IEC 61937-11:20 21作为IEC 61937-11:20 21 RLV提供，其中包含国际标准及其红线版本，显示了与前一版本相比技术内容的所有变化。IEC 61937-11:20 21描述了传送根据MPEG-4 AAC格式及其扩展（频谱带复制、参数立体声和MPEG环绕）编码的非线性PCM比特流和根据MPEG-D USAC格式编码的非线性PCM比特流的方法，在MPEG-4 LATM/LOAS中成帧。IEC 61937-11:20 21取消并取代2010年发布的第一版和修正案1:20 18。本版构成技术修订版。 与上一版相比，此版本包括以下重大技术变更: a)已添加MPEG-D USAC。

IEC 61937-11:2021 is available as IEC 61937-11:2021 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.

IEC 61937-11:2021 describes the method to convey non-linear PCM bitstreams encoded in accordance with the MPEG-4 AAC format and its extensions (spectral band replication, parametric stereo and MPEG surround), and non-linear PCM bitstreams encoded in accordance with the MPEG-D USAC format, framed in MPEG-4 LATM/LOAS. IEC 61937-11:2021 cancels and replaces the first edition published in 2010, and Amendment 1:2018. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
a) MPEG-D USAC has been added.