Hi,
I would like to record some training/advertising videos, in a similar format to those offered by CBT Nuggets (and others). Essentially this means I need to be able grab real video (e.g. webcam or DV camcorder, etc) as well as what is on the computer screen (VNC Recorder maybe) and audio.
In terms of output I would like it to be in Ogg Theora format as these seems to be supported both on Linux & Windows (though media player plugins), it is also an open standard which beats all the other available formats.
Does anyone have any suggestions for such a program, even if it is suite of different programs. My google/freshmeat search results have so far been not very useful.
Thanks in advance
Lee
Lee W wrote:
I would like to record some training/advertising videos, in a similar format to those offered by CBT Nuggets (and others). Essentially this means I need to be able grab real video (e.g. webcam or DV camcorder, etc) as well as what is on the computer screen (VNC Recorder maybe) and audio.
In terms of output I would like it to be in Ogg Theora format as these seems to be supported both on Linux & Windows (though media player plugins), it is also an open standard which beats all the other available formats.
Does anyone have any suggestions for such a program, even if it is suite of different programs. My google/freshmeat search results have so far been not very useful.
get a Hauppauge PVR-150 card, load up the ivtv drivers (ivtvdriver.org), plug in your source video via svideo and then you can do a simple:
cat /dev/video0 > file.mpg
And out comes a valid MPEG-2 encoded file. You can use the ivtvctl program to change the resolution and bitrate of the captured video. After you have the video, converting it into Ogg Theora shouldn't be an issue.
Oh, and the CPU usage is tiny so you can capture several streams with multiple PVR-150 cards in a decent desktop box.
--Ajay
On Sat, 2005-11-26 at 23:14 -0800, Ajay Sharma wrote:
Oh, and the CPU usage is tiny so you can capture several streams with multiple PVR-150 cards in a decent desktop box.
Just FYI, it's more than just CPU usage. A "raw" analog NTSC video stream (I'm assuming NTSC) is over 30MBps. Considering it goes from card to memory to disk -- possibly all over the same, shared 32-bit @ 33MHz PCI bus (133MBps), it saturates much of the PCI bus, so frame loss is probable.
So having at least an MJPEG compressed stream reduces that far more to a measly 1-6MBps (depending on compression ratio), and MPEG-2 typically to under 1MBps. You usually want to capture MJPEG if you are going to edit the video (especially if you need high quality, individual frames), or MPEG-2 when you only might recorder/cut it or possibly convert it to a lower-quality anyway.
Thanks for the couple of suggestions.
I briefly drifted into Ubuntu land and came across a couple of tools that use OGG natively.
It is not a perfect solution but I can use Istanbul (a GNOME screen full screen recorder) to record the visual element as a theora file. Then use any OGG capable program to record the audio. Finally using oggzmerge to merge the two OGG files into another OGG file that combines the audio & video.
If anyone else is interested the two tools can be found at the links below:-
http://live.gnome.org/Istanbul
http://annodex.net/software/liboggz/
Thanks again
Lee
-----Original Message----- From: Bryan J. Smith [mailto:thebs413@earthlink.net] Sent: 27 November 2005 16:01 To: CentOS mailing list Subject: Re: [CentOS] Video Recording
On Sat, 2005-11-26 at 23:14 -0800, Ajay Sharma wrote:
Oh, and the CPU usage is tiny so you can capture several streams with multiple PVR-150 cards in a decent desktop box.
Just FYI, it's more than just CPU usage. A "raw" analog NTSC video stream (I'm assuming NTSC) is over 30MBps. Considering it goes from card to memory to disk -- possibly all over the same, shared 32-bit @ 33MHz PCI bus (133MBps), it saturates much of the PCI bus, so frame loss is probable.
So having at least an MJPEG compressed stream reduces that far more to a measly 1-6MBps (depending on compression ratio), and MPEG-2 typically to under 1MBps. You usually want to capture MJPEG if you are going to edit the video (especially if you need high quality, individual frames), or MPEG-2 when you only might recorder/cut it or possibly convert it to a lower-quality anyway.
-
Ajay Sharma -
Bryan J. Smith -
Lee W