ubuntu 或者 debian 安裝 libpng

安裝指令：

apt-get install libpng12-dev zlib1g-dev
           

或者:

apt-get install libpng-dev
           

日志：

# apt-get install libpng-dev
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Note, selecting 'libpng12-dev' instead of 'libpng-dev'
The following packages were automatically installed and are no longer required:
  libnfsidmap2 libtirpc1
Use 'apt-get autoremove' to remove them.
The following extra packages will be installed:
  zlib1g-dev
The following NEW packages will be installed:
  libpng12-dev zlib1g-dev
0 upgraded, 2 newly installed, 0 to remove and 15 not upgraded.
Need to get 454 kB of archives.
After this operation, 1,068 kB of additional disk space will be used.
Do you want to continue? [Y/n] y
Get:1 http://mirrors.byted.org/debian/ jessie/main zlib1g-dev amd64 1:1.2.8.dfsg-2+b1 [206 kB]
Get:2 http://mirrors.byted.org/debian/ jessie/main libpng12-dev amd64 1.2.50-2+deb8u3 [248 kB]
Fetched 454 kB in 0s (5,565 kB/s)
Selecting previously unselected package zlib1g-dev:amd64.
(Reading database ... 76601 files and directories currently installed.)
Preparing to unpack .../zlib1g-dev_1%3a1.2.8.dfsg-2+b1_amd64.deb ...
Unpacking zlib1g-dev:amd64 (1:1.2.8.dfsg-2+b1) ...
Selecting previously unselected package libpng12-dev:amd64.
Preparing to unpack .../libpng12-dev_1.2.50-2+deb8u3_amd64.deb ...
Unpacking libpng12-dev:amd64 (1.2.50-2+deb8u3) ...
Processing triggers for man-db (2.7.0.2-5) ...
Setting up zlib1g-dev:amd64 (1:1.2.8.dfsg-2+b1) ...
Setting up libpng12-dev:amd64 (1.2.50-2+deb8u3) ...
           

在 ffmpeg 編譯過程中，如果系統有 libpng，在 codecs 中預設會添加 libpng，如果系統中沒有 libpng，那麼 codec 中預設會不支援 png 的編碼；