信息技术.多媒体框架(MPEG)音频技术.第2部分:立体声对象编码(SAOC)

[中文适用范围]： ISO/IEC 23003 的这一部分指定了空间音频对象编码 (SAOC) 技术的参考模型，该技术能够基于较少数量的传输通道和附加参数数据重新创建、修改和渲染多个音频对象。 在操作SAOC系统的优选模式中，传输的信号可以是单声道或立体声的。 音频对象可以由单声道和立体声信号表示，或者具有 MPEG 环绕 (MPS) 多通道背景对象 (MBO) 格式。 附加参数数据的数据速率明显低于单独传输所有对象所需的数据速率，从而使编码非常高效。 同时，这确保了传输信号与传统设备的兼容性。 当需要多通道渲染设置（例如5.1扬声器设置）时，SAOC系统充当代码转换器，将附加参数数据转换为MPS参数，并连接到充当渲染设备的MPS解码器。 对于某些渲染设置（例如双耳或普通立体声设置），SAOC 系统使用其自己的渲染引擎充当解码器。 另一个关键功能是来自不同流的 SAOC 参数数据可以在参数级别进行合并，以允许 SAOC 流的组合，类似于多点控制单元 (MCU) 的功能。 [外文原描述]： ISO/IEC 23003-2:2010 specifies the reference model of MPEG Spatial Audio Object Coding (SAOC): an efficient parametric coding technology designed to encode, transmit, and interactively render multiple audio objects for playback with various kinds of channel configurations (mono, stereo, 5.1, headphones/binaural). Rather than performing a discrete coding of the individual audio input signals, MPEG SAOC captures the perceptually relevant properties of audio signals into a compact set of parameters that are used to synthesize a flexibly rendered audio scene from a transmitted downmix signal. MPEG SAOC extends MPEG Surround in a way that provides several significant advantages in terms of additional functionality available to users. It allows the user on the decoding side to interactively control the multi-channel rendering of each individual audio object on different kinds of sound reproduction setup. In addition, MPEG SAOC inherits many advantages of MPEG Surround technology, like transmission (in a backward compatible way) of complex multi-object audio content at bitrates not much higher than what is required for its mono or stereo downmix. MPEG SAOC processing effectively reuses the multi-channel rendering functionality of MPEG Surround in a computationally efficient manner. Therefore, MPEG SAOC technology can be directly used to extend MPEG Surround and upgrade existing distribution infrastructures for stereo or mono audio content (teleconferencing systems, music downloads, Internet streaming, etc.) towards the delivery of audio content while retaining full compatibility with existing receivers. Rendering can be interactively controlled by the end-user and is independent of the playback system setup. Key features of MPEG SAOC are: interactive rendering of audio objects on the decoder/receiver side; transmitted SAOC bit stream is independent of loudspeaker (or headphones) configuration; low-power processing mode (e.g. for applications on portable devices); low-delay processing mode (e.g. for communication applications); flexibly selectable bitrate overhead, allowing scalability from low bitrate applications such as Internet streaming to high-quality applications such as custom remix of music; it can be applied upon audio using any coding scheme; backward compatibility: the default downmix is always available for legacy playback devices.