Preferred levels for background ducking to produce esthetically pleasing audio for TV with clear speech

In audio production, background ducking facilitates speech intelligibility while allowing the background to fulfill its purpose, e.g., to create ambience, set the mood, or convey semantic cues. Technical details for recommended ducking practices are not currently documented in the literature. Hence, we first analyzed common practices found in TV documentaries. Second, a listening test investigated the preferences of 22 normal-hearing participants on the Loud- ness Difference (LD) between commentary and background during ducking. Highly personal preferences were observed, highlighting the importance of object-based personalization. Sta- tistically significant difference was found between non-expert and expert listeners. On average, non-experts preferred LDs that were 4 LU higher than the ones preferred by experts. A sta- tistically significant difference was also found between Commentary over Music (CoM) and Commentary over Ambience (CoA). Based on the test results, we recommend at least 10 LU difference for CoM and at least 15 LU for CoA. Moreover, a computational method based on the Binaural Distortion-Weighted Glimpse Proportion (BiDWGP) was found to match the median preferred LD for each item with good accuracy (mean absolute error = 1.97 LU ± 2.50)

Comparing the effect of audio coding artifacts on objective quality measures and on subjective ratings

A recent work presented the subjective ratings from an extensive perceptual quality evaluation of audio signals, where isolated coding artifact types of varying strength were introduced. We use these ratings as perceptual reference for studying the performance of 11 well-known tools for objective audio quality evaluation: PEAQ, PEMO-Q, ViSQOLAudio, HAAQI, PESQ, POLQA, fwSNRseg, dLLR, LKR, BSSEval, and PEASS. Some tools achieve high correlation with subjective data for specific artifact types (Pearson’s r > 0.90, Kendall’s t > 0.70), corroborating their value during the development of a specific algorithm. Still, the performance of each tool varies depending on the artifact type and no tool reliably assesses artifacts from parametric audio coding. Nowadays, perceptual evaluation remains irreplaceable, especially when comparing different coding schemes introducing different artifacts

Source separation for enabling dialogue enhancement in object-based broadcast with MPEG-H

Low intelligibility of narration or dialogue resulting from high background level is one of the most common complaints in broadcasting. Even when the intelligibility is not compromised, listeners may have personal preferences that differ from the mix being broadcast. Dialogue Enhancement (DE) enables the delivery of optimal dialogue mixing to each listener, be it in terms of intelligibility or for aesthetic preference. This makes DE one of the most promising applications of user interactivity enabled by object-based audio broadcasting, such as MPEG-H. This paper investigates the use of source separation methods to extract dialogue and background from the complex sound mixture for enabling object-based broadcasting when dialogue is not available from the production process, as for example, with legacy content. The presented source separation technology integrates several separation approaches with known limitations into a more powerful overall architecture. In addition, the paper evaluates the subjective benefit of DE using the Adjustment/Satisfaction Test in which the listeners made extensive use of the dialogue level personalization. The fact that the preferred dialogue level had a high variance among the listeners indicates the need for this functionality. Even when an imperfect separation result was used for enabling DE, the possibility for personalizing the dialogue level lead to increased listener satisfaction

Grafting of recovered shoots reduces bois noir disease incidence in vineyard

Bois noir (BN) disease of grapevine is associated with 'Candidatus Phytoplasma solani' (CaPsol). Due to its multifaceted ecology, BN control is extremely difficult. Several studies showed that BN recovery can be elicited by abiotic stresses and treatment with resistance inducers. In this study, field trials along with molecular analyses have been conducted to evaluate if grafting of recovered shoots can increase the BN recovery rate in symptomatic grapevines and decrease the new CaPsol infection rate on asymptomatic grapevines. Field trials were performed in two vineyards (cv. Chardonnay/Kober 5BB) in Franciacorta (Lombardy Region, northern Italy). Grafting ef-fects were evaluated by symptom observation and CaPsol detection by nested-PCR stamp gene amplification for three consecutive years and compared with non-grafted control vines. Obtained data showed that BN incidence was lower in grafted plants, mainly due to a statistically significant increase of recovery rate, four times higher than in non-grafted plants. These data indicated that grafting of recovered shoots can efficiently induce BN recovery, opening an interesting scenario for its utilization in sustainable strategies of vineyard management

Loudness differences for Voice-over-Voice audio in TV and streaming

Voice-over-Voice (VoV) is a common mixing practice observed in news reports and docu- mentaries, where a foreground voice is mixed on top of a background voice, e.g., to translate an interview. This is achieved by ducking the background voice so that the foreground voice is more intelligible, while still allowing the listener to perceive the presence and tone of the background voice. Currently there is little published research on ducking practices for VoV or on technical details such as the Loudness Difference (LD) between foreground and background speech. This paper investigates the ducking practices of nine expert audio engineers and the preferred LDs of 13 non-expert listeners of ages 57 years and older. Results highlight a clear difference between the LDs used by the experts and those preferred by the non-expert listeners. Experts tended toward LDs of 11.5–17 LU, while non-experts preferred a range of 20–30 LU. Based on these results, a minimum LD of 20 LU is recommended for VoV. High inter-subject variance due to personal preference was observed. This variance makes a substantial case for the introduction of personalization in broadcast and streaming. The audiovisual material used for the tests is provided at https://www.audiolabs-erlangen.de/resources/2020-VoV-DB