Mirrored Display: Video ... and sound?

Discussion in 'Apple TV and Home Theater' started by idunn, Jun 17, 2010.

  1. macrumors regular

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    #1
    I know this subject has been addressed elsewhere, but please bear with me as possibly not in this manner. Or I'm just missing something.


    Question: If mirroring the display from a MacBook to an HDTV how would it be possible to have both video and audio if using separate cables for each?

    There is no issue with video using a mini-dvi to HDMI cable. However without the combined video and audio of the newest mini-dvi ports, a separate audio cable is required. I used a 3.5 mini-plug from computer to white and red RCA jacks for the HDTV, but achieved no sound in trying near every configuration: video in (sans yellow video, since HDMI), component, HDMI (in conjunction with).

    Instructions for this Sony HDTV indicate computers should be connected via VGA (video) and a 3.5 mini-plug (audio). Without these cables I desisted, but VGA would be inferior to HDMI in any event, and video alone works fine via HDMI. I might perhaps use the 3.5 mini-plug (sans VGA), but this likely will not work because only ONE input is allowed at a time. But in such configuration two inputs would be required, HDMI for video, and a separate input (PC) for audio. The HDTV never recognized the RCA audio cable at any input, so unable to select in any event. Possibly a defective cable, but it is new. Or perhaps for a computer it will only accept the VGA/mini-plug configuration for some reason?

    The RCA inputs in conjunction with an HDMI port are indicated for use with a satellite/cable box, with no other HDMI connected. Use of an HDMI input from Comcast, an HDMI input from computer, and use of these two RCA inputs had no better effect, no sound.

    Apparently a newer computer with a mini-dvi port capable of combined video and audio would make this a moot issue as one HDMI connection would suffice, just as that from Comcast does for its video/audio signal.

    But it is often said on this forum that video and audio must be accounted for separately, as more usually the case. Since they require two separate inputs, and the HDTV can only select but one at a time, how could this ever work?


    Thanks
     
  2. macrumors demi-god

    CWallace

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    #2
    Does your Sony share audio inputs between video inputs?

    My Sharp shares a 3.5mm audio input between one of the HDMI and the VGA input. Within the TV setup you assign which video input gets the audio.
     
  3. macrumors regular

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    Probably not shared

    Apparently it does not share video and audio inputs.

    There are segregated areas, such as Video In, Component In, PC In, HDMI in, Audio Out, etc. Where applicable there are ports in each area for video and audio. This would discount my first notion, which did not work, of using HDMI In for video and the RCA video/audio port of Video In for audio, this as both areas easily accessible on the side of the HDTV. However using HDMI and the RCA ports in the HDMI In section revealed no better result.

    As before, have tried about every configuration save the Mini-Plug audio of the PC In section, but will not use VGA for video, and even if audio happened to work from this port still the issue of how to select that in conjunction with HDMI, with but one input allowed. The HDMI In section seemed the best hope for a combined video/audio signal.
     
  4. macrumors demi-god

    CWallace

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    #4
    Fortunately, my new iMac sends video+audio out over the Mini-DisplayPort connector so I now just use an MDP to HDMI cable and it's golden.

    (I used to use a 15" MBP, so I had DVI to HDMI for video and a 3.5mm to 3.5mm cable for audio)
     
  5. macrumors 68020

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    #5
    could you post the model # of your TV?

    you could use something like this which will combine the audio and video output of your mac into one HDMI cable.
     
  6. macrumors 6502

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    #6
    I have my 27 inch iMac connected to my 47 inch LG HDTV in the living room. They're actually each in different rooms but since there's only one wall between them I simply have an HDMI cable going through the wall to connect them. I also use a mini display port to HDMI adapter (in my case the Griffin video converter) that transfers both video and audio over the single connection. Both the sound and video quality are quite good.

    However, one issue that I have yet to completely resolve is that turning on the HDTV always causes my iMac screen to flicker blue on and off. After about a minute the screen returns to normal but only sometimes. Other times it stays stuck on blue, forcing me to restart the computer. Obviously this is some kind of resolution switching issue because the blue flicker is what normally happens briefly when you switch the resolution on any Mac. And since the HDTV is essentially an external monitor to my iMac there's some kind of confusion going on there.

    This seems to happen whether I have mirror mode on or off and no matter what resolution I set my iMac to prior to turning on the HDTV. And once again it doesn't happen all the time. Since you're doing this with one of the new iMacs as well I'm curious if you have had any similar issues and/or have any suggestions for resolving this?

    I've already tried repairing disk permissions, resetting the PRAM, and doing an SMC reset to no avail. I should note that I also had a similar problem with my late 2006 iMac running Leopard although it was much less frequent.

    Any suggestions would be greatly appreciated. :)

    -PN
     
  7. macrumors regular

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    #7
    Converting Adapter

    The HDTV in question is a Sony KDL-46Z4100.

    Thank you for reference to the Mini Audio/Mini-DVI/HDMI converting adapter. My understanding others had connected computer to HDTV with separate video and audio cables, but since that has yet to work this adapter seems a likely solution. Since I have the separate cables, using them would be preferable if someone knows how.

    Just a note that I do experience blue screen flicker when first making a connection between computer and HDTV. It is surely a synchronizing of resolution between the two. Thankfully nothing freezes or other issues.
     
  8. macrumors 68020

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    #8
    from page 11 of the manual
    http://www.docs.sony.com/release/KDL40Z4100.pdf

     
  9. macrumors regular

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    That tried

    Yes, one of the configurations I tried, and seemingly most plausible if using HDMI. However, no sound. Two other HDMI ports were also in use, one for Comcast and one for a DVD player. Possibly a conflict there, although not sure why, as only one input can be selected at a time.

    Thank you for reference to the Sony pdf; it appears to be the same as supplied paper instructions.
     
  10. macrumors 68020

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    #10
    try plugging into another audio source, like an ipod or something. to see if you get audio with HDMI4.

    try headphones into your macbook to make sure something is actually coming out.

    check the volume on the macbook, sometimes it adjusts the volume when you plug something in.
     
  11. macrumors regular

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    Signal fine

    Yes, there is correct audio output from the MacBook. Checked this with headphones to verify, while sending video signal to HDTV via HDMI. So use of headphones one solution. Another would be separate audio equipment. But would be nice to use HDTV's audio as it is convenient and rather good.
     
  12. macrumors demi-god

    CWallace

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    #12
    I get the momentary blue screen in both Mirror Mode and "Secondary Monitor Mode", but it always pops right back to the desktop. If I am in Mirror Mode, my iMac display drops to 1920x1080 while the HDTV is receiving a signal. If I am in "SMM", it stays at 2560x1440.
     
  13. macrumors 6502

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    #13
    I finally have discovered some kind of pattern at least that suggests what the cause of the issue might be. It looks like when my LG HDTV is set to the input that is used for my iMac (HDMI 2) when the TV is turned on then everything works as expected, just like you described above. I've been able to turn on the TV successfully a bunch of times in a row this way with no issues. But when the TV is turned on with it set to the input that my cable box is plugged into (HDMI 1) the issue occurs most of the time.

    I'm not certain why this is the case but at least in the meantime I need only remember to select the HDMI 2 input before turning the television off so it's already on that input when the television is next turned on then I won't freeze up my iMac. I will still investigate this, and perhaps even call Apple, but it least it appears I won't have to worry about any more crashes.

    -PN
     
  14. macrumors 601

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    #14
    I know it doesn't say it in the manual, but could there be a option on the Sony's menu that toggles on/off the audio jacks for HDMI4? If it's missing from the manual, it wouldn't be the first time.

    On my Sharp, Input4 HDMI has aux. audio inputs, but I have to turn them on using the menu. After all, unless the audio jacks are auto sensing, how would the TV know if you're using a separate audio signal or using audio via HDMI?
     
  15. macrumors regular

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    #15
    Maybe


    Good idea. Could be the Sony doesn't automatically detect the audio RCA input in conjunction with HDMI video input. I see no obvious provision for manually selecting the RCA input on/off; the closest possible may be in Channel Selection where new antenna or cable channels can be checked for. Of the four HDMI inputs only number 4 seems to associated with the RCA inputs, due position and design. I tried this configuration without luck, but as noted perhaps without the RCA inputs being recognized.
     

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