1. infoframe是什么？
Various types of auxiliary data can be carried from the Source to the DTV Monitor using InfoFrames. This
section describes the InfoFrames that have been defined so far
将source端的auxiliary信息通过接口发送到sink端。
sink端应通过CEA扩展在其EDID中包括与接口相关的（例如HDMI）VSDB来声明InfoFrame功能。当找到合适的（例如HDMI）VSDB时，source端应仅具有InfoFrame功能
DVI不支持任何InfoFrame的传输，而与CEA扩展版本号无关。 CEA-861-D接收器设备接受此处定义的任何InfoFrame
2. infoframe种类
Five types of InfoFrames are defined in CEA-861-D
- Vendor Specific InfoFrame 特定于供应商的InfoFrame
- Auxiliary Video Information InfoFrame 辅助视频信息InfoFrame
- Source Product Description InfoFrame 源产品描述（SPD）InfoFrame传达源设备的名称和产品类型。这使用户可以在更改DTV监视器上的输入时查看正在选择哪个设备
- Audio InfoFrame 音频信息
- MPEG Source InfoFrame MPEG信息
| Info Frame Type Code | Type of InfoFrame |
|---|---|
| 00h | resev |
| 01h | Vendor Specific |
| 02h | Auxiliary Video Information |
| 03h | Source Product Description |
| 04h | Audio |
| 05h | MPEG Source |
| 06h-ffh | Reserved for future use |
The assigned type codes for these InfoFrames are shown in Table 4. The first byte of the
InfoFrame designates the type of InfoFrame while the second byte indicates the version of that particular
InfoFrame.
All future versions of a specific InfoFrame shall be backward compatible with previous versions. They may contain additional information, but old and new devices should be able to access and interpret the information previously present. All of the InfoFrames defined in CEA-861-D are version 1 except for the AVI InfoFrame which has a version 1 (now obsolete) and version 2.
The InfoFrame Length Field is contained in the third byte of each InfoFrame. This length field is the total number of bytes in the InfoFrame Payload. It does not include the Type, Version, or Length fields. In the case of the Vendor Specific InfoFrame, the length includes the 24-bit IEEE Registration ID, as well as any additional bytes defined by the vendor to be in the InfoFrame (see Table 5).
3. 各类怎么使用
vendor specific infoframe
特定于供应商的InfoFrame的内容在表5中定义。具有指定的24位IEEE注册标识符的产品制造商或组织可以使用此InfoFrame来传输未在其他地方定义的信息。供应商特定负载将由24位IEEE编号所引用的组织定义。首先发送最低有效字节的24位IEEE编号（也称为“ company_id”或OUI）。建议供应商特定有效负载包含“长度字段”以促进可扩展性，但这不是必需的
| Byte # | Field Name | Contents |
|---|---|---|
| n | Vendor Specific InfoFrame Type Code | 01h |
| n+1 | Vendor Specific InfoFrame Version | 01h |
| n +2 | InfoFrame Length（Lv） | Total number of bytes in InfoFrame Payload including IEEE Registration ID |
| n +3 | 24 bit IEEE Registration Identifier | |
| n +4 | ~ | ~ |
| n +5 | ~ | ~ |
| n+Lv-1 | Vendor Specific Payload | Vendor Specific Payload |
Auxiliary Video Information (AVI) InfoFrame
比较重要的infoframe，设置hdmi的dsp经常需
The AVI is carried in the AV-stream from the source device to the DTV Monitor as an InfoFrame.
AVI作为源帧从源设备到DTV监视器的AV流中传输
If the source device supports the transmission of the Auxiliary Video Information (AVI) and if it determines
that the DTV Monitor is capable of receiving that information, it shall send the AVI to the DTV Monitor
once per VSYNC period. The data applies to the next full frame of video data.
如果源（source）设备支持传输辅助视频信息(AVI)，并确定DTV显示器（sink）能够接收该信息，则应在垂直同步周期内（Vsync）将AVI发送给DTV显示器一次。该数据适用于下一个全帧视频数据
For DTV Monitors that support any video format with video identification code greater than 7, or that
simultaneously support two different aspect ratios for the same video format timing (e.g., dual-aspect ratio
timings such as 720x480p), the DTV Monitor shall be able to receive and decode the AVI InfoFrame
described in this Section. Simultaneous support of timings available in two different aspect ratios shall be
indicated by listing both formats in the EDID data structure at the same time.
If, for some reason, an indication is received that conflicts with the video format being received (e.g., the
source device indicates 4:3 but sends the 1920x1080i format), then the DTV Monitor shall ignore the
conflicting information in the AVI.
If a DTV Monitor supports YCbCr (in addition to RGB), then it shall include the version 3 CEA Extension
with at least one of the YCBCR bits set and shall be capable of receiving the AVI. If no AVI is being sent
from the source device, then the DTV Monitor shall assume the video data is RGB.
The information on “Active Format Aspect Ratio,” bar widths, overscan/underscan, non-uniform picture
scaling, and colorimetry is information that can be used by the DTV Monitor to improve the picture. Use of
this information by the DTV Monitor is optional. If this information is present at the source device and
valid,8 and if the DTV Monitor is capable of receiving the AVI, it is required that this information be sent.
For DTV Monitors not capable of receiving AVI, the DTV Monitor shall not declare in its EDID data
structure more than one format that is the same except for picture aspect ratio at the same time.
Format of Version 2 AVI InfoFrame
verson1没人用
Data Byte 1 (Table 8) contains bits that describe overscan/underscan (e.g., computer graphics or video),
two bits to indicate whether optional YCBCR is being used, and bits that indicate the presence of valid
active format and/or bar information. If the bar information and the active format information do not agree,
then the bar information shall take precedence.
A source shall set S=1 (S1=0, S0=1) or S=2 (S1=1, S0=0) if it is confident of the accuracy of those
values. Otherwise, it shall set S=0 (no data). The source shall follow these rules for setting S even in the
absence of an indication that the sink responds to S.
A sink should adjust its scan based on S. Such a device would overscan if it received S=1, and
underscan if it received S=2. If it receives S=0, then it should overscan for a CE format and underscan for
an IT format. A sink should indicate its overscan/underscan behavior using a Video Capabilities Data
Block (see Section 7.5.6).
All DTDs and SVDs shall be listed in order of priority; meaning that the first is the one that the display
manufacturer has identified as optimal
