mirror of
https://git.ffmpeg.org/ffmpeg.git
synced 2024-12-27 09:52:17 +00:00
50 lines
1.6 KiB
Plaintext
50 lines
1.6 KiB
Plaintext
\input texinfo @c -*- texinfo -*-
|
|
|
|
@settitle Video Hook Documentation
|
|
@titlepage
|
|
@sp 7
|
|
@center @titlefont{Video Hook Documentation}
|
|
@sp 3
|
|
@end titlepage
|
|
|
|
|
|
@chapter Introduction
|
|
|
|
|
|
The video hook functionality is designed (mostly) for live video. It allows
|
|
the video to be modified or examined between the decoder and the encoder.
|
|
|
|
Any number of hook modules can be placed inline, and they are run in the
|
|
order that they were specified on the ffmpeg command line.
|
|
|
|
Three modules are provided and are described below. They are all intended to
|
|
be used as a base for your own modules.
|
|
|
|
Modules are loaded using the -vhook option to ffmpeg. The value of this parameter
|
|
is a space seperated list of arguments. The first is the module name, and the rest
|
|
are passed as arguments to the Configure function of the module.
|
|
|
|
@section null.c
|
|
|
|
This does nothing. Actually it converts the input image to RGB24 and then converts
|
|
it back again. This is meant as a sample that you can use to test your setup.
|
|
|
|
@section fish.c
|
|
|
|
This implements a 'fish detector'. Essentially it converts the image into HSV
|
|
space and tests whether more than a certain percentage of the pixels fall into
|
|
a specific HSV cuboid. If so, then the image is saved into a file for processing
|
|
by other bits of code.
|
|
|
|
Why use HSV? It turns out that HSV cuboids represent a more compact range of
|
|
colors than would an RGB cuboid.
|
|
|
|
@section imlib2.c
|
|
|
|
This allows a caption to be placed onto each frame. It supports inserting the
|
|
time and date. By using the imlib functions, it would be easy to add your own
|
|
graphical logo, add a frame/border, etc.
|
|
|
|
|
|
@bye
|