Syncing 2 video sources

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djembeplay

Well-known member
Hey everyone,

I'm planning a personal project where I will need to sync two separate video sources of equal length to play at the same exact time. In other words, let's say I have 2 separate videos, each consisting of 500 frames @ 24 fps. I need to have both of those videos play their first frame at the EXACT same time and play their last frame at the EXACT same time on two separate monitors. They cannot be off-sync with each-other in the slightest.

Oh, and the video is going to be 1080p. The best way I can think of is to have a PC with dual outputs playing 2 separate videos, one for each monitor. But... I have trouble playing 1080p video on my PC which is pretty fast... and that's just one stream. But, then again, I have only tried playing 1080p uncompressed AVI's... which at that point I think it may be my HDD having trouble keeping up.

Could I play 2 separate 1080p videos from one computer but from 2 separate HDDs at full frame rate if I used some sort of lossless compression such as PNG? And even then, is there any software that could sync the playing of these two files together?

Does anyone have any other ideas?

Thanks.
 
I can't play uncompressed video smoothly at all, and I've got a fast SATA drive.. it's just too much bandwidth to try and cram through the data pipe..

If Mpeg-2 (the standard HDV format) or Mpeg-4 (the standard HD-DVD format) don't work for you, you could try the Morgan MJPEG2000 codec.
 
Hey,

Thanks for the input.

So do you think a dual-core with 2 SATA drives, one video on each, would be able to play 2 1080p mpg2/4 videos simultaneously? I guess I could just run that test on my own system.

Mikko- Well, as of right now I only have about $700 I could spend on the entire set-up. I would built the PC myself, completely bare-bones except for the essentials. That would save me money. Then I would need to pick up a couple monitors... actually most LCDs cant display full 1080p afaik, so I wouldn't even need to run a full 1080p signal to both now that I think about it.

As for application, I am an experimental artist and this is going to be an installation piece for a gallery.

It is entirely essential to have the two videos sync up exact. Does anyone have any other ideas that may work better than running the two monitors / video feeds off of a computer? In theory, the single computer method should work well...

Another question; Say I can play 2 videos at the same time without frame loss... How could I get them both to play at the exact same time? Is there any software that can do this?

Actually, I just thought of something... let's say I went with 720p video streams. What if I just rendered one single movie at 2732x720 with the two separate videos split down the middle... then I set up the desktop to span across both monitors, then centered the movie so it fit on both screens. Then, I wonder if one SATA drive could handle this... and if it is possible to encode an mpeg2/4 at this resolution.

Anywho, I'm just sort of thinking out loud here. I'm going to go do some tests. Let me know if you are interested in the results and/or have any more input.

Thanks.
 
Your budget of around $700 is probably not enough to do what you want. I know of a couple of playback machines that will do what you want, but they are not cheap. And putting together a machine to play back 2560x720 smoothly across two monitors will cost you your budget just in the video card.

I would try using the h.264 codec. I have seen some very good footage at 720p with a small file size this way. And I know, indirectly, of an HP laptop model that has h.264 hardware rendering so it plays that codec very smoothly.

Other than that, you can try to find an audio visual company in your area that can rent you either a Grass Valley Turbo, which is a hard drive based video playback system and can do 1080i in MPEG-2, or a Doremi unit which will play HD in various states of compression. Perhaps you can get their prices down by crediting their rental in the description of your piece.

Good luck with your endeavors.
 
The single large movie spanning monitors will work for sync. Set up an SATA striped raid to increase your read speed. The more drives you add to the raid the faster it will read. However, this will easily exceed your budget.
 
Hey,

Your right, it did work. I tested it with various formats last night on my editing system, playing video back via 2 SATA drives in a RAID0 config.

Uncompressed of course did not work, and compressing to a PNG lossless still yielded frame-loss. I eventually compressed it to an XViD and got some pretty sharp results. At 2732x720, the playback was smooth as butter and the quality, at least with the clip I was working with, hardly seemed compromized at all.

I actually wonder if it would work from a single SATA as well. I will try it - I have a SATA outside of my RAID0 config that I use for windows and programs files.

CRT monitors will display an HD video pretty well, right? They are relatively cheap. I have problems on my LCD... there are these lines that appear in motion as if the last frame and the current are meeting in the middle of the screen... almost seems like a refresh rate thing.
 
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