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Film Mode ?

Discussion in 'LCD & LED LCD TVs' started by richjthorpe, Feb 22, 2005.

  1. richjthorpe

    richjthorpe
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    Hi all,

    I've noticed a few people going on about 'Film Mode' on LCDs (My Sharp has it too). What does 'Film Mode' do and how does it do it ?

    I've read that it has something to do with 2:2 pulldown, but what the hell is that ?!

    :confused:

    Thanks,

    Richie.
     
  2. duncs

    duncs
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    Hi,

    As far as I can tell, film mode converts a 24/25 frame per sec source into a 30 frame per sec output. I don't know how it does it or what effect it has on the image, nor how it relates to 2:2 pulldown.

    I found this somewhere on the web.

    3:2 and 2:2 pulldown detection- 3:2 pulldown detection for NTSC and 2:2 film detection for PAL is an advanced film mode processing technique. It helps maximise image detail and sharpness for NTSC or PAL sources that originated from film. When such materials are detected, this technology applies video processing algorithms that optimise the conversion of film-based video- resulting in richly detailed images with sharply defined lines.

    Hope this helps (a little) :)

    Just found this

    So I guess the 30 frames per sec only refers to NTSC
     
  3. richjthorpe

    richjthorpe
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    Thanks for that Duncs.

    So DVDs need to have Film Mode encrypted on them for a TV with 'Film Mode' option to be able to process the Film Mode images, correct ? Kind of like 16:9 widescreen format detection ?

    Richie.
     
  4. duncs

    duncs
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    As far as I am aware (someone more knowledgable may be able to correct me) it is all done automatically. When a DVD is played, the image is analysed to see how many frames a second are being output. if there are 24 frames (which most films are shot at) the 2:2 pulldown will output 25 frames durring the same time that 24 frames would be displayed. However, as PAL runs at 50htz each image is displayed twice. This leads to films in the UK being 4% shorter duration.

    The film mode also does some other magic I guess to help the image display as intended. I would imagine that the "film mode" may create new frames that is a composite of the preceding and following frames. This would give 50 individual frames a second rather than 25 frames and would give a sharper image as each frame is no longer interlaced.

    I'm no expert by any strech of the imagination so please don't take this as gospel ;)

    more info

    http://www.michaeldvd.com.au/Articles/PALSpeedUp/PALSpeedUp.asp
     
  5. McE

    McE
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    The Film mode of the sharp is "inverse 3:2 pull-down"....

    now could someone translate this into something I can understand? ;)

    "3-2 pulldown - An uncommon variation of 2-3 pulldown, where the first film frame is repeated for 3 fields instead of two. Most people mean 2-3 pulldown when they say 3-2 pulldown."

    That would cause judder isn't it?


    another site says: "We also discovered that 2:3 pull-down--important for nonprogressive and non-HD sources--functions only when you select Film mode from the Advanced menu."

    and another one: "When set to "On," the film mode automatically detects, analyzes, and converts a film source (24 fps) to video (30 fps) using 3-2 Pulldown."


    :confused:

    btw: if somebody has an PS2 via component... strange things happen with film mode on...
     
  6. LcdGuru

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    'Film-mode' is a special way of deinterlacing 24fps movie footage for display on a 50Hz progressive scan screen. Technically 2-2 pulldown is used for 50Hz content, and 2-3 pulldown for 60Hz.

    The practical benefit is a 50% boost in vertical resolution and the elimination of interlace line flicker.

    My Sharp GA4 lets me toggle film mode on and off - the improvement is visible - but not that dramatic. One reason is the slow response of the LCD tends to filter out the line flicker anyway. However, I hear the improvement is more dramatic on CRTs.

    I can also see the resolution improvement - but it's in the vertical direction only - so objects just get a little bit sharper - but nothing to write home about.

    PS. You must remember to switch film mode off for regular 50Hz video - otherwise adjacent field pairs get meshed together - causing a combing effect on the edges of moving objects.
     
  7. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    You guys need to go do some searching....

    Film is 24 frames per second.

    VIDEO in USA is 60 interlaced FIELDS per second
    VIDEO in UK is 50 interlaced FIELDS per second

    To turn film in to video for broadcast or for playback out of a dvd player you need to do some stuff to it to make the numbers match

    For 50Hz they split the 24 pictures in to 48 half resolution images. These are called interlaced fields. Then they speed it up as has been mentioned so tht film is over faster.

    For 60Hz countries they split the images up in to 48 half resolution fields then repeat every fourth one to create 12 extra fields to get to 60...
    ie
    PIC1 ODD LINES, PIC 1 EVEN LINES, PIC2 ODD LINES, PIC 2 EVEN LINES, PIC2 EVEN LINES, PIC 3 ODD LINES, PIC 3 EVEN LINES, PIC 4 ....can you see the 2:3:2:2 sequence happening?

    Your display can't wor by displaying interlaced images like that whch comes out of a DVD player or stb. So inside there is a processor that de-interlaces the half resolution fields and coverts them to progressive frames. In order to do this and create the highest resolution artefact free images the processing needs to be capable of recognising which fields are from the same FRAME. If it can stick them together you get full resolution if it gets it wrong it can be a bit of a mess.

    The ability to do this is called FILM detection...or film mode....or inverse telecine...or for 60Hz sources 2:3 detection or for 50Hz sources 2:2 detection. You need 2:2 for good UK TV and DVD playback. You need 2:3 for US or 60Hz sources.

    Hope this is a little use,

    Gordon
     

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