live video switching (was: Linux Tools for Serious > Photographers)

Len Ovens len at
Wed Aug 8 19:45:53 UTC 2012

On Wed, August 8, 2012 8:03 am, Luke Kuhn wrote:
> I didn't know LiVES could do anything like that, as it has to "import" all
> video files before use. Kdenlive (in repo, and which I use for making

If LiVES has to import first, then the feature of taking live streams was
just another way to import a video file. That is not what I was talking
about. As far as I know, we are not shipping kdenlive this cycle, though
it has been made easier to install. I don't get the idea it does live
video switching/fading either. By live switching I mean having two or more
video streams coming in direct from cameras for example and being able to
see both streams at the same time as well as the result of the switching
(that is at least three live views)... probably four to include at least
one stream from the local drive. The resultant video is then output as
video that can be broadcast at the same time the incoming video is being
made. Bonus if the audio can be mixed on the same machine. or at least
added to the stream. Anything less is editing/VJing.

The thing that I am trying to say however, is that I don't think we need
to worry about finding an app that does that. That kind of work really
can't be done solo. It requires a team of people. A min. of 4 if the
switcher can produce as well, but still need two for camera and one for
audio. I suppose one could get away with two people if one camera is
stationary and the audio is set a little low and there is no need to
transition audio streams. In my opinion the result would be sub-standard.
Normally, seven people would be used.  (even at a place that skimps on
_everything_) The only place I see this being used is in a live setting
for filling large screens behind or to the side of a stage where it was
important to show the performer. We would be getting into specialty
work... a very small group of people and a set of apps we probably can't
test on any of our HW. (anyone have at least a dual video input card as
well as video out?) My machine has trouble giving smooth video from a
cheap webcam... and the video out is way lagged behind the input. I think
live video work would require getting rid of X and handling the video
directly with a video version of jackd. I think there is a reason it is
hard to find software that can do this stuff, not enough people want it or
the hardware is just not there yet. I did find a thread where someone was
looking for such stuff, the responses were all that it was better to get
hardware, that any of the software solutions showed noticeable lag. So
computers have gotten faster, but they are still not there yet.

Len Ovens

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