Posted on March 3, 2015 in ATSC News
ATSC 3.0 Audio System tests will be world’s first to evaluate immersive sound for a broadcast television standard
From Suzanne Vega to the Henry Mancini orchestra, from Robert Plant to Fleetwood Mac, from applause and sports tracks to cinematic sound effects, about 60 sound tracks have been selected for testing the three proposed audio systems for the ATSC 3.0 next- generation television broadcast standard.
This marks an exciting first step in the audio standardization testing process, with experts from the ATSC’s Ad-hoc Group on ATSC 3.0 Audio (TG3/S34-2) selecting the audio test content. This group of experts – which included representatives of Dolby Labs, DTS, Fraunhofer IIS, NBCU, Samsung, Technicolor and Qualcomm – convened for two grueling days at the Qualcomm listening lab in San Diego.
Their task: to choose specialized audio content to be used in the upcoming subjective listening tests of the three proposed ATSC 3.0 audio systems.
ATSC member companies and others contributed more than 150 pieces of audio content as candidates for the testing. From this pool, the expert-listener group was assigned to choose the most appropriate clips for each of five different channel formats.
These formats include 2.0 (stereo), 5.1 (surround), and three immersive audio (or “3D audio”) formats. Criteria for selection included the following:
New Territory: Immersive Audio
The ATSC 3.0 Audio System tests will be the first to evaluate any type of immersive sound for a broadcast television standard. Test materials were selected for three Immersive Audio formats:
Different Genres of Content Selected
Consistent with ITU-R recommendations, 12 audio clips representing different genres of content (such as spoken-word, various musical styles, sports, sound effects, and so on) were selected for each channel format, along with two clips to be used for listener training in each format. The ITU standardized testing processes also specify that the run-length of all content used for these tests be 10-20 seconds and that loudness is the same level for all content. Not all of the content was contributed in such form, so some editing and loudness-matching also was performed by the expert listeners at the San Diego meeting.
In the end, the experts selected about 60 different clips (12-14 clips each for 5 different channel formats). Among them is Suzanne Vega’s song “Tom’s Diner,” a rare a cappella solo, with very little reverb added, which is why it originally came into use for this purpose, and has since become one of “Audio Testing’s Greatest Hits.”
Other selections in the ATSC 3.0 audio test set include pieces from the Henry Mancini orchestra (“Moon River”), Robert Plant (a live version of “Whole Lotta Love”), Fleetwood Mac (“Never Going Back Again” from Rumours), a clip from the Chicago soundtrack featuring Catherine Zeta Jones’ vocal, and an excerpt from NBC Nightly News. The rest are from lesser known classical or jazz artists, specialized solo-instrument recordings, applause, sports commentary/game sounds (golf and hockey), ambient recordings and cinematic sound effects.
According to ATSC Audio Testing Co-Coordinator Skip Pizzi of NAB, the Qualcomm lab proved to be a highly appropriate facility, given its design to ITU specifications for listening tests. The ATSC thanks Qualcomm’s Deep Sen, Nils Peters and Martin Morrell for being gracious and competent hosts.
Audio Testing Alphabet Soup: ITU BS.1116 and MUSHRA
The test and evaluation regime that will be applied to all three proposed systems will include rigorous subjective listening tests based on industry norms set out by the International Telecommunications Union (ITU-R) in its BS.1116 and BS.1534 testing protocols, the latter also known as MUSHRA (or Multi-USer Hidden Reference with Anchor) testing. The testing process will be managed by ATSC TG3/S34-2, the Ad-hoc Group on ATSC 3.0 Audio, under the direction of S34-2 Chair Jim Starzynski of NBC Universal, and ATSC Audio Testing Coordinators Skip Pizzi of NAB and Paul Thomsen representing CEA.
Posted in ATSC News
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The Advanced Television Systems Committee, Inc., is an international, non-profit organization developing voluntary standards and recommended practices for digital terrestrial broadcasting. ATSC member organizations represent the broadcast, broadcast equipment, motion picture, consumer electronics, computer, cable, satellite, and semiconductor industries. ATSC also develops digital terrestrial broadcasting implementation strategies and supports educational activities on ATSC standards.