Everyday One Step Forward

Outline

Outline

Adaptive Quant is claimed as the biggest performance improvement of x264 optimization history. According to AQ's author Jason Garrett-Glaser's explaination variance-based adaptive quantization

The (very rough) intuitive justification works something like this. Imagine every macroblock has just one frequency coefficient.  This coefficient can be big or small.

If a …

Outline

Doc of MB Tree

Process

The x264 decide slice type in a GOP structure unit, which include one reference frame (I,P) and no / several non-reference frame (B). The processed frame will be shift out frame lookahead frame list and put into frame's current list.

if( !h->frames.current …

Outline

Rate control allows selection of encoding parameters to maximize quality under the constraint imposed by specified bitrate and decoder video buffer. The rate control in H.264/AVC can be performed at three different granularities – group of pictures level, picture level and macroblocks level. At each level, the rate …

Outline

In this chapter, we make a brief review of `x264_encoder_open' function. In this function, x264 mainly did several jobs like

x264_threading_init                             // initial thread
x264_validate_parameters                        // validate the configure parameters
x264_sps_init                                   // initial sps parameters
x264_pps_init                                   // initial pps parameters
x264_cqm_init                                   // quant & dequant parameters initial
Init frames parameters, such as max reference numbers …

Introduction

x264 version compilable by visual studio, generated by Shift Media Project I have forked my own version and put it in my github website: git@github.com:huyunf/x264.git

Code Overview

h = x264_encoder_open( );

for(loop by frame number){
    ...
    encode_frame( );
    ...
}

The x264_encoder_open() function does several initial task for the …