Four image qualities of H.264 (BP, EP, MP, HP) and Profile, Level, Encoder

Introduction

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       First of all, it is necessary to clarify that the so-called AVC is actually the H.264 standard, which was developed by the Joint Video Team (JVT) composed of ITU-T and ISO/IEC. ITU-T named this standard H.264 ( Formerly called H.26L), while ISO/IEC calls it MPEG-4 Advanced Video Coding (AVC) It is positioned to cover the entire field of video applications, including: low bit rate wireless applications, standard definition and high High-definition TV broadcast applications, video streaming applications on the Internet, transmission of high-definition DVD video, and high-quality video applications applied to digital cameras, etc.

Three specifications of AVC

From low to high are: Baseline, Main, High.

Baseline (minimum Profile) level supports I/P frames, only supports non-interlaced (Progressive) and CAVLC, generally used for low-level or applications that require additional fault tolerance, such as video calls, mobile video, etc.;

The Main (main Profile) level provides I/P/B frames, supports non-interlaced (Progressive) and interlaced (Interlaced), and also provides support for CAVLC and CABAC for mainstream consumer electronics product specifications such as low decoding (relatively speaking ) mp4, portable video players, PSP and Ipod, etc.;

The High (High-end Profile, also called FRExt) level adds 8×8 intra-prediction, custom quantization, lossless video encoding and more YUV formats (such as 4:4:4) to Main for broadcast and video Disc storage (Blu-ray movies), HDTV applications.

The specifications of AVC are mainly for compatibility, and different specifications can be applied on the same level of platform. As for the Baseline@L xx, Main@L xx, and High@L xx forms are the code stream levels at different levels. The larger the value, the larger the code stream and more resource-intensive. So in terms of code stream [email protected]<[email protected]<[email protected].

BP, EP, MP, HP

H.264 has four picture quality levels, namely BP, EP, MP, HP:

1. BP-Baseline Profile: Basic image quality. Support I/P frame, only support non-interleaving (Progressive) and CAVLC;

2. EP-Extended profile: Advanced image quality. Support I/P/B/SP/SI frame, only support non-interleaving (Progressive) and CAVLC;

3. MP-Main profile: Mainstream image quality. Provide I/P/B frames, support non-interlaced (Progressive) and interlaced (Interlaced), and also support CAVLC and CABAC support;

4. HP-High