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

Hi!

I used a 650D for a while this spring and I was, to my big surprise, 
actually able to get a clean HDMI out of it (no text as long as no 
buttons were pressed and the battery was OK). An Avermedia LGX capture 
box reported it to be a 30 Mbps/s 1080p60. I mainly used it for 
capturing via USB though, just as you intend to. I think that I got the 
low frame rates when setting it to film mode on the dial on the top of 
the camera. I think we had it on M, Av or Tv, can't remember, and got 
decent frame rates and picture quality. It's nowhere near a GH4 or GH5, 
which we're using now (via HDMI 4k), but rather good anyway. The main 
advantage over a web cam is the optics of course. Pixel wise 
(compression and so on) you may be in the same ballpark as the best web 
cams. The 450D also works with USB live capture, but has slightly more 
compression.

I found my old post from March here (testing a 550D, more or less same 
results with the 650D): "I wanted to get a decent live feed from a DSLR 
via USB and have tried a Canon EOS 550D and a Nikon D7100. The 550D 
gives me an almost acceptable 1056x704 at 26-30 fps and the D7100 a mere 
640x426 at 24 fps." I just can't seem to find the test results from the 
650D and 450D.

/Fredrik

On 21/12/2020 08:58, Marcus Meissner wrote:
> 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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