Hi Sylwester, On Mon, Sep 24, 2012 at 06:51:41PM +0200, Sylwester Nawrocki wrote: > Hi Sakari, > > On 09/24/2012 03:44 PM, Sakari Ailus wrote: > > How about useing a separate video buffer queue for the purpose? That would > > provide a nice way to pass it to the user space where it's needed. It'd also > > play nicely together with the frame layout descriptors. > > It's tempting, but doing frame synchronisation in user space in this case > would have been painful, if at all possible in reliable manner. It would > have significantly complicate applications and the drivers. Let's face it: applications that are interested in this information have to do exactly the same frame number matching with the statistics buffers. Just stitching the data to the same video buffer isn't a generic solution. > VIDIOC_STREAMON, VIDIOC_QBUF/DQBUF calls would have been at least roughly > synchronized, and applications would have to know somehow which video nodes > needs to be opened together. I guess things like that could be abstracted > in a library, but what do we really gain for such effort ? > And now I can just ask kernel for 2-planar buffers where everything is in > place.. That's equally good --- some hardware can only do that after all, but do you need the callback in that case, if there's a single destination buffer anyway? Wouldn't the frame layout descriptor have enough information to do this? Kind regards, -- Sakari Ailus e-mail: sakari.ailus@xxxxxx XMPP: sailus@xxxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
