MSDN DOC关于FourCC的解释1

Recommended 8-Bit YUV Formats

for Video Rendering

� 2018年05月31日

本文内容

1. Introduction

2. YUV Sampling

3. Surface Definitions

4. 4:4:4 Formats, 32 Bits per Pixel

5. 4:2:2 Formats, 16 Bits per Pixel

12. Converting 4:2:2 YUV to 4:4:4 YUV

13. Converting 4:2:0 YUV to 4:4:4 YUV

14. Other YUV Formats

15. Identifying YUV Formats in Media Foundation

16. Related topics

Gary Sullivan and Stephen Estrop

Microsoft Corporation

April 2002, updated November 2008

This topic describes the 8-bit YUV color formats that are recommended for

video rendering in the Windows operating system. This article presents

Windows. Decoder vendors and display vendors are encouraged to support

the formats described in this article. This article does not address other uses of

YUV color, such as still photography.

The formats described in this article all use 8 bits per pixel location to encode

the Y channel (also called the luma channel), and use 8 bits per sample to

encode each U or V chroma sample. However, most YUV formats use fewer

than 24 bits per pixel on average, because they contain fewer samples of U

and V than of Y. This article does not cover YUV formats with 10-bit or higher

Y channels.

备注

For the purposes of this article, the term U is equivalent to Cb, and the term V

guidelines for converting between YUV and RGB formats and for converting

between different YUV formats.

� Identifying YUV Formats in Media Foundation. Explains how to describe YUV

format types in Media Foundation.

YUV Sampling

Chroma channels can have a lower sampling rate than the luma channel,

without any dramatic loss of perceptual quality. A notation called the "A:B:C"

notation is used to describe how often U and V are sampled relative to Y:

� 4:4:4 means no downsampling of the chroma channels.

� 4:2:2 means 2:1 horizontal downsampling, with no vertical downsampling.

Every scan line contains four Y samples for every two U or V samples.

� 4:2:0 means 2:1 horizontal downsampling, with 2:1 vertical downsampling.

samples are represented by a circle.

The dominant form of 4:2:2 sampling is defined in ITU-R Recommendation

BT.601. There are two common variants of 4:2:0 sampling. One of these is

used in MPEG-2 video, and the other is used in MPEG-1 and in ITU-T

Compared with the MPEG-1 scheme, it is simpler to convert between the

MPEG-2 scheme and the sampling grids defined for 4:2:2 and 4:4:4 formats.

For this reason, the MPEG-2 scheme is preferred in Windows, and should be

considered the default interpretation of 4:2:0 formats.

Surface Definitions

This section describes the 8-bit YUV formats that are recommended for video

rendering. These fall into several categories:

� 4:4:4 Formats, 32 Bits per Pixel

� 4:2:2 Formats, 16 Bits per Pixel