Alright, I'll bite. Tony Nugent (tony@xxxxxxxxxxxxxxxxx): > On two occasions earlier this month I asked a question about why > v4l-conf (and therefore xawtv) was all of a sudden failing with the > following error: "can't open /dev/video0: Cannot allocate memory". The following is my understanding of this problem. Hopefully someone will correct me if I'm wrong: v4l-conf is only necessary for using the 'overlay' mode of xawtv/V4L where the capture card copies frames directly to video memory, rather than having the data go through the CPU. It works by using the DGA extension to get an address for video memory, closing the DGA extension, assuming that address is still valid, and then using it to tell the capture card where to send its data. Mark Vojkovich, currently with nVidia and one of the authors of the nVidia drivers, is very much against this abuse of the DGA API. Specifically because of the newer Geforce cards where the assumption about validity of the pointer is false, and hence, is my understanding of why this fails. The solution to this is that overlay mode should be deprecated. The functionality, where the frames are transferred directly to video memory, has been put into an XFree86 extension called, simply, "v4l", and this allows the X server to be made aware of what's going on, and lets it handle memory allocation properly. Add the line: Load "v4l" in the modules section of your XF86Config-4 file to enable this extension, which allows xawtv use that to negotiate the transfers. There are, however, quality issues with both this method and the old overlay method, and personally I would recommend you try out my TV app as well. It's called tvtime: http://tvtime.sourceforge.net/ It does processing on the video frames from V4L before uploading them to the server, increasing quality (but eating CPU). It does not require v4l-conf or the "v4l" X module. > What I have observed over the past month or so is that newbie or > help-me posts from "users" are almost always ignored. > [...] > Ok, so this is obviously a developers-only maling list. And if I was > a v4l developer then this is definitely the place to be. While I agree that it is unfortunate that user requests are often ignored, I would hope you have some sympathy for those of us who have only so much free time to devote to our software projects, let alone all the mailing lists. I don't think people actively ignore requests as much as have to make decisions about how to spend their limited free time. > Thanks for not making it plainly clear on the list's web page (URL > below) that user-like messages would be ignored. I'm tempted to add > "thanks for wasting my time" but I don't want to sound so rude. That's ok, it's rude enough just like that. I'm sure if someone had time to update or even make a web page for this list, they'd first post a reply to your messages. -- Billy Biggs vektor@xxxxxxxxxxxx
