关于MPEG-4标头

Question

我检查了一些MPEG-4视频标头，看到了一些字节数组，如下所示：

00 00 01 B0 01 00 00 01 B5 89 13

我知道00 00 01部件，但是B0 B1和B5 89 13部件到底是什么意思呢？实际上，如果我把这个字节数组放在MPEG-4流的前面，它工作得很好。

但我不知道这些值是否适用于不同的mpeg-4流来源？

Answer 1

0x000001B0 -> Visual Object Sequence Start (VOSS) Code
0x000001B5 -> Visual Object Start (VOS) Code

您可以在"ISO/IEC 14496-2“文档中找到完整的MPEG-4基本视频标题详细信息。这是您要的详细信息。

可视化对象序列开始(VOSS)代码

-> 4 bytes visual object sequence start code = long hex value of 0x000001B0
-> 8 bits profile/level indicator = 1 byte unsigned number

可视对象开始(VOS)代码

-> 4 bytes visual object start code = long hex value of 0x000001B5
-> 1 bit has id marker flag = 1/4 nibble flag

_ID_Marker_Section_
-> 4 bits version id = 1 nibble unsigned value - only if marker is true
  - version id types are ISO 14496-2 = 1
-> 3 bits visual object priority = 3/4 nibble unsigned value - only if marker is true
  - priorities are 1 through to 7

-> 4 bits visual object type = 1 nibble unsigned value
  - types are video = 1 ; still texture = 2 ; mesh = 3 ; face = 4
-> 1 bit video signal type = 1/4 nibble flag
  - NOTE: if this is false Y has a sample range of 16 through to 235