SGI: Video

So I've had this little O2 for a while; it's been a nice machine, but now I'm wanting to try something new with it: video capture. (It seems there are a multitude of threads in this subforum on the subject already!) I have the A/V module, so as far as I know it's simply a matter of hooking up the inputs. Video in works like a charm, for all intents and purposes behaving like a television with the correct encoding; MediaRecorder, on the other hand, does not behave so well. It'll get through some video just fine, displaying exactly as it ought to; however, invariably it seems to drop all video at certain points. To give an example, playing a PlayStation game on a PS2 through the composite video input: It shows the boot-up video, displays the PS logo just fine, and sometimes will even display some of the title video, but past that point it just stops all video support it seems. Again, live video in through all of this works perfectly, hence my confusion. Audio works perfectly as well; even while video frames are "dropped", the audio comes through with no problems. This is before I even hit the "Record" button. Restarting the program does not fix the problem.

Is there something I'm doing incorrectly? I can't find any information on my particular problem online or in the program's help files, so I'm at a wall at this point. Any help would be appreciated.

PAL vs NTSC?

Both PAL and NTSC seem to work beautifully in just VideoIn. (I have both PAL and NTSC devices, and have switched back and forth in software and hardware.) Both display this issue, though.

I recall another poster had problems like this, you might find it by searching the forum. The O2's AV hardware has a memory access limitation that can cause DMA to stop if there is not enough physical memory available within a certain range. I think the problem is worse on some IRIX versions later than 6.5.15.

I initially thought that might be the cause, but if it were, wouldn't the VideoIn feed cut in the same places? It plays on just fine (and confirmed even while trying to get video to work in MediaRecorder) when MediaRecorder cuts out, again before even beginning to record. While I'm not sure it makes a difference in this case, I'm also using IRIX 6.3.

how do you record? what file type and if so which compression? and to what device?

Well that's just it: No recording is being done. This is before I even touch the record button. The one time I tried, I let it go for about ten seconds, after which it said something to the effect of "no frames were captured at all, so no video was saved".

oh i see. well then it might be a hardware issue.
i guess you tried multiple different sources and cables?

Multiple sources, multiple cables, yep. All work perfectly fine with little more than a flicker here and there on VideoIn, but all fail to show more than the first bit in MediaRecorder. I suppose it could be hardware-related, but to have different responses from different things feels to me like I'm doing something wrong with the software.

do you have any other (recording)software you could try?

I had similar difficulties a few years ago - the answer was, the graphical tools for recording suck. Use the command line and all goes well.

The instructions may have been on Ian's site and they are certainly here in nekochan archives ... also, as Robespierre suggests, O2's work best for video at somewhere around 6.5.14-17.

There is a lot of discussion of this problem buried here - over to your right and up there is FAQ, Search, Members, and User Control Panel. The one you want is Search

The differences I'm seeing between my experiences and everyone else's I've found on this site or elsewhere is, in this case, not even the preview video shows up in MediaRecorder. Like, it'll show a bit, and on some equipment quite a large amount, after which it just stops even trying to show video, whereas it's still showing the exact same video on the live video input. This is all before I even start trying to record, i.e. I've not hit the record button and MediaRecorder acts like it can't see the video feed it was just seeing not two frames previous. :V

Well, all I can say is, I was trying to make a short video on the O2 years ago using Media Recorder without success. Searched here and maybe at Ian's place, found several people (maybe foetz ?) saying "Don't even mess with that pos, use the command line, here's an example ..."

I did that and it worked. Sorry if you don't like that answer.

It's not that I dislike the answer, so much as I cannot find the references you're referring to. I don't mind using the command line one bit, but it's important to know the incantation.

What is Ian's site, for example? As I can't seem to find the data here, perhaps I could find it there? All I've found thus far on anything related to this sort of video capture has been lurkertech.com, which only seems to include information on writing video capture programs in their entirety, something that seems a little excessive for this.

We best call on the wreck. If I help you with a search, we'll end up learning how to build a steam locomotive

You can start with < man mediarecorder > but I'll be the first to admit, sometimes man pages are less than crystal-clear.

Ian is Ian Mapleson, much good info on his site about various SGI-related tasks. He also posts here sometimes.