This section lists all input and output plugins which are included in the OpenVIP distribution.
When importing a file in the OpenVIP Editor, an appropriate input
plugin is chosen automatically. If you are processing files using the
command line interpeter (see Using OpenVIP
from command line), you can override the autodetection mechanism by
specifying the format parameter, which forces OpenVIP
to use the given plugin.
The FFMpegInput plugin reads multimedia files
using the FFmpeg
libraries, which provide support for a wide range of codecs and file
formats (see FFmpeg
documentation); this means that you don't need to install any
codecs separately.
FFMpegInput plugin has been tested with AVI,
DV, MOV, MPEG, MP3, VOB, WMA, and WMV file formats. These formats can be
imported in the OpenVIP Editor; other formats supported by FFmpeg can be
processed only using the command line interpreter (see Using OpenVIP from command line).
The following table lists the plugin's parameters in network file format.
Table 4.80. FFMpegInput parameters
| Parameter | Values | Description | Required |
|---|---|---|---|
| format | FFMpeg | plugin name | no |
| filename | valid filename | file to load | yes |
If you don't set the format parameter to
FFMpeg, only the formats listed above are accepted;
otherwise you can read all files supported by FFmpeg libraries.
When opening a multimedia file for the first time,
FFMpegInput plugin creates a so-called index
file, which contains information about keyframes, samples, etc. Note
that creating index can take a few minutes for large (hundreds of MB)
multimedia files. The index files are stored in the system temp
directory and can be deleted using the clear_cache
script from the OpenVIP distribution.
The FFMpegOutput plugin writes multimedia
files using the FFmpeg
libraries, which provide support for a wide range of codecs and file
formats (see FFmpeg
documentation); this means that you don't need to install any
codecs separately.
The following table lists the plugin's parameters in network file format.
Table 4.81. FFMpegOutput parameters
| Parameter | Values | Description | Required |
|---|---|---|---|
| format | FFMpeg | plugin name | yes |
| filename | string | valid filename | yes |
| file_format | string | output file format | no |
| video_codec | string | video codec | no |
| video_bitrate | integer | bitrate in kbps | no |
| audio_codec | string | audio codec | no |
| audio_bitrate | integer | bitrate in kbps | no |
If you don't specify the file_format
parameter, FFmpeg will automatically guess a suitable one according to
the filename extension. The same is true for the codec and bitrate
parameters. All supported formats and codecs are listed in the FFmpeg
documentation.
The WavInput plugin is able to read uncompressed WAV files that contain either 8-bit unsigned or 16-bit signed samples.
The WavOutput plugin writes uncompressed WAV
files that contain 16-bit signed samples (mono or stereo).
The ImageInput plugin can read sequences of
bitmap files using the ImageMagick library. It supports
JPEG, PNG, GIF and many other formats.
The following table lists the plugin's parameters in network file format.
Table 4.84. ImageInput parameters
| Parameter | Values | Description | Required |
|---|---|---|---|
| format | Image | forces the use of this plugin | no |
| filename | string | wildcard filemask | yes |
| sorttype | string | alphabetical or
numerical (default:
alphabetical) | no |
| fps | real number | frames per second of the output video stream (default:
1) | no |
| output_length | integer | number of frames in the output video stream | no |
| be_smart | boolean | try to load a whole sequence based on the name of a
single image (default: on) | no |
| allow_varying_dimensions | boolean | don't insist on input images having the same dimension
(default: off) | no |
The filename parameter can be specified as
a wildcard mask with ? and * symbols. All files that match the wildcard
mask will be loaded.
When given a file name in the form of
<prefix><number>[<extension>], the
plugin will load all files with the same prefix and extension provided
be_smart is turned on.
The order in which the images are loaded is determined by the
sorttype parameter - to load the sequence
img10.jpg, img3.jpg,
img7.jpg in the correct order
img3.jpg, img7.jpg,
img10.jpg you have to switch to numerical
sorting.
The value of output_length can be greater than the actual number
of files available on disk. In this case the plugin repeats the files
from beginning. For example, if there are two files
img1.jpg and img2.jpg
available on disk and you specify
output_length=5, the output stream will consist
of img1.jpg, img2.jpg,
img1.jpg, img2.jpg,
img1.jpg.
A videostream in which frames have various dimensions is by all
means invalid. Therefore set the
allow_varying_dimensions parameter to
true only if you are sure that the following plugins
can handle it.
This plugin writes a sequence of numbered bitmap files using the ImageMagick library. It supports JPEG, PNG, GIF and many other formats.
The following table lists the plugin's parameters in network file format.
Table 4.85. ImageOutput parameters
| Parameter | Values | Description | Required |
|---|---|---|---|
| format | Image | selects this plugin | yes |
| filename | string | wildcard filemask | yes |
| numwidth | integer | a minimal width (in digits) of the number in an output file name | no |
If the filename parameter contains an
asterisk, it will be replaced by the image number in the output file
names. If the filename doesn't contain an
asterisk, the number will be placed right before the extension. The
numbering always starts from zero.
In case you supply the numwidth parameter
the numbers will be left-padded with zeros to have the required number
of digits. Otherwise the width is determined by the length of the
greatest number.
AviInput plugin reads AVI files using the
Video for Windows functions (and thus can be used
only in Windows).
The following table lists the plugin's parameters in network file format.
Table 4.86. AviInput parameters
| Parameter | Values | Description | Required |
|---|---|---|---|
| format | Avi | forces the use of this plugin | no |
| filename | string | a valid filename | yes |
Currently this plugin cannot open palleted files, only truecolor ones (which is most of them anyway). It also cannot open files with variable bitrate MP3 audio, but FFMpegInput can.