Originally featured on BroadcastEngineering.com
Miranda adds 5.1 audio processing for HD broadcasters
Miranda Technologies has added new 5.1 audio processing capabilities to its Densité series signal processing modular range at NAB, which address widespread problems experienced by many broadcasters with audio for HD.
The new device addresses three problems: loudness measurement and control; handling Dolby metadata; and maintaining 5.1 surround sound when playing out stereo legacy content.
Using Densité series DAP-1781 audio processing module, broadcasters can now perform loudness measurement and correction, Dolby E and AC-3 encoding and decoding, and high-quality 5.1 to stereo downmixing and stereo to 5.1 upmixing.
The DAP-1781 is an eight-channel digital audio processor, which can perform accurate loudness control and measurement, using ITU-R BS.1770 or LEQ(A). The loudness value can be used to trigger an alarm if the value does not match with the associated metadata. It can also go one step further and insert corrected dialnorm metadata into a program stream, or alternatively modify the audio levels of the program to match a target dialnorm value.
The new module performs high-quality Dolby E and/or AC-3 decoding and encoding directly on the card. By pairing two DAP cards to a video processor, it is possible to perform both decode and re-encode in a single functional block. This eliminates the need for separate encoder and decoder boxes and greatly simplifies the system design and its ongoing operation. The DAP solution was developed by integrating encoder and decoder submodules designed by Dolby, thus ensuring the same quality end users have come to expect from dedicated box encoders and decoders.
The DAP processor can also perform the highest quality stereo to 5.1 upmixing using Linear Acoustic upMAX technology. A channel surround field synthesizer creates an infinitely adjustable, multichannel signal that is downmix-compatible. This makes it ideal for converting legacy two-channel audio content into 5.1 programs.
Visit the BE@NAB blog for an inside look.
View Miranda's Xmedia suite at NAB2008.