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Audio & Video Out of Sync

Discussion in 'DIRECTV HD DVR/Receiver Discussion' started by HHH309, May 18, 2009.

  1. HHH309

    HHH309 Cool Member

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    Nov 9, 2008
    I have an HR20 HD DVR and have noticed for about 2 weeks that the Audio & Video seems to be out of sync. I have called Tech Support and they said to leave the TV on and unplug the receiver for about 30 seconds. Well, I did this a week ago and still have the same problem. Also, it seems to be worse on the HD channels. Has anyone else noticed this problem?
     
  2. gsslug

    gsslug Legend

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    Sep 13, 2006
    This is probably not going to be the answer to your problem but I had similar problem after doing a fast forward in a recorded show. When the show resumed the audio and video were out of sync. Pressing the button that caused the recording to jump back a few seconds would put them back in sync. Haven't had that problem for awhile so they must have fixed it in a software update.

    You didn't say if this was occurring all the time or only under certain conditions but I have an HR20 and did have this problem but only under the condition described.
     
  3. HHH309

    HHH309 Cool Member

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    Nov 9, 2008
    It's doing it all the time. It does when I'm watching Live shows and on programs I have on my DVR. By the way some of the shows on the DVR were from a month ago before this started. Now they are out of sync too.
     
  4. CopyCat

    CopyCat Member

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    Jan 21, 2008
    South Carolina
    The NBC feed (Channel 2) is almost always out of sync in Charleston, yet the OTA channel (2.1) is fine. The problem comes and goes.
     
  5. EricJRW

    EricJRW Icon

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    Jul 6, 2008
    Keller, TX
    This is something I see from time to time, not only on my HR21, but on my previous Samsung SIR-TS360. I chalk it up to at least two things:

    1. The digital stream itself. Sometimes the creation of the digital content just does not have the A/V in sync.

    2. The DVR itself seems to cause this problem. Sometimes hitting the pause button will help, but most times (at least for me) the only thing that really helps is a reset (I'm becoming more convinced a reset via the menus works better than a RBR).
     
  6. GaryAZ

    GaryAZ Mentor

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    Jul 30, 2007
    I don't know if your box is broken but this is going to happen from time to time in the world of HD video. A TV engineer told me with so many encoders and decoders in the stream, sometimes it's impossible to tell where the problem lies. I bought a home theater amp with adjustable audio delay so I can compensate. I don't need it very often but I'm glad I have it. Sync issues are really annoying - especially when watching a musical program.
     
  7. DeanS

    DeanS Legend

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    Aug 23, 2006
    The only time I experience audio sync issues is with 1080p/24 fps PPV movies (the ones that are pushed down by satellite and are located in the Top Movies folder) The first film I watched had no problem. But both "Slumdog Millionaire" and "The Reader" had slight lip syncing issues. It wasn't overly distracting, but I don't think it should be there.

    My HR20 is connected to my Sony KDL-40Z4100 via HDMI and Motion Flow is turned "off." The HR20 indicates a a 1080p source and the Sony display indicates that the material is in 1080p/24 fps. Is it worth trying to pursue a refund from D* or is this just an issue on only a few 1080p films or certain home setups?
     
  8. Spanky_Partain

    Spanky_Partain Active Member

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    Dec 7, 2006
  9. David MacLeod

    David MacLeod New Member

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    Jan 29, 2008
    possibly an audio receiver issue?
     
  10. DeanS

    DeanS Legend

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    Aug 23, 2006
    I don't think it is an audio receiver issue, that I can tell. My older HK receiver is decoding the Dolby Digital signal from the HR20 just fine on all other HD content. BTW, this issue is NOT related to local channels from D*. The audio sync issue is only with the new 1080p/24 fps PPV content I'm watching. I have been careful to make sure that motion enhancement on the LCD is "off". Should I also turn off "Cinemotion" when watching 1080p/24fps movies? Any suggestions are welcome.
     
  11. TomCat

    TomCat Broadcast Engineer

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    Aug 31, 2002
    You are right, at least about the source of these problems (not sure I'm with you on the reset).

    A and V are separate elemental streams in the digital world, but that there is a problem is a little ironic since they are encapsulated together into the same multiple-program transport stream. But of course packetized delivery implies that things arrive non-simultaneously, by definition. A system was needed to resync everything at decode, and that is something called PTS or Presentation Time Stamps which are little markers that are supposed to resync or adjust the audio stream timing to match that of the video at decoding.

    But there are two problems with that; providers are not real good about making sure these markers are there and available the way they are supposed to be, and consumer equipment is not good at tracking it, either (some providers and equipment are better than others).

    MPEG is elastic in that it can slow down and speed up. When encoding becomes difficult, it might slow down a bit. Audio stays steady, but sometimes can get ahead of video that slows down if not corrected by PTS.

    At about 20 ms early or 45 ms late, lipsync is detected (late is tolerated better because some delay is normal in nature). If the problem is chronic, it is probably the originator that is not keeping things in sync. If sporadic, it may be fixable as you say simply by pausing the DVR for a second or changing channels to force a resync (I like to do a "jump back"). These are issues that will get better as the technology improves, thankfully.

    One often-overlooked source of chronic lipsync is in flat-panel displays. There is always some latency in the video in them, especially in the cheaper versions such as Vizio and Insignia (otherwise good sets). Most sets have built-in audio delay to compensate for the video latency which puts things back in sync, but if you do not route your audio through the switcher in the TV set and instead route it directly into the AVR, then that delay compensation is not in play. Delay settings in the AVR could correct that, but I recommend pre-switching audio sources (that have associated video) directly in the TV first, and then taking a switched output to the AVR, which also avoids double switching when you change components.
     
  12. TomCat

    TomCat Broadcast Engineer

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    Aug 31, 2002
    There is the real possibility that "cinemotion" has a bit more delay than normal processing, as the rule of thumb is that more processing means more latency. But my guess would be that this would be minimal, and would not cause noticeable delay. Try it and see.

    A frame of video is 17 ms (a TV refreshes every 17 ms, IOW). In deinterlacing video (for instance, from 1080i to be displayed on a 1080p TV) there will be at least one frame of latency involved, as field 1 is held in a buffer while field 2 is acquired, and then the two are stitched together progressively as they are finally scanned. But additional processing could add as much as another frame or two. If that pushes audio out of that -20 ms to +45 ms comfort zone, it could be a contributor to the problem.
     
  13. DeanS

    DeanS Legend

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    Aug 23, 2006
    TomCat and others....

    Thanks for your input on my audio/video sync problem. I did a little experimenting last night. I played the opening portions of several 1080p/24fps PPV movies, listening to both the audio from the HK receiver (connected to the HR20 using the optical digital audio connection) and then the audio from the LCD TV speakers (which is through the HDMI connection from the HR20). The audio and video were in sync when listening just through the internal speakers of the LCD TV. However, the audio and video were out of sync using the DD feed from the HR20 to my HK receiver.

    In flipping through the documentation that came with the LCD TV (Sony KDL-40Z4100) I noticed that there is a digital audio out jack on the back of this LCD TV. Do you think my audio/video sync problem would be solved by connecting the LCD's digital audio out jack to the HK receiver rather than from the HR20? Would the Sony "pass through" the DD audio stream (3/2.1) from the HR20 to the HK receiver? The Sony is currently connected via HDMI to the HR20.

    Sorry for the long explanation, but this problem is bugging me. Plus it's quite an effort to access the back side of my HT setup so I wanted some assurances that this might work before I start to move furniture.

    Thanks.
     
  14. EricJRW

    EricJRW Icon

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    Jul 6, 2008
    Keller, TX
    It's been a while since I looked at specs or other's first hand experience with TVs, but the last time HDMI TVs with optical out were being discussed (in another forum), the optical out was usually only passing 2.1 or 2.0, not the full digital stream. I never understood this, but that's the way the TVs being discussed were working. Hopefully it's better now, so bottom line is give it a try and see what happens. But, since getting back there is tough...

    The other thing is to check your HK and see if there are any delay settings you can tweak. This is pretty common on digital receivers. I always thought it was delay from front to rear, but now I'm led to believe it is also to compensate for sync issues. Anyway, might be worth a look at the manual.
     
  15. CCarncross

    CCarncross Hall Of Fame

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    Jul 19, 2005
    Jackson
    99.9% of all tvs will not pass the DD signal back out of the tv from the digital output when using HDMI input. That digital out is really only for the sound from the tv's own internal ATSC tuner to get to an a/v system...so that idea will almost certainly NOT work. you didnt mention it, but does your HK receiver have a delay setting so you can adjust for it? you'll probably need to turn it on for the 1080p stuff and turn it off for all other material if its only when watching 1080p content. Luckily my Denon has HDMI inputs so it essentially handles the sync.
     
  16. DeanS

    DeanS Legend

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    Aug 23, 2006
    Well, my back is a little sore, but success!! The optical out on this Sony LCD TV passes the full DD output to my older HK receiver. In a classic case of RTMF I should have noted that Sony's setup instructions recommended this in the first place. It was simply a matter of disconnecting the optical out from the HR20 and using the optical out on the Sony LCD TV. Audio and video are in perfect sync in DD 3/2.1 for all sources, including the 1080p/24fps PPV movies from D*. Thanks for the advice, everyone.....
     
  17. EricJRW

    EricJRW Icon

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    Jul 6, 2008
    Keller, TX
    Good to hear!
     

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