need to draw over the video and send data as

[salocin]

hi, I´m planning to use VLC (modifing it, when needed) to capture video from a couple of webcams (no audio needs) and stream this video signals. I also need to capture some sensors data (via serial port) and stream this info sincronized with the video. That would be the server.
On the other side the client would have to be able to display the video (one, or both channels at the same time), and draw some simple graphs related with the sensors data recived, on the overlay surface.

It´s possible to render transparent bitmaps on the overlay?

It´s possible to to encode the info I want to sent as subtitle steam in real time (while this info are not characters but floats) ?

Of course I have many other questions, but I don´t want to ask too many at the same time....

[The DJ]

First of all, you need one VLC client per running stream.
Second, to stream your sensor data you would need to encode it into a audio or spu track i guess. I guess developing your own format for that would be best.

Then overlaying on the client side.
VLC support subtitle overlays, which can be in color, so why not. But i don't think it will work out of the box.

There are also video filters that do something like this like the logo filter for instance which displays a single png image on top of the video.

So it's possible, it's just gonna be a lot of work.

[salocin]

Thanks a lot for your (very fast) answer.

I´m going to start this project in two weeks (after my exams) so I guess that I´ll came back here when I get into troubles.

I know that there is a lot to do, but I also think that it does worth it. Because it will make a lot wider the possible uses of VLC. For example it would be able to act as an interface (control signals apart) for teleoperation of robots (An RC Helicopter in my case).

Thanks again, Salocin.

[The DJ]

You should talk to some of the people of matroska.org team. their file format allows for control sequences (although it is not streamable yet).

Anyway. you should consider doing a bit more design work on this idea before you start. Too make sure you don't get stuck along the way.

[Dnumgis]

There was a patch floating around to render SVG( scaleable vector graphics) on top of the video. If svg can represent the data in question, then you could just send SVG as a subtitle track with i.e the OGM container, and render it using that patch on the client side.

[rici80]

I have to put an svg picture over a video.

I use:
vlc ./movie.avi --spu --osd --text-renderer=svg --sub-filter=marq --marq-marquee=”$(cat ./image.svg)”

the only problem is that vlc scale my svg picture to put them into a small square in the centre of the video...

I don't know why.... is this a bug or a my error??

Help me please...
Thanks a lot