Star TV India Launches 5.1 Surround Sound

Background

As one of India’s leading broadcasters, Star TV have always been viewed as innovators and leaders in adopting new technology for broadcast in India.

Recently, Star TV launched four channels in high definition (HD). Of these, two were movie channels (Star Gold and Star Movies), one an English language entertainment channel (Star World), and one a local language entertainment channel (Star Plus), which included production of eight hours of fresh content every day. Star TV decided to adopt multichannel audio for all of their HD channels, and they called in Dolby to provide them with the information, training, and support they needed to implement a 5.1-channel audio solution.

The Challenge

India has traditionally used mono audio for broadcasting because the existing distribution chain is dominated by analog cable television networks, which do not support multiple audio channels. It was therefore necessary to enable the entire broadcast system for multichannel audio, from production and postproduction to transmission.

Since production and postproduction for Star Plus is carried out by independent production houses, a training program was put in place for the staff of 15 different production facilities in addition to Star’s in-house personnel. Star TV also made a conscious decision to initially distribute the HD channels exclusively on direct-to-home platforms, which are digital and can support multichannel audio.

Dolby’s Support

Dolby provided extensive support to Star TV to achieve this milestone in record time. We provided a comprehensive training program for local audio engineers, location audio recording staff, postproduction supervisors, QA personnel, operations staff, and management to help them understand and implement multichannel audio.

We also provided systems support for selecting equipment and adapting workflows to accommodate audio postproduction and improved location sound.

The Methodology

To provide a robust means of delivering correct metadata across the entire production chain, Star TV decided to implement Dolby® E workflows, so that the metadata could be set and encoded in the Dolby E audio stream at the point of production. Although other options were available, such as multichannel PCM with metadata, Star TV chose Dolby E because it served the requirements of Star TV’s particular infrastructure.

Because Star TV had decided to switch entirely to a file-based workflow, Dolby E encoding and decoding were implemented using software plug-ins that integrated with the nonlinear editing (NLE) systems (Final Cut Pro® and Avid® Media Composer®) and the audio workstations (predominantly Pro Tools®). OEM plug-ins such as Neyrinck’s SoundCode and Minnetonka’s SurCode™ were adopted. For loudness measurement, Star TV implemented the Dolby Media Meter, which would also work as a plug-in on the digital audio workstations.

SoundCode was found to be more suitable for the Final Cut Pro–based platforms because of its ability to decode and play back Dolby E directly from the timeline. The SurCode plug-in was preferred for Avid-based workstations.

For quality assurance, an automated loudness estimation and correction mechanism was implemented by integrating the Dolby DP600 Program Optimizer into the QA workflow. External automation was used to demux the audio from MXF wrappers, pass it through the DP600, and rewrap the corrected audio back into the MXF file.

To maintain compatibility with existing mono workflows, the MXF file also contained a mono mix-down of the 5.1-channel mix. The DP600 was also used for automated loudness estimation and correction and for conversion of discrete 5.1-channel audio to Dolby E for the movie channels.

A manual quality control workflow was put in place for subjective evaluation of the mix. This was implemented using software decoder plug-ins on NLE platforms so that Dolby E could be played back directly from the timeline.

Observations

Dolby E has proved to be beneficial in preserving the metadata from content creation to decoding in a consumer’s home. The transcode to Dolby Digital Plus at the transmission center has been configured to preserve the incoming metadata, ensuring that home listening environments produce the best audio possible.

The use of software encoder and decoder plug-ins has facilitated the use of an end-to-end, file-based workflow, which would not have been possible using only hardware-based encoding and decoding.


 
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