DVD recorder audio in?

Discussion in 'Playback Devices' started by BobR, Nov 29, 2003.

  1. BobR

    BobR Agent

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    I've been looking at some DVD recorders and it seems that they have digital audio out but only left and right analog audio in. Does that mean that they only record in 2 channel? I'm not sure how I would use that. I currently run everything (DVD player, Dish PVR receiver) into my receiver and it gets decoded there. The receiver has digital audio out for recording but that's not much help if the recorder doesn't have digital audio in. It looks like I would have to use it like a VCR when recording and then what happens to all my 5.1 sound?
     
  2. Ken Chan

    Ken Chan Producer

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    Those two channels could contain matrixed Dolby Surround, but it wouldn't be 5.1. If you have 5.1 material that you want to record through the L/R analog ins, the 5.1 would be downmixed to 2.0 Dolby Surround. The DAC (either on the player doing to the downmix or your receiver) would convert those two digital channels into analog. The recorder would take the analog L/R and digitize it at 48KHz, and record that as PCM, or if it could, encode that back into AC-3.

    But once it is downmixed, you lose the true 5-channel separation, and the .1 LFE, which is always discarded when downmixing. You would still have surround sound. In other words, it would be very similar to recording on a VCR, which can record analog matrixed Dolby Surround.

    //Ken
     
  3. BobR

    BobR Agent

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    Thanks, does anyone know if there are any DVD recorders that do record 5.1? I assume that would mean a digital audio input. I'm just surprised that since 5.1 sound has always been one of the big DVD features, these recorders don't handle it.
     
  4. Steve Berger

    Steve Berger Supporting Actor

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    It's probably a licencing issue, I think the AC-3 encoding licence costs a fortune right now. A little like Adobe Acrobat , the reader (decoder) is free (cheap) but the writer/creator (encoder) is expensive.
     
  5. larry mac

    larry mac Stunt Coordinator

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    I too was interested in these a while back but when learned they don't record digital sound became disinterested. I'm not spending hundreds of dollars for dolby pro logic sound. That's just plain loco IMHO.
     
  6. Doug Pyle

    Doug Pyle Second Unit

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    I agree with larry. I am surprised & didn't know until this thread that 5.1 sound was not supported in current DVD recorders. I've been following DVD recorders with interest until this bit of info. No 5.1 = No sale.
     
  7. Scott Merryfield

    Scott Merryfield Executive Producer
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  8. Michael Reuben

    Michael Reuben Studio Mogul

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  9. Reece

    Reece Stunt Coordinator

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    I believe the only real reason that 5.1 encoded sound can not be transferred to the recorder is to discourage any piracy of commercial content like movie and concert dvds. However I agree with some of the other posts that this is a severe limitation for such an expensive device and IMHO unfairly punishes those consumers that only wish to use it for legal purposes.

    I was interested in the Panasonic DMR-E100HS . From what I read it has a firewire port on it so that you can download video and/or images from a camcorder or a digital still camera that has that functionality. When using this feature, since all content would be digital from the camcorder to the Panny DMR recorder, I wonder if it could also transfer 5.1 encoding as well? Since commercially produced content is encrypted and cannot be recorded digitally anyway, this would prevent piracy while allowing the home video enthusiast to transfer his/her original content to the device.

    Right now my purchase dollars hangs on this question.
     
  10. Kevin Chu

    Kevin Chu Auditioning

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    I have the Panasonic DMR-E60 and in the instruction manual it says that this unit is capable of recording 2 channel Dolby Digital. How is this possible if the unit itself does not have digital input; it only has digital outs? The only audio inputs are the RCA, white and red.

    For example, I have the Time Warner DVR box where some of the programs broadcast in 5.1 dolby digital sound but when record the show and play it back through my Denon 3300 receiver, it does not play back dolby digital?

    Can someone explain how this unit can record 2 channel dolby digital but not have a digital in?
     
  11. Michael Reuben

    Michael Reuben Studio Mogul

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  12. Kevin Chu

    Kevin Chu Auditioning

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    If the unit converts the analog signal to a digital one, does this mean that when playing the self recorded dvd, my receiver will read it as dolby pro logic?

    The reason I asked is because when watching programs broadcast in 5.1 dolby digital, my receiver reads "digital TV" however when playing self recorded disc it reads "pro logic".
     
  13. Ken Chan

    Ken Chan Producer

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    I'm confused. In your first sentence, you're asking "will it", but in the second, you're saying that it does.

    Technically, there's no such thing as "recorded in ProLogic". Audio can be recorded or encoded in Dolby Surround -- that's what it says on the logo. Years ago, there were non-ProLogic Dolby Surround decoders (four speakers: left, right, and a pair of mono surrounds, no center), but not any more. So the confusion is understandable.

    With an analog signal, like plain old non-digital TV or VHS, there's really no way to tell if the stereo signal you're getting is actually Dolby Surround. (There are logos at the ends of shows and on the box.) You can certainly turn on ProLogic decoding for a plain non-Surround stero signal, but the results might end up being "wrong", with things going into the center or rears when they're not really supposed to, but some people don't mind, so they just leave it on.

    With Dolby Digital 2.0, there's a flag, so a digital signal can clearly state (1) it is Surround (2) it is NOT Surround, and (3) don't know. For (1) and (2), the receiver could automatically switch to the right mode. As I explained in post #2 above, the 5.1 gets downmixed to 2.0 Dolby Surround, but once it gets converted to analog, the flag gets lost. With a DVD recorder, when it's converting the analog to digital, since there's no way to tell with an analog signal, the proper thing to do is set it to (3) "don't know". In that case, the receiver is free to handle it any way it wants. It might just be using whatever stereo processing mode you used last.

    I suppose it's also possible that the DVD recorder is improperly setting the flag to (1) "is Surround" and the receiver is acting accordingly.

    //Ken
     

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