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Author Topic: Extracting Analog Audio from HDMI  (Read 13057 times)

Dave Gunnell

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Extracting Analog Audio from HDMI
« on: January 23, 2013, 09:16:19 pm »

Hi All:

I provided audio and video projection for an event last weekend, and one of the presenters showed up with a presentation on his iPad 2.  I had the Apple widget that provides an HDMI jack, but it later occurred to me that I have no way to break the audio out of that stream (luckily his presentation did not have any audio content).  My projector is DVI input as well (no HDMI), so it cannot break the audio out for me.

After the gig I did some looking around and came across this box from Calrad.  Also saw an almost identical item on Markertek (likely from the same manufacturer).  Also found this one on the B&H website.  Anyone ever used any of these?  Is there something else out there that I should be looking at?  I would prefer a unit from a name-brand manufacturer (with XLR outputs), but I don't see much out there...

Thanks.

Dave
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Greg_Cameron

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Re: Extracting Analog Audio from HDMI
« Reply #1 on: January 23, 2013, 11:25:10 pm »

Since HDMI is technically a consumer interface (now more pro-sumer), there aren't a whole lot of full pro accessories. My day job makes several devices that provide  HDMI functionality, but only the top end frame synchronizer provides balanced audio extraction. I'll mention the idea of an HDMI audio extractor with balanced audio for our mini converter line to our marketing and engineers to see if they think their might be a viable market for it.
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Ed Walters

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Re: Extracting Analog Audio from HDMI
« Reply #3 on: January 24, 2013, 08:32:19 am »

Hi All:

I provided audio and video projection for an event last weekend, and one of the presenters showed up with a presentation on his iPad 2.  I had the Apple widget that provides an HDMI jack, but it later occurred to me that I have no way to break the audio out of that stream (luckily his presentation did not have any audio content). 

Be careful with the idea of pulling the audio from HDMI. I've found that a lot of computers/etc with HDMI outputs do not encode their audio onto the HDMI; it's pretty much a crapshoot if a given laptop has audio with it's HDMI, including some but not all Apple products.

Ed Walters
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Trevor Ludwig

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Re: Extracting Analog Audio from HDMI
« Reply #4 on: January 24, 2013, 10:17:45 am »

Does plugging HDMI into an iPad disable the phones jack completely?

Hi All:

I provided audio and video projection for an event last weekend, and one of the presenters showed up with a presentation on his iPad 2.  I had the Apple widget that provides an HDMI jack, but it later occurred to me that I have no way to break the audio out of that stream (luckily his presentation did not have any audio content).  My projector is DVI input as well (no HDMI), so it cannot break the audio out for me.

After the gig I did some looking around and came across this box from Calrad.  Also saw an almost identical item on Markertek (likely from the same manufacturer).  Also found this one on the B&H website.  Anyone ever used any of these?  Is there something else out there that I should be looking at?  I would prefer a unit from a name-brand manufacturer (with XLR outputs), but I don't see much out there...

Thanks.

Dave
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Tommy Peel

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Re: Extracting Analog Audio from HDMI
« Reply #5 on: January 24, 2013, 10:21:33 am »

Be careful with the idea of pulling the audio from HDMI. I've found that a lot of computers/etc with HDMI outputs do not encode their audio onto the HDMI; it's pretty much a crapshoot if a given laptop has audio with it's HDMI, including some but not all Apple products.

Ed Walters

This is definitely a problem; I've got a mid 2009 Macbook Pro and it will not output audio over HDMI. I know the newer Macbooks will(maybe 2010 and newer; a Google search should tell) and there are some adapters for Macbooks that get the video from the Mini DisplayPort and audio from a USB sound card and combine the 2 into a HDMI output. I think that all iPads will to audio over HDMI however other laptops are a crapshoot.
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Jordan Wolf

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Re: Extracting Analog Audio from HDMI
« Reply #6 on: January 24, 2013, 10:25:19 am »

Be careful with the idea of pulling the audio from HDMI. I've found that a lot of computers/etc with HDMI outputs do not encode their audio onto the HDMI; it's pretty much a crapshoot if a given laptop has audio with it's HDMI, including some but not all Apple products.
Ed,

That is definitely something to think about.  I have access to an iPad 2 with the HDMI dongle; I'll have to experiment with it next week while at work.

I would think that an external sound card could be used in conjunction with HDMI outputting video, but that's an assumption I'd rather not make in the middle of AV trench warfare.  I have a friend at the local Apple store; maybe he can help me through various HDMI hookups to see how they fare.
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Benjamin Krumholz

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Re: Extracting Analog Audio from HDMI
« Reply #7 on: January 24, 2013, 06:04:18 pm »

You could plug the HDMi into a small tv or monitor that has rca or a headphone jack

Hi All:

I provided audio and video projection for an event last weekend, and one of the presenters showed up with a presentation on his iPad 2.  I had the Apple widget that provides an HDMI jack, but it later occurred to me that I have no way to break the audio out of that stream (luckily his presentation did not have any audio content).  My projector is DVI input as well (no HDMI), so it cannot break the audio out for me.

After the gig I did some looking around and came across this box from Calrad.  Also saw an almost identical item on Markertek (likely from the same manufacturer).  Also found this one on the B&H website.  Anyone ever used any of these?  Is there something else out there that I should be looking at?  I would prefer a unit from a name-brand manufacturer (with XLR outputs), but I don't see much out there...

Thanks.

Dave
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Thomas Dameron

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Re: Extracting Analog Audio from HDMI
« Reply #8 on: January 24, 2013, 06:53:27 pm »

On the show I'm on this week we have a presenter driving content from an iPad.  After looking into most of what's discussed below we found that an Apple TV is the best solution for our uses.  You add a wifi router and the iPad connects to the Apple TV wirelessly using Airplay.  HDMI is converted to DVI and into the switcher.  We got an inexpensive optical SPDIF to analog adapter to get the audio out.  The box also has coax SPDIF so it'll be useful with Ls9s putting the digital i/o to use later on.  I could have kept it digital between the console and the Apple TV, but I wanted the analog gain stage so I could have quick control when levels jump around for different clips.

It winds up being a few different bits and pieces, but all ones that have other uses down the road.  However, the whole kit is cheaper than any of the Aja/Extron/etc converters that are all one trick ponies.  The client was thrilled that the iPad could still walk about.  The main shortfalls is that it will only work with Apple devices, but that isn't a problem for our application.  Also, I've got hearsay that only the current iPad will work like this, and legacy devices may not.  The person didn't confirm, but they said that iPad 1 is audio only via Airplay.

thomas d.

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Ryan Peacher

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Re: Extracting Analog Audio from HDMI
« Reply #9 on: January 24, 2013, 09:27:52 pm »

The client was thrilled that the iPad could still walk about.  The main shortfalls is that it will only work with Apple devices, but that isn't a problem for our application.  Also, I've got hearsay that only the current iPad will work like this, and legacy devices may not.  The person didn't confirm, but they said that iPad 1 is audio only via Airplay.

thomas d.

The 1st generation iPad will do video over AirPlay... It cannot do "mirroring" over AirPlay...

Only the 2nd generation and up can do full "mirror mode" Airplay...

As far as the audio output through Apple devices... The setup that I run at our local downtown theater consists of outputting video and audio over HDMI, as well as optical audio out of our iMac... The setup that I put together runs 1080res HDMI video output with embedded audio into an HDMI to HD-SDI box, and into out matrix system throughout the building... At the same time, the iMac is running optical audio out via the built-in mini-TOSlink connector (which is made into the headphone audio out jack), into our cinema audio system...

The iMac is setup in the Audio/MIDI setting utility to be a multi-output device... This allows me to be able to send the audio out the Mini Display Port through an HDMI adapter, and onto the rest of the building via HD-SDI, as well as simultaneously sending audio to our Denon DN-A7100 pre-amplifier...

If you need to send analog out instead of optical via TOS-link, you can do the same and use a regular 3.5mm TRS  cable into a DI or console... You should be able to do the same with a USB audio interface as well (as far as doing a multi-output device in the Audio/MIDI utility)...

If you want any screen shots of what I am talking about as far as the multi-output setup, just let me know!
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