Dolby Atmos Bitstream Analysis

This folder includes one ATMOSFrame extracted from a unlocked Dolby Atmos Cinema MXF essence (extracted with asdcplib), and a C style pseudo code to show its structure. It aims to prove that IAB Application Profile 1 is equal to Dolby Atmos Bitstream.

This structure was identified with the instructions from ST 2098-2:2019 and RDD57:2021.

Informative notes

Steps of analyzing

1. Use asdcplib tool asdcp-unwrap to extract the Dolby Atmos Cinema MXF.

asdcp-unwrap <Input File>.mxf DCPIAB

2. Take its second frame DCPIAB000002.atmos and use a HEX editor to analyse, following the guide from ST 2098-2 and RDD57.

Pseudo code notes

The pseudo code is roughly C style, but aims to prove the structure. Each symbol was started with a number that tells this symbol takes how many bits. It may quote another symbol's number, or write as ? to announce that we don't care about its size.

Each element was named as "NameElement()", included in "{}" symbols. The content was named as "Name()", included in "{}" symbols.

As we are not familiar with DLC lossless coding, we did not analyse AudioDataDLC element.

For ObjectDefinition element, as we need to reduce working, we only analyse those whose MetaID is 0x01, 0x02, 0x3A, 0x76, which represents the structure more clearly.

杜比全景声比特流分析

这个文件夹包含了一个从未加密Dolby Atmos Cinema MXF精华（使用asdcplib提取）中提取的一个ATMOSFrame，和一个表明它的结构的C风格伪代码，旨在证明IAB应用配置文件1同杜比全景声比特流等价。

这一结构是根据ST 2098-2:2019和RDD57:2021中的指导识别的。

信息性备注

分析步骤

1. 使用asdcplib工具asdcp-unwrap提取该Dolby Atmos Cinema MXF。

asdcp-unwrap <Input File>.mxf DCPIAB

2. 取其第二帧DCPIAB000002.atmos并遵守ST 2098-2和RDD57的指导，使用十六进制编辑工具对其进行分析。

伪代码备注

这个伪代码大致是C语言风格的，但旨在表明结构。每一个符号由一个代表该符号占据多少位的数字开头。它可能引用其它符号的数值，也可能被写作?代表不关心其大小。

每一个元素都被命名为“NameElement()”，包含在花括号中。内容被命名为“Name()”，包含在花括号中。

由于并不熟悉DLC无损音频编码，AudioDataDLC元素未被分析。

针对ObjectDefinition元素，仅分析了MetaID为0x01, 0x02, 0x3A, 0x76的四项，以节约工作。