Re: Video capture on EOS 650d only with 4 to 8 fps?

On Mon, Dec 21, 2020 at 04:07:03AM +0100, Thomas Orgis wrote:
> Am Sun, 20 Dec 2020 21:20:56 -0500
> schrieb Alan Corey <[email protected]>: 
> 
> > I'm not a Canon person but where are you putting your video?  The
> > transfer off is likely to be a bottleneck.  There are adapters that
> > replace memory cards but send by wifi, one of those may help.
> 
> I am using the USB connection. My Camera doesn't do Wifi, even —
> but yes, it apparently would with an Eye-Fi adapter. But even then,
> we're talking about 480 MBit/s for USB 2. Wifi (from a vintage DSLR) is
> hardly faster than that.
> 
> The movie file for 10 seconds is 19M in size. That's less then
> 2 MBit/s. Or is gphoto2 taking a RAW stream from the camera and
> compressing it to MJPEG itself? That would match the resolution of
> 960x640, which as raw RGB would be 369 MBit/s (as YUV422 only 246 MBit/s).
> 
> Can someone confirm what is the mode of operation of
> 
> 	gphoto2 --capture-movie
> ?
> I don't see that forming such a serious bottleneck so that only 4 fps
> get through, unless it's the camera itself being slow to serve.
> 
> But I don't believe that this is a true hardware limitation, as Canon's
> own webcam tool (for some other OS) lists this model and older ones as
> supported and I guess they don't mean to server 4 fps for high-quality
> video conferencing.
> 
> I do not see significant CPU usage by gphoto. So, anyone with an EOS of
> similar vintage can share if there is smooth video possible?

The Canon EOS sends us JPEG frames and libgphoto2 passes them through.

How many frames per second does "gphoto2 --capture-movie=10s" report?
(To rule out ffmpeg rate issues.)

This might be largely by either delay handling or slow USB ports.

Is the camera connected directly to your machine or a USB2 hub at least?

Ciao, Marcus


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