Organisation internationale de normalisation

HOA Issues

Gregory Pallone, Orange, presented

m37894

Proposed modifications on MPEG-H 3D Audio

Gregory Pallone

The contribution notes that when presenting via loudspeakers and listening in the near field, the perceived spatial cues, e.g. interaural level, may be incorrect. It gives use cases in which such near-field listening will occur, e.g. inside a car.

The results of an experiment are reported, in which far-field and near-field presentation are simulated using binaural rendering and presentation. Near Field Compensation (NFC) simulates moving the speakers further from the listener.

The contribution proposes to modify the 3D Audio specification in two places as follows:

Preprocessing block NFC processing (should be switched active if UseNfc is true and the speaker listener distance r_max is samller NfcReference Distance), pre-processing block DRC-1 for HOA and as an alternative to rendering to loud-speakers, a computational efficient binaural rendering directly using the HOA coefficients (H2B, see 13.3.1). Computational more efficient but mathematically equivalent ways to implement the processing chain may be found in Annex G.

with:

Preprocessing block NFC processing (should be switched active if r_max < NfcReferenceDistance in case UsesNfc flag is active, or if r_max < 1.5 meters in case UsesNfc flag is inactive, with r_max the maximum speaker distance of the listening setup), pre-processing block DRC-1 for HOA and as an alternative to rendering to loud-speakers, a computational efficient binaural rendering directly using the HOA coefficients (H2B, see 13.3.1). Computational more efficient but mathematically equivalent ways to implement the processing chain may be found in Annex G.

Nils Peters, Qualcomm, noted that the contribution uses a very regular set of loudspeaker positions, and wondered if the tested quality might be less with e.g. the MPEG-H 3D Audio 22.2 loudspeaker positions.

Oliver Weubolt, Technicolor, questioned how realistic or prevelant is the use case of the close-placed loudspeaker listening.

The Chair asked experts work together to draft the intent of the Orange proposal in more clear and concise language. This topic will continue to be discussed.

AhG Report

The Chair presented

m37901

Report of AHG on 3D Audio and Audio Maintenance

Schuyler Quackenbush

Experts agreed that the report represents the AhG activity. The Chair will upload it as a contribution document.

The AhG meeting was adjourned at 5:50pm

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