macos/unix下x264開發
x264新手入門
下載x264源碼
videolan提供下載地址，git安裝（沒有git的自己裝一下），終端進入你想保存源碼的目錄，輸入：
git clone git://git.videolan.org/x264.git稍等幾分鐘，下載完x264文件夾
安裝yasm
yasm是一個彙編庫，包含很多底層彙編代碼，包括SIMD指令，用於加速，如果沒有安裝將會報錯，用macos下用mac port安裝：
$ make configure
Makefile:3: config.mak: No such file or directory
cat: config.h: No such file or directory
./configure
Found no assembler
Minimum version is yasm-1.2.0
If you really want to compile without asm, configure with --disable-asm.
make: *** [config.mak] Error 1編譯
進入x264目錄，配置編譯
make configure成功後回生成可執行文件x264，驗證，如果出現下述反饋說明編譯成功啦！
$ ./x264 --help
x264 core:148 r2579 73ae2d1
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 (no) 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 (configured at compile time)
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 (requires cfr input)
Ratecontrol:
-B, --bitrate <integer> Set bitrate (kbit/s)
--crf <float> Quality-based VBR (0-51) [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
select_every:step,offset1[,...]