ffmpegでMP4のビットレートを下げてビデオを圧縮する
納品されてきたmp4が2Mbpsもありファイルサイズがデカい・・・ もう少し品質下げても十分閲覧可能なので1Mbpsに変更します
ffmpegのインストール
$ brew install ffmpeg
ビデオの情報を確認
$ ffprobe -i video_2000kbps.mp4
ffprobe version 4.2.1 Copyright (c) 2007-2019 the FFmpeg developers
built with Apple clang version 11.0.0 (clang-1100.0.33.8)
configuration: --prefix=/usr/local/Cellar/ffmpeg/4.2.1_1 --enable-shared --enable-pthreads --enable-version3 --enable-avresample --cc=clang --host-cflags='-I/Library/Java/JavaVirtualMachines/adoptopenjdk-13.jdk/Contents/Home/include -I/Library/Java/JavaVirtualMachines/adoptopenjdk-13.jdk/Contents/Home/include/darwin -fno-stack-check' --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libbluray --enable-libmp3lame --enable-libopus --enable-librubberband --enable-libsnappy --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librtmp --enable-libspeex --enable-libsoxr --enable-videotoolbox --disable-libjack --disable-indev=jack
libavutil 56. 31.100 / 56. 31.100
libavcodec 58. 54.100 / 58. 54.100
libavformat 58. 29.100 / 58. 29.100
libavdevice 58. 8.100 / 58. 8.100
libavfilter 7. 57.100 / 7. 57.100
libavresample 4. 0. 0 / 4. 0. 0
libswscale 5. 5.100 / 5. 5.100
libswresample 3. 5.100 / 3. 5.100
libpostproc 55. 5.100 / 55. 5.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'video_2000kbps.mp4':
Metadata:
major_brand : mp42
minor_version : 512
compatible_brands: isomiso2avc1mp41
creation_time : 2019-06-19T08:51:24.000000Z
encoder : HandBrake 1.0.7 2017040900
Duration: 00:00:16.06, start: 0.000000, bitrate: 2407 kb/s
Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv, bt709), 1124x1080 [SAR 135:304 DAR 281:608], 2408 kb/s, 30 fps, 30 tbr, 90k tbn, 180k tbc (default)
Metadata:
creation_time : 2019-06-19T08:51:24.000000Z
handler_name : VideoHandler
Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 2 kb/s (default)
Metadata:
creation_time : 2019-06-19T08:51:24.000000Z
handler_name : Stereo
bitrate: 2407 kb/s
これを1024kb/sに変更します
別名で再エンコード
$ ffmpeg -i video_2000kbps.mp4 -vb 1024k video_1024kbps.mp4
動画を閲覧してみて問題ないことを確認
採用！