On Thu, 19 Nov 2009 09:08:22 +0100 Hans de Goede <hdegoede@xxxxxxxxxx> wrote: > Hi, > Hi, thanks for commenting on this. > On 11/17/2009 11:41 AM, Antonio Ospite wrote: > > Hi, > > > > gspca does not implement vidioc_enum_frameintervals yet, so even if a > > camera can support multiple frame rates (or frame intervals) there is > > still no way to enumerate them from userspace. > > > > The following is just a quick and dirty implementation to show the > > problem and to have something to base the discussion on. In the patch > > there is also a working example of use with the ov534 subdriver. > > > > Someone with a better knowledge of gspca and v4l internals can suggest > > better solutions. > > > > > Does the ov534 driver actually support selecting a framerate from the > list this patch adds, and does it then honor the selection ? > Yes it does, it can set framerates as per the list I added (in fact I got the list looking at what the driver supports), and I can also see it honors the framerate setting, from guvcview fps counter in the capture window title. So only framerate enumeration is missing. > In my experience framerates with webcams are varying all the time, as > the lighting conditions change and the cam needs to change its exposure > setting to match, resulting in changed framerates. > > So to me this does not seem very useful for webcams. > As long as the chips involved (bridge, ISP, sensor) are powerful or smart enough then the camera won't have problems. I guess that for ov534/ov538 the usb bandwidth is the limiting factor for the framerates, as we are using a raw format. > Regards, > > Hans Btw, did you take a look at the patch anyway? Can you suggest a better place where to put the structures needed for this functionality? Regards, Antonio -- Antonio Ospite http://ao2.it PGP public key ID: 0x4553B001 A: Because it messes up the order in which people normally read text. See http://en.wikipedia.org/wiki/Posting_style Q: Why is top-posting such a bad thing? A: Top-posting. Q: What is the most annoying thing in e-mail?
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