I looked at the pictures as well and I noticed a few things: The aspect ratio of the impactvcb-e isn't right, it's too narrow. What width and height did you specify when capturing? I can't test this myself as I'm abroad, but try 720x480 or 768x480. I also noticed that the cx23885 driver selects slightly incorrect default brightness, contrast and saturation values. Whether that is the cause of the color differences is debatable, but you can try using my repo: git://linuxtv.org/hverkuil/media_tree.git Checkout the cx23 branch. This branch contains a pile of cleanup patches including a conversion to the control framework, which should ensure correct (to my knowledge) defaults for the color controls. Regards, Hans On 04/25/2014 02:48 PM, Steven Toth wrote: > Doh, HTML cause vger to drop it. Resending. > > On Fri, Apr 25, 2014 at 8:47 AM, Steven Toth <stoth@xxxxxxxxxxxxxx> wrote: >> On Fri, Apr 25, 2014 at 8:19 AM, Steve Cookson <it@xxxxxxxxxx> wrote: >>> >>> Hi Guys, >>> >> >> Hello again. >> >>> >>> (I'm copying Ezequial on this because of the work he has done on the >>> stk1160). >>> >>> My colleague (a Doctor) had this to say on the medical images I posted >>> earlier (see below): >>> >>>> The impactVCB-e image is redder and less clear. The dvc100 and easycap >>>> seem similar to me and both of them are not as good as the original one. >>> >>> So I have to ask how is it that the cheap little EasyCap is performing at >>> the same level as the Dazzle DVC100 and better than the ImpactVCB-e? >>> >> >> Its usually either because the Linux engineers simply aren't focused on >> improving quality for the last 'mile', or that the ADC/Video digitizer >> differers between products. 'Redder' isn't usually a differentiation between >> video digitizer silicon, its miss-configuration - for example. >> >> >>> >>> It seems to me that the more complex and expensive DVC100 and ImpactVCB-e >>> should perform well and that the EasyCap should be the runner up. >>> >> >> Not necessarily, but I can understand why you may think that. The reality is >> - you are measuring the work of individuals who we're not paid to create >> these Linux drivers. They work well enough for their needs, they scratched >> their own itch, then they moved on, more than likely this is the case. So, >> you are seeing a mixture of different silicon, different attention to >> detail, different default values and different levels of commitment in the >> driver developers. >> >>> If the DVC100 and ImpactVCB-e had had the same love and attention that >>> Ezequial has shown the EasyCap would they outperform it? >>> >> >> Hard to say. With my experience working for Hauppauge, directly in their >> engineering team, having worked on literally hundreds of products, lots of >> different video digitizer, they're all fairly close quality wise in general, >> with good signals, with the right drivers. >> >> What makes a good video digitizer stand out from a poor one, it how it >> performs in very poor signal conditions. >> >> >>> >>> The ImpactVCB-e is easier to use internally and the Dazzle is external. >>> Does the fact that the ImpactVCB-e has a PCI-e connector help it at all? >>> >> >> >> Invariably not. >> >> >>> >>> Otherwise I should just focus on EasyCap for my raw SD capture and move >>> on. >>> >> >> You need to make that judgement call. If you are building a business around >> medical imaging and have no engineering capability to improve drivers, go >> with what your gut says and what's available to you today. You shouldn't >> rely on the good will of Linux engineers to fix your business requirements >> in their spare time, in the coming weeks or months. >> >> Or, hire a consultant to improve the drivers for you and the rest of the >> Linux community. This what everyone else does. >> >> - Steve >> >>> >>> Thanks, >>> >>> Steve >>> >>> >>> On 23/04/14 16:22, Steve Cookson wrote: >>>> >>>> Hi Guys, >>>> >>>> I would be interested in your views of the comparisons of these images. >>>> The still is the image of a duodenum taken during an endoscopy and recorded >>>> to a DVD player (via an s-video or composite cable). Although the endoscope >>>> is an HD endoscope, the DVD recorder isn't and the resulting video is >>>> 720x480i59.94. >>>> >>>> Here are further details of the video:- >>>> >>>> Format : MPEG Video v2 >>>> Format profile : Main@Main >>>> Format settings, BVOP : Yes, Matrix : Custom, GOP : M=3, N=15 >>>> Bit rate mode : Variable >>>> Bit rate : 4 566 Kbps >>>> Maximum bit rate : 10 000 Kbps >>>> Width : 720 pixels >>>> Height : 480 pixels >>>> Display aspect ratio : 4:3 >>>> Frame rate : 29.970 fps >>>> Standard : NTSC >>>> Color space : YUV >>>> Chroma subsampling : 4:2:0 >>>> Bit depth : 8 bits >>>> Scan type : Interlaced >>>> Scan order : Top Field First >>>> Compression mode : Lossy >>>> Bits/(Pixel*Frame) : 0.441 >>>> >>>> The video was played through Dragon Player and the video signal has >>>> exited through a mini-VGA port defined as 640x480 and passed through a >>>> VGA->S-Video converter to an s-video cable. >>>> >>>> The cable has in turn been connected in turn to a Dazzle DVC100, an >>>> EasyCap stk1160 and a Hauppauge ImapctVCB-e. >>>> >>>> Each setting (eg brightness and contrast etc) has as near as possible to >>>> mid-range and a screengrab taken. >>>> >>>> The results are shown here: >>>> >>>> Original: >>>> http://tinypic.com/usermedia.php?uo=fNkd6hpTbcMrgmD6gSf74Ih4l5k2TGxc >>>> >>>> Dazzle DVC100: >>>> http://tinypic.com/usermedia.php?uo=fNkd6hpTbcMaOf4QTsIefYh4l5k2TGxc >>>> >>>> ImpactVCB-e: >>>> http://tinypic.com/usermedia.php?uo=fNkd6hpTbcM7i72IqGujuIh4l5k2TGxc >>>> >>>> STK1160: >>>> http://tinypic.com/usermedia.php?uo=fNkd6hpTbcPO7kmQk/IS94h4l5k2TGxc >>>> >>>> I would be grateful for your views on the quality of the images. >>>> >>>> Is one of materially higher quality than the others, or can I adjust the >>>> settings to improve the quality of one of them more. >>>> >>>> It seems to me that the Hauppauge is marginally better than the others. >>>> What do you think? >>>> >>>> Can I improve the test? >>>> >>>> Regards >>>> >>>> Steve. >>>> >>>> >>>> >>>> -- >>>> 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 >>>> >>> >> >> >> >> -- >> Steven Toth - Kernel Labs >> http://www.kernellabs.com >> > > > -- 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
