From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from smtp1.sscnet.ucla.edu ([128.97.229.231]:50655 "EHLO smtp1.sscnet.ucla.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754515AbZIOOtR (ORCPT ); Tue, 15 Sep 2009 10:49:17 -0400 Message-ID: <4AAFA955.9080501@cogweb.net> Date: Tue, 15 Sep 2009 07:48:53 -0700 From: David Liontooth MIME-Version: 1.0 To: Andy Walls CC: linux-media@vger.kernel.org Subject: Re: Reliable work-horse capture device? References: <4AAEFEC9.3080405@cogweb.net> <20090915000841.56c24dd6@pedra.chehab.org> <4AAF11EC.3040800@cogweb.net> <1253011177.3166.16.camel@palomino.walls.org> In-Reply-To: <1253011177.3166.16.camel@palomino.walls.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: Andy Walls wrote: > On Mon, 2009-09-14 at 21:02 -0700, David Liontooth wrote: > >> Mauro Carvalho Chehab wrote: >> >>> Hi David, >>> >>> Em Mon, 14 Sep 2009 19:41:13 -0700 >>> David Liontooth escreveu: >>> >>> >>> >>>> We're setting up NTSC cable television capture devices in a handfull of >>>> remote locations, using four devices to capture around fifty hours a day >>>> on each location. Capture is scripted and will be ongoing for several >>>> years. We want to minimize the need for human intervention. >>>> >>>> I'm looking for advice on which capture device to use. My main >>>> candidates are ivtv (WinTV PVR 500) and USB, but I've not used any of >>>> the supported USB devices. >>>> >>>> Are there USB devices that are sufficiently reliable to hold up under >>>> continuous capture for years? Are the drivers robust? >>>> >>>> I need zvbi-ntsc-cc support, so a big thanks to Michael Krufty for just >>>> now adding it to em28xx. Do any other USB device chipsets have raw >>>> closed captioning support? >>>> >>>> I would also consider using the PCIe device Hauppauge WinTV-HVR-2200, >>>> but I need analog support. >>>> >>>> Appreciate any advice. >>>> >>>> >>> If you look for stability, the most important item is to choose a good stable >>> server distribution, like RHEL5. You'll be better serviced than using a desktop >>> distro with some new (not so stable) kernel and tools. >>> >>> In terms of stability, the PCI devices are generally more reliable, and, among >>> all drivers, bttv is the winner, since it is the older driver, so, in thesis, >>> more bugs were solved on it. That's the reason why several surveillance systems >>> are still today based on bttv. If you need a newer hardware, then you may choose >>> saa7134, cx88 or ivtv devices. >>> >>> I don't recommend using an USB hardware for such hard usage: it will probably >>> have a shorter life (since it is not as ventilated as a PCI device on a >>> server cabinet), and you might experience troubles after long plays. In terms >>> of USB with analog support, em28xx driver is the more stable, and we recently >>> fixed some bugs on it, related to memory consumption along the time (it used to >>> forget to free memory, resulting on crashes, after several stream >>> start/stop's). >>> >>> There's a tool at v4l2-apps/test made to stress a video driver, made by >>> Douglas. I suggest that you should run it with the board you'll choose to be >>> sure that you won't have memory garbage along driver usage. >>> >>> Cheers, >>> Mauro >>> >>> >> Thank you, Mauro! I much appreciate the advice. >> >> I also see I misattributed the zvbi-ntsc-cc support for em28xx -- kudos >> goes to Devin Heitmueller for great work on this. >> >> As for the ventilation issue for USB devices, that may not be a serious >> obstacle. If the USB sticks such as Hauppauge HVR-950 have reliable >> components, we could strip the plastic casing and mount the unit next to >> a fan inside the case. >> >> Memory leaks would be a serious problem on the other hand; thank you for >> pointing to the stress test. >> >> I would be happy to use bttv, but I can't find cards. I also need to >> grab audio off the PCI bus, which only some bttv cards support. >> >> We've been using saa7135 cards for several years with relatively few >> incidents, but they occasionally drop audio. >> I've been unable to find any pattern in the audio drops, so I haven't >> reported it -- I have no way to reproduce the error, but it happens >> regularly, affecting between 3 and 5% of recordings. Audio will >> sometimes drop in the middle of a recording and then resume, or else >> work fine on the next recording. >> >> Our fallback is ivtv. I was hoping to use USB so that we could get >> blades instead of 3U cases; it's also getting hard to find good >> motherboards with four PCI slots. >> > > > I will point out that, for a fallback position, the cx18 driver also > performs very reliably with essentially the same feature set as ivtv > (since it started out as a cut and paste from ivtv). > > The HVR-1600 is the card with which I do most of my testing. It is a > PCI bus device and can perform analog (with VBI) and digital capture > simultaneously, but not 2 analog streams simultaneously. I know of two > users who have at least 3 of these boards in one machine. (I mention > the HVR-1600, in case you have a hard time finding the PVR-500 or > similar analog only cards.) > > Of course for you, it sounds like one analog capture device per PCI slot > is suboptimal. From a bus throughput perspective, I'd assume you'd > really want a multiple analog input PCI or PCIe capture card, that could > do compression on board. > > Regards, > Andy > Thanks Andy, that's a useful suggestion for a fallback. Cheers, Dave