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Interlacing -- why is this still an issue?
  • ahblezaahbleza

    I'm working for a producer whose editor demands PAL 50i. I've tried to persuade him that 25p will give superior results, but the editor insists that 50i is better for a TV channel workflow. What has been the experience of other editors working in PAL land? Surely 25p is going to give fewer artifacts and smoother video, even though most TVs are going to be showing in 50i (or even 60i.)

  • 16 Replies sorted by
  • RobertoRoberto

    By the time that editor gets through that bottle of scotch you bribe him with, he'll have started to think 25p was his idea in the first place ;-)

  • nomadnomad

    No, it's not going to give you smoother video!

    25p has half the temporal resolution of 50i. Fast movements (think sports, news, docu) will look smoother, even if you get more artifacts than progressive formats from the GH2.

    When filming 24 or 25p, you'll need to adhere to strict panning rules and more controlled camera motion in general.

    OTOH, who wants to shoot shallow depth for news or the like? If it's a typical TV subject, why not use a TV camera?

    GH2 is all about cinematic creations.

  • balazerbalazer

    GH2 is all about cinematic creations? GH2 has great 50p and 60p.

  • RamboRambo

    Only issue is, if your intended delivery destination is the web, when converting 50/60i or p to 24/25/ or 30p you lose some of that smoothness. Apart from that, shooting interlaced gives you heaps of options to render down to.

    If he insists on 50i, shoot it on a camcorder.

  • willianalemanwillianaleman

    Everytime I see these types of expressions: "Cinema camera, cinematic creation" to refer to the limitations of some digital camera formats to reproduce medium to fast motion, I have to ask myself: Since when has motion not been a part of cinema as a tool to tell a story?

    For a long time, medium to fast motion has been part of "cinema" as an art form, but in the digital era the limitation of motion has been increased. Manufactures and media writers justify this limitation to the market by saying that this X camera is a "Cinema" one, meaning we can not do fast motion with it. A very convenient way to justify the limitation, even when the limitation is in the medium not in the craft or art form. We have accepted the limitation, but to tell us and to transform a lie into a conventional statement, saying that the reason that X camera can not do motion without showing side effects is because it is a "cinema camera" is a fault story.

  • nomadnomad

    Well, I was rather referring to the higher degree of production value and control, like well-planned camera movements, in cinematic production as opposed to news, sports or documentary. Just like @Rambo, I'd rather suggest a video camcorder for such situations if smooth movement is asked for.

    Of course cinema will not be restricted to 24p in the future. Peter Jackson has shot his "Hobbitt" in 48 fps (progressive, of course) and we might adapt that format one day for cinema.

    When I saw fiction for the first time as a 48 fps projection in 4K, it was kind of strange, though. I felt like watching a theater stage through a well-cleaned window and not a movie. But that's a culturally acquired perception and not a law of nature, anyway.

  • GrunfGrunf

    HD or SD? I know a guy who routinely shoots 720p50, then downconverts to interlaced SD PAL MPEG-2 for airing.

  • RobertoRoberto

    @Grunf

    Yep, TV stations often produce streams in 720p, SD and 1080i for broadcast on different channels.

  • willianalemanwillianaleman

    Accordingly to NTSC, interlace is still the standard format for broadcast TV in USA and countries that have adopted the NTSC format. The spec sheet for delivery format in postproduction facilities has to be conformed to this format if the program is going to be televised.

  • FW200FW200

    Atleast here in The Netherlands the broadcast standards are either 625i50 or 1080i50.. 720p50 is simply not used.. We do sometimes do programs in Psf (SD or HD), but it's mostly for stuff like festivals or show programs.. And that still gets transmitted as an interlaced signal..

    1080p50 is not a big thing yet, mostly because the HD OBV's that are around atm can't support it. And it would be a costly thing to upgrade perfectly fine HD OBV's to 3G/1080p just because people want 1080p50. Any new OBV's being built do have 1080p50 in mind though.. but the broadcasting playout architecture isn't really ready for it either..

  • nomadnomad

    Here in Germany all public channels broadcast 720p50 (ARD, ZDF, Arte).

  • Vitaliy_KiselevVitaliy_Kiselev

    Btw, all this 1080p50, 1080p60, I am not talking about 4K could have issues, due to satellites feed restrictions.
    Most providers like to pack as many channels as possible, frequently with dismal bitrates.
    generally, it is main reason to like 1080i modes for them.

  • Greek_m43Greek_m43

    I work in promos and commercials at my news station and we shoot everything at 1080/24p. Most stations have some sort of "flipping" system before the spot goes into the storage drives for air. I send all my spots at h.264 1080/24p and it all converts just fine.

  • soundgh2soundgh2

    BBC on crunchy Freeview :

    http://www.tomshardware.co.uk/BBC-HD-1080p-Freeview-HD-Settop-Boxes,news-35640.html

  • ahblezaahbleza

    Question: if we're shooting 1080i50 or 1080p25, we assume PAL because of the frame rate -- but is there really any other difference when it comes to NTSC? I know that SD mandates PAL should have 525 lines, but in Brazil, for example, they have PAL-M which uses 525 lines @ 30 fps.

    So when it comes to HD -- I don't really see a big difference except frame rate, since the resolution is the same.

  • FW200FW200

    PAL-M is more like NTSC really.. Hence the 525 (480) lines versus the normal 625 (576) lines in PAL...

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