Jennih Posted October 25, 2007 Share Posted October 25, 2007 Hi all, I do some work for a school in Bristol and have become involved in their talent night which ther run for charity. Now last year we upped the presentation level by outputting live video via a projector and this worked pretty well but we used a CCTV quad processor to handle the camera switching and as I'm sure you know the switching was fairly "glitchy" to say the least. Also when having to play video sequences, etc. we had to switch the projectors input, not ideal to say the least. Well this year I'd like to "up our game" and do some rudementay video mixing that doesn't glitch but the school doesn't see this as a good use of expendature so this is all out of my pocket. So I'm looking for a cheap way to improve the video mixing. My budget is pretty low (v. low hundreds) so I was thinking of a PC based solution as I've already got most of the hardware. Does anyone have any ideas how I could pull this off, be it software, hardware, etc. Link to comment Share on other sites More sharing options...
Andrew C Posted October 25, 2007 Share Posted October 25, 2007 I'd be inclined to hire a video mixer, and leave the PC well alone. Alternatively you could look at a proper scaler/switcher (Kramer and others) which would allow you to combine camera, DVD, and PC feeds; all switchable to the projector, without glitches. This one is a small unit but a better one should be hire-able for not much cash. Link to comment Share on other sites More sharing options...
James Posted October 25, 2007 Share Posted October 25, 2007 Jennifer. What are you after? Are you just after seemless switching or are you after mixing? (Just cuts or cuts and fades) What are all your sources you wish to use? eg, Cameras - how many - what type - what video signal are you using if you know? (eg Composite, CVBS, Pal, S-Video, Y/C etc?) What are you using for video playback? (eg Computer VGA 1024\768\60hz? DVD, VHS, MiniDV? Basicaly Video is not simple, nor is it cheep to do well. I do a lot of work with Churches and my long held policy is that Poorly done video is often worse and more distracting than no video so my advice is that if you realy think requires "upping their game" to get an acceptable - non embarasing result then it might be better to wipe your hands of it and walk from this event than try to do something on no budget at all. Sorry James Link to comment Share on other sites More sharing options...
Jennih Posted October 25, 2007 Author Share Posted October 25, 2007 Well, last year people were impressed with the increased production quality of the show as compared to previous years (easily pleased I guess) so though I'd like fully professional kit I'm just trying to make things better than last year. I'm hoping that each year I can improve the quality a bit more and this year it's moving away from the unsynced CCTV quad processor to something a little better. What we are actually trying to achieve is this: Live video from Four sources (minimum), input from a PC for pre-prepared video sequences (logos, etc), the possiblity to run powerpoint presentations, and possibly using the same PC as a DJ rig, handling the music for the night and maybe some visualisations on the screen. It'd be nice to be able to transition between these sources but a simple glitch free switch would do. I could go into more detail but that's the basics of it. Last year we did most of this, with the music being handled by a separate DJ rig (and separate DJ who I was not happy with) and the glitchy video. In the summer of this year we upped it again by using a wireless video transmitter to make one camera "roving" around the venue though I think we'll bench that till we can get a more reliable transmitter. I understand this isn't going to be professional quality, but until there's budget for it, I just take baby steps and make it a little better each time. EDIT: Oh, lastly, it'd be nice to record the output so we could potentially sell a DVD of the night and make more for the charity, but this is really incidental. Link to comment Share on other sites More sharing options...
boatman Posted October 25, 2007 Share Posted October 25, 2007 Hi Jenni, The problem is, that to achieve smooth video mixing, all of your sources need to be synchronised and it is very unlikely that this will be the case. Do your live video sources have a sync input? If so you may be able to time them up using the PC video output as a reference. To do that the PC needs to be outputting the same video format as the live sources and you will need a distribution amplifier to feed isolated signals to each camera. Assuming that you can get all of the live sources timed up then you need to look at the other sources. For a start, are they all on the same video standard? The simplest video format for mixing purposes is a composite PAL (also know as CVBS), but nowadays most video equipment doesn't have that format as an output. I'm sorry to say that the setup you used last year is about as good as you'll be able to get without major expenditure. Link to comment Share on other sites More sharing options...
Hilary Watts Posted October 25, 2007 Share Posted October 25, 2007 I've used ScreenMonkey together with a video mixer for a similar event. A single PC was used to run and select between Powerpoint, recorded video and still images and also, when required, to select the output of a video mixer which in turn selected a live feed from one of four cameras. Without the video mixer you're not going to get a glitch-free transition from one camera to another, although it may be possible to put two (or more?) TV-in cards in the PC and then select the output from one or other via ScreenMonkey, which gives a reasonably clean switchover. ScreenMonkey will also output Winamp visualisations to the projector. Since ScreenMonkey is free it may leave you with sufficient to enable you to hire a video mixer for the night! Hilary Link to comment Share on other sites More sharing options...
Jennih Posted October 25, 2007 Author Share Posted October 25, 2007 Ok, plan B. I really don't want to rent, I just don't like throwing money away to "borrow" stuff. Now I don't think I can afford a 4 in 1 out vision mixer but a 2 in 1 out off of eBay might be doable. So, could I take a 2 in one out mixer, wire it to a 6 in 2 out AV Matrix unit giving me a 6 in one out unit? You just switch the matrix while the matrix output is "Off screen". E.G: Mixer on A, Matrix through output 1 on input 6, switch Matrix output 2 to input 4 with associated glitch (which it offscreen) then fade from A to B using the mixer. A bit complicated but I have a matrix unit so it cuts the cost majorly. That'll give my up to 5 live and PC for Powerpoint, video, etc. Think it'll work? Link to comment Share on other sites More sharing options...
boatman Posted October 25, 2007 Share Posted October 25, 2007 Not unless your sources are all in the same format and synchronised. If you work in a format that involves colour sub-carrier (CVBS, S-video) that needs to be synchronised as well. Link to comment Share on other sites More sharing options...
Jennih Posted October 26, 2007 Author Share Posted October 26, 2007 Ok, now I put on my confused hat. :huh: I thought one of the major things a vision mixer did was fix the syncing issues. If the picture glitches while trying to crossfade between two sources what would be the point? Anyway, to clarify. I would have 1 x 6 In 2 Out Composite AV Matrix Switcher with no sync.I would have a 2 In 1 Out Composite Vision/video Mixer. Now you may say no it doesn't work that way, but to me I don't see the difference between using that and using a 4 In 1 Out Mixer as long as the AV switcher is switched while "offscreen". :) Link to comment Share on other sites More sharing options...
James Posted October 26, 2007 Share Posted October 26, 2007 Ok, now I put on my confused hat. :) I thought one of the major things a vision mixer did was fix the syncing issues. If the picture glitches while trying to crossfade between two sources what would be the point?Basicaly Video is not simple, nor is it cheap to do well. You need to make sure that the video is timed correctly before it gets to the vision mixer to make sure that the pictures do not glitch. Then what you say would work... You would however need a time base corrector for each video source. Some domestic vision mixers include TBCs You would also have to get the output of your computer to be 625/25i PAL through the use of a scan converter or similar. James Link to comment Share on other sites More sharing options...
Jennih Posted October 26, 2007 Author Share Posted October 26, 2007 Ok, that's what threw me off. I thought that the TBC was built into all Vision mixers, hence the confusion. Ok, so theoretically it'd work if all inputs were in the same format (already done as all input is via composite including the PC as I've already got that done) and the vision mixer has a built in TBC. Still a lot of faffing around, tempted to blow the budget and get a 4 in one out. I might need your advice as to whether the one I look at has a TBC though! :) EDIT: Any idea if a Panasonic WJ-MX10 will work without a separate TBC? Link to comment Share on other sites More sharing options...
boatman Posted October 26, 2007 Share Posted October 26, 2007 Hi Jenni, Actually you will need a dual channel TBC, one for each of the mixer inputs. Many years ago, long before the time-base corrector was invented, I used to work for the BBC and I remember well many days spent crawling about in cable ducts adding delay lines to get everything timed correctly. Link to comment Share on other sites More sharing options...
Shez Posted October 26, 2007 Share Posted October 26, 2007 Maybe I need to borrow your confused hat too Jenni, but... My understanding is that most video mixers of the panasonic AV / MX type have two buses, A and B that you can mix between. There'll be two or more video inputs available to the mixer (four on the one I have at work) and they can all be from any (unsynchronised) source. You might assign input 1 to bus A and input 2 to bus B, and you can then then dissolve /wipe /whatever from 1 to 2. You can then assign input 3 to bus A and dissolve from 2 to 3 and so on. You can only ever mix between two sources at a time but there's nothing to stop you using a simple hardware switch to switch the non-active input to another before you mix to it. (I have the vaguest of recollections that on some mixers, one input might be a master that the others are internally synced to, so you wouldn't be able to externally switch signals on that master input)There's an AV55 (which I've got) and an MX50 on fleabay at the moment - either of them would give you four inputs that you cut cut seamlessly between. Link to comment Share on other sites More sharing options...
peternewman Posted October 26, 2007 Share Posted October 26, 2007 I think James and boatman are confusing things slightly, although understandably. Certainly the Panasonic MX70 has two TBCs, one on each bus, as described by Shez. I think the V4 is the same, it's definitely got two. Basically as James says most of the domestic/prosumer/cheap ones seem to have a TBC per bus, so you do as Shez mentions. If you added a TBC per input, then you could crash cut between outputs on the live bus, instead of having to choose the next camera on the preview bus and then cut between buses. But adding the extra TBCs would be expensive, so I can't imagine anyone makes one like that. The more expensive vision mixers require all the signals to be synced like James and boatman mentioned. I don't know for definite about the MX10, but I'd be surprised if it didn't have two TBCs. I imagine a spec sheet would clear it up, but I think the mixer predates the Internet, so it might not be too easy to find one. Basically as long as you stay away from the pro mixers, Grass Valley, Sony etc then you should be okay. I think most problematic ones will probably have a separate control surface and processing box, but that could be a large generalisation. Anyway assuming you've got two TBCs, you should be able to use the matrix to add additional inputs, and as long as the computer is outputting composite too that should work okay. Link to comment Share on other sites More sharing options...
boatman Posted October 26, 2007 Share Posted October 26, 2007 Jenni asked for a cheap solution and I think that it is not possible to purchase a working, used AV mixer with dual channel TBC for much less than £1000. That isn't cheap. Here's one for starters. This one is a lot cheaper and might do the job. Link to comment Share on other sites More sharing options...
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