[FFmpeg-user] Brighten dark video before reducing size?

[Gilles]

On Tue, 11 Dec 2012 11:31:49 +0000 (UTC), Carl Eugen Hoyos
<cehoyos at ag.or.at> wrote:
>> I was wondering if ffmpeg could apply some filters 
>> before further reducing the filesize?
>
>Definitely, please see the fine filter documentation:
>http://ffmpeg.org/ffmpeg.html#Video-Filters
>(hue, lut, geq and mp=eq2 come to mind.)

I've tried the following commands, but none worked to brighten a dark
video:

I tried each of those commands, but observed no change:
-vf mp=eq2=1:1.68:0.3:1.25:1:0.96:1 
-vf "lutyuv=y=val*1.3"
-vf "lutyuv=y=val*2.0"
-filter:v lutyuv="y=gammaval(0.7)"

Here's how I used the command, where HERE contained one of the
switches above

ffmpeg -ss 00:05:00 -t 20 -i input.mp4 HERE -vf scale=640:-1 -c:v
libx264 -pix_fmt yuv420p -c:a copy -shortest -f mp4 output.mp4

Thank you.

PS: More information about the input file:

c:\>ffprobe.exe -i input.mp4
ffprobe version N-66595-g1c4c78e Copyright (c) 2007-2014 the FFmpeg
developers
  built on Oct  3 2014 22:01:53 with gcc 4.9.1 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-w32threads
--enable-av
isynth --enable-bzlib --enable-fontconfig --enable-frei0r
--enable-gnutls --enab
le-iconv --enable-libass --enable-libbluray --enable-libbs2b
--enable-libcaca --
enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc
--enable-lib
modplug --enable-libmp3lame --enable-libopencore-amrnb
--enable-libopencore-amrw
b --enable-libopenjpeg --enable-libopus --enable-librtmp
--enable-libschroedinge
r --enable-libsoxr --enable-libspeex --enable-libtheora
--enable-libtwolame --en
able-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc
--enable-libvorbis
 --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264
--enable-
libx265 --enable-libxavs --enable-libxvid --enable-zlib
  libavutil      54.  9.100 / 54.  9.100
  libavcodec     56.  2.101 / 56.  2.101
  libavformat    56.  7.104 / 56.  7.104
  libavdevice    56.  1.100 / 56.  1.100
  libavfilter     5.  1.102 /  5.  1.102
  libswscale      3.  1.100 /  3.  1.100
  libswresample   1.  1.100 /  1.  1.100
  libpostproc    53.  1.100 / 53.  1.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'input.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf54.18.100
  Duration: 00:27:31.04, start: 0.000000, bitrate: 1415 kb/s
    Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p,
1280x720
[SAR 1:1 DAR 16:9], 1283 kb/s, 25 fps, 25 tbr, 90k tbn, 50 tbc
(default)
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(und): Audio: aac (mp4a / 0x6134706D), 44100 Hz,
stereo, fltp, 12
5 kb/s (default)
    Metadata:
      handler_name    : SoundHandler