# Membrane FFmpeg Video Filter Plugin
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This package contains elements providing video filters based on [ffmpeg video filter feature](https://ffmpeg.org/ffmpeg-filters.html#Video-Filters).
Currently only the TextOverlay element is implemented, based on [ffmpeg drawtext filter](https://ffmpeg.org/ffmpeg-filters.html#drawtext-1).
This element enables adding text on top of given raw video frames.
PRs with the implementation of other video filters are welcome!
## Installation
The package can be installed by adding `membrane_ffmpeg_video_filter_plugin` to your list of dependencies in `mix.exs`:
```elixir
def deps do
[
{:membrane_ffmpeg_video_filter_plugin, "~> 0.8.0"}
]
end
```
## Usage
### TextOverlay
Below example pipeline adds "John Doe" text over h264 video in a specified style.
```elixir
defmodule VideoFilter.Pipeline do
use Membrane.Pipeline
alias Membrane.File.{Sink, Source}
alias Membrane.H264.FFmpeg.{Parser, Decoder, Encoder}
alias Membrane.FFmpeg.VideoFilter.TextOverlay
@impl true
def handle_init(_opts) do
children = %{
file_src: %Source{location: "input.h264"},
parser: %Parser{framerate: {10, 1}},
decoder: Decoder,
text_filter: %TextOverlay{
text: "John Doe",
x: :center,
fontsize: 25,
fontcolor: "white",
border?: true
},
encoder: Encoder,
file_sink: %Sink{location: "output.h264"}
}
links = [
link(:file_src)
|> to(:parser)
|> to(:decoder)
|> to(:text_filter)
|> to(:encoder)
|> to(:file_sink)
]
{{:ok, spec: %ParentSpec{children: children, links: links}}, %{}}
end
end
```
Frame from original video:
![input](readme/input.png)
Output frame with filter applied:
![output](readme/output.png)
## Copyright and License
Copyright 2021, [Software Mansion](https://swmansion.com/?utm_source=git&utm_medium=readme&utm_campaign=membrane_ffmpeg_video_filter_plugin)
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Licensed under the [Apache License, Version 2.0](LICENSE)