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Dolby Digital Sync Issues - Help - Identify problem and how many affected..

Discussion in 'DIRECTV HD DVR/Receiver Discussion' started by rbootss, Mar 22, 2007.

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  1. mrb

    mrb Legend

    Sep 14, 2006
    It is not specific to HDMI or component...it's because of how long it takes to convert the video data to a picture on your hdtv screen vs how long it takes to convert the audio data to sound via your receiver. in general, switching between hdmi and component should not solve the problem...unfortunately.

    I think using a non-digital (red/white) cable from the HR20 to the receiver would maybe solve it, but then you don't have 5.1 or better sound to accompany the nice picture on the screen!

    just in the middle of growing pains of technology. to me it's the same as the fact that I can get the absolute best looking television picture for free over the air...but I need a antenna like from the 50s to get it and then I have to arrange it, re-arrange it, etc...to get the signal to come in. ironic, no?
  2. mrb

    mrb Legend

    Sep 14, 2006
    Yeah, I've seen that one online. No way my wife will let me spend another penny on the av system in our house. Got the plasma a few months ago, now getting "another receiver!!" (the HR20)...gotta make it work with what we have for now, but I AM glad to hear a real person's review of those audio signal delay boxes...maybe I'll sneak one in somehow. :)

    SENATOR Cool Member

    May 9, 2006
    I've had audio sync issues, but none that I could decisively label as a receiver issue, since it seems to only be affecting certain channels (HGC HD Preview and ESPN HD).

    SENATOR Cool Member

    May 9, 2006
    LOL... My wife just read me the same riot act after wanting to buy a 3rd optical cable. :D
  5. indirectv

    indirectv Banned User

    Mar 25, 2007
    Some people diss the sync boxes, but I had serious problems, and set the box for HR20 and DVD player (different sync gaps) and voila. Never touched them since. And there is a remote, so if you need to adjust on the fly, you can do it. They are much more effective than the built-in sync fixers on DVD players (which only work on analog sound, at least on my Sony DVD player) and HT receivers.

    I ordered the Felston, but it didn't work with my receiver. So I tried the Alchemy2, and it was great.

    I understand the money thing completely. My wife still rolls her eyes when I mention the sync box. But it worked for us, and she was happy about that. Good luck.

    Oh, I have the digital audio box (toslink and coax, one input for each), not the HDMI box. My HT receiver doesn't do HDMI switching.
  6. indirectv

    indirectv Banned User

    Mar 25, 2007
    You can get optical cables cheap. Try www.rameletronics.net
  7. armophob

    armophob Difficulty Concen........

    Nov 13, 2006
    Fort Pierce, FL
    DD Audio Sync Problem-

    I have to restart my receiver to get it to "see" the DD signal once and a while. I can't narrow it down to what I was doing at the time, because it happens occasionally and I don't notice till I get into the show.

    Audio Video Receiver Type-

    Sunfire Theater Grand II

    Audio connection to HR20


    Frequency of occurrence

    Someetimes when changing channels from a DD source to non-DD source and back

    HR20 Native on/off status

    Both - Native on

    Video connection status HDMI/Component

    Both - Component

    HR20 Software


  8. mrb

    mrb Legend

    Sep 14, 2006
    Well, I learned a good lesson last night in not trusting everything you read on these boards...and I taught it to myself.

    I went a bragged to a very good friend who KNOWS computers and film (he's an AFI film school grad and a Hollywood editor) and I was, ahem, schooled on the fact that my explanation of this wasn't quite right. I stand corrected...although my explanation was a whale of a lot easier to understand than his - which I have copied below for your education.

    At least I was right that it is the HD display technology that causes the lip sync issues...someday it'll be worked out.

    So, mea cupla friends...!

    Here's his response to my post:

    "found and read your posts, just to clarify for you:

    pullup/pulldown has absolutely nothing to do with a time delay in decoding and encoding. it is a physical placement or removal of frames in the signal chain to compensate for different frame rates without video stuttering. the simplest illustration of this is film/ HD to SD video. Film/HD runs at 24 fps, SD at 29.97 so a device that is "upconverting" 29.97 to 24 fps actually has to remove/combine frames from the SD video to get rid of them.

    therefore if you have a signal coming in that is at NTSC 29.97 fps your TV, if it has a 3:2 pulldown enabled, is trying to "upconvert it" by applying a pullup to 24 fps (it is removing 5.97 frames per second). Your audio system will not know this of course, because it is just sucking in the 29.97 audio from the same source as your TV, and your audio will be out of sync because IT is still playing at 29.97 fps whilst the picture is at 24 fps. that you suggest your TV plays it in synch makes sense because the TV is performing the pullup/ pulldown for the audio and the video.

    this has nothing to do with the time it takes to do the decoding or encoding. this is a transparent process that does not affect this issue and anyone who tells you that is lying, including the manufacturer of the so-called delay box which is in all likelihood pulling up or down the audio.

    it is just a question of frames being physically placed in the signal chain, or removed. things are initially close to being in sync but the differential in the frames per second mounts up over time so there is substantial drift and after a few minutes you can be several seconds out of synch.

    its worth mentioning that when an upconverting DVD player is upconverting, here's what the whole chain of events was (and this is only one example):

    24fps film (assuming it was a film) --> 24p HD master --> 29.97 SD master (adds in "fake" frames composed of multiple fields to make up for the 5.97 difference in fps -- "pull up")--> DVD --> upconverting player removes 5.97 fake frames per second ("pull down")--> 24fps display like your HD set.

    so even though the process on the display end involves "removing" frames it is really only removing frames that the process added in in the first place. so you can see where running something that originates at 29.97 through a process that removes 5.97 frames per second, while play audio alongside which is running at 29.97 seconds all the time, would cause things to go out of sync.

    and by the way you're not an idiot.... it took a whole class of grad film students in their 2d year to properly get a handle on this concept!!"
  9. w6fxj

    w6fxj DBSTalk Club Member

    Aug 10, 2005
    Roy - Welcome to the modern digital world!

    Your problem obviously is a Pioneer incompatibility with DireTV's DD protocol. Pioneer tech support is going to tell you that they have no "reported" problems. Just like DirecTV tech support says there are no problems with the HR20. Dolby just sells the license to use their technology. They do not hold Pioneer engineer's hands when they develop products.

    You should consider upgrading your AV receiver to a more modern HDMI capable receiver. I use an Onyko TX-SR803 and a TX-SR804. Both have very good HDMI switching and adjustable audio delay to compensate for variations in input and output equipment. These work with my HR10-250 and HR20-700 DVR's with my NEC 50XR5 plasma and Sharp LC-37 LCD.
  10. bonscott87

    bonscott87 Cutting Edge: ECHELON '07

    Jan 21, 2003
    I was thinking on this last night and was going to post a similar thing today.
    I don't want to get at whose "fault" it is for this but think about it this way:
    The HR20 doesn't have this problem except on this particular line of Pioneer receivers it seems. This would lead me to believe it's a Pioneer problem.
    On the Pioneer side they will say that their receiver works fine and it's DirecTVs problem.
    Now in my research I'll lay more blame on Pioneer here as there are reported problems with DD on these models from more then just the HR20 (DVD players and HR10's for example).

    It's possible that DirecTV could tweak something on their end with DD encoding to help but they then run the risk of breaking DD overall which in fact seems pretty solid. Why mess with something that only effect .005% of the user population? That would be my thought anyway.

    This line of receivers seems quite old as well. Reviews I pulled up date back to 2002. So it could just be a bug in the implimentation of DD at the time that Pioneer used and could be more of an issue as time marches on with newer equipment connected to it.

    My suggestion might be to upgrade to a newer receiver. I'll bet you can get one nowadays with twice as many features for half or third of the cost of it. I know it's hard to do that but I needed to do the same thing. I had a 6 year old Sony (I know, I was a noob with audio) and I just ran out of inputs plus DD started to act flacky. When I got the HR20 I replaced with a Yamaha. Was worth every dime.
  11. mrb

    mrb Legend

    Sep 14, 2006
    No, this issue affects many other brands of receivers. I have a Sony. Neighbors have Onkyo. It's not just Pioneer.
  12. bonscott87

    bonscott87 Cutting Edge: ECHELON '07

    Jan 21, 2003
    These guys problems are not the same as your problem.

    They don't have a problem with lip synching being off.

    Their problem is that the receiver isn't "kicking in" with DD and it's silent. In other words it either doesn't see the DD stream at all or it's getting confused and not decoding anything.

    I guess it's a lip synch problem if you consider there is no audio at all not being synced. :D ;)
  13. mrb

    mrb Legend

    Sep 14, 2006
    You're absolutely right, I apologize! I was reading another lip sync thread at another forum and got mixed up with this one. :)
  14. sigma1914

    sigma1914 Well-Known Member DBSTalk Club

    Sep 5, 2006
    Allen, TX
    I can't read, I was off topic.
  15. lambo881

    lambo881 New Member

    May 3, 2007
    I also have a Pioneer receiver, VSX-49TXi. Just installed my HR20-100 tonight and get the same problem. Damn frustrating...

    SWORDFISH Legend

    Apr 16, 2007

    Bonscott -

    This problem is not just with Pioneer receivers. From earlier posts in this thread:

    johern using a Onkyo TXSR674 loses sound and has to change signal input to get sound back.

    jimmyt using an Onkyo TXSR600 loses audio when changing channels and has to power down receiver to get audio back.

    armophob using a Sunfire Theater Grand II loses sound when changing channels and has to restart receiver to get sound back.

    The new guy (me) has the same problem. When I change from an SD channel to an HD channel, the center channel audio drops out. The only way to get it back is to change to a different audio signal then change back, or power the receiver off then on. The problem occurs intermittently and only occurs on HD channels (both MPEG2 and 4). I am using a Panasonic Home theater system (I don't have the model number with me) connected to the HR20-700 (current national release)with an optical cable.

  17. njohnson

    njohnson New Member

    Aug 11, 2007
    I really hate to reply to a banned user's post but I am concerned about his possibly misleading statement regarding two excellent products my company sells.

    He mentions the Felston delay box did not work on his receiver and he got an Alchemy which did. I recall this customer and he reported the Felston DD540 was only giving him some of the Dolby Digital channels and he exchanged it for the Alchemy DDL. We knew that wasn't possible because both the Felston and Alchemy delay boxes delay the individual bits in the s/pdif bitstream. They never decode the audio and therefore can not discriminate the channels. If they upset the audio stream in any way you would get a pop or drop out and not the loss of only one channell as he reported. He had some other problem but in this case our "customer is always right" philosophy has resulted in this post with misinformation. Both Felston and Alchemy products are excellent and we have never seen a case where either one of them would not work with a users receiver as long as it was digital audio (s/pdif). Neither of them delays analog audio.

    I also realize this thread is a blend of two unrelated topics - one where a receiver isn't decoding the s/pdif audio and is losing sound completely whih has nothing to do with lip-sync and discussions about lip-sync itself but I felt I should correct this post.
  18. mluntz

    mluntz Icon

    Jul 13, 2006
    The only issue I have is sometimes is on the crappy TNT HD. Serious lipsync issues at times! No other problems that I have noticed anywhere else.
  19. kaa1954

    kaa1954 Legend

    Sep 23, 2006
    I am also experiencing audio pops & loss of audio issues with my 49TX. I noticed it yesterday when I went into media share to play music. The funny thing is that I would loose audio every time a new song starts. Now this deviates from the original set up issue of going from a DD signal to a non DD signal which actually does set up the initial problem.
    As a work around I can tune to a non DD station before accessing media share & all songs play properly.
    This was also an issue on the HDTivo HR-10 also but was corrected in some of the latest updates.(6.3d?) It is definitly a compatability issue that I think the HR20 folks should address.
  20. DeathRowsFinest2g

    DeathRowsFinest2g Mentor

    Sep 13, 2007
    A problem i have, is there is a delay in the switch of audio from my receiver and my HR-20. From DD to PCM. ie watching Prison Break in DD and then going to analog audio in the commercials. The didn't happen with my old Time Warner DVR.
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