1. x264 Adaptive Quant

    Wed 06 December 2017
    By YF

    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 …
    Tagged as : Video Codec x264
  2. x264 Slice Type Decision

    Wed 06 December 2017
    By YF

    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 …
    Tagged as : Video Codec x264
  3. x264 Rate Control

    Tue 05 December 2017
    By YF

    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 …

    Tagged as : Video Codec x264
  4. x264 Encoder Open

    Mon 20 November 2017
    By YF

    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 …
    Tagged as : Video Codec x264
  5. x264 Overview

    Tue 14 November 2017
    By YF

    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 …

    Tagged as : Video Codec x264

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