I would like one of these two things (whichever is cheaper).
1) a USB webcam with raw 24bpp RGB (not compressed, and not raw YUV) output.
2) a video capture USB dongle (or frame grabber USB dongle) with raw 24bpp RGB output. (I already have a composite video NTSC camera that would work well with such a capture solution)
This is so my program that I'm going to write that will use this video stream for input does not need to do any additional processing such as YUV to RGB conversion or JPEG or MPEG decompression. The raw 24bpp RGB video stream would be then directly used directly in my video processing/machinevision application. USB type must be USB 2 as my PC does not have USB 3 ports.
Unfortunately my Googling has not yielded many results. Most places do not advertise what format their device actually outputs (as it is usually handled by the software they package with their device, so the end user doesn't need to know or care about the format, or at least the company doesn't think the end user cares). Of the places that DO talk about their devices format they all are either compressed (such as MJPEG, MPEG, MPEG2, MPEG4, or H264) or they are a YUV format (usually chroma subsampled as YUV420 or YUV422). I have yet to see a device advertised as outputting a raw 24bpp RGB video stream. Maybe someone on these forums has had more luck, and can advice me on where to get such a product.
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first shot in Google
search for something like this, beware that demosaicing algorithm must run in software... (usually part of the driver).
btw you can try also some DIY go for astronomy (or sky observation) pages/forums and ask about USB camera capable to output RAW Bayer (usually as 8 bit grayscale) - similar to famous SPC880/SPC900NC CCD cameras .
Last edited by pandy; 25th Sep 2014 at 04:40.
I think you're asking for trouble by insisting on trying to transfer RGB over USB 2.0, unless you want to capture at less than D1 resolution. You'll need a transfer rate that never drops below 31 MB/sec, which is dangerously close to real-world limits.
I assume you're aware that composite can't transmit RGB; any capture from that camera will be a transmogrification of what the sensor is picking up.
Never mind. I failed to notice the webcam I found has built-in image compression even if the description says RGB 24bpp.
Speed limit is not problem unless camera use 3 sensors for components - normally when 1 sensor is used, RGB video is a Grayscale video (and later demosaicing is performed). USB 2 should be sufficient.
So the camera collects less than 3 bytes for each "pixel" it delivers. But in my experience with webcams that have an RGB mode -- the bayer filter is applied in the camera. So indeed 3 bytes per pixel is transmitted over the USB cable, and YUY2 or YV12 transmission requires less bandwidth (2 bytes per pixel and 1.5 bytes per pixel, respectively).
Even if you find a webcam that transmits raw bayer data over USB you can't go too much over 720x480 at 30 fps before hitting the real world USB 2.0 limit of ~30 MB/s. You'll need a USB 3.0 webcam for uncompressed HD video.
Last edited by jagabo; 28th Sep 2014 at 08:31.
if you can feed it an HDMI input, this Magewell dongle seems similar to what you're looking for. It works with USB 2.0 by having hardware that can lower HD resolutions and usb 3.0 is needed for lossless 1080p/1080i. It's $300
Maybe use Sewell's Composite to HDMI adapter for your current NTSC camera? Really not sure about that.
If down the line you need component to hdmi:
And sorry, but I have to say it. If it was me, I would just forget about the whole RGB thing and use a $20 generic version of EZcap 148, which has component and composite connections, with Virtualdub
Last edited by ezcapper; 28th Sep 2014 at 14:55. Reason: wrong link for the component adapter
If you read ezcapper's other posts a pattern emerges, He is a shill for ezcap.
And by the way it CAN'T BE USB3 (as much as I want it to be), because my laptop (even though it's quite new, as I bought it just a couple years ago) does NOT have USB3 ports. It only has USB2. When I bought my laptop, though USB3 did exist, it was only available in the "best of the best" computers (read as, "the most expensive computers"), and I didn't shell out a lot of money for my laptop when I bought it, and I sure as anything am not going to shell out more money for another one now, just to get a USB3 port. It is a very good computer overall, so I have no need to replace it, and getting a new one just for the USB3 port would be a waste of money. So I hope you can find a USB2 webcam for me, with the specifications that I need.
Note that I do not need a huge resolution, just standard 640x480 (VGA) resolution from the camera. And I don't need a full 30fps (it would be nice, but not absolutely necesary for my application), so data-rate will not be a problem. If the camera's max-framerate is only 15fps, that would be fine, even 5 or 10 fps would be fine. So again, the data-rate will not be a problem, and should EASILLY be handled by a USB2 connection, without any video compression algorithm being used by the camera, thus allowing a full RGB24 or RGB32 RAW signal to be sent from the camera to my computer via the USB2 connection.
Looks like I finally found something to my specifications (and even exceeds my specs). It can be configured to output raw debayered RGB or YUV, or truly raw bayer RGB. Resolution is 752x480. Frame rate is 60fps. USB connection type is USB2. Price is $275.
Link to product page:
Link to specs document:
Assuming you were being finicky about colorspace because quality is important -- 0.3mp works for you!?
The spec sheet says 8-bit and 16-bit raw Bayer data (color). What about your 24 bpp requirement?
And by the way there are several variants of this camera. This was the cheapest color one from this company. They also make a monochrome (grayscale) version, which is basically the same as this color camera, but without a bayer-filter in front of the image sensor chip (which is probably even better for astrophotography, and in particular the photometry measurements, than the color camera).
And there are several others that have a lower frame rate, but much higher resolution. All cameras listed below this line have a higher resolution than 752x480, and they cost $100 more than the preiviously mentioned cameras ($375).
1328x1048 at 23fps http://www.ptgreystore.com/firefly-mv-13-mp-color-usb-20
And those were just CMOS chip cameras. They also make CCD chip cameras. All cameras below this line are CCD cameras.
1296x964 at 18fps (color) http://www.ptgreystore.com/chameleon-13-mp-color-usb-20
1296x964 at 18fps (monochrome) http://www.ptgreystore.com/chameleon-13-mp-mono-usb-20
Once again - ALL cameras are RGB, they sent (if configured correctly) grayscale RAW RGB that can be debayered or in software (driver) on in hardware (camera FE).