SGI: Video

I'm running an A/V O2 with a 300mhz R5k and 256mb ram (and currently an unpatched install of 6.5.15) which is just barely enough for video capture supposedly and I have my Sony camcorder plugged in and want to capture 640x480 videos. I have the system setup with a second 18gb disk for scratch space and for saving the videos to (as to free up the system disk) however I'm still having trouble getting something decent.
Normally either the video is twitching (during recording and after when it has been saved but it's not visible in the viewfinder on the camera so the O2 is doing it somehow) or the final result is horribly interlaced.

I'm assuming either my encoding settings need to eb fine tuned or my video settings need to be adjusted or simply put I'm asking too much from the system. I honestly don't know what is up.
Another issue I'm having is that Media Recorder keeps forgetting its settings. I set the scratch space to be /dsk2/Video/.Video_Scratch and the videos to be saved to /dsk2/Video but if I close the program and reopen it, all my settings reset and I ahve to set teh path to save and the location of the scratch space again.

I don't know quality of original movie but 90% of ugliness is caused by interlacing. You must remove it from every frame to use video captured trough o2. I'v personally used imagemagick.

fwiw you don't 'remove interlace', you combine/blend/average two fields in an interlaced format to make a frame. it will never look 'good' unless you play interlaced video on an interlaced display. a computer screen is not interlaced hence the ugliness. you could also video capture motionless scenes and get much better results. THIS IS NORMAL.

as tomo says you can use imagemagick to blend the fields, or mediaconvert which has several special field combination algorithms.

What tomo & skywriter said re: interlacing is correct - this is normal for video capture. If you intend to re-output the video for playback on a television, you probably should not remove the interlacing. If you intend to output digital video files for playback on computers, however, then go ahead and remove it.

As far as twitching or timing issues, the O2 is very sensitive to time sync, and the poor signal quality output by most consumer-level equipment may cause dropped frames, judder, and other issues. You might try re-routing the signal through better equipment or using a time-base corrector. I think there should be info on Google groups about these issues with video capture on SGI.

EDIT: See here , here , and here .

Ah, so I'll need an external application to recombine the frames. Sounds ugly but I guess it's all Ic an do as I don't see anyone making a way to do so on Irix any time soon...
Hmm, I am using Acoustic Research audio cables but a very thin guage video cable. I'll try and find a much better video cable and try again. It could be that the timing is being messed a little in the cable. I could alsr try messing with the settings in the video panel I could also route it through my Sony editing deck first as well but that's plugged into my Indigo2 and I kinda wanted a "camera-to-digitizer" solution with nothing like a VCR in between.


hat certainly would eliminate interlacing but wouldn't that mean a reduced framerate as the system can only capture so much at a time?

mediaconvert IS on irix. it is supplied by dmedia.



that my young friend was sarcasm.

Sorry, it was early and I just got off work.
I'll try feeding a video through mediaconvert and see what happens.

Holy crap.
I did a high quality capture at 640x480 and when I try to feed it through mediaconvert I don't even reach 20% before the converted file completely eats up all my free space. This is horrible. It's even worse than Avid VideoShop.

http://lurkertech.com/lg/

Uncompressed SD video is ~ 25 MB/s or so.

you have to maintain the MJPG format (Motion JPG). also, i think it was dmconvert? there is a command line capture program that works much better than the gui tools, it might also be a part of dmconvert.

I'm using the mediarecorder app that comes with irix to record video coming in from the O2 Video module and because it's an O2 I got no hardware compression.
I might look into better software for Video I/O but not right now as I got too much on the go.
I do have an Indigo2 with both the Galileo Video and Cosmo compression boards however I would not prefer to drag it out and put it in place of my O2.
I don't know which of the various compression formats are Motion JPEG. Right now I have been using "QuickTime JPEG A" as it sounds the closest to "Motion JPEG"
Bah. I wish there was like a DIVX plugin or something.

Anyways, I ran another test video before I read what you said Jan-Jaap and yeah, I'm getting roughly 10mb/s when making an SD recording using my current settings. For dumping back to tape that's okay but for Youtube that's not suitable at all. At least I can output video files now that Youtube will even understand. Avid Videoshop was notorious for making .mov files that were not compatible on anything but a mac.
http://www.youtube.com/watch?v=b1syHWlOhx8

You most certainly do have hardware compression on the O2.

To make things easier, try using one of the presets in Media Recorder. There should be something like "SGI video production" that will configure video capture to use the O2's built-in M-JPEG video compression, which occurs in realtime so there's minimal post-processing of captured video.

That's what I'm using however I'm using cross-platform mode.