Hello, readers!

Some weeks ago we released a new version of Grilo and the Plugins set (yes, it sounds like a 70’s music group :smile:). You can read the announcement here and here. If you are more curious about all the detailed changes done, you can take a look at the Changelog here and here.

But even when you can read that information in the above links, it is always a pleasure if someone highlights what are the main changes. So let’s go!

Launch Tool

Regarding the core system, among the typical bug fixes, I would highlight a new tool: grl-launch. This tool, as others, got inspiration from GStreamer gst-launch. So far, when you wanted to do some operation in Grilo, like performing a search in YouTube or getting the title of a video on disk, the recommended way was using Grilo Test UI. This is a basic application that allows you to perform the typical operations in Grilo, like browsing or searching, and everthing from a graphical interface. The problem is that this tool is not flexible enough, so you can’t control all the details you could require. And it is also useful to visually check the results, but not to export the to manage with another tool.

So while the Test UI is still very useful, to cover the other cases we have grl-launch. It is a command-line based tool that allows you to perform most of the operations allowed in Grilo, with a great degree of control. You can browse, search, solve details from a Grilo media element, …, with a great control: how many elements to skip or return, the metadata keys (title, author, album, …) to retrieve, flags to use, etc.

And on top of that, the results can be exported directly to a CSV file so it can be loaded later in a spreadsheet.

As example, getting the 10 first trailers from Apple’s iTunes Movie Trailers site:

$ grl-launch-0.2 browse -c 10 -k title,url grl-apple-trailers
23 Blast,
A Most Wanted Man,
ABC's of Death 2,
About Alex,
"Alexander and the Terrible, Horrible, No Good, Very Bad Day",
Are You Here,
As Above / So Below,
10 results

As said, if you re-direct the output to a file and you import it from a spreadsheet program as CSV you will read it better.

dLeyna/UPnP plugin

Regarding the plugins, here is where the fun takes place. Almost all plugins were touched, in some way or other. In most cases, for fixing bugs. But there are other changes I’d like to highlight. And among them, UPnP is one that suffered biggest changes.

Well, strictly speaking, there is no more UPnP plugin. Rather, it was replaced by new dLeyna plugin, written mainly by Emanuele Aina. From an user point of view, there shouldn’t be big differences, as this new plugin also provides access to UPnP/DLNA sources. So where are the differences?

First off, let’s specify what is dLeyna. So far, if you want to interact with a UPnP source, either you need to deal with the protocol, or use some low-level library, like gupnp. This is what the UPnP plugin was doing. Still it is a rather low-level API, but higher and better than dealing with the raw protocol.

On the other hand, dLeyna, written by the Intel Open Source Technology Center, wraps the UPnP sources with a D-Bus layer. Actually,not only sources, but also UPnP media renderers and controllers, though in our case we are only interested in the UPnP sources. Thanks to dLeyna, you don’t need any more to interact with low-level UPnP, but with a higher D-Bus service layer. Similar to the way we interact with other services in GNOME or in other platforms. This makes easier to browser or search UPnP sources, and allows us to add new features. dLeyna also hides some details specific to each UPnP server that are of no interest for us, but we would need to deal with in case of using a lower level API. The truth is that though UPnP is quite well specified, each implementation doesn’t follow it at 100%: there are always slight differences that create nasty bugs. In this case, dLeyna acts (or should act) as a protection, dealing itself with those differences.

And what is needed to use this new plugin? Basically, having dleyna-service D-Bus installed. When the plugin is started, it wakes up the service, which will expose all the available UPnP servers in the network, and the plugin would expose them as Grilo sources. Everything as it was happening with the previous UPnP source.

In any case, I still keep a copy of the old UPnP plugin for reference, in case someone want to use it or take a look. It is in “unmaintained” mode, so try to use the new dLeyna plugin instead.

Lua Factory plugin

There isn’t big changes here, except fixes. But I want to remark it here because it is where most activity is happening. I must thank Bastien and Victor for the work they are doing here. Just to refresh, this plugin allows to execute sources written in Lua. That is, instead of writing your sources in GObject/C, you can use Lua. The Lua Factory plugin will load and run them. Writing plugins in Lua is a pleasure, as it allows to focus on fixing the real problems and leave the boiler plate details to the factory. Honestly, if you are considering writing a new source, I would really think about writing it in Lua.

And that’s all! It is a longer post than usual, but it is nice to explain what’s going on in Grilo. And remember, if you are considering using Grilo in your product, don’t hesitate to contact with us.

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Juan A. Suárez



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