mpeg-4 - 关于 MPEG-4 标头

Question

我检查了一些 MPEG-4 视频标头，并在开始时看到了一些如下所示的字节数组：

00 00 01 B0 01 00 00 01 B5 89 13

我知道零件，00 00 01但零件到底是什么意思？实际上，如果我把这个字节数组放在一个 MPEG-4 流的前面，它就可以正常工作。B0 B1B5 89 13

但我不知道这些值是否适用于不同的 mpeg-4 流源？

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 基本视频标头详细信息。这是您要求的详细信息。

视觉对象序列开始 (VOSS) 代码

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

可视对象启动 (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