ffmpeg # macOS 添加drawtext支持

brew install freetype
brew install fontconfig
brew install fribidi

查看安装之后，可以用brew info查看安装信息。比如:

localhost:FFmpeg Private$ brew info freetype
freetype: stable 2.10.0 (bottled)
Software library to render fonts
https://www.freetype.org/
/usr/local/Cellar/freetype/2.10.0 (61 files, 2.3MB) *
  Poured from bottle on 2019-03-30 at 22:43:32
From: https://github.com/Homebrew/homebrew-core/blob/master/Formula/freetype.rb
==> Dependencies
Required: libpng ✔
==> Analytics
install: 190,060 (30 days), 402,661 (90 days), 1,470,828 (365 days)
install_on_request: 9,541 (30 days), 17,319 (90 days), 67,023 (365 days)
build_error: 0 (30 days)

可以看到freetype的作用是: Software library to render fonts, 版本是: stable 2.10.0

然后编译时加入:

--enable-libfreetype \
--enable-libfontconfig \
--enable-libfribidi \

后续就可以利用:

 -vf drawtext=fontcolor=white:fontsize=40:text='Hello World':x=0:y=100

来添加文字，默认文字是: "/Library/Fonts/Microsoft/Verdana.ttf"，等价于:

 -vf drawtext=fontcolor=white:fontsize=40:text='Hello World':x=0:y=100:fontfile='/Library/Fonts/Microsoft/Verdana.ttf'

可以用fontfile来指定特定字体，字体存放在"/Library/Fonts/Microsoft/"中:

localhost:FFmpeg Private$ ls /Library/Fonts/Microsoft/
Abadi MT Condensed Extra Bold       Kaiti.ttf
Abadi MT Condensed Light        Kino
Andale Mono             Lucida Blackletter
Arial Black             Lucida Bright
Arial Bold Italic.ttf           Lucida Calligraphy
Arial Bold.ttf              Lucida Console.ttf
Arial Italic.ttf            Lucida Fax
Arial Narrow                Lucida Handwriting
Arial Rounded Bold          Lucida Sans
Arial.ttf               Lucida Sans Typewriter
Baskerville Old Face            Lucida Sans Unicode.ttf
Batang.ttf              MS Gothic.ttf
Bauhaus 93              MS Mincho.ttf
Bell MT                 MS PGothic.ttf
Bernard MT Condensed            MS PMincho.ttf
Book Antiqua                MS Reference Sans Serif.ttf
Bookman Old Style           MS Reference Specialty.ttf
Bookshelf Symbol 7.ttf          MT Extra
Braggadocio             Marlett.ttf
Britannic Bold              Matura Script Capitals
Brush Script.ttf            Meiryo Bold Italic.ttf
Calibri Bold Italic.ttf         Meiryo Bold.ttf
Calibri Bold.ttf            Meiryo Italic.ttf
Calibri Italic.ttf          Meiryo.ttf
Calibri.ttf             Microsoft Yahei.ttf
Calisto MT              MingLiU-ExtB.ttf
Cambria Bold Italic.ttf         MingLiU.ttf
Cambria Bold.ttf            MingLiU_HKSCS-ExtB.ttf
Cambria Italic.ttf          Mistral
Cambria Math.ttf            Modern No. 20
Cambria.ttf             Monotype Corsiva
Candara Bold Italic.ttf         Monotype Sorts
Candara Bold.ttf            News Gothic MT
Candara Italic.ttf          Onyx
Candara.ttf             PMingLiU-ExtB.ttf
Century                 PMingLiU.ttf
Century Gothic              Palatino Linotype Bold Italic.ttf
Century Schoolbook          Palatino Linotype Bold.ttf
Colonna                 Palatino Linotype Italic.ttf
Comic Sans MS               Palatino Linotype.ttf
Consolas Bold Italic.ttf        Perpetua Bold Italic.ttf
Consolas Bold.ttf           Perpetua Bold.ttf
Consolas Italic.ttf         Perpetua Italic.ttf
Consolas.ttf                Perpetua Titling MT
Constantia Bold Italic.ttf      Perpetua.ttf
Constantia Bold.ttf         Playbill
Constantia Italic.ttf           Rockwell
Constantia.ttf              Rockwell Extra Bold
Cooper Black                STHUPO.TTF
Copperplate Gothic Bold         STLITI.ttf
Copperplate Gothic Light        STXINGKA.ttf
Corbel Bold Italic.ttf          STXINWEI.ttf
Corbel Bold.ttf             STZHONGS.ttf
Corbel Italic.ttf           SimHei.ttf
Corbel.ttf              SimSun-ExtB.ttf
Curlz MT                SimSun.ttf
Desdemona               Stencil
Edwardian Script ITC            Tahoma
Engravers MT                TaiLeb.ttf
Eurostile               Times New Roman Bold Italic.ttf
Fangsong.ttf                Times New Roman Bold.ttf
Footlight Light             Times New Roman Italic.ttf
Franklin Gothic Book Italic.ttf     Times New Roman.ttf
Franklin Gothic Book.ttf        Trebuchet MS
Franklin Gothic Medium Italic.ttf   Tw Cen MT Bold Italic.ttf
Franklin Gothic Medium.ttf      Tw Cen MT Bold.ttf
Gabriola.ttf                Tw Cen MT Italic.ttf
Garamond                Tw Cen MT.ttf
Georgia                 Verdana Bold Italic.ttf
Gill Sans MT Bold Italic.ttf        Verdana Bold.ttf
Gill Sans MT Bold.ttf           Verdana Italic.ttf
Gill Sans MT Italic.ttf         Verdana.ttf
Gill Sans MT.ttf            Wide Latin
Gill Sans Ultra Bold            Wingdings 2.ttf
Gloucester MT Extra Condensed       Wingdings 3.ttf
Goudy Old Style             Wingdings.ttf
Gulim.ttf               himalaya.ttf
Haettenschweiler            mingliu_hkscs.ttf
Harrington              monbaiti.ttf
Impact                  msyi.ttf
Imprint MT Shadow           taile.ttf