MPEG-H: The next generation audio format

　　In 2015, a new audio format was invented and introduced, which can provide more audio channels and more possibilities for sound design and sound storytelling. If the previous audio formats are aimed at enhancing people's auditory experience, the new generation of MPEG-H audio can not only bring a richer auditory experience, such as stereo, surround sound and immersive sound, but also provide users with controllable audio channels. It can provide up to 16 separate audio channel outputs, which users can assign to any audio channel such as surround sound, immersive audio channel and interactive channel, multilingual audio channel, etc. MPEG-H provides users with maximum freedom and personalized control.

　　As audio technology becomes more advanced, I am often asked the question: Why create enhanced audio components?

　　有四个理由可以作为这个问题的答案：第一媒介的环境是多变的，使用不同的设备，在用户控制和预设方面经常有着显著的争议，特别是在改善动态范围和语言方面。在商业娱乐化盛行的今天，在其中增加个人化的品味选择会更能够适应分众传播的要求。

　　Secondly, people can now hear good quality audio. There have been huge advances in audio playback over the past few decades. This trend will continue in the future with the introduction of sound bars, DSP processing and wireless interfaces.

　　再次，消费者在寻找更先进的娱乐刺激，而声音是他们评判的重要因素。上一代音频技术所代表的从单声道到立体声、从立体声到环绕声的听觉体验改变对消费者来说是十分明显的。研究表明，高质量的音频格式对提高听觉体验有着显著的作用。拟真音频将是完整听觉体验的最后一块拼图。

　　Finally, for those who want to take control of their own audio, MPEG-H gives them full freedom and personalized choices. Users can add different sound elements according to their personal preferences, such as multi-language commentary, sounds picked up by microphones worn by coaches during sports games, etc.

　　MPEG-H brings more than just immersive and interactive audio. It is an effective broadband audio format that can transmit immersive audio, surround sound and stereo sound, and provide users with a completely personalized audio experience that includes numerous interactive elements.

　　You may be wondering how this format works in a broadcast environment. Let's start with the transmission of different audio programs, which can be stereo, surround or immersive audio. Many audio professionals find it difficult to transmit both stereo and surround signals through a mixing console. With MPEG-H, they can transmit another type of mix, immersive audio. Currently, the surround sound signals transmitted by most mixing consoles are "down-converted" in the home TV set-top box. This process is to add the signals of the surround left, center, right and left and right surround channels according to a certain algorithm to obtain a stereo mix signal.

　　The downside of this downconversion is that it simply sums the signals of all channels to get a stereo signal, which is a compromise between the two signals. If the immersive audio is downconverted in the same way, the effect may be worse, any details will be greatly weakened, and all the sounds will sound like they are aggregated together.

　　Now think about how wonderful it would be if all audio elements (parameters) could be preserved and your user interface could intelligently output stereo, surround, immersive and interactive audio according to your speaker configuration or personalized listening device and needs. The control data would tell the set-top box (or audio playback device) how to render each audio channel according to the user's playback format without destroying the expression and creative ideas of the producers of the audio program.

　　MPEG-H Audio is not a passive listening experience. Let’s take sports broadcasts as an example of interactive audio. Due to the limitations of current broadcast transmission technology, broadcasters cannot transmit multi-language commentary and what coaches and players say on and off the field. For a true sports fan, he may want to listen to the coach’s instructions off the field or the players’ communication on the field, rather than a single-language commentary. Therefore, MPEG-H becomes the ideal audio transmission format in this case.

　　Interactive audio transmission allows broadcasters to transmit personalized mixed signals for those enthusiastic sports fans in addition to producing public signals of sports games. Interactive audio allows viewers/listeners to choose the elements (content) they are interested in, such as what their idols say in the game or commentary in different languages, giving users complete freedom in choice.

　　Surround sound and immersive audio have always been committed to solving the problem of the sense of presence and enjoyment of the listening experience. MPEG-H audio uses a "scene-based" rendering method, which can intelligently block the transmission of certain channels based on the user's listening device (including mobile phones, laptops, radios and set-top boxes, etc.). MPEG-H perfectly solves the problems encountered in transmitting high-quality audio signals.

　　Surround sound audio signals in movies and drama programs have strict requirements on speaker placement, which is generally difficult to achieve in the home. Because the user's home is not designed for multi-channel playback, the center speaker is usually not placed in a standard position, and the surround sound speakers are difficult to install in a standard position. Speaker manufacturers have realized these listening difficulties, and bar speakers can solve the problem to a certain extent and the price is getting lower and lower. DSP can solve the problems of speaker placement and some room acoustics and can "self-calibrate". Finally, wireless speakers can solve the wiring problems often encountered in speaker installations in the home.

　　Frankly, I was a little concerned about the performance of the speaker bar. But considering that the audio played can be optimized specifically for this speaker, I am satisfied. The scene-based rendering technology can optimize the audio according to the user's speaker layout design, and its speaker parameter library can be continuously updated according to future products.

　　Another bright spot for MPEG-H Audio is that more and more people are listening to music with headphones. Many consumers use earbuds or headphones to watch videos or play games on their mobile devices, and headphones solve many listening difficulties and problems that speakers cannot solve.

　　MPEG-H Audio provides a flexible solution for many listening environments. MPEG-H solves many of the production and distribution problems of high-quality audio that have been encountered since the introduction of surround sound. MPEG-H technology has been proven, and a new, smoother program production model has entered the testing phase in the fields of broadcast signal production and broadband signal transmission.