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Thread: GOP error generated by imported m2v file

  1. #1
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    GOP error generated by imported m2v file

    When importing in DVDmaestro a SA m2v file generated by vsplit13c I get the following error:

    "Temporal References in GOP #14635(Zero-based) are out of sequence(0xc10b000a)"

    Any thoughts on its meaning will be much appreciated.

  2. #2
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    Not much to say other than this happens sometimes wether due to rain fade/crazy long GOP headers that are sometimes transmitted/sunspots/who knows and that jdiner et. all are working on keeping it from happening.
    Try to re-record this show and you can then get a usable stream.

    r

  3. #3
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    Originally posted by r00g
    Not much to say other than this happens sometimes wether due to rain fade/crazy long GOP headers that are sometimes transmitted/sunspots/who knows...
    But it's from an SA Tivo not a DTivo.

    We have SA posts in the DTivo area and vice-versa! Can get real confusing, huh!!!!!?!!!
    Philips Standalone v3.01 w/2-80G drives and Tivonet.

  4. #4
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    Whether is't from an SA Tivo or a DTivo shouldn't make a difference. The problem is in the original DTV datastream. An SA Tivo just drags the GOP fault along with the converted digital stream from the DSS receiver. Right now there's not a lot that can be done with a GOP fault in the streakm. I have heard that the latest version of MPEG2VCR supposedly has a GOP correction option included in the program but I haven't seen it yet. Can anyone out there confirm or deny this?
    Please don't PM me or any other members looking for personal assistance. You'll do better by posting (after you've exhausted the search feature, of course) and taking advantage of the collective expertise of the membership instead of a single individual that may or may not be able to help you. Thank you and enjoy your stay at DDB!

  5. #5
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    I know you're not going to like this, but what about using RMPEG to transcode it to 90% of it's original size? I have used it as a method of last resort on a couple of !@#$% ty files that just wouldn't cooperate, and it seemed to correct the errors.

    I know that correcting the GOP header without transcoding is far preferable, but at least this is something that I KNOW works - albeit introducing a generational loss in quality.

  6. #6
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    Originally posted by captain_video
    Whether is't from an SA Tivo or a DTivo shouldn't make a difference. The problem is in the original DTV datastream. An SA Tivo just drags the GOP fault along with the converted digital stream from the DSS receiver...
    But the DSS receiver is feeding analog video to the SA Tivo!
    Philips Standalone v3.01 w/2-80G drives and Tivonet.

  7. #7
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    But the DSS receiver is feeding analog video to the SA Tivo!
    True, but if there's a GOP error in the original DTV digital stream it's probably carried along with the converted analog signal. Converting the signal from digital to analog isn't likely going to make a GOP error vanish.
    Please don't PM me or any other members looking for personal assistance. You'll do better by posting (after you've exhausted the search feature, of course) and taking advantage of the collective expertise of the membership instead of a single individual that may or may not be able to help you. Thank you and enjoy your stay at DDB!

  8. #8
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    catain_video, since it is analog the standalone
    would not know the difference between
    a mpeg stream coming from a directv or coming
    from the output of a camcorder or other video source
    which is not mpeg

    so how could a GOP mpeg error be transferred over
    a format (s-video) that has no way of transferring mpeg
    related information.

    remember GOP is the term for Group of Pictures

    as in the frames IBPBP

    MPEG does not send the frames in the
    order that they are to be displayed. so when playing
    back it needs a buffer of the frames to be able to
    play them back in the proper order.

    and analog video is real time, in order.
    seeya
    cory

  9. #9
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    First let me state that I am in no way an expert on this subject and I am just expressing my opinion based on a few assumptions, so take it for what its worth.

    I am assuming that there is some glitch in the digital datastream that is causing a GOP error. The DTV digital data is converted from a non-standard MPEG2 format to an analog output by the DTV receiver. The SA Tivo takes the analog feed from the DTV receiver and converts it back to digital using its own MPEG2 encoder.

    I am assuming that whatever is causing the GOP error is due to something in the video portion of the signal that is carried over from the original datastream. Remember that the digital data being extracted from the SA Tivo is an MPEG2 format. Since I do not know what the nature of the GOP error is and what actually causes it I am just making a WAG about what's going on. As I said, I'm no expert in this area so I could be completely off-base.

    I've noticed that GOP errors occur on my DTivo if I am recording a signal that contains an large amount of pixelisation. Surely, a DTV receiver cannot accurately convert such a garbled mess to a clean analog signal. A SA Tivo will similarly have difficulty converting a distorted analog signal to a digital MPEG2 signal, possibly resulting in the GOP error.
    Please don't PM me or any other members looking for personal assistance. You'll do better by posting (after you've exhausted the search feature, of course) and taking advantage of the collective expertise of the membership instead of a single individual that may or may not be able to help you. Thank you and enjoy your stay at DDB!

  10. #10
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    well a vcr or standalone tivo can record static.

    and that is not a video format but it can still record it.
    and play it back.

    just like a normal hauppauge card can record static as well.

    i do not own a standalone box but i know people who do.
    i do own a normal hauppage wintv card.
    a hauppauge wintv-hd card for full 1080i recordings.

    and also a hardware based mpeg2 encoder from dazzle
    (dvd creation station 200).

    i use that dazzle box to grab things that i cant
    convert using jdiners program. ie i get gop's or audio
    sync problems on something that i really want to put on dvd.
    what i do then is just play it on the tivo and
    capture it with the dazzle.
    then burn that to a dvd. i should have mentioned that before.
    the quality is actually very good. much better than the recordings
    that the standard hauppauge card can do.
    but you lose ac3 and some quality and it does it in
    real time so thats a pain.
    seeya
    cory

  11. #11
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    A VCR or SA Tivo will record whatever signal is fed to it as long as it has a synch signal present. Horizontal synch is a series of pulses that reside in between each line of video, whether there is actual image information in the line or not. The synch pulse tells the electron beam when to line back up with the edge of the display to begin its next horizontal scan or sweep across the CRT. If you've ever seen a cable TV signal that was scrambled it was most likely due to the fact that the horizontal synch signal was suppressed such that it could not be detected by the horizontal synch circuit of the TV or VCR it was being fed to. With no synch present, the electron beam scans at random, resulting in the distorted image. The image is restored by recreating the synch pulses so that each line can be retraced correctly, resulting in a stable image. I realize this was a bit off topic but I thought I'd throw it in to give you an idea of what's going on and why the image can be recorded and displayed, even if it's garbage.

    From what I know about MPEG2, a single frame is captured and then subsequent frames are processed by only capturing the delta info so that each frame does not have to be stored in its entirety. The delta info is applied to the first full frame to create the subsequent images. A new frame is captured at regular intervals, depending on the type of video being broadcast (more frequent for moving action; less frequent for static images). A GOP header is the full frame that precedes the subsequent delta info, hence the term Group of Pictures. If the image is garbled when the GOP header or subsequent delta image is captured, a GOP error occurs. If this garbled image is converted from digital to analog and then back again, the garbled image is still there. The Tivo creates a new set of GOPs when it reconverts the video stram to digital. If the garbled image is part of the converted stream, won't a GOP error be recreated as a result?

    As I said, I'm no expert on the subject but I've read a few posts here and there on the subject. If anyone can confirm or dispute my findings, I'd appreciate the feedback.
    Please don't PM me or any other members looking for personal assistance. You'll do better by posting (after you've exhausted the search feature, of course) and taking advantage of the collective expertise of the membership instead of a single individual that may or may not be able to help you. Thank you and enjoy your stay at DDB!

  12. #12
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    It appears that a Group Of Pictures is made out of a GOP header and, in the case of DVD NTSC standard, 18 I,P or B pictures where I is a reference picture and P and B are predicted pictures. The GOP header specifies the number of pictures in the group and and GOP synchronization information, i.e. when should the GOP play wrt the beginning of the video.
    As a stream is being manipulated, errors can creep in the header, e.g. the synchronization time gets fouled up(my error, I believe) or too many pictures are put in the GOP.
    Last edited by durian; 10-14-2002 at 06:01 PM.

  13. #13
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    Ok. Now that this has come up again. Send me a clip that has the GOP error in it. As small as still works through VSplit/TyTool to split. Meaning I don't need the output but the .ty file itself.

    Use TyFileSplit to get a chunk that can be processed and then loads and reports the GOP temporal error.

    Once I can see one that causes I can identify what it is and try to fix it. Todate no one has been able/willing to send me one. So the answer is at the moment Vsplit is unaware of them and is either causing them or simply doing nothing to fix them.

    If I can get more than one that would be even better... So everyone that is concerned about it take some time, make me some clips and we can hopefully get it resolved.

    --jdiner

  14. #14
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    Will do.

  15. #15
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    well the only further comment to make is that i can take a file
    that has a gop error when using tytool and
    when i play it on the tivo and record it to a hardware
    mpeg encoder over analog connection it
    records without any problems.

    the gop's dont seem to happen very often.
    in fact i think i have audio sync problems 10 times
    as often as i have gop's.
    wish i would have saved some of the ones with gop
    seeya
    cory

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