Garbled top line of Video

Discussion in 'TiVo Home Media Features & TiVoToGo' started by tim321, Apr 2, 2007.

  1. Apr 2, 2007 #1 of 40
    tim321

    tim321 New Member

    5
    0
    Apr 2, 2007
    Looking for some help on and issue I have when I download from my Tivo. The top line of the video is all garbled. Does anyone have any ideas on how to adjust for that?

    I am using and Intel Mac and using TivoDecoder Manager.

    Thanks
     
  2. Apr 2, 2007 #2 of 40
    steve614

    steve614 what ru lookin at?

    10,722
    0
    May 1, 2006
    Dallas, TX
    What you're seeing is the VBI, which is the info for closed caption, etc.
     
  3. Apr 2, 2007 #3 of 40
    ocntscha

    ocntscha Member

    149
    0
    Oct 22, 2003
    His garbled line, is your VBI, is my vertical blanking interval. Any idea why he's seeing it or what he can do about it?
     
  4. Apr 3, 2007 #4 of 40
    dlfl

    dlfl Cranky old novice

    8,844
    676
    Jul 6, 2006
    Dayton OH
    See this post. Do an advanced search with key words "top", "line", and "noise" in this (Home Media Features) forum. Apparently only some models produce this line and apparently the Desktop Plus codec filters it out (in some cases at least). I believe the VBI is always there in the TV signal but it doesn't show on normal TV's because of vertical overscan.

    If it's there in your files, I think the only way to get rid of it is to process them with a program that will crop them (e.g., gui4ffmpeg, aviSynth, etc.) This will take some time and may degrade quality -- is it worth it?
     
  5. Apr 3, 2007 #5 of 40
    WayneCarter

    WayneCarter Active Member

    1,290
    0
    Mar 16, 2003
    When the (analog) TV signal was being defined, an amount of time was allowed to account for the set-to-set differences in the time required for the scan to return (the scan generators were just analog oscillators adjusted by manually set reactors). As TV circuitry has improved (ie scan is now generated digitally based on a precise clock), the need for the "slop" (aka "Overscan") has largely gone away - and some of the overscan zone has been preempted by datalinks as mentioned in the earlier posts to this thread.

    If the "Static" didn't show on the TV, it will most likely not appear on the TV when the edited video is shown on a TV. If the video is being prepared for a digital display device, such as a computer, the "static" should be removed or masked.
     
  6. Apr 3, 2007 #6 of 40
    tim321

    tim321 New Member

    5
    0
    Apr 2, 2007
    I am putting this on my iPod and and I do see the VBI Line on the top. Any way I can get rid of it with out loosing video quality?

    Thanks - Tim
     
  7. Apr 3, 2007 #7 of 40
    Dan203

    Dan203 Super Moderator Staff Member TCF Club

    50,303
    5,782
    Apr 17, 2000
    Nevada
    If you upgrade to TiVo Desktop Plus it contains an extra plug-in which will actually trip off the top few lines of the video to eliminate this line. Alternatively there are some 3rd party media players out there that have an overscan mode which can eliminate this line as well.

    Dan
     
  8. Apr 3, 2007 #8 of 40
    tim321

    tim321 New Member

    5
    0
    Apr 2, 2007
    Do the offer TiVo Desktop Plus for Mac users?
     
  9. Apr 3, 2007 #9 of 40
    steve614

    steve614 what ru lookin at?

    10,722
    0
    May 1, 2006
    Dallas, TX
    I don't know about the 'plus' version.

    Check here.
     
  10. ocntscha

    ocntscha Member

    149
    0
    Oct 22, 2003
    Sigh, I see this question come up every so often, somebody says they are getting static at the top, a hoard of people pop out of the woodwork to say its the vbi, its the vbi, its the vbi, just move along folks. Like seeing the VBI in your downloaded videos is as normal as breathing. And thats it, its dropped for another month or two until someone else asks the same question.

    What I've never seen answered is why do only some people see that static in their downloads? I'm making an assumption here, I'm assuming the vast majority of people never run into this problem, I never have and I figure if it was a normal occurence I'd see FAR more chatter about it on these forums than I do. But everytime it comes up, everyone responds like it is normal. I get the whole VBI explanation but to me its not much of an explanation. Ok fine, we have the technical term for what the static is, but does anyone have a credible reason why only some people see it? To me it seems something must be wrong. The TV broadcast is out of specification, their cable company is screwing up the signal, maybe these peoples Tivos are defective, or maybe its just certain video codecs that are problematic.

    Or, maybe you guys do all routinely see that static and just by some dumb luck I've never run into it?
     
  11. jmemmott

    jmemmott New Member

    393
    0
    Jul 12, 2003
    Santa Cruz, CA
    If you did dig deeply into those posts, you would find that attempts have been made to answer your questions as well but the VBI idea seems simpler and resonates in this forum so it survives. Is it VBI, I suspect that it is not – or at least not what people think of when they traditionally talk about VBI. Most of the VBI data such as closed captioning is stored elsewhere in the MPEG stream and the information content of the “static” line is a little to limited to account for all of the information needed to reproduce the VBI content. My own speculation leads to information needed for Tivo popup ads and similar content.

    I would also label it an artifact. The content of the static line is handled at the hardware level in the Tivo. The older “240” Tivos with a different Mpeg encoder do not create it. The series two’s starting with the 540’s which use a newer Broadcom chip set all seem to create it.

    There is no such thing as overscan in an mpeg file and all video stored on your tivo is a type of mpeg file. When the analog signal is encoded to mpeg, this information is intentionally added as the first scanline of every mpeg picture. When the Tivo plays the video back, it strips off this scan line and uses the information for some thing else.

    When the series 2 was first designed, no one was expected to take the video off the box so the existence of this noise in the first scan line didn’t matter. With the release of TivoToGo it showed up as an annoyance that Tivo has tried to address in the plus version of the Windows software. It can’t be resolved in other versions because it is burned into every picture by the hardware. The only choices are to use a decoder and/or player that mimics the hardware and strips the first scan line ( plus version, et. al. ), re-encode or touch up every picture ( DVD software ) or live with it.

    You are also right that every so often someone new rediscovers all of this and the discussion reoccurs until everyone realize these are still the only options and chooses their own most acceptable solution...
     
  12. rambler

    rambler Member

    488
    1
    Dec 3, 2005
    Tivo should give away the Plus version of TTG to owners of the 540 models (like me). How about it Tivo? That line is annoying!!
     
  13. ocntscha

    ocntscha Member

    149
    0
    Oct 22, 2003
    Thanks for the informative response jmemmott. Wow. The only Tivo I have is a 240 Series which apparently explains why I've never seen any static line, ever, Plus version of Tivo To Go or not.

    I had absolutely no idea the static line actually is par for the course with the 540s which is why I was so incredulous about the "normal as breathing" sentiment I see expressed every time the topic comes up.

    Hmm, well then out of the possible explanations I offered in my previous post it sounds like "these peoples Tivos are defective" is likely the correct answer. I had no idea "these people" was all 540 owners.

    The older Series 2s transfer to a PC fast and without static, the newer Series 2s transfer slow and with static, the Series 3s don't transfer at all. :thumbsdown: :thumbsdown:
     
  14. steve614

    steve614 what ru lookin at?

    10,722
    0
    May 1, 2006
    Dallas, TX
    Yeah, 540 owner here. I've always accepted the VBI was "the static" I see.
    Most of the time, I don't even notice it, unless the show I'm watching doesn't catch my interest.
    What I see when I really concentrate: The top line looks like a squished version of timecode information like you see at the bottom of some DVD movie deleted scenes.
     
  15. greg_burns

    greg_burns Now in HD

    6,392
    2
    May 21, 2004
    Slower...
    My 240 has the line in downloads last time I checked, IIRC.
     
  16. ocntscha

    ocntscha Member

    149
    0
    Oct 22, 2003
    If there's a point in telling us you don't know whether your 240 exhibits the line problem or not, I'm missing it.
     
  17. Hash

    Hash CMD-82 ECM

    55
    0
    Apr 6, 2006
    I have done video capture and editing for a number of years now. This "static" is not unique to TiVo video files. EVERY capture card or tuner card that I have ever used produced this embedded information. The fact that the older TiVos did not produce a video file with this is not an indication that they were better - but, that they were worse. Those units produced a file that was less faithful to the original broadcast. If anything, a TiVo that doesn't produce this would be "defective".

    Well, as for getting rid of it - if you are encoding to an AVI file, any "decent" video editing program (I use the free VirtualDub) will have a 'crop' feature. That will do it. If you are staying with MPEG, you will most likely see a significant hit in video quality if you try to edit it out, as decent MPEG2 editing / encoding programs are still hard to find.

    Hash​
     
  18. ocntscha

    ocntscha Member

    149
    0
    Oct 22, 2003
    Do you have a way of interpreting the embedded information in a .tivo file? Assuming for the sake of argument that the static actually is embedded information, if there's no way to interpret the meaning of that information then its really nothing more than useless static.
     
  19. greg_burns

    greg_burns Now in HD

    6,392
    2
    May 21, 2004
    Slower...
    My point was that people were stating this was only a 540 problem. It is not.
     
  20. ocntscha

    ocntscha Member

    149
    0
    Oct 22, 2003
    Says the man who yesterday doubted his recollection. Which is it, your memory suddenly improved overnight or you've gone and verified the 240/static problem first hand?
     

Share This Page