Playback Quality Issues

Discussion in 'Apple TV and Home Theater' started by rscott505, Mar 21, 2008.

  1. rscott505 macrumors member

    Joined:
    Feb 11, 2008
    #1
    I am overall happy with :apple:TV (about a 7.5 out of 10), but have some issues with playback which I'm curious to find out if others have similar issues and/or solutiosn to them.

    The first issue is that sporadically while watching movies and TV shows, I will get some distortion in the playback (usually starting at the bottom of the screen). It reminds of the old days when you had to adjust the tracking on a VCR. It's like a little distortion or wave. It's not on the screen for more than a few seconds, but it's somewhat distracting when it happens.

    I have checked my connections (HDMI cable) and they are secure. By the way, I have a 37 inch LCD 1080p television, and my ATV is set to playback at 1080p as well.

    Just curious if anyone else has had this happen or knows what causes this and/or a solution.

    The second issue is a bit more bothersome. In scences that have black background or that are shot in low light, there is distortion in the picture. The best way I can describe it is to say that it looks pixelated, but that is not completely accurate.

    I wasn't sure if this is a limitation of digital files being shown on a larger screen TV or not. I kind of have the same problem on my iPhone and iPod, but since it's a smaller screen, it's not as noticeable.

    Again, any thoughts on the nature of this issue, or any cure would be greatly appreciated.

    Thanks in advance.
     
  2. killmoms macrumors 68040

    killmoms

    Joined:
    Jun 23, 2003
    Location:
    Washington, DC
    #2
    The first thing you're describing sounds like tearing, which happens when the playback device doesn't compensate for a difference in frame rate between the source material and the refresh rate of the screen and draws incomplete screen updates to the screen based on the refresh cycle.

    The second sounds like normal compression weaknesses on low bitrate digital video (in this case, macroblocking). What sorts of files are these?
     
  3. rscott505 thread starter macrumors member

    Joined:
    Feb 11, 2008
    #3
    The second sounds like normal compression weaknesses on low bitrate digital video (in this case, macroblocking). What sorts of files are these?[/QUOTE]

    Thanks for getting back to me. On this second issue, I am using files from iTunes, which I assume (I know it's dangerous to asssume, but it's my best guess) are mp4 files.

    If it's normal, then so be it. I can live with it. If not, is there any way to change settings to eliminate it.

    Also, does this appear in HD content from the movie rental store?

    As for the first issue, is there any fix for this?

    Thanks again.
     
  4. killmoms macrumors 68040

    killmoms

    Joined:
    Jun 23, 2003
    Location:
    Washington, DC
    #4
    You will likely not see macroblocking on HD rentals, because they are dramatically higher bitrate (and use a higher complexity subset of the H.264 codec's features).

    Essentially, the files that iTunes sells have to be compatible with all their portable devices. The decoding chips in those devices are limited in their power, since they have to be battery efficient. So all iTunes content for sale is encoded in what's called H.264 Baseline Profile (Low Complexity). This cuts out a lot of the codec's more processor-intensive features and leads to less high quality video.

    Videos which do not utilize these "shortcuts," if you will, will not exhibit these issues.

    As for the tearing issue, I was not aware that Apple TV had difficulty in this area. I haven't heard about it before, so I'm wondering if it's some strange issue with your TV or what.
     
  5. rscott505 thread starter macrumors member

    Joined:
    Feb 11, 2008
    #5
    Thanks for the explanations.

    Very informative and helpful.
     
  6. MikieMikie macrumors 6502a

    Joined:
    Aug 7, 2007
    Location:
    Newton, MA
    #6
    I would also recommend that you download a HD Video podcast from your Apple TV (or stream it if your connection is fast enough). I think you'll see what the Apple TV can really do.

    As killmoms said, the quality of the video files you are watching from the ITMS is way below what most of us experience. (Most of us rip and encode our owned DVDs.)
     
  7. rscott505 thread starter macrumors member

    Joined:
    Feb 11, 2008
    #7
    I would ripe and encode, but the one time I tried to do that with a movie I own, while the quality was excellent, I could not view the movie in full wide screen. There were two large black borders on the side.

    Is there a way to rip and encode so it shows in full wide screen, yet doesn't degrade in quality?

    (I'm using Handbrake for both ripping and encoding. I have just downloaded mac the ripper, and am trying to figure out how it works (although it doesn't seem difficult.))

    Thanks in advance.
     

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