[gentoo-user] Re: Logitech C920 HD Pro Webcamera ... view: YES record: NO ?
gmx.de> writes: > the Logitech c920 HD Pro webcam is able to deliver 1920xq080x30fps > (H.264). > > Now I am trying to display (watch) and record the video stream. > Currently I am using guvcview. This 'gstreamer tidbit' might be useful to you: http://www.oz9aec.net/index.php/gstreamer/473-using-the-logitech-c920-webcam-with-gstreamer hth, James
[gentoo-user] Re: Logitech C920 HD Pro Webcamera ... view: YES record: NO ?
gmx.de> writes: > the Logitech c920 HD Pro webcam is able to deliver 1920xq080x30fps > (H.264). Some interesting notes and comments at the bottom of this page: http://www.ideasonboard.org/uvc/ Also, in the past, I have found the best comments on various camera hardware in the relevant kernel driver. Sometimes that is a unique driver, other times it is a unified kernel driver for a similar group of video cameras. Sometimes you can go way back to where the kernel driver for a given video camera first appeared (got supported) in the linux kernel for detailed information on the limitations of a given piece of hardware. Often, the poorer performance on Linux, was intentionally due to the actions of the manufacturer, particular on max frame rate, bit minipulations and other key parameter settings of the cameras. Once folks learned the protocols (decoded them) on windows, they would make those adjustments with windows software and reverse engineer the driver software so as to be able to support various linux drivers. Logitech is very reasonable (at least compared to other vendors) but even there newer hardware rarely works with the best of a given feature set, until the product has been out for a while. If not, Logitech should have a published interface specification so and to make reverse engineering not necessary? Dunno know the specifics on the model your listing, as I've been out of that 'game' for a while now, but all those tigers still have the same stripes Good hunting! hth, James
[gentoo-user] Re: Logitech C920 HD Pro Webcamera ... view: YES record: NO ?
gmx.de> writes: > I found it before...this is the updated, more recent version: > http://www.oz9aec.net/index.php/gstreamer/487-using-the-logitech-c920-webcam-with-gstreamer-12 Thanks, I do not keep current with video anymore > It works so far as I can view the stream...but cannot trigger a > record. You cannot record with any of several application or just one in particular? It seems like I vaguely remember somewhere a howto, to setup a generic small ram drive to 'enhance' the performance of recording on a linux system, but I cannot find the link right now. I use to have problems with resources where if much of anything else was using the HD, even though (record) bandwidth of the mobo sata chip and the drive were no where near the limit, I'd have problems with sustained video recording. Buffer overload? Registers can't keep up? Commerical system all have CAM (Content Addressible Memory) to put the memory on steroids for all sorts of low latency performance capabilities and gains I never tracked down that problem nor found a fix that was not too expensive. My guess is it would be a customized, minimized, highly tweaked kernel that would work best for video recording and latency-bandwidth issues, etc. I was working on multiple medium resolution streams. A singular, hi-res video stream might be even more problematic. It would be an interesting test to put your recording efforts onto a multi disk (raid) array specifically tuned for write speed and see if that fixes your issues? Drop the quality way down and see if you can record then. It that works, then what I just wrote about is your demon. If not, then it's a bug, syntax,decoding or other algorithmic issue. Dunno. > (Background: I am watching crows with this cam, and if anything > interesting happens I want to press REC to capture everything to > disk) If you are drawing a paycheck, for watching crows, or just maximizing crop yeilds, you are my new, favorite hero... Black Crows are one of my favs.. Red-headed woodpeckers are a close second... (we have lots in Florida) hth, James
[gentoo-user] Re: Logitech C920 HD Pro Webcamera ... view: YES record: NO ?
gmx.de> writes: > I've git "somethiong" working for me: > With vlc "Capture device" and a lot of setting I am able > to wath and record if wanted the stream of the c920. > BUT > There is big delay between audio and video (audio delayed) > and a smaller delay between reality and strem (which doesn't > matter in my case). > How can I fix the delay between video and audio? http://www.videolan.org/developers/x264.html Is my recommendation to ask the folks for some syntax snippets. I use to have a link to all sorts of command line examples to manually filter, convert and perform all sorts of video magic. I cannot find the link now. These x.264 devs a VLC/videolan are the best open source h.264 coders around good hunting! James
Re: [gentoo-user] Re: Logitech C920 HD Pro Webcamera ... view: YES record: NO ?
James [14-06-07 17:40]: > gmx.de> writes: > > > > the Logitech c920 HD Pro webcam is able to deliver 1920xq080x30fps > > (H.264). > > > > Now I am trying to display (watch) and record the video stream. > > Currently I am using guvcview. > > This 'gstreamer tidbit' might be useful to you: > > http://www.oz9aec.net/index.php/gstreamer/473-using-the-logitech-c920-webcam-with-gstreamer > > > > hth, > James > > > > > > hie James, Thanks! :) I found it before...this is the updated, more recent version: http://www.oz9aec.net/index.php/gstreamer/487-using-the-logitech-c920-webcam-with-gstreamer-12 It works so far as I can view the stream...but cannot trigger a record. (Background: I am watching crows with this cam, and if anything interesting happens I want to press REC to capture everything to disk) Bets regards, mcc
Re: [gentoo-user] Re: Logitech C920 HD Pro Webcamera ... view: YES record: NO ?
James [14-06-07 17:52]: > gmx.de> writes: > > > > the Logitech c920 HD Pro webcam is able to deliver 1920xq080x30fps > > (H.264). > > Some interesting notes and comments at the bottom of this page: > > http://www.ideasonboard.org/uvc/ > > > Also, in the past, I have found the best comments on various camera > hardware in the relevant kernel driver. Sometimes that is a unique > driver, other times it is a unified kernel driver for a similar group > of video cameras. Sometimes you can go way back to where the kernel > driver for a given video camera first appeared (got supported) in the linux > kernel for detailed information on the limitations of a given piece > of hardware. Often, the poorer performance on Linux, was intentionally > due to the actions of the manufacturer, particular on max frame rate, > bit minipulations and other key parameter settings of the cameras. Once > folks learned the protocols (decoded them) on windows, they would make > those adjustments with windows software and reverse engineer the > driver software so as to be able to support various linux drivers. > > Logitech is very reasonable (at least compared to other vendors) but even > there newer hardware rarely works with the best of a given feature set, > until the product has been out for a while. If not, Logitech should > have a published interface specification so and to make reverse engineering > not necessary? > > Dunno know the specifics on the model your listing, as I've been out > of that 'game' for a while now, but all those tigers still have the same > stripes > > Good hunting! > hth, > James > > > > Hi, I've git "somethiong" working for me: With vlc "Capture device" and a lot of setting I am able to wath and record if wanted the stream of the c920. BUT There is big delay between audio and video (audio delayed) and a smaller delay between reality and strem (which doesn't matter in my case). How can I fix the delay between video and audio? Best regards, mcc
