De-embed Audio from an HDMI or SDI Stream into HAL

Often, the audio sources feeding HAL System inputs originate inside an HDMI stream from a video server or Blu-ray player. There are a few products that remove, extract, split or de-embed the HDMI audio so it can feed a HAL, RAD or EXP input. Typically, these devices include an HDMI output that passes the video content onto a display, and the audio is left in the HDMI output stream in case the display also wants to output the audio.

Take a deep breath, and keep repeating: "Us audio folks love HDMI..."

Take a deep breath, and keep repeating: “Us audio folks love HDMI…”

Example approaches:  

Use an HDMI-to-analog audio output gadget (below) to feed any RAD, HAL or EXP analog audio input.  To keep the audio in the digital domain, use an HDMI to S/PDIF output device supplying the RAD5 AES3 I/O.  See this RaneNote on interfacing S/PDIF to the AES3 found on the RAD5. To rack mount the RAD5, or any RAD, see this post.

As of this posting, here are a few products that remove the audio and output it as analog audio, digital audio, or both.

Kramer FC-46xl

Extron HAE 100

Crestron HD-DA-2

Misc (Amazon)

SDI Audio Extraction

If your application has the audio embedded in an SDI stream, here’s a couple gadgets to extract the audio. Both of these are 8-channel devices and include a DB-25 to XLR breakout cable. These are what you’d use, for example, if you’ve got 7.1 surround sound feeding a HAL-based cinema mastering suite.

For analog audio I/O with SDI – use AJA HD10AMA

For digital audio I/O with SDI – use AJA HD10AM

Caveat emptor

Complicating the above for HDMI applications is HDCP, the scheme that copy protects the HDMI data. Depending on the content being played and its source, HDCP may or may not prevent a system’s ability to play the content in question. Check with the video content provider to be sure – yet this is often nearly impossible. It’s the display device that initiates the negotiation that enables or disables the video and audio content from playing.

Surround sound protocols can also be persnickety. Be sure to check with the manufacturer of these digital audio extraction devices if you need them to pass on surround sound protocols to encoders.

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