution
    in the chroma channel (i.e., you don't really get as many bits
    PER PIXEL for color as you think you need).
    Again, absurd numbers. The eye cannot resolve detail
    beyond a certain point (approx. 60 black/white cycles per
    visual degree is a good rule of thumb for the maximum),
    and anything above that is a waste. But this means that you
    can't just concern yourself with the number of pixels in
    the image - the image size as displayed to the viewer and the
    expected viewing distance also come into play.
    Sample rate is never a system requirement, except in
    terms of a maximum permissible sample rate to fit within
    system bandwidth constraints. The sample rate REQUIRED
    for a given pixel format and frame rate is driven by those
    parameters, and then you just see whether or not it's going to
    fit in the available bandwidth.

    As usual, it seems you haven't learned anything at all about
    the field you're trolling in before making up absurdities.

    Bob M.
  18. Radium

    Radium Guest

    I am well aware of that. Most digital video uses -- MPEG-layer or some
    other form of compression -- not linear PCM. I don't know why?
    Why isn't linear-PCM used in video?
    Are you sure that isn't that the bit-rate? There is a world of
    difference between bit-rate and sample-rate.

    For example, CD audio has a sample rate of 44,100 hz but a bit rate of
    1,411,200 bps.
    Linear-PCM doesn't have to be used but what harm is caused by using it?

  19. Hi Radium!

    Depends to the CD.... not every Compact Disc Audio is full 16bit.

    1-bit CD-Audio Technology makes theoretically a better use of the real
    existing Resolution on the CD, processing only what is really there.

    Best Regards,

    Daniel Mandic

    P.S.: But 1,411,200 bps can happen. ;-)
  20. Guest

    What??? Then it isn't CD audio.

    Links please.
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