> I�ve looked at the V4L2 API description about this capturing; looks good,
> but I�m missing one detail: what happens when program can�t dequeue fast
> enough (or deliberately throttles the framerate). More specifically: when
> the queue is full, do you drop the last frame captured, or the oldest?
bttv never ever throws away a captured frame. If there is no free buffer
to put data in, bttv stops capture (i.e. it keeps the old data).
> I ask
> because originally in my webcam driver I simply dropped the last frame;
> however, this quickly leads to stale data in the buffer (I used a few
> internal buffers to queue data);
Well, bttv has no internal buffers but uses only the ones queued by the
application...
> be nice to write a few words about it. Or turn it into an option. Sometimes,
> all an application is interested in is the latest frame, and don�t care
> about queueing, or dropping a few frames (maybe using only one buffer
> will do the trick?).
That's the way to go IMHO. If the app don't need queued frames, it
simply should'nt use multiple buffers.
Gerd
--
Gerd Knorr <[EMAIL PROTECTED]> -- SuSE Labs, Au�enstelle Berlin
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