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4. ffmpeg源码下载在android下的编译参数分析讲解~1
发布时间：2021-05-26 17:38:02编辑：雪饮阅读（）
安裝git
因爲接下來需要用git去獲取ffmpeg源代碼的最新版
root@ubuntu:~/ff# apt-get install git
Reading package lists... Done
Building dependency tree
Reading state information... Done
Suggested packages:
git-daemon-run | git-daemon-sysvinit git-doc git-el git-email git-gui gitk gitweb git-arch git-cvs git-mediawiki git-svn
The following packages will be upgraded:
git
1 upgraded, 0 newly installed, 0 to remove and 221 not upgraded.
Need to get 3,183 kB of archives.
After this operation, 77.8 kB of additional disk space will be used.
Get:1 http://us.archive.ubuntu.com/ubuntu xenial-updates/main amd64 git amd64 1:2.7.4-0ubuntu1.10 [3,183 kB]
Fetched 3,183 kB in 14s (221 kB/s)
(Reading database ... 61695 files and directories currently installed.)
Preparing to unpack .../git_1%3a2.7.4-0ubuntu1.10_amd64.deb ...
Unpacking git (1:2.7.4-0ubuntu1.10) over (1:2.7.4-0ubuntu1.1) ...
Setting up git (1:2.7.4-0ubuntu1.10) ...
用git獲取ffmpeg
用安裝好的git獲取的ffmpeg一般的都是最新的，例如這裏用git獲取最新ffmpeg源代碼如：
root@ubuntu:~/ff# git clone https://git.ffmpeg.org/ffmpeg.git ffmpeg
Cloning into 'ffmpeg'...
remote: Enumerating objects: 1147, done.
remote: Counting objects: 100% (1147/1147), done.
remote: Compressing objects: 100% (952/952), done.
remote: Total 627631 (delta 740), reused 236 (delta 195)
Receiving objects: 100% (627631/627631), 149.76 MiB | 8.25 MiB/s, done.
Resolving deltas: 100% (504633/504633), done.
Checking connectivity... done.
用wget獲取ffmpeg
如果知道了ffmpeg具體的某個版本源代碼下載地址也可以直接用wget獲取，如：
root@ubuntu:~/ff# wget http://ffmpeg.org/releases/ffmpeg-3.4.tar.bz2
--2021-05-26 17:27:22-- http://ffmpeg.org/releases/ffmpeg-3.4.tar.bz2
Resolving ffmpeg.org (ffmpeg.org)... 79.124.17.100
Connecting to ffmpeg.org (ffmpeg.org)|79.124.17.100|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 10171702 (9.7M) [application/x-bzip2]
Saving to: ‘ffmpeg-3.4.tar.bz2’
ffmpeg-3.4.tar.bz2 100%[=====================================================================================>] 9.70M 4.06MB/s in 2.4s
2021-05-26 17:27:25 (4.06 MB/s) - ‘ffmpeg-3.4.tar.bz2’ saved [10171702/10171702]
make -j参数简介
在Linux编译程序的时候，IO往往不是瓶颈，那CPU就应该是一个影响编译速度的重要因素了。
用make -j带一个参数，可以把项目在进行并行编译，比如在一台双核的机器上，完全可以用make -j4，让make最多允许4个编译命令同时执行，这样可以更有效的利用CPU资源。
在多核CPU上，适当的进行并行编译还是可以明显提高编译速度的。但并行的任务不宜太多，一般是以CPU的核心数目的两倍为宜。
关键字词：ffmpeg