24FPS vs 60FPS

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    • #44362
      Avatarmrkinyo7
      Participant

      I am trying to get a firm understanding of the differences between 24 FPS and 60FPS. While I don’t truley know the difference, I typically use the 24 FPS when I want a movie look and 60FPS for my son’s sports and low light situations.

    • #185775
      AvatarJaimie
      Participant

      The FPS business is confusing at best partly because FPS is used in two different ways. 24 FPS generally means 24 frames per second which is a film standard. 60 FPS generally means 60 fields per second which is the interlaced TV standard. Since a TV frame is made up of two fields, 60 fields per second equals 30 TV frames per second. Actually, the TV standard is 29.97 frames per second, but that’s not important in this discussion.

      It would seem that there is not much difference between 24 and 30 frames per second, but there is because the TV frames are painted on the screen twice – once for the odd numbered scan lines and once for the even numbered scan lines. This is where the 60 fields per second comes in, one field contains the odd numbered lines and the other field contains the even numbered. This is called interlaced scanning and is abbreviated in HDTV as 1080i or 1080 lines interlaced. In TV, the frame rate is always 30 frames per second.

      In the case of 24 frames per second, the frame is usually scanned progressively which accounts for the abbreviation 1080p. This means that the scan lines are painted on the screen one after the other so there is no need to interlace two fields.

      Interlaced scanning was originally implemented to reduce flicker on CRT displays, but it has the added advantage of smoothing out motion. The cost of the smoothing is a reduction in sharpness on fast moving subjects. That sharpness reduction is due to the fact that two adjacent scan lines are actually created 1/60 of a second apart and the subject has moved during that time interval. The smoothing comes from the fact you are getting 60 “looks” at the picture every second as opposed to either 30 or 24 in the progressive scan modes.

      Progressive scan provides a sharper picture of moving subjects because, presumably, all scan line were exposed at the same time. This is true if the camera has a shutter system that allows that simultaneous exposure, most do not. Most progressive scan cameras scan every line from top to bottom meaning that the bottom of the picture is captured slightly later than the top. The result is a slight horizontal stretching of rapidly moving objects.

      To my eye on the videos we shoot, neither the slight blurring due to interlacing nor the stretching due to progressive scanning is important because the eye doesn’t focus clearly on fast subjects. But I also think the interlaced scanning produces smoother motion because the 60 fields per second provide more views of the subject (higher sampling rate).

      If you watch closely, fast motion on film movies is not really smooth nor sharply focused. Pans are also jerkier than on TV, especially fast pans. That is neither good nor bad, it is a characteristic of the art form.

      In the end, I shoot everything in 1080i 30 frames per second because nobody has every told me they wanted jerkier pans etc.

      Jaimie

    • #185776
      Avatarmrkinyo7
      Participant

      Wow! This is the type of thoroughness that I wish that we could all use when answering questions. I have a much better understanding of the differences between the two. I’ve tried to read a lot about this online but I have to say that no one was able to explain this so that I could understand.

      Thank you. By the way what type of stuff do you shoot?

    • #185777
      AvatarXTR-91
      Participant

      Just let me say if the 60FPS you’re talking about is 60p, then definitely shoot with it, unless you’re really trying to conserve camcorder memory. If you’re not, than 60i would be the better option for non-web video. 24p would be for economy purpose or special effect.

    • #185778
      Avatarmrkinyo7
      Participant

      @ XTR-91, thanks for the further clarification on the 60p and 60i. I would typically shoot video in the 24p mode when I shoot anything other than sports and only use the 60i for shooting sports. This is all good information. I thought that the 24P was a good quality mode of video. I have actually shot some of my son’s football games in this mode to give it the movie look. It’s cool. What type of camcorder do you shoot with.

    • #185779
      AvatarXTR-91
      Participant

      Panasonic HDC-TM700. Shoot 1920×1080/60p video and then convert it to 480/24p for streaming online (though it does take a long time).

      I wish my camera’s 1080/60i mode had a higher bitrate, as artifacting is much more of a problem with 60i on my cam.

    • #185780
      Avatarmrkinyo7
      Participant

      The TM700 appears to be a really good camera with a GREAT Leica lens! In fact I really wanted the HSC HD700 (I think that’s right). How do you convert the video to stream online. I’m very new at this but I have IMovie, Premiere Pro CS4 and Final Cut Pro.

    • #185781
      Avatarroblewis56
      Participant

      I often shoot sports and other subjects that have fast
      motion. My camera is a Canon HF11. It
      has frame rate choices of 24p, 30p and 60i, the p standing for progressive and
      the i standing for interlaced. Clearly the faster frame rate is better so 30p
      is preferred over 24p, but is 60i better than 30p? Not necessarily since the
      second scan in interlaced occurs later possibly resulting in a shifted image.
      Also the Canon manual states: “Recordings made with the [PF24], [PF30]
      frame rate are converted and recorded on the memory as 60i”. So to help
      clarify I carried out the experiment shown in the video by shooting a train
      passing in front of the camcorder at about 60-70 mph. In the computer, using
      either Adobe Premier Elements or CyberLink PowerDirector the 30p clips show a
      single image while the 60i clips show a split image. You can see this in the
      freeze frames. However, when uploaded to YouTube the video for 60i is not
      split. However, a DVD made from 60i clips show a split image.

      http://www.youtube.com/watch?v=nxrBd5N4lIw

    • #185782
      AvatarJaimie
      Participant

      I never thought something as esoteric as frame rates would spur so much discussion. I guess it is because the different protocols provide a level of artistic control that was previously unobtainable.

      To either clarify or mystify further – I’m not sure which – I’ll try to address some comments above. First off, Thank you Mrkinyo for your kind words, I can sympathize with anyone who is confused when it comes to this sort of thing. As far as what I shoot, I shoot anything that moves. I mostly shoot events and performances which include weddings, sports, meetings etc. I use several Sony HVR-Z1,5,7U series cameras.

      It is unfortunate that the words “frame” and “field” both begin with the letter “f” so the abbreviation FPS could mean either frames or fields per second. But here’s the fact, 60i almost always means 60 interlaced fields per second. That is the same as 30 (actually 29.97 but the difference does not matter) frames per second. Also, 30p means 30 frames per second. A frame is a whole picture whereas a field is half a picture. That’s why it takes two fields to make a frame. Interestingly, the data rate for the two standards is the same. After all, every 1/30 of a second all the pixels are transmitted regardless of whether they are scanned progressively or interlaced. Of course, the compression method will change the actual data rate, but that is different consideration.

      History:

      I have read blogs where the writer seemed to attach some special or almost magical importance to 24 frames per second. There isn’t. Originally, when movies were silent, the frame rate was 16 fps. When sound came along it was found that a faster film speed was needed to record the optical sound track. Thus, the speed was raised to 24 fps because it was the lowest film speed that allowed reasonable optical sound recording.

      For TV, 30 frames per second was selected back in 1945 because it reduced the effect of 60 Hz hum bars caused by 60 Hz ripple in the power supplies of early TVs. Interlaced was selected because early TV screens (cathode ray tubes or CRTs) showed too much flicker when progressively scanned.

      Anyway, my point is shoot whatever standard appeals to to and your type of work. But remember that all analog TVs and the majority of digital TVs default to the 60i standard. That means no matter what you shot at, the viewer is seeing 60i. This is not true for video dubbed to film or for video displayed on a computer or special editing devices.

    • #185783
      AvatarXTR-91
      Participant

      WinFX Free Converter is a great video converting program.

    • #204926
      Avatarreyve
      Participant

      What do most DVD players play more smoothly, 23.97 or 29.97?

       

      i wonder which would be better to shoot in for smoother, non-freezing.skipping DVD's, 23.97, 29.97, or 60i?
       

    • #204932
      AvatarRob
      Participant

      @reyve

       

      Your question here has nothing to do with the skipping you asked about in your previous post. 

       

      When a DVD player detects video with a framerate of 23.98fps, the DVD player adds a pull-down pattern to convert it to 29.97fps.

       

      When a DVD player detects video with a framerate of 29.97fps, it plays the video as is.

       

      60i is 29.97fps. It's interlaced footage. That's what the "i" stands for. Progressive footage @ 29.97fps is described ad 30p. 

       
    • #204933
      Avatartdesaul
      Member

      Thank you, Jamie, for the indepth and concise (at the same time!) explanation of frame/field rates. I hope you don't mind, but I've copied both of your replies and printed them for future reference! I occassionally teach kid technology such as video and game production and your explanations are excellent for these usages.

       

      I'm particularly fond of your insistence that it is really up to the videographers preference. I'm constantly telling the students that it is ART and they need to find their own style.

       

      If you would like me to credit you fully on the print outs, please PM me.

       

      Good Job!

       

       

    • #205330
      AvatarMrHotter
      Member

      It seems I'm not the only person trying to figure this out.

       

      I've been experimenting with camera settings, project settings, and publish setting to try and figure out what would give me the best end results.

       

      I have the Canon Vixia HF G10. It can shoot in true 24p, but it gives a warning about not being able to convert to standard definition with the camcorder. I should have ignored that, because I'm going to be saving this as DvD, Blue Ray, and a digital file. My other option was PF24, but that ended up giving me a 29FPS file. In the end, that may be a better setting for me since I've been making a 30p file to make my DvDs.

       

      I think I need to take some classes in digital editing. I'm getting back into video after not working in the field since Avid was a 'new and exiting' way to make a rough edit before going into the 'real' edit bay.

       

       

    • #207034
      AvatarRonE
      Participant

      There seems to be continual confusion over NTSC 29.94 frame rate. 60i is 59.97 fields, real exposures of the camera, a second. This is the same temporal motion as 60p ( 59.94p ) just happen to be half the vertical resolution.  29.94 is the timecode for 60i, incrementing each 2 field ( 2 fields= 1 frame ) hence 29.97fps.  30p ( 29.97p ) are real frame exposures per second so will have half the exposures of the observed motion compared to either 60i or 60p and will NOT be as smooth motion and will have a low frame rate judder on pans etc just like 24p.  60i and 30p have the same timecode but they do not look the same !!!  A CRT displayed 60i since the system was designed that way. A lcd or plasma display has to deinterlace 60i to display on its 60P display. This is done in many ways some good some bad !!  For the new 120hz etc interpolating displays they recreate the missing fields and create a full 120fps  refresh for a smooth image on playback.

       

      As for 24p. To be shown on a NTSC TV the playback rate has to be altered to sync with the refresh rate of the display. A LCD or plasma normal 60hz display will not display 24p without pulldown ( you cannot divide 24 into 60 and get an integer value )  So 2:3 pulldown is applied, 2 times the first frame, 3 times the second frame etc ( 2×12+ 3×12 = 60 )  A display that is a multiple of 24 like 120hz can display 24p correctly if enabled to do so ( normally over HDMI from a Blueay player). So on a TV, film has the pulldown cadence not seen in a real cinema when real film is projected.

       

      Ron Evans

    • #207036
      Avatargldnears
      Member

      " So on a TV, film has the pulldown cadence not seen in a real cinema when real film is projected.".

       

      Yehbut . . . . projected film at 24 frames per second, due to the projectors shutter actually appears on the screen as 48 images per second

       

      Rick Crampton

    • #207040
      AvatarRonE
      Participant

      Depends on the projector. My film projector has 3 blades so the flicker rate is 72. My other Super 8 projector has 5 blades flicker rate is 120. Or for the normal Super 8 rate of 18fps would be 54 and 90.  The real difference is all the film frames are repeated the same number of times rather than 2:3 pulldown were there are differences half are repeated 2 times the other half 3 times. 

       

      Ron Evans

    • #207041
      Avatargldnears
      Member

      " Depends on the projector."

       

      I'm only familiar with standard theatrical 35mm  projection . . . I was working in post production in Hollywood during the interum when TV shows were being shot on 35mm and posted on videotape. It was an uneasy marriage.

       

       

       

    • #207062
      AvatarGreattree
      Member

      Can I add another variable to this discussion.  When I first changed to an HD camera I used 50i (PAL) but found with the extra definition, motion (like legs of running animals and even quite slow pans) gave quite blurred or jerky video which was unpleasant to watch on the TV. I, therefore changed to 25p which has seen quite an improvement in the tv display and has also made editing much easier, particularly when trying to be frame accurate. However, the motion is still a long way from being perfect and pans in particular look very "Blurred".  I have since upped the shutter speed from the standard 1/50 to 1/125 and it does seem to have made an improvement, but this is just a personal view and I have done no real comparison tests.  It would be interesting to know what those of you who use their cameras all day every day have to say. Do you ever use different shutter speeds other than for very fast moving subjects such as motor racing??? Ultimately, I assume that 60p will eventually be the cure all, but I don't think that it will be affordable for pensioners in the years that I have left.  Nigel

    • #207720
      Avatarneilrued
      Participant

      Nigel,

       

      If you are looking for a reasonably priced camera able to shoot native 1920 x 1080 resolution at 60p (progressive frames per second) may I suggest the JVC Everio GZ-EX515?

       

      The bit rate of the GZ-EX515's AVCHD codec is 24Mbps (24 Megabits per second), matching the bit rate of broadcast quality cameras. The 60p specification is true 60 full HD (1920 x 1080) frames per second. There is an option to configure the camera for 1920 x 1080 60i.

       

      The GZ-EX515 also permits installing 40.5mm diameter optical filters. I am currently experimenting with the Tiffen circular polarizer, Neutral Density 0.6, and Sky 1-A filters. I purchased a rubber lens hood featuring a threaded outer ring to permit installing these filters, whilst using the hood for bright sunny days during outdoors' shoots.

       

      This camera can shoot time lapse footage at 1920 x 1080 60p, and slow motion at a Standard Definition (SD) resolution of 720 x 480 at 250fps, on 60i setting. For some reason, JVC decided to upscale the footage to 1920 x 1080 60i when writing to the SD card; personally I would have preferred it was left at SD resolution.

       

      The GZ-EX515 allows me to manually adjust the focus; I discovered through experimentation, this was best for shooting time lapse footage at sunset, On auto focus, the fuzzy logic algorithm tends to blur the image completely as the twilight turns into night.

       

      Sorry for the above digression, I thought the above experiences I've had so far with this camera may be useful?

       

      Returning to the topic of frame rates, 23.976 frames per second was selected because this was the best frame rate to allow film to be recorded for simpler post-production workflow to broadcast over the 60i (59.97 interlaced fields (half frames) per second) analog NTSC color TV system. Some Prosumer cameras offer selectable 23.976p, 24p frame per second rates, to offer the option of shooting footage for TV broadcasting (@ 23.976p) or for showing at cinemas (@ 24p).

       

      Other Prosumer cameras, such as the Sony NEX-FS700 offer 23.976p but no 24p frame rate selection option. With a digital film/video editor offering the function, it is possible to modify 23.976p to 24p for maintaining lip synchronization.

       

      The higher priced Sony CineAlta cameras, starting at $17,000, such as the PWM F5 and PWM F55, offer 24p cinematographic frame rates.

       

      It's not fair to compare the GZ-EX515 with the NEX-FS700 because the NEX-FS700 costs 24 times the price, however the GZ-EX515 does provide some manual controls for focus and exposure, and SD at 250fps.

    • #207729
      AvatarSun City Dave
      Participant

      I'm not quite sure where the conversion is taking place, but I've noticed that when I view an older movie shot at 24 fps frame-by-frame, every 4th frame is repeated which pads it out to 30 fps.

    • #207744
      Avatargldnears
      Member

      " I'm not quite sure where the conversion is taking place, " . . . . .  Well, let's see . . . . . If the movie was shot on film at 24 frames per second, and then wound up on analog videotape which is 30 frames per second ( okay, okay 29.97 fps ) the 24 film frames are scanned with the 3:2 " pulldown " scheme which repeats a couple or three of the film frames to fill out the 30 video frame count per second. Not until the wonderful world of " digital " did we have such a wealth of different frame rates to choose from . . . .

    • #207754
      Avatargldnears
      Member

      In the second posting on this thread, Jamie said, " Actually, the TV standard is 29.97 frames per second, but that's not important in this discussion. " . . . . Apparently it is important because of the misconception that video frame rates are actually 24 or 30 or 60 or whatever. In the USA video world, for instance, what is commonly refered to as 24 frames per second is in actuallity 23.976 frames per second. This is apparently a carry over from the NTSC analog days when it was necessary to shift the video sync frequency just far enough away from the color sampling frequency so that they didn't interfere with each other. But continually mentioning the actual frame rates would cumbersome, and so the " generic " is used. For most folks it doesn't really matter since they have no way to differentiate between 24 and 23.976 so long as they stay within the video realm. How the gear handles this is transparent to most videographers. But if one were to actually want to convert their video project to film, let's say, the difference needs to be taken into account . . . . . but that would be the responsibility of the technician running the digital to film transfer, and he would be well aware of what it takes to accomplish this.    So for our purposes we need only to consider 24 or 25 or 30 or 50 or 60 frames per second . . . . . and Jamie is right.

    • #207906
      Avatarneilrued
      Participant

      As TV broadcasters gradually switch off their analog transmitters, and viewers update to flat wide screen TVs. through attrition of their ageing analog TV sets; the frame rate conversion will become an issue of converting 50p or 60p to 50i or 60i because even in digital video broadcasting, digital video free to air broadcasts in countries such as Australia transmit in 50i, to maintain compatibility with the older analog system, to allow analog TV users to use HD "set top boxes", to view 1080i or 720i HD wide screen broadcasts as SD "letterbox" images.

       

      Some brands of wide screen HDTVs matched with same brand Blu Ray players, permit Blu Ray movies with 24p play back capability, to be viewed at a cinema frame rate of 24 progressive frames per second.

       

      Indie or studio film makers have the option to potentially release movies directly to Blu Ray, using 24p frames per second.

       

      Film makers using cameras that only offer 23.976p can convert their footage to 24p with a PC/Mac based video editing software to maintain lip sync (synchronisation).

       

      There is no real technical reason why a camera offering 23.976p cannot offer 24p; the restriction is purely a firmware (i.e. the computer program running in the camera) issue.

       

      Some folks in other film making web sites, speculate camera manufacturers offering 24p on their cinematographic/professional cameras and not offering 24p on their prosumer models, do not want sales of their higher cost professional cameras be dented by sales of their lower cost prosumer models. Although these may be opinions without any basis on fact?

    • #207911
      Avatargldnears
      Member

      " As TV broadcasters gradually switch off their analog transmitters, and viewers update to flat wide screen TVs. through attrition of their ageing analog TV sets . . . "  You are in Australia? Here in the US, the digital revolution has long since been fought and lost ( depending on one's perspective ). I can't right off remember when the last analog transmitter was shut down.           " Film makers using cameras that only offer 23.976p can convert their footage to 24p with a PC/Mac based video editing software to maintain lip sync (synchronisation). "    23.976p  – IS –  24P, it's just running on an ever-so-slightly slower sync frequency ( clock ).  For those determined to dub their 23.976p cinematic wonder to film, it's only necessary to run the " camera " or kinescope or whatever one wishes to call it, at the video sync frame rate of 23.976 frames per second.            As for interlaced video, I suspect we'll have it around for a very long time due to fast moving subjects such as sports. Interlaced video has A LOT less blurring and strobing than progressive scanning of fast moving objects.        Personally I don't understand this passion for " a film look ". Just because we have a nostalgic love for steam rail locomotives, why reject the cleaner, more efficient, modern diesel-electric, or all-electric locomotives?? It's the story that counts, after all ! Before too long the film projectors will be in the corner gathering dust and public venues will be projecting 2K, 4K, or 8K digital offerings which will dazzle the eye with brightness and detail that film simply can not match. By then maybe film prints of today will be relegated to retrospective " art " shows and viewed by a handful of folks as the " golden years ", similarly as such current gatherings look adoringly at the ground breaking black and white movies of the 20's and 30's ??

    • #208380
      Avatarneilrued
      Participant

      Rick, sorry for the delayed reply.

       

      Yes I live in Australia and over here, the corporate and government cultural trend is to update through technological attrition, and gradually switch over to new technology.

       

      The Australian analog TV transmitters will start a gradual decommissioning starting this year and progressing through until next year. I presume the timing for the switchover was announced officially by the government after receiving corporate recommendations from the commercial TV networks, as to when their analog TV equipment would require major overhauls.

       

      The comment about running 23.967p footage on a PC/Mac to convert to 24p, mainly applies to footage shot on digital cameras.

    • #208381
      Avatarneilrued
      Participant

      I wanted to correct a comment I made in an earlier post:

       

      "Other Prosumer cameras, such as the Sony NEX-FS700 offer 23.976p but no 24p frame rate selection option."

       

      I had a chance to read the operator's manual for this camera, and the Sony NEX-FS700 DOES offer 24p frame rate. The 23.976p rate is only offered for 60i shooting mode.

       

    • #208386
      Avatargldnears
      Member

       

       

      " Yes I live in Australia and over here, the corporate and government cultural trend is to update through technological attrition, and gradually switch over to new technology.

       

      The Australian analog TV transmitters will start a gradual decommissioning starting this year and progressing through until next year."                                     According to Wikipedia, the Australian TV switchover to digital transmission has been carried out by regions with only a few remaining to make the transition.

       

      " The comment about running 23.967p footage on a PC/Mac to convert to 24p, mainly applies to footage shot on digital cameras. "                          Okay, but think logically for a moment: How do you suppose that in the real world a system of ANY type could actually record 23.967 frames?? In NTSC TV land . . . in which Australia does not reside . . . . 23.967 frames per second represents a 60 Hz clock which has been slowed to 59.94 Hz. The reason for this has been fully explained previously. 23.967 frames per second ( by " God's " clock in the " real world " of 60 Hz ) – IS – 24 frames per second in the artificial world of 59.94 Hz!!              It's tragic that there is so  much misconception over this simple fact!

    • #208390
      Avatargldnears
      Member

      Oh, wait! Isn't Oz in the land of PAL? There is no problem such as we here have to deal with in NTSC Land!

    • #208550
      Avatarzach114798
      Participant

      the quality is better in 60 frames per second, and produces more grain and noise, and 24 is used in film, however newer films are switching to 60 now.

       

      check out my channel i would appreciate it alot

       

      http://www.youtube.com/user/LucasRFilms?feature=mhee

    • #208552
      Avatargldnears
      Member
      "

      the quality is better in 60 frames per second, and produces more grain and noise, and 24 is used in film, however newer films are switching to 60 now. "          what?

    • #206970
      AvatarSpotlightOn999
      Participant

      Rob

      I recently purchased a Sony NEX FS-100U to shoot live bands, usually up close in low light situations, but sometimes on large stages with bright lights.  What is the best setting to record at for public access tv?   Only recently heard about the 29.97 fps but am not clear which will be clearest video setting for sometimes fast moving harmonica players, in particular.  The options on my videocam range from 1080 / 30 p FX or FH to 1080 / 60 p PS, 1080 / 60 i FX, FH or HQ or LP, as well as the lower options. I also need to know optimal setting for production in AVCHD for dvd & Youtube, and mpeg-2 for the tv stations, which  usually have older equipment and must injest it.  It takes up to 12 hrs to produce one 28 to 58 min video, and sometimes my computer just stops and won't proceed.  I have a 2010 HP Envy 3D laptop using Windows 7, which I use a fan on since it produces so much heat.  Many thanks for your help! 

    • #207065
      AvatarRonE
      Participant

      You should have twice as smooth a video with 50i than 25p as you are taking twice as many exposures they just happen to be half the vertical resolution. The issue could be that your TV is not deinterlacing very well. I see no difference between 60i and 60p on my Sony 240hz LCD though I do shoot now 60p  on the cameras that can do that.I edit on a 60i timeline a mix of 60i and 60p just fine I use Edius as my editor and normally shoot theatre with 4 or 5 AVCHD cameras two of which now shoot 60P.

       

      I am not that young either 71.

       

       

      Ron Evans

    • #207072
      AvatarCreekhouse
      Participant

      Frame rate won't affact Image quality as much as it will change the look and feel of the video you are shooting.  Less FPS, more blur in the motion, more FPS, less blur.  Personally, if you have a camcorder that can shoot 60p, I would shoot that 9 time outta 10. 

       

      How do you like your Sony NEX FS-100U?  I have been looking at that camcorder the past several months and contemplate making it my next big purchase.

       

      Jon

      Charleston Videography

    • #207073
      AvatarGreattree
      Member

      Thanks for the comment.  Unfortunately, neither of my Canon cameras will shoot 60p….I've had them a few years now. Its either 25 full frames per second or 50 1/2 frames interlaced. I think that the higher definition is making the motion blurr just that bit more obvious and probably the 20% of extra frames per second with NTSC compared to PAL goes a little way towards hiding the effect for you in the States. The images shot at 1/125 are just that touch sharper when any subject motion is involved and I believe they show a little better on the tv. PS I'm a bit ahead of you @ 77. But that is now a small percentage difference!!!!!!!  Nigel

    • #207735
      Mike WilhelmMike Wilhelm
      Keymaster

      Are you watching on an older TV?

    • #207743
      AvatarRonE
      Participant

      Normal 2:3 pulldown would alternate doubling or tripling frames. 12 x 2 = 24, 12 x 3= 36. 24 + 36 = 60 the refresh rate for most sets in North America or NTSC lands where mains alternating current is 60hz. This would be true for progressive or interlaced displays at 60hz. For 120 hz display it is possible , depending on playback system and display , to correctly show 24p, ie display each frame 5 times just like a 5 bladed film projector. I have a 3 bladed and  5 bladed film projector ( originally intended for telecine ).

       

      Ron Evans

    • #207746
      AvatarRonE
      Participant

      29.97fps is timecode in an interlaced video that is 59.97 individual fields ( half vertical resolution frames ) only difference to 60p is they will be full resolution frames. Very confusing I know. 60i cameras take 60 exposures just like 60p cameras they just record fields not full frames so the temporal motion is the same which is why 60i is a lot smoother than 30p because there are twice as many exposures in the same time period. The confusion is the timecode for this is 29.97fps, timecode increments every 2 fields,  so people think that is close to 30P, its not. 

       

      So the 24P film frames have to be divided up into 60 fields for  interlace video ( 29.97 fps timecode) with 2:3 pulldown. This will give individual frames to fields and the playback systems will know what to do to reasamble the 24p image on a suitable display on computer editing program. In other words finding the correspondding odd and even fields extracted from the full frame 24p image for inclusion in the 60i stream.

       

      Ron Evans

    • #207748
      AvatarSun City Dave
      Participant

      You can see the way that film shot at 24 fps is converted to 30 by going to any of the Military Channels and looking at film shot during World War II.  Pause the film and then advance it one frame at a time.  For one program, they generated each fifth frame by blending back frames and forward frames.  Come to think of it, I guess this was accomplished by the number of blades on the shutter.  πŸ˜‰    On another program, they simply froze every 4th frame so that the sequence became 1,2,3,4,4,5,6,7,8,8,9,10,11,12,12,etc. which would imply that it was done elctronically to incorporate 24 fps film into a modern 30 fps production.  Obviously, if you ran the old 24 fps film faster to get 30 fps, you would get a Keystone Cops effect.

       

      One of the other respondants to my comment mentioned the shutter…  My favorite sound is the sound of a 35mm projector coming up to speed.  Second best sound is a Broadway pit orchestra.  And third favorite sound is a newspaper printing press coming up to speed.  Sadly, #1 and #3 will soon be a thing of the past.  ;-( 

    • #208476
      Avataradrianwillis360
      Participant

      You, Know your stuff. I'm confused about Something, and I would like to ask for your help, please. TV refeh rates, Dose 60hz = 60fps, I want a TV for gaming on the PS4, mot games will be from 30fps to 60fps.

    • #208544
      Avatarneilrued
      Participant

      Hello Adrian,

       

      Please accept my apologies for the delayed reply, I've been busy finalizing assessment tasks for a course I have completed.

       

      I hesitate to recommend a particular TV model or brand because different manufacturers apply color decoding and image rendering differently. Whilst for regular programming and Blu Ray play back these differences are not noticeable, when taking a look at demanding applications with high frame rates, these differences may become more bothersome for some folks.

       

      The reason is that not everybody's eyes respond to color in the same way. Some people are more sensitive to the red and infra-red region of the spectrum, and others are more sensitive to the blue and ultraviolet regions. I'm in a rare minority where I'm sensitive to a wide spectral range. For instance I can see Near Infra Red light at 780nm, as faint red glow, and I can see a bluish haze during sunset in summer. Other people can't see what I see, they see one or the other.

       

      When comparing TV sets in a store, what doesn't help is that retailers employ the old trick of adjusting the settings on particular models so the brightness, contrast and color look their best, and on other brands or models, they adjust these to look at their worst. This helps them sell more of a particular brand or model they want to sell most of. Sometimes some retailers will push a particular brand or model, if they don't have the particular short list of brands or models you ask for. They even try to tell you that they are all the same because this or that brand all use the same LCD panels. There are actually two countries I know of that make LCD panels; China and South Korea. Also there's no way to know for sure which models use Chinese or South Korean panels.

       

      The origin of the panel doesn't matter because brands such as Panasonic or Sony, have very good quality controls and they buy the best panels from Chinese and South Korean manufacturers. The other parameters influencing quality are the electronics and the firmware used to generate the images.

       

      For highest possible performance, I'd list all models with the fastest response panels, bearing in mind the rough general principle the faster the LCD's response time, the higher the price of the TV. The fastest LCD panels are 5ms, and the generally cheaper TVs use 8ms panels.

       

      Another aspect to consider, is the maximum progressive frame rate a TV's electronics can deliver. Here is where careful attention to a TV's technical specifications are important; first don't trust the manufacturers' published technical specifications because they omit or embellish some parameters.

       

      I was disappointed that even JVC, Panasonic and Sony were not properly representing some models of High Definition video cameras; for years their previous models used Standard Definition image sensors, and they used firmware upscaling in their cameras' microcontrollers to generate an artificial HD image. This is the reason a lot of so-called HD footage published online, doesn't have the same image sharpness as what's available when viewing Blu Ray movies shot on a true 1920 x 1080p resolution image sensor camera, and viewed on a true HD (1920×1080) panel.

       

      Later generations of HD camcorders used 1280 x 720p or 1440 x 1080p image sensors and used upscaling technologies.

       

      The first camcorders I have seen that uses a native 1920 x 1080p image sensor, are the new JVC Everio GZ-EX505/515/555.

       

      Blu Ray movies are sometimes shot using true 1920 x 1080p image sensor cameras, or shot with 3840 x 2160p image sensor cameras and scaled down to 1920 x 1080p for current generation Blu Ray players.

       

      After the 1080 and 2160 vertical image sensor resolutions, I put the letter 'p', to designate 'progressive' instead of 'i' for inter-laced.

       

      60Hz does not automatically mean 60p, here's why: When the first analog TV systems were developed, the designers initially did not allow for the way the human visual system perceived the electron scanning used to build up an image on the screen. Consequently people saw visual artefacts such as flickering and jerky motion of fast moving objects.  To work with the way the human visual system functions, the analog TV researchers devised techniques such as a blanking interval between each frame, and inter-laced scanning. To sum up, the original TV scanning used progressive scanning and would show full frames 30 times a second without blanking intervals between each frame. Unfortunately the human visual system did not react well to this, and they redesigned the scanning system to send 60 half frames per second, and introduce a blanking interval between each half frame, to fool the human visual system into seeing 30 full progressive frames per second.

       

      Why do they use 60Hz?

      In the USA, the alternating current (a.c.) voltage delivered to homes, used a 60Hz cycle; to minimize interference in the TV picture, they synchronized the frame rate to the a.c. mains frequency. To match the TV frame rate as close as possible to the 24 frames per second used in Hollywood films, they halved the TV full frame rate to 30 frames per second. Essentially to the 24 film frames, they electronically interleaved 6 blank frames between certain intervals of film frames, to pad the required 30 frames per second.

       

      How does interlacing work?

      Each NTSC image frame was made up of 480 vertical lines. In the first scan, the TV camera electronics scanned every odd numbered vertical line, and this was the odd 240 half frame, next the TV camera scanned every even numbered vertical line, producing the even 240 half frame. Each half frame was sent at the rate of 60 frames per second, with blanking intervals between each frame. The blanking intervals consisted of 22.5 additional lines with no image information, so each half frame had a total of 262.5 vertical lines. The human visual system automatically blends the two half frames and we see it as a full frame with reasonably smooth motion and free of flickering.

       

      Why are frame rates these days expressed as 29.97?

      In the development of Black and White TV technology, the bandwidth for the image was set at 5.5MHz, with a sound frequency set at a particular frequency separated just enough from the image bandwidth to prevent interference between the image and sound.carriers. With the introduction of color, space had to be allowed for the color sub-carrier frequency, and to prevent interference with the Black and White luminance (brightness) image and sound carriers, the NTSC TV standard was modified from 60 half frames per second to 59.94 half frames per second, or from 30 full frames per second to 29.97 full frames per second.

       

      This is why video camera specifications for interlaced video settings on NTSC specify 60i as 59.94i, and 30p as 29.97p. For prosumer cameras they specify for film camera compatible frame rates, the 24p as 23.98p under 60i setting. The reason for the slight reduction in the frame rate, was to accomodate the color information, whilst maintaining backward compatibility with older Black and White TV sets.

       

      High Definition TV sets, even those with 1920 x 1080p LCD panels, receive broadcast TV signals as 60i (59.94i) signals to maintain backwards compatibility with older color Standard Definition TV sets; essentially the High Definition half frame interlaced images (1920 x 540) have their resolution reduced by a Standard Definition set top box, and the same frame rates are used for display by these older TV sets.

       

      I'm not certain if the situation is different when connecting a wide screen HDTV, using an HDMI connector to a Blu Ray player, or a PS4, if the information is sent using 60i or 60p or higher (60 full frames per second) frame rates.

       

      Another feature TV manufacturers promote is the 100Hz or 200Hz smooth motion technology their TV sets can display, for smoother motion. On some Internet forums, some people have found the 100Hz smooth motion feature annoying to their eyes and prefer to leave it switched off, other folks don't mind this feature.

       

      The best decider are your own eyes. I'd suggest going online and researching as many online Internet forums as you can, where different PS4 owners discuss their experiences with their TV sets. From that, I'd generate a short list of TV brands and models, and visit as many different stores as you can to view the image quality and response to fast moving images, and judge which screens look the best to your eyesight, and further reduce your short list.

       

      Next I'd research online to find out how many HDMI ports (the more the better) each model has; if you can get a model with four HDMI ports, then you'd be doing well: one port for your Blu Ray player, one port for your PS4, one port for a laptop, and one port for a HD camera.

       

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