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VOD Surround Sound Issue

Discussion in 'DIRECTV HD DVR/Receiver Discussion' started by Variant, Mar 20, 2017.

  1. Variant

    Variant Cool Member

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    Watched "Passengers" this evening via VOD on my HR24-500. For some reason, the audio seemed to be playing out of every one of my speakers except for the rear right. I verified it was connected and working correctly, but throughout the whole movie that speaker just stayed silent.

    Afterward, read around and came across a post suggesting I try *disabling* DD on my HR24. Did so, and sure enough, the same movie played correctly across all speakers.

    Explanation I'm seeing is that someone at DTV probably reversed the audio streams and put PCM on the DD stream and DD on the PCM stream (mentioned on the ATT DTV forums, though not for this specific VOD movie).

    May help someone else!
     
  2. Rich

    Rich DBSTalk Club DBSTalk Club

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    If PCM was enabled you should still be able to use every speaker, no? You won't get 5.1 but every speaker should be outputting sound.

    Yet another reason why I don't bother with D*'s PPV.

    Rich
     
  3. MysteryMan

    MysteryMan Well-Known Member DBSTalk Club

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    Physical media (Blu-ray/4K Ultra HD). Still the best way of utilizing your Home Theater system.
     
  4. peds48

    peds48 Genius.

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    Well not really. Unless you are using some of the AVR fake audio modes.


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  5. Rich

    Rich DBSTalk Club DBSTalk Club

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    Yup, I rarely have problems with NF BDs. And they're a lot cheaper than PPV.

    Rich
     
  6. Rich

    Rich DBSTalk Club DBSTalk Club

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    Never saw a reason not to use the...don't see why you'd call them "fake"...I use them for normal sound on all content using a Sony AVR. If you have the speakers why not use them?

    Rich
     
  7. peds48

    peds48 Genius.

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    They are "fake" because the audio (PCM) does not carry the data for the individual speakers (surround sound), so the AVR makes them up.

    A stereo (PCM) signal only has left and right audio, anything besides that and is fake, not saying it doesn't sound good or bad, but the AVR is synthesizing or making up the rest of the speakers


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  8. inkahauts

    inkahauts Well-Known Member

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    Actually that's not technically correct.

    A simple example with two channel stereo. While they have only two channels discrete they can purposefully be mixed for receivers to pull out a middle channel from what's in the left and right. Also rears too actually. It's just not discrete and full range. But thy can purposefully mix a center channel into two channel stereo. That's where Dolby pro logic came from before digital created the ability to go discrete surround at full range.

    Add in a lot of the sound fields are meant to help the mixed sound recreate the channels as though they where in specific kinds of auditoriums etc.

    So calling them fake isn't really accurate.

    So I'd say what the op found was someone screwed up and he was getting 4 channel instead of 5 for dd on the movie. When he switch DD off he got a pro logic surround mode which is really the formate everything is mixed into for two channel stereo.

    I dont by this idea the swapped the formats. Not to mention all he needs to do is look at the front panel and see what format it says it's receiving.
     
  9. peds48

    peds48 Genius.

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    I used air quotes. "fake" refers to the fact that neither center or rears are included in the data stream, those are being ARTIFICIALLY created by the AVR.


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  10. inkahauts

    inkahauts Well-Known Member

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    And that's what I'm trying to explain to you. It's not artificially done all on the receiver side. The signal is mixed in a way that the receiver can tell what should go to which speakers. It's just no where near as good as true discrete. But the signal is mixed for receivers to know what sound should come from a center channel. It's not just guessing.
     
  11. peds48

    peds48 Genius.

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    Got it wrong again.
    From the Wikipedia

    In 2000, Dolby introduced Dolby Pro Logic II (DPL II), an improved implementation of Dolby Pro Logic created by Jim Fosgate[4]. DPL II processes any high quality stereo signal source into five separate full frequency channels (right front, center, left front, right rear and left rear). Dolby Pro Logic II also decodes 5 channels from stereo signals encoded in traditional four-channel Dolby Surround. DPL II implements greatly enhanced steering compared to DPL, and as a result, offers an exceptionally stable sound field that simulates 5 channel surround sound.

    Key word the is SIMULATES.....

    Keep trying all you want, but a stereo signal carries just two channels

    Dolby Pro Logic - Wikipedia


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  12. Variant

    Variant Cool Member

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    Wow, this spawned quite a discussion. :)

    I agree, BD is of course the preferred way to truly enjoy great movie audio (and video). I haven't used VOD much previously, but did in this case and just found it odd that one single speaker wasn't getting any audio. Pure speculation on the reasons for which I could certainly be way off, but things were definitely 'fixed' by disabling DD on the HR24.
     
  13. inkahauts

    inkahauts Well-Known Member

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    Did you even read what you just quoted? It even states what I have been saying, that Dolby pro logic isn't strictly 2 channel audio and the receiver just guesses. It says right there it can decode stereo signals with traditional dpl surround 4 channel encoding, which is what I have been saying all along. Most movies where encoded this way that where sold on vhs tapes and was the default sound format for a lot of the first dvds that hit the market, because most people didn't have DD receivers. Heck a lot of dvds only had DPL when they first hit.

    As a general rule, anything that was to be from a center channel is actually mixed identically in both left and right speakers, and honestly, I cant recall how they encoded the rears, but the rears where encoded so they where identical sound as well. And the surrounds and center are only highs and a little mids, only the left and right have full stereo range. That's the watered down version of how they did it, but gives you an idea.

    What they are talking about simulating is taking either a strictly 2 channel stereo signal or a dolby pro logic encoding and simulating it being a full 5 channel Dolby digital signal. That is what Dolby Pro Logic 2 is. That is simulated since no one can encode full range 5 channels without going to dolby digital or newer. That's similar to what dts neo6 does as well. Pro Logic is encoded from the source. That's not debatable, its how its done. Otherwise ti would have just been called stereo, and you wouldn't have seen discs and vhs tapes marketing that they where encoded for dolby pro logic surround sound. I have talked to enough people who engineered av receivers to know, oit was a huge deal to understand the technical ways they did all this back in the day. Which is a lot more reliable than Wikipedia, although this case, is actually correct and backs up what I have been saying, not what you are misinterpreting it seems.

    Doly pro logic is not identical to stereo but comes across in a traditional two channel stereo format that a pro logic receiver can then decode beyond what a traditional stereo receiver can, and give you more surround sound that just a stereo signal, but not nearly the level of Dolby digital. Personally id say its as close to a halfway point between 2.0 signal and a 5.1 signal as you can get.
     
  14. inkahauts

    inkahauts Well-Known Member

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    Did you enjoy the movie? Thats what matters most if you paid for it on vod. ;)
     
  15. peds48

    peds48 Genius.

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    Wow. Never seen so much BS in one post. Re- read again. Two different technologies at play. At home and cinemas.


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  16. inkahauts

    inkahauts Well-Known Member

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    Uh nope. Nothing to do with cinema. That's an entirely different ball of wax. What where you doing in the late 90s and early 2000s? I was selling and learning all the details of this stuff from the people who designed 5000 receivers and such. I studied the technologies. Sorry but you don't get it and how the different sound fields have evolved over the years that are in people's homes.

    Pro logic is surround sound that is encoded into two channel stereo. It was done because all people had was analogue and two wires to connect from a VHS player to a sound system.

    It allowed people with simple stereos to get stereo and people with the advanced Dolby pro logic receivers to get surround sound.

    And that's not to be confused with the noise stuff Dolby did for cassettes and such.

    I get the feeling you probably haven't heard of quadrophonic stereo either. Totally different but still a surround sound audio format from way back.

    You should try and understand what I'm saying before falsely claiming I'm talking about cinemas. I'm not at all.
     
  17. peds48

    peds48 Genius.

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    You should read the wiki again because apparently you dont get it. The signal coming out of the DIRECTV receivers are 2 channel stereo, then the AVR SIMULATES, using encoders and such a 5 channel signal. If what is coming out f the DIRECTV box is 2 channels but the AVR fills 5 speakers then that would be a "fake" signal on my books.

    Just because I wear I pilot suit, doesn't make me a pilot....ROTFLOL!!!!


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  18. Troch2002

    Troch2002 Member

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    You shouldn't put so much stock in Wiki...



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  19. Rich

    Rich DBSTalk Club DBSTalk Club

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    Not an audiophile, huh?
     
  20. peds48

    peds48 Genius.

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    You don't need to be an audiophile to understand physics.


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