Harvid decodes still images from movie files and serves them via HTTP.
Its intended use-case is to efficiently provide frame-accurate data and act as second level cache for rendering the video-timeline in Ardour.
Apart from the source-code and packages from your linux-distributor, binaries are available for OSX, Windows and Linux at http://x42.github.com/harvid/ .
Harvid is a standalone HTTP server, all interaction takes place via HTTP. After launching it, simply point a web-browser at http://localhost:1554/
The OSX bundle and window installer come with a shortcut link to launch
the server. On Linux or with the OSX package, harvid is usually started
from a terminal by simply typing harvid<enter>.
Harvid can also be run directly from the source folder without installing it. Get its build-dependencies (see below), run
make
./src/harvid
When used from ardour, ardour will automatically start the server when you open a video. Ardour searches $PATH or asks your for where it can find harvid. The easiest way is to simply run:
sudo make install
Harvid can be launched as system-service (daemonized, chroot, chuid, syslog), and listen on specific interfaces only in case you do not want to expose access to your movie-collection. However, is no per request access control.
For available options see harvid --help or the included man page which
is also available online at http://x42.github.com/harvid/harvid.1.html
ffmpeg is used to decode the movie. The source code should be compatible and compile with libav.
For encoding images, libpng and libjpeg are required.
A good start is to look in the debian/ folder that comes with the source
code (it is excluded from source archives via .gitattributes). In particular
the file debian/rules which demonstrates the use of PREFIX and DESTDIR.
Harvid is highly concurrent makes use of all available CPUs. It will spawn multiple decoder processes, keep them available for a reasonable time and also cache the video-decoder's output for recurring requests.
The cache-size is variable only limited by available memory. All images are served from the cache, so even if you are not planning to use the built-in frame cache, the cache-size defines the minimum number of concurrent connections.
The HTTP request interface is documented on the homepage of the server itself: http://localhost:1554/
The default request-handler will respond to /?file=PATH&frame=NUMBER
requests. Optionally &w=NUM and &h=NUM can be used to alter the geometry
and &format=FMT to request specific pixel-formats and/or encodings.
/index[/PATH] allows to get a list of available files - either as tree or
as flat-list with the ?flatindex=1 as recursive list of the server's docroot.
/info?file=PATH returns information about the video-file.
Furthermore there are built-in request handlers for status-information, server-version and configuration as well as admin-tasks such as flushing the cache or closing decoders.
The &format=FMT also applies for information requests with
HTML, JSON, CSV and plain text as available formatting options.