BluRay player - frameskipping? Datarate too high?

Discussion in 'Blu-ray and UHD' started by prizm4, Jan 13, 2007.

  1. prizm4

    prizm4 Auditioning

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    Hi Guys,

    I was at a department store recently here in Australia, where they had BlueRay on display. They had an "Onkyo" BlueRay player and playing a demo disc on a large plasma.

    One thing I noticed was the framerate seemed to drop a bit with fast movement/panning - it was like the datarate was too high for the player to keep up (kinda like playing a DVD on an old Pentium II). Has anyone else experienced this jerkiness with fast motion? Maybe it was because it's a cheap no-name BlueRay player?

    Prizm
     
  2. JeremyErwin

    JeremyErwin Producer

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    yeah, onkyo's one of those shady Japanese brands...
     
  3. Chris S

    Chris S Cinematographer

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    Onkyo makes a blu-ray player..? I thought they were an HD-DVD supporter. [​IMG]
     
  4. Dave Moritz

    Dave Moritz Producer
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    I was under the same impresion as well that if it was an Onkyo player it was HD-DVD. At least thats was the news from CES that Onkyo was making a HD-DVD player. I am suprised that it would be out allready though.
     
  5. Adam Barratt

    Adam Barratt Cinematographer

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    Heh. That's the first time I've heard Onkyo called a "cheap no-name". [​IMG]

    Onkyo is a member of the Blu-ray Disc Association, but doesn't have a player out yet, and has only officially announced production of an HD DVD player at this point (as far as I know).

    Adam
     
  6. ChristopherDAC

    ChristopherDAC Producer

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    You may be noticing 3-2 judder, if the 24 fps film is being output at 60 Hz. Film doesn't really have a high enough framerate for smooth pans and fast motion, and the 3-2 thing just accentuates that. I still prefer it to 4% speedup.
     
  7. Cees Alons

    Cees Alons Moderator
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    That's not an alternative.


    Cees
     
  8. ChristopherDAC

    ChristopherDAC Producer

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    What do you mean? The two methods of mastering 24 fps material for TV that I am aware of are, one : for 60 Hz television systems, assign 3 and 2 fields (1 and 1.5 frame) alternatively per film frame, keeping the average framerate but introducing a cyclic tempo error, or two : for 50 Hz television systems, transfer at 25 fps, two fields per frame, keeping the relative timing constant but introducing a gross speed error.

    I'm aware that there are motion-compensating transfer methods, similar to those used for standards-converting television, but my understanding is that they yield unsatisfactory results (because of the low framerate of the source material). In this case, the conversion from 24 to 60 is being done in the player, so the only way to avoid it would be if the display accepted 24 Hz. If it did, the effect wouldn't appear. To output at 50 Hz, it would either have to speed up 4%, or insert a jump field twice a second, which would be rather noticable.


    EDIT : In case the above wasn't clear, what I mean is that the video display apparently will only accept 50 Hz or 60 Hz input. Since the conversion from 24 fps is being done in the player, it can either output at 60 Hz with 3-2 judder, or it can speed playback up by 4% and output at 50 Hz. I'm not perfectly sure that the second option would work, but it's conceivable. Of the two, my preference would be for the 3-2 effect, as I said above.
     
  9. Cees Alons

    Cees Alons Moderator
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    Yes, so given your video display system (60 fps or 50fps), one is not an alternative for the other.
    I'm even under the impression that most US consumers cannot buy a 50 fps TV set at all.


    Cees
     
  10. Don May Jr

    Don May Jr Stunt Coordinator

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    I have seen the "frame skipping" issue you mention and I, too, wonder if it is a data rate/buffer issue with higher bit rate encoding. I have a PS3 connected to my display via HDMI. The very first BLU-RAY disc I watched on my PS3 was KINGDOM OF HEAVEN (encoded in high bit rate MPEG2) and the frame skipping was so prevalent, that I turned it off after about 30 minutes. It is VERY slight, but it's there and it was pretty nasty during camera pans. For the record, I'm watching everything on an NTSC PS3 with an NTSC Sony LCD rear-projection.

    It's not a PS3 issue, either, because I noticed it on the first BLU-RAY demo disc playing in my local Best Buy when the Samsung player first came out.

    I did watch CRANK the other day and did not notice the problem, though. Maybe it's only on some of the earlier discs, or discs with high average MPEG2 rates?

    It's definitely there on some discs and definitely annoying. I have seen it on both the Samsung and the PS3. Even my bud over at DVDMANIACS.NET noticed it and called me immediately after he started watching a BLU-RAY movie (he wanted to see if I had the same problem).

    I'd just like to add, for the conversation about display methods above, etc... Why is it that I do not see these same issues on HD DVD discs and only BLU-RAY? I honestly believe that it has nothing to do with the way NTSC/PAL televisions display the pulldown, etc. If it did, wouldn't it be that way on HD DVD discs, too?
     
  11. ChristopherDAC

    ChristopherDAC Producer

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    Quite so. The original poster is, however, in Australia, and my impression is that HDTVs sold there, as in Europe, will accept both rates. Under such conditions a choice is possible, at least in principle.
     
  12. Chris S

    Chris S Cinematographer

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    Is it possible it could it be an issue with the MPEG-2 codec? Do you see similar issues on titles that are using AVC? That might explain why you aren't seeing similar problems with HD-DVDs.
     
  13. Karim Nogas

    Karim Nogas Stunt Coordinator

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    I've noticed this issue with both xXx and The Guardian, the only two discs I've watched so far (with Sony's player). Mildly distracting but thankfully it only happend a few times during the movie.
     
  14. Karim Nogas

    Karim Nogas Stunt Coordinator

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    Well, it's been 3/3, with the latest problem stemming from The Manchurian Candidate. Any quick cut scenes or panning results in the frame seemingly skip a bit and then my display informing me '1080i'. It is quite noticeable and the more action, the more likely it occurs. I'm connecting via component and have Sony's BD player with the latest firmware. There is no problem with SD-DVDs.

    Does anyone have a clue as to a workaround?
     
  15. Karim Nogas

    Karim Nogas Stunt Coordinator

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    I almost went through an entire viewing of Black Hawk Down last night without any frameskipping until near the end. The frame skips a bit and my TV then displays 'DTV - 1080i' almost as if the BR player is negotiating/handshaking with the component inputs of the TV.

    Could this be a problem with the display and NOT the player?

    Thanks.
     

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