[gst-devel] Please help me!!!

Ronald Bultje rbultje at ronald.bitfreak.net
Mon Nov 25 04:05:08 CET 2002

Hi Gustavo,

On Mon, 2002-11-25 at 04:44, Gustavo Sverzut Barbieri wrote:
>    3) I want to be able to seek in the stream(both live and already
> recorded), so I can go to directly to the minutes I want (from the file
> named as the hour it was recorded)

Then you definately need MPEG.

>    4) In future I want to make one v4l card to record 2 or more
> channels  at the same time (swaping between channels each frame, so I
> can record 2  or more cameras with only 1 v4l device)

I would *highly* disagree here. The card needs several moments to sync
with the new input, which would leave you with a framerate of maybe 2
fps per input. Using two cards is so much easier, and these cards are
cheap anyway.

>    Since I cannot find a ready to use solution I'll develop mine and
> I'm thinking about gstreamer as my framework. But I want to know if it
> is possible to do and how to do that (basic guidelines). And some
> specific things about GStreamer:
>    1) There is a v4l capture interface?

Yes. v4lsrc (video4linux) and v4l2src (video4linux2) both exist.

>    2) There is any crop plugin so I can crop the border noise?

Not that I know of. You'd have to write your own.

>    3) There is any bitmap overlay plugin (so I can put the "clock" over
> the frames)


>    4) There is any stream server inside gstreamer that is seek capable
> and can output to any type of player (mplayer and windows media player
> by instance). What is the best format to stream?

There is no stream server plugin in Gst for video. We do have several
audio stream server plugins. MPEG is your choice, I guess...

>    5) How optimized are GStreamer encoders? It's possible to record 4
> v4l inputs at 640x480 @ 25 fps? It's possible to use lavcodec (from
> ffmpeg, very optimized)

We have ffmpeg encoder plugins.


Ronald Bultje <rbultje at ronald.bitfreak.net>
Linux Video/Multimedia developer

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