Projection During Live Show. Live Cam & Laptop HDMI via a splitter. Questions.

[stonehedge99]

Hi Guys,

I need to have a projection done during a show. The 2 sources feeding the PJ would be a laptop (outputting HD video clips via HDMI) and the second is a DSLR cam which is on a tripod and relaying video to the PJ. I bought a simple HDMI switcher so that the PJ can take the signal from the live cam or the laptop alternately. The HDMI wires as 10 mtrs from the DSLR to the hdmi switcher and only 1 mtrs from the laptop to the switcher. And then the switcher out hdmi cable runs 10 mtrs to reach the PJ which might be anywhere near the apron of the stage.

Ive tried this set up and it works, but sometimes it doesn't there seem to be drop outs and i need to cycle thru the switcher several times to get it to recognize mainly the DSLR cam. But i guess the problem is with the switcher. Ive taken the same laptop to other events and they interfaced it thru their switchers (problem is in the dark venues and with their set up i don't know where and what type of setup they used) and had the PJ almost 20-30 mtrs away and it all worked fine.

Do i need a booster of some sorts. What about the small M/F type thumb drive sized signal boosters that you find on ebay and the Alibaba.com websites ? Would those work ? Please advice.


Thanks

 

[seanandkate]

Your problem might also be with your DSLR camera. The video recording off DSLRs are usually limited to around 5 minutes or so of continuous shooting because of the heat it generates from the sensor (YMMV depending on make and model). You might legitimately be losing signal because the camera has stopped sending it.

 

[Mwchris]

Lots of possible issues. As Seanandkate mention most DSLR cameras has a max amount of time you can capture/record in video mode. If you give specific models we might be able to help.

10m of HDMI is 30+ feet. Most equipment starts to exhibit dropouts at around that length, which is where I suspect your problem lies. I would keep your HDMI to less than 3m and use blauns to transmit and receive. The cheapest would be over cat 6, the HD-SDI, and finally Fiber. I've had mixed results with cat 6, so my choice is HD-SDI, but you are talking a decent chunk of change.

One other possible issue is the switcher you are using. If it is passive then the projector is probably dropping signal each time you switch causing syncing errors, searching and more. Basically because you are dropping the signal it has to go through the HDMI handshake everytime you switch which might cause an issue. If you use an active switcher they typically keep an active signal to the projector and just change the source internally. Again, model information would be helpful.

Telling us more about the deatils of your setup (Mac or PC, model, projector model, dslr model, switcher model, etc) would be helpful.

 

[stonehedge99]

Firstly, I'm not recording video at all. That's why i emphasized that its only a Live Cam.

Secondly and this is just to clear things out of the way, id like to point out that DSLR's don't record for 5 mins. They record for a period of up to 12 mins if recording in 1080p. I'm a heavy DSLR user using 3 bodies and an array of lenses for a few years now, expensive hobby yes . They mainly stop recording because of the filing system of the SD Card. They close the file at 4 gb because the card filing system doesn't allow it to write a file larger than 4 GB. Of course there have been firmware hacks (Magic Lantern ?) etc to even breach this. It is also a valid point that temp can play a part and ive seen the temp high indicator flashing after long repeated shoots with RECORDING.

But in this case im not even using it for recording. Its only a live view out cam and will not be used for recording. In other words monitor out to show live close-ups of something such as example objects, flash cards that are in a stage lecturer/speakers hand. Now monitor out is a totally different story and has nothing to do with temperature. If you set the DSLR to not auto sleep at all, then your cam would be live nonstop. There's no limit as to keep a DSLR on. Its just on and you set it not to go into standby. In this way a camera can be on for as long as its battery dies out. The only difference is you will have tethered an external monitor instead of using the LCD on the cam back.

So the drop outs are not camera based. The camera has proved to be live all the time. Its either the switcher or the length of the cable and im trying to identify which based on your experiences and cable lengths that you have used successfully. There are also some HDMI splitter boosters, which might solve my problem ?

 

[stonehedge99]

Sorry to have missed out on mentioning....

Im using a Win XP PC with HDMI out. The projector is a Benq DLP native widescreen HD projector with 'HDMI in' port available. 10 Mtrs cable between DSLR (uses a HDMI to mini HDMI convertor to plug into the cam) and the switcher. 1 mtr cable between laptop to switcher. Then switcher sends output to the PJ over a 10 Mtr cable. The switcher is a no-name brand. Cant go for very expensive ones either. Any decent one will do because i use this set up etc only about 5-6 times a year.

 

[ruinexplorer]

It may also depend on what gauge cable you are using. For that length I'd recommend that you use 24AWG cable. The second issue is that video connections aren't really designed to be repeatedly connected and disconnected. When you add in the non-locking function of HDMI, then this will exacerbate the situation, especially with the needs of the handshake. If it does not have a truly solid connection, this could be expected. It also depends on the video card and how it handles the handshake. Some will hold the last setting if it loses connection assuming that the connection will remain, while others will drop out until it has a solid communication once more. HDMI is quicker to drop out as it requires HDCP confirmation to always be present.

 

[Mwchris]

So, basic trouble shooting here.

Try your setup with shorter cables, say 3m or less for each leg. For example, 3m from camera to switcher and then 3m or less to projector. That gives you a total of around 6m or, 18 feet of HDMI cable. That is very doable in most cases. If the problem still persists then you can 1) try even shorter cables, or 2) take the switch out of the equation and go directly to the projector to see if the switch is the cause.

You are really pushing the limits on your cable length with HDMI, and cheap switchers are nortorisly bad for introducing delay. So it could be both issues.

I do a lot of video projection gigs and a quality switcher and cable can make or break the show. That said I still use VGA 90% of the time. VGA cable is cheap, all projectors typically have multiple VGA inputs, it can support HD resolutions (although not a true Digital signal), and it can travel hundreds of feet with out a booster.

 

[stonehedge99]

i agree with finding a quality switcher booster. But having 3 mtrs wires is a no go. How is it possible. It defeats the logic of the situation at hand. In a stage show, you seriously think its possible for the system light desk show control guy with dmx etc (which means even the sound guy etc everyone sits next to him) can be put right next to the projector ? The projector is the most position sensitive which means it would have to be discrete somewhere on stage throwing onto a projection panel. And id ask my lights and sound team with their entire jing bang to sit right in the middle of the stage so they can be 3 mtrs from the projector ? Then i wonder how they are even selling 20 meter lengths of HDMI cable in the industry ? And the cam being 3 meters away from the means he will also most likely be onstage and in the cone of the projected beam for all you know.

But i will try and get 24awg wires as that seems more practical to start troubleshooting with.

 

[Mwchris]

Dude, calm down. You get very defensive about every suggestion people have made. There are a lot of knowledgable people on this site, but your attitude is off putting to say the least.

My suggestion to try shorter cables is for troubleshooting the issue and not for a show. Personally, I test most new projects small scale before going all out.

It would be of no benefit to purchase a thicker gauged cord if the length is the issue.

It would also be no benefit to buy a signal booster if the switcher is the issue.

I believe you have about a 50-50 chance of it being length of the cables or the switcher or both!

Testing with shorter cables will tell you for sure if it is the cables or the switcher. (Not sure where you are from, guessing EU, but shorter cables are available locally where as longer ones typically have to be ordered. Just another reason to try shorter first.)

If you tell us what switcher specifically we might be able to offer some information on potential issues with distance.

Further more saying you have tried it and it worked or that it worked in another venue with their wiring means nothing. 20-30 m was most def. not done over HDMI.

When you tried it and it worked was it in the same location using the same wiring? If the answer is yes it leads me to believe there is a HDMI handshake issue and the only way to fix it is to get a better switcher that keeps the connection active and does the switch without having to redo the handshake.

 

[ruinexplorer]

First off, let's all calm down as we are here to help one another and freely offer our own experiences (which may or may not be of use). The difficulty in the written word and the challenges of techniques and equipment from around the world only adds to potential misunderstanding and frustration.

That being said, HDMI can be transmitted over longer runs of cable, including runs up to 30m. There are some caveats to that, including the quality of the signal (both ends for the handshake) and quality of the equipment. For DVI, which uses the same protocol, I regularly would run signals of up to 50 feet on copper without issue. When I ran 100 feet on copper, then I occasionally would run into issue, so I stopped doing that.

We might be able help out better if we knew all of the specific equipment being used. All that this community can do is offer advice as we don't have physical ability to work with the equipment, which we all must understand. Thus, what might be working intermittently could be due to a physical connection, improper equipment, or simply some setting on the equipment. Hopefully we can find something that can help.

 

[stonehedge99]

Hey Chris !

Please don't take offense my tone of voice was not meant as condescending or anything. I was just rattling off in a manner of speaking. Maybe it was so late in the night here that i wasn't paying attention to how it sounded. Don't take it seriously. I apologize if it sounded rude.

About the camera recording duration. Instead of just taking what might be useful i offered to explain about the DSLR cam which i know well about, so it may benefit others who might stumble on this thread with similar issues to what im having. At least it will clear some things out of the way for them.

On a side note ive tried this setup in my house. Using the same wires and the same cheap no brand switcher and it worked. But i only tried it a short while. I shall try to retest at home today for a longer duration.

 

[stonehedge99]

We might be able help out better if we knew all of the specific equipment being used. All that this community can do is offer advice as we don't have physical ability to work with the equipment, which we all must understand. Thus, what might be working intermittently could be due to a physical connection, improper equipment, or simply some setting on the equipment. Hopefully we can find something that can help.

Apart from the equipment which i mentioned above. The only things i don't know the brand name for are the cables and the switcher. Unfortunately in my situation the only 2 things that might be factoring in this problem. The switcher - http://www.aliexpress.com/item/free...litter-for-HDTV-1080P-PS3-8173/495143705.html

Ofcourse i bought it for about 3 times that price mentioned. But its still a cheap one. The problem is there arent any branded ones in my country. All the stores have the same ones which i have given a link to.