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Fig 6. A guide to reading the Loudness Model Evaluation Diagram of Fig 7. Finally, it should be noted that the idea of a perceptually based level calculation is not new. An aging, but respectable measure such as “CBS Loudness”, is still being used with success for automated level control [9]. This model has served as a Je facto reference for objective loudness measurement, in the broadcast community.

Figure 6 A guide to reading the Loudness Model Evaluation Diagram of Fig 7. Finally, it should be noted that the idea of a perceptually based level calculation is not new. An aging, but respectable measure such as “CBS Loudness”, is still being used with success for automated level control [9]. This model has served as a Je facto reference for objective loudness measurement, in the broadcast community.

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Fig 1. Dynamic Range Tolerance for consumers under different listening situations. While DTV in itself must be able to cover several consumer situations, other emerging digital broadcast platforms widen the dynamic range target even further.
Fig 1. Dynamic Range Tolerance for consumers under different listening situations. While DTV in itself must be able to cover several consumer situations, other emerging digital broadcast platforms widen the dynamic range target even further.
Table 1. Typical noise levels measured by the author. All environments are realistic for broadcast consumption today. In situations with significant backgrou nd noise, such as inside various transports or urban environments, see Table 1, it’s a challenge to get a wid message across - be it music or s reproduction distortion being added, listener’s ears. The latter is becomi recent studies suggest that headphone 5-10 dB above the same person’s e dynamic range poken - without or damaging the ng important as evels may be set preference when listening through speakers, see Fig 2. f the same holds true in noisy environments, where iPods are often used, mobile platforms could pose a threat to hearing.
Table 1. Typical noise levels measured by the author. All environments are realistic for broadcast consumption today. In situations with significant backgrou nd noise, such as inside various transports or urban environments, see Table 1, it’s a challenge to get a wid message across - be it music or s reproduction distortion being added, listener’s ears. The latter is becomi recent studies suggest that headphone 5-10 dB above the same person’s e dynamic range poken - without or damaging the ng important as evels may be set preference when listening through speakers, see Fig 2. f the same holds true in noisy environments, where iPods are often used, mobile platforms could pose a threat to hearing.
Fig 3. Typical noise spectrum in a moving car with the windows closed (upper trace), and when idling (lower trace). Fig 3 shows spectral noise conditions inside a car [3]. Low frequency noise from the road-tire contact is the main source, as long as the windows are kept closed.
Fig 3. Typical noise spectrum in a moving car with the windows closed (upper trace), and when idling (lower trace). Fig 3 shows spectral noise conditions inside a car [3]. Low frequency noise from the road-tire contact is the main source, as long as the windows are kept closed.
Fig 4. Weighting filters used in combination with Leq measures. A, B, C, D, M and RLB (green). The tests suggested that a relatively simple Leq measure close to a C weighing, labeled “teq(RLB)”, under certain conditions was a good predictor of perceived loudness.
Fig 4. Weighting filters used in combination with Leq measures. A, B, C, D, M and RLB (green). The tests suggested that a relatively simple Leq measure close to a C weighing, labeled “teq(RLB)”, under certain conditions was a good predictor of perceived loudness.
Fig 5. A dose approach to Loudness. Audio segment 1, 2 and 3 may produce the same dose measure, even though their level profiles over time are quite different.
Fig 5. A dose approach to Loudness. Audio segment 1, 2 and 3 may produce the same dose measure, even though their level profiles over time are quite different.
Fig. 7. Evaluation of different Loudness Models (names at the bottom) using a wide range of broadcast audio material [8]. Loudness models to the left are in better agreement with human listeners than models to the right of the chart. Red indication at the top signifies outlier audio segments, misjudged by more than 6 aB of a particular loudness model.
Fig. 7. Evaluation of different Loudness Models (names at the bottom) using a wide range of broadcast audio material [8]. Loudness models to the left are in better agreement with human listeners than models to the right of the chart. Red indication at the top signifies outlier audio segments, misjudged by more than 6 aB of a particular loudness model.
Fig 8. Example of Loudness Meter combining a realtime measure in the outer ring with a history in the “radar view”.
Fig 8. Example of Loudness Meter combining a realtime measure in the outer ring with a history in the “radar view”.
Routing internally at the station is based on linear digital audio, typically using AES/EBU and/or SDI transports. Fig 9. Example of Dolby LM100 meter measurement before and after automatic loudness correction during transmission. Challenging 20 sec broadcast segments butt edited over 5:30 minutes.
Routing internally at the station is based on linear digital audio, typically using AES/EBU and/or SDI transports. Fig 9. Example of Dolby LM100 meter measurement before and after automatic loudness correction during transmission. Challenging 20 sec broadcast segments butt edited over 5:30 minutes.
¥. OlAllONS USING Metadata OMY fOr Film Normal content transmitted using automatic realtime control of loudness and format (fixed metadata). Feature films transmitted with or without dynamic range correction (dynamic metadata). Fig. 10. Three different ways of handling Loudness Control, Multichannel audio and Data Reduction in digital broadcast. DTV transmission relies solely on metadata when it comes to loudness control and speech intelligibility. In Fig 10, drawing no. 2, the Ingest Gate (i2) is used to datareduce import programming, and to inspect metadata associated with it. Downstream of Ingest, metadata must always be available and preserved, meaning no analog transfers or sample rate converters. Routing internally at the station is based exclusively on datareduced, synchronous digital audio. Data encoders and decoders are used for breakouts and monitoring. Audio/video synchronization needs special attention in designs where an arbitrary number of monitoring posts are needed. In production studios, metadata has to be attached to all programs. Production can be native mono, stereo or 5.1 as required. OB and Live production can be incorporated using fixed metadata with appropriate upstream dynamics processing.
¥. OlAllONS USING Metadata OMY fOr Film Normal content transmitted using automatic realtime control of loudness and format (fixed metadata). Feature films transmitted with or without dynamic range correction (dynamic metadata). Fig. 10. Three different ways of handling Loudness Control, Multichannel audio and Data Reduction in digital broadcast. DTV transmission relies solely on metadata when it comes to loudness control and speech intelligibility. In Fig 10, drawing no. 2, the Ingest Gate (i2) is used to datareduce import programming, and to inspect metadata associated with it. Downstream of Ingest, metadata must always be available and preserved, meaning no analog transfers or sample rate converters. Routing internally at the station is based exclusively on datareduced, synchronous digital audio. Data encoders and decoders are used for breakouts and monitoring. Audio/video synchronization needs special attention in designs where an arbitrary number of monitoring posts are needed. In production studios, metadata has to be attached to all programs. Production can be native mono, stereo or 5.1 as required. OB and Live production can be incorporated using fixed metadata with appropriate upstream dynamics processing.
The main part of dynamic range translation and loudness control should be done at the station, leaving only smaller corrections to be performed at the consumer. Fig 11. Example of dynamic range re-mapping: From Home Theatre/DVD to Living Room listening conditions (Fig 1).
The main part of dynamic range translation and loudness control should be done at the station, leaving only smaller corrections to be performed at the consumer. Fig 11. Example of dynamic range re-mapping: From Home Theatre/DVD to Living Room listening conditions (Fig 1).
Fig 12. Example of dynamic range re-mapping: From Home Theatre/DVD to Living Room listening conditions (Fig 1). Fig 11 and fig 12 show rational transfer characteristics complying with the DRT of the consumer, without affecting level already on target.
Fig 12. Example of dynamic range re-mapping: From Home Theatre/DVD to Living Room listening conditions (Fig 1). Fig 11 and fig 12 show rational transfer characteristics complying with the DRT of the consumer, without affecting level already on target.
REFERENCES Fig 13. Example of multiband dynamic range re-mapping of a 5.1 feature film to domestic listening conditions (Fig 7). Black curve: Center channel. Orange curve: L, R, Ls, Rs.
REFERENCES Fig 13. Example of multiband dynamic range re-mapping of a 5.1 feature film to domestic listening conditions (Fig 7). Black curve: Center channel. Orange curve: L, R, Ls, Rs.
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