Ambidio: An Introduction to Immersive Stereo, Workflow, and Evaluation
Date & Time
Tuesday, October 22, 2019, 4:00 PM - 4:30 PM
Next generation audio (NGA) formats have become standard in the distribution pipeline for premium cinematic content. This has given the content creator the flexibility to render to various speaker configurations while incorporating channel, object, and scene based description formats. However while NGA for home entertainment is gradually getting adopted by broadcasting and OTT platforms, the majority of audiences still consume content on devices with stereo speakers such as TVs, mobile phones, laptops, and tablets. Studies also have shown that personal devices are getting more and more viewing hours. Therefore delivering a better experience to the audience using stereo speakers while maintaining artistic intent in sound has become a critical issue in this era. In this paper we introduce Ambidio—a two-channel audio deliverable that takes advantage of the compactness of the stereo signal stream while delivering surround sound-like experiences through stereo speakers with robust psychoacoustic models. The workflow for producing an Ambidio deliverable is presented here. It was developed through close collaboration with experienced re-recording mixers in the industry to ensure seamless integration with existing post production pipeline for both feature films and episodic television. Extensive listening tests are conducted amongst audio professionals to compare Ambidio with the original surround sound mix, and the results show that the Ambidio version, with two channels of audio, can faithfully preserve the envelopment of the mix while maintaining the color of the sound. Multiple encoding and decoding procedures are also tested to emulate the delivery pipeline of leading broadcasting and streaming platforms of both video and audio, under different encoding conditions even with low sample rates and low bit rates. The test results show that the encoding does not affect the immersiveness, and sound quality stays the same as the regular stereo deliverable going through the same procedure. The immersive stereo version can serve as a good alternative deliverable for home entertainment including film and TV.
Technical Depth of Presentation
What Attendees will Benefit Most from this Presentation
With the industry-wide goal of delivering higher quality content true to the original intent, and the consumer trend of stereo listening, it is beneficial for all levels of people to understand a more immersive stereo deliverable. Executives and directors that run the studios and broadcasting/streaming services will learn about trends that the industry is only gradually aware of. It is also beneficial for engineers/technologists that support the creation of content and delivery methods of the platforms to understand the technology and how can they adopt it. The user study results will give insights on how audience and creatives react, which is essential in all business, technology, and creative aspects.
Take-Aways from this Presentation
In this presentation, we will address the importance for the industry to put more emphasis on the stereo audio deliverable, as it is the primary listening method for most content outside of the cinema through digital and OTT services in particular. We will propose an alternative two-channel audio deliverable that can faithfully deliver the creators’ intent using only stereo speakers. We will share the workflow adopted by premium Hollywood post-production studios, and how it is seamlessly integrated into the existing audio production pipeline. We will also share the results of subjective listening tests from the “golden ears” in the audio industry and also general audience. We hope that by sharing this information content creators will raise their awareness on creating better, more immersive two-channel audio deliverables to enhance the audience experiences and have a basic understanding on how to adopt Ambidio from a technology standpoint.