README.txt

FFMPEG CRT TRANSFORM
--------------------

Windows batch script for a configurable simulation of CRT monitors (and some
older flat-panel displays too), given an input image/video.

Requires a *git-master* build of FFmpeg from 2021-01-27 or newer, due to a
couple of bugfixes and new features.

See https://github.com/viler-int10h/FFmpeg-CRT-transform/ for the latest
version.


USAGE AND CONFIGURATION:

   Syntax: ffcrt <config_file> <input_file> [output_file]
   
   * <input_file> must be a valid image or video.  Assumed to be 24-bit RGB (8
     bits/channel).

   * If [output_file] is omitted, the output will be named
     "(input_file)_(config_file).(input_ext)".

   * All settings/parameters are commented in the sample configuration files,
     which you can find in the "presets" subdir.
     NOTE: the included presets aren't guaranteed to accurately simulate any
     particular monitor model, but they may give you a good starting point!


TIPS:

   * Input is expected to have the same resolution (=*storage* aspect ratio,
     SAR) of the video mode you are simulating, including overscan if any.

   * The aspect ratio **of the simulated screen** (=*display* aspect ratio,
     DAR) is not set directly, but depends on the SAR and on the *pixel*
     aspect ratio (PAR):  DAR=SAR×PAR.  The PAR is set with the PX_ASPECT
     parameter.

   * The aspect ratio **of your final output** is set separately with the
     OASPECT parameter.  If it's different from the above, the simulated
     screen will be scaled and padded as necessary while maintaining its
     aspect ratio, so you can have e.g. a 4:3 screen centered in a 16:9 video.

   * Processing speed and quality is determined by the PRESCALE_BY setting.
     This also affects FFmpeg's RAM consumption, so if you get memory
     allocation errors try a lower factor.

   * *Most* of the processing chain uses a color depth of 8 bits/component by
     default.  Setting 16BPC_PROCESSING to yes will make all the intermediate
     steps use 16 instead.  That makes the process twice as slow and RAM-
     hungry, but if your settings are giving you prominent banding artifacts
     and such, try going 16-bit.

   * By default the output colorspace is 24-bit RGB (8 bits/component), but
     you can change that by setting OFORMAT to 1: for videos, this will output
     YUV 4:4:4 at 10 bits/component.  For images, you'll get 48-bit RGB (16
     bits/component), which works with .png or .tif for instance.
     (Of course, to get the most out of this, you'll want 16bpc processing as
     mentioned above)

   * In general, speed is the weakest link in this whole thing, so you may
     want to test your config file on a still .png image (or on a few seconds
     of video) first, tweak things to your liking, and tackle longer videos
     only after you've finalized your settings.


WRITE-UPS, VIDEOS, SAMPLE IMAGES:

1. Color CRTs:
   https://int10h.org/blog/2021/01/simulating-crt-monitors-ffmpeg-pt-1-color/

2. Monochrome CRTs:
   https://int10h.org/blog/2021/02/simulating-crt-monitors-ffmpeg-pt-2-
   monochrome/

3. Flat-Panel Displays:
   https://int10h.org/blog/2021/03/simulating-non-crt-monitors-ffmpeg-flat-
   panels/


VileR