On Tuesday 15 January 2008, Herton Ronaldo Krzesinski wrote:
> Em Tuesday 15 January 2008 18:56:35 Laurent Pinchart escreveu:
> > Hi Herton,
> >
> > On Tuesday 15 January 2008, Herton Ronaldo Krzesinski wrote:
> > > Hi Laurent, thanks for the commit and advice. We played with the webcam
> > > again (sorry for delay) and we found out that it isn't really reporting
> > > the FID bit, but only end of frame marker (EOF). This is strange
> > > indeed, as from what I understand from UVC spec FID is required while
> > > EOF is optional.
> >
> > The bmFramingInfo field in the probe&commit control can be used by the
> > device to report if it supports FID and/or EOF. However, for known
> > frame-based formats, the field must be ignored. Just out of curiosity,
> > could you print the field's value when reading the probe and commit
> > controls ?
>
> It's always 0x00, falls at else in size check inside uvc_get_video_ctrl:
> uvc_get_video_ctrl: size != 34, bmFramingInfo = 0x00
>
> > > I reworked the quirk that Claudio made against revision 166 from svn,
> > > but now using the EOF to sync the stream (the previous quirk was ok,
> > > but on laggy communication, like using to transmit a video stream over
> > > internet etc., the frames would overlap etc. resulting in many display
> > > issues):
> >
> > Your patch could drop the last payload of each frame. Could you please
> > try the attached patch ?
>
> It works, but gives a different behaviour: for example, I simulate lag
> in luvcview placing a sleep(1) at the start of uvcGrab function, with
> this patch it captures only some frames at start and stops, with the
> patch I posted I receive continous snapshots.

I'm not sure to understand. Could you please elaborate ?

Best regards,

Laurent Pinchart
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