Re: Is 4:3 a dead Duck?

Discussion in 'NZ Computing' started by Boots, Feb 23, 2011.

  1. Boots

    Boots Guest

    On Wed, 23 Feb 2011 10:35:55 +1300, Robert Cooze wrote:

    > Some early tests I was able to double the frame rate and image size in
    > software remix the audio and clean up the video. then down sampled it to
    > 480x360and dropped the frame rate to 25fps. The results where much
    > better than the original VCD/SVCD that I made those many years ago.


    I see no value in doubling the frame rate if your original frame rate was
    25fps unless you're wanting to change to a format incompatible with
    analogue TVs.

    PAL in NZ is 720x576 so you've dropped image quality by about 1/3 and
    increased and decreased the frame rate for no good purpose. :)


    --
    "Filtering the Internet is like trying to boil the ocean"
    Boots, Feb 23, 2011
    #1
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  2. Boots

    Richard Guest

    On 23/02/2011 8:36 p.m., Boots wrote:
    > On Wed, 23 Feb 2011 10:35:55 +1300, Robert Cooze wrote:
    >
    >> Some early tests I was able to double the frame rate and image size in
    >> software remix the audio and clean up the video. then down sampled it to
    >> 480x360and dropped the frame rate to 25fps. The results where much
    >> better than the original VCD/SVCD that I made those many years ago.

    >
    > I see no value in doubling the frame rate if your original frame rate was
    > 25fps unless you're wanting to change to a format incompatible with
    > analogue TVs.
    >
    > PAL in NZ is 720x576 so you've dropped image quality by about 1/3 and
    > increased and decreased the frame rate for no good purpose. :)


    Obsolete analog is 50 fields, that may contain 25 frames. If the soucre
    is from an 8mm video, then it is interlaced PAL, 50 fields. Needs
    deinterlacing to go to 50 frames. No point dumbing it down to 25 frames.

    Not sure why the OP is interested in writing out to obsolete formats, a
    decent deinterlace to 50 frames (since its not film mode there is
    movement between fields so taking it to 25 will suck despite some
    software only offering that option)

    I havent played with interlaced video or authoring obsolete DVD in quite
    some time on a PC so I dont know what current software there is to deal
    with it available now.
    Richard, Feb 25, 2011
    #2
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  3. Boots

    Boots Guest

    On Fri, 25 Feb 2011 14:13:24 +1300, Richard wrote:

    > Obsolete analog is 50 fields, that may contain 25 frames. If the soucre
    > is from an 8mm video, then it is interlaced PAL, 50 fields. Needs
    > deinterlacing to go to 50 frames. No point dumbing it down to 25 frames.


    That's 50 fields each containing 1/2 of a frame - alternate lines. This
    was done as a technique in order to reduce visible flicker caused by the
    scanning nature of the Cathode Ray Tube.

    If you combine each two fields you'll get one full progressively scanned
    frame - at 25 full frames per second. However, as there is an audio track
    along with those 50 fields various techniques are used to interpolate an
    additional frame in between each of the 25 frames - some are as basic as
    simply duplicating the field and doubling it's size using various
    techniques to guess what the intermediate data should be.


    --
    "Filtering the Internet is like trying to boil the ocean"
    Boots, Feb 25, 2011
    #3
  4. Boots

    Richard Guest

    On 25/02/2011 10:55 p.m., Boots wrote:
    > On Fri, 25 Feb 2011 14:13:24 +1300, Richard wrote:
    >
    >> Obsolete analog is 50 fields, that may contain 25 frames. If the soucre
    >> is from an 8mm video, then it is interlaced PAL, 50 fields. Needs
    >> deinterlacing to go to 50 frames. No point dumbing it down to 25 frames.

    >
    > That's 50 fields each containing 1/2 of a frame - alternate lines. This
    > was done as a technique in order to reduce visible flicker caused by the
    > scanning nature of the Cathode Ray Tube.
    >
    > If you combine each two fields you'll get one full progressively scanned
    > frame - at 25 full frames per second. However, as there is an audio track
    > along with those 50 fields various techniques are used to interpolate an
    > additional frame in between each of the 25 frames - some are as basic as
    > simply duplicating the field and doubling it's size using various
    > techniques to guess what the intermediate data should be.


    Only if it is film sourced, anything coming from a video camera will
    have movement between the 2 fields, so combining them makes the edges
    all jagged on anything moving, more advanced interlacing is needed. 2
    fields only add together to make a frame if they came from a frame to
    start with, which is only the case on a few cameras and things that are
    made from film which is the whole reason for reverse telecine as a
    deinterlace method, which does what you suggested.

    OP is talking about analog video footage from an old video 8 camera, so
    it will defiantly have proper interlaced video. Selection of the
    deinterlace algorithm used is very important. More advanced ones give
    very good results, crap ones have everything bouncing up and down all
    over the show.
    Richard, Feb 25, 2011
    #4
  5. Boots

    Boots Guest

    On Sat, 26 Feb 2011 00:18:06 +1300, Richard wrote:

    > Only if it is film sourced, anything coming from a video camera will
    > have movement between the 2 fields


    If it's "film sourced" it will be at 24 frames per second.


    --
    "Filtering the Internet is like trying to boil the ocean"
    Boots, Feb 25, 2011
    #5
  6. Boots

    Boots Guest

    On Sat, 26 Feb 2011 00:18:06 +1300, Richard wrote:

    > so it
    > will defiantly have proper interlaced video.


    "Defiantly"??


    --
    "Filtering the Internet is like trying to boil the ocean"
    Boots, Feb 25, 2011
    #6
  7. Boots

    Richard Guest

    On 26/02/2011 11:51 a.m., Boots wrote:
    > On Sat, 26 Feb 2011 00:18:06 +1300, Richard wrote:
    >
    >> Only if it is film sourced, anything coming from a video camera will
    >> have movement between the 2 fields

    >
    > If it's "film sourced" it will be at 24 frames per second.


    And sped up to 25 for the pal conversion like almost every show on TV
    these days.
    Richard, Feb 27, 2011
    #7
  8. Boots

    Richard Guest

    On 26/02/2011 11:53 a.m., Boots wrote:
    > On Sat, 26 Feb 2011 00:18:06 +1300, Richard wrote:
    >
    >> so it
    >> will defiantly have proper interlaced video.

    >
    > "Defiantly"??



    Yeah, fucked that up when right clicking on the misspelled word. Oops.
    Richard, Feb 27, 2011
    #8
  9. Boots

    Boots Guest

    On Sun, 27 Feb 2011 13:46:29 +1300, Richard wrote:
    >>> so it will defiantly have proper interlaced video.

    >>
    >> "Defiantly"??

    >
    > Yeah, fucked that up when right clicking on the misspelled word. Oops.


    :)


    --
    "Filtering the Internet is like trying to boil the ocean"
    Boots, Feb 27, 2011
    #9
  10. Boots

    Boots Guest

    On Sun, 27 Feb 2011 13:45:46 +1300, Richard wrote:

    >> If it's "film sourced" it will be at 24 frames per second.

    >
    > And sped up to 25 for the pal conversion like almost every show on TV
    > these days.


    So if what you're saying is true, then all films on TV here in NZ will be
    shorter in duration and the entire audio track will be noticeably higher
    in pitch.


    --
    "Filtering the Internet is like trying to boil the ocean"
    Boots, Feb 27, 2011
    #10
  11. Boots

    victor Guest

    On 27/02/2011 2:27 p.m., Boots wrote:
    > On Sun, 27 Feb 2011 13:45:46 +1300, Richard wrote:
    >
    >>> If it's "film sourced" it will be at 24 frames per second.

    >>
    >> And sped up to 25 for the pal conversion like almost every show on TV
    >> these days.

    >
    > So if what you're saying is true, then all films on TV here in NZ will be
    > shorter in duration and the entire audio track will be noticeably higher
    > in pitch.
    >
    >



    The 4% speed-up is common knowledge.
    Film for TV are also shot at 25 fps
    24fps source is also telecined by inserting a pulldown field every 12
    frames but it isn't as common.

    Plenty of background here
    http://en.wikipedia.org/wiki/Telecine#Frame_rate_differences
    victor, Feb 27, 2011
    #11
  12. Boots

    Richard Guest

    On 27/02/2011 5:52 p.m., victor wrote:
    > On 27/02/2011 2:27 p.m., Boots wrote:
    >> On Sun, 27 Feb 2011 13:45:46 +1300, Richard wrote:
    >>
    >>>> If it's "film sourced" it will be at 24 frames per second.
    >>>
    >>> And sped up to 25 for the pal conversion like almost every show on TV
    >>> these days.

    >>
    >> So if what you're saying is true, then all films on TV here in NZ will be
    >> shorter in duration and the entire audio track will be noticeably higher
    >> in pitch.
    >>
    >>

    >
    >
    > The 4% speed-up is common knowledge.
    > Film for TV are also shot at 25 fps
    > 24fps source is also telecined by inserting a pulldown field every 12
    > frames but it isn't as common.
    >
    > Plenty of background here
    > http://en.wikipedia.org/wiki/Telecine#Frame_rate_differences


    Usually see the half second judder on music vids where the speedup would
    be unacceptable

    American dad etc are quite noticable with the speedup.

    Sometimes they pitch correct so you dont have that as a problem, but the
    tempo is still faster. This is part of the reason that ntsc dvds were
    prefered for many things.
    Richard, Feb 27, 2011
    #12
  13. Boots

    Boots Guest

    On Sun, 27 Feb 2011 17:52:24 +1300, victor wrote:

    > The 4% speed-up is common knowledge.


    I would dispute that. Knowledge it may be, "common" it certainly is not.


    --
    "Filtering the Internet is like trying to boil the ocean"
    Boots, Feb 27, 2011
    #13
  14. Boots

    Boots Guest

    On Sun, 27 Feb 2011 18:28:56 +1300, Richard wrote:

    > Sometimes they pitch correct so you dont have that as a problem, but the
    > tempo is still faster. This is part of the reason that ntsc dvds were
    > prefered for many things.


    29.97 frames per second?


    --
    "Filtering the Internet is like trying to boil the ocean"
    Boots, Feb 27, 2011
    #14
  15. Boots

    victor Guest

    On 27/02/2011 8:12 p.m., Boots wrote:
    > On Sun, 27 Feb 2011 17:52:24 +1300, victor wrote:
    >
    >> The 4% speed-up is common knowledge.

    >
    > I would dispute that. Knowledge it may be, "common" it certainly is not.
    >
    >


    Now you know
    victor, Feb 27, 2011
    #15
  16. Boots

    Richard Guest

    On 27/02/2011 8:13 p.m., Boots wrote:
    > On Sun, 27 Feb 2011 18:28:56 +1300, Richard wrote:
    >
    >> Sometimes they pitch correct so you dont have that as a problem, but the
    >> tempo is still faster. This is part of the reason that ntsc dvds were
    >> prefered for many things.

    >
    > 29.97 frames per second?


    which with a 2:3 cadence makes basically 24 so the audio is not rooted
    Richard, Feb 27, 2011
    #16
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