X264
x264的官网上有编译好的Windows、Linux、Mac平台对应的二进制文件，比如Windows下是exe文件，可以直接用该文件来进行编码的操作。
官网地址： www.videolan.org/developers/…
C:\Users\jesson\Desktop\x264>x264-r2901-7d0ff22.exe --help
x264 core:155 r2901 7d0ff22
Syntax: x264 [options] -o outfile infile
Infile can be raw (in which case resolution is required),
or YUV4MPEG (*.y4m),
or Avisynth if compiled with support (yes).
or libav* formats if compiled with lavf support (yes) or ffms support (no).
Outfile type is selected by filename:
.264 -> Raw bytestream
.mkv -> Matroska
.flv -> Flash Video
.mp4 -> MP4 if compiled with GPAC or L-SMASH support (no)
Output bit depth: 8/10
.
Options:
-h, --help List basic options
--longhelp List more options
--fullhelp List all options
Example usage:
Constant quality mode:
x264 --crf 24 -o <output> <input>
Two-pass with a bitrate of 1000kbps:
x264 --pass 1 --bitrate 1000 -o <output> <input>
x264 --pass 2 --bitrate 1000 -o <output> <input>
Lossless:
x264 --qp 0 -o <output> <input>
Maximum PSNR at the cost of speed and visual quality:
x264 --preset placebo --tune psnr -o <output> <input>
Constant bitrate at 1000kbps with a 2 second-buffer:
x264 --vbv-bufsize 2000 --bitrate 1000 -o <output> <input>
Presets:
--profile <string> Force the limits of an H.264 profile
Overrides all settings.
- baseline,main,high,high10,high422,high444
--preset <string> Use a preset to select encoding settings [medium]
Overridden by user settings.
- ultrafast,superfast,veryfast,faster,fast
- medium,slow,slower,veryslow,placebo
--tune <string> Tune the settings for a particular type of source
or situation
Overridden by user settings.
Multiple tunings are separated by commas.
Only one psy tuning can be used at a time.
- psy tunings: film,animation,grain,
stillimage,psnr,ssim
- other tunings: fastdecode,zerolatency
Frame-type options:
-I, --keyint <integer or "infinite"> Maximum GOP size [250]
--tff Enable interlaced mode (top field first)
--bff Enable interlaced mode (bottom field first)
--pulldown <string> Use soft pulldown to change frame rate
- none, 22, 32, 64, double, triple, euro (requ
ires cfr input)
Ratecontrol:
-B, --bitrate <integer> Set bitrate (kbit/s)
--crf <float> Quality-based VBR (-12-51) [23.0]
--vbv-maxrate <integer> Max local bitrate (kbit/s) [0]
--vbv-bufsize <integer> Set size of the VBV buffer (kbit) [0]
-p, --pass <integer> Enable multipass ratecontrol
- 1: First pass, creates stats file
- 2: Last pass, does not overwrite stats file
Input/Output:
-o, --output <string> Specify output file
--sar width:height Specify Sample Aspect Ratio
--fps <float|rational> Specify framerate
--seek <integer> First frame to encode
--frames <integer> Maximum number of frames to encode
--level <string> Specify level (as defined by Annex A)
--quiet Quiet Mode
Filtering:
--vf, --video-filter <filter0>/<filter1>/... Apply video filtering to the
input file
Filter options may be specified in <filter>:<option>=<value> format.
Available filters:
crop:left,top,right,bottom
resize:[width,height][,sar][,fittobox][,csp][,method]
select_every:step,offset1[,...]
Syntax: x264 [options] -o outfile infile
Outfile type is selected by filename:
.264 -> Raw bytestream
.mkv -> Matroska
.flv -> Flash Video
.mp4 -> MP4 if compiled with GPAC or L-SMASH support (no)
指定码率 --bitrate
x264 --bitrate 1000 -o output.264 input_640x360_yuv420p.yuv
指定帧率 --fps
x264 --fps 10 -o output.264 input_640x360_yuv420p.yuv
指定编码速度 --preset
x264 --preset ultrafast -o output.264 input_640x360_yuv420p.yuv
配合视觉优化 --tune
--tune <string> Tune the settings for a particular type of source
or situation
Overridden by user settings.
Multiple tunings are separated by commas.
Only one psy tuning can be used at a time.
- psy tunings:
film,
animation,
grain,
stillimage,
psnr,
ssim
- other tunings:
fastdecode,
zerolatency
YUV
YUV （YCrCb）:像素格式 视频编码
Y 灰度
U （蓝⾊）
V （红⾊）
Y 分量 没有 UV 1⽐1
采样当中：
UV采样率 < Y采样率
A：B： C
存储格式：
平⾯格式（planar）、Semi-Planar、打包格式
单独数组
Y0 Y1 Y2 Y3。。。
U0 U1 .。。
V0。V1
YUV420P IYUV I420 YU12
每4个Y分量 共享 ⼀组UV
