Sync troubles with Blackmagic capture (on page 2)

MrDys · Post by **MrDys** » Fri Mar 28, 2014 8:54 am

Arturo00 wrote:MrDys
I've been on the lookout for a decent and cheap portable capture device for ages! I assume you're going direct out of your LZX or some other composite source. What are you doing for scaling?

Yep, I have this little box in between the composite out and the HDMI in on the rocket: http://www.ebay.com/itm/Mini-AV2HDMI-Composite-RCA-CVBS-AV-to-HDMI-Converter-Adapter-DVD-720P-1080P-New-/351035099723.

It works far better than I expected.

Arturo00 · Post by **Arturo00** » Sat Mar 29, 2014 11:57 am

MrDys wrote:
Arturo00 wrote:MrDys
I've been on the lookout for a decent and cheap portable capture device for ages! I assume you're going direct out of your LZX or some other composite source. What are you doing for scaling?
Yep, I have this little box in between the composite out and the HDMI in on the rocket: http://www.ebay.com/itm/Mini-AV2HDMI-Composite-RCA-CVBS-AV-to-HDMI-Converter-Adapter-DVD-720P-1080P-New-/351035099723.

It works far better than I expected.

Nice! That's such a tiny box! I'm currently using a few boxes cascaded together to go from CV to VGA to HDMI. This looks very good and so cheap. And the quality is ok?

Thanks for pointing these out!

Arturo00 · Post by **Arturo00** » Sat Mar 29, 2014 12:04 pm

Actually, scratch that. I have a Kramer VP-410 to go from CV to HDMI. It's from HDMI to CV that I have to go through multiple boxes. Either way, that little guy looks very useful!

arnoux · Post by **arnoux** » Wed Apr 16, 2014 5:35 am

We pulled the trigger on the Blackmagic..
We are having some problems tho

#1 when sending a gif to our synth through the capture device sometimes it looses sync and the gig scroll for a second..

But this looks like a problem related to our (maybe slow?) computer..

#2 we are not able to capture/record on the computer, we tried Final Cut and After Effects, no external video showing on the screen..

Any experienced wiggler with a helpful advice?

Thanks in advance for your help.

arnoux · Post by **arnoux** » Wed Apr 16, 2014 12:27 pm

Problem #2 is solved, we are able to capture but the resolution is low, 720x576, is this the maximum resolution possible recording a video-synth through the Blackmagic? Or are we missing something in the "settings"?
We tried to read the manual and some tutorials but we are not able to figure this out..

Thanks in advance for your time!

MrDys · Post by **MrDys** » Wed Apr 16, 2014 1:50 pm

It sounds like it's capturing in SD. You'll probably need an upscaler (see my recommendation above) to have it capture at a higher res. From the docs, it doesn't look like the Blackmagic has an upscaler built-in.

kjellb · Post by **kjellb** » Wed Apr 16, 2014 5:39 pm

As long as the output of the video synth is SD I think it is OK to capture at this resolution and then render to higher resolutions in software if needed.

arnoux · Post by **arnoux** » Thu Apr 17, 2014 1:35 am

Thanks for your helpful replies, kjellb we'll try to render something with Final Cut at higher res and see what happens.
MrDys now it's clear, everything is so new to us in this field that the word upscaler was nonsense til yesterday. nwt it makes sense! Thanks for your suggestion!

arnoux · Post by **arnoux** » Mon Apr 28, 2014 2:19 pm

Another day another "problem"!

Using a still immage from After Effects going through the Infinity into the composite input on the VSG the immege shakes a bit, what could it be? We can find nothing usefull in the settings..

arnoux · Post by **arnoux** » Thu Jun 19, 2014 11:21 am

arnoux wrote:Another day another "problem"!
Using a still immage from After Effects going through the Infinity into the composite input on the VSG the immege shakes a bit, what could it be? We can find nothing usefull in the settings..

I quote myself as we didn't find a solution to this problem.. We are sending some footages processed on After FX (we also tried Final Cut) into the LZX system: the immage is not stable. Anyone can help?

Possible calibration on the VSG? Or is it a software problem?

Many thanks in advace.

kjellb · Post by **kjellb** » Thu Jun 19, 2014 11:42 am

What kind of format is the still image rendered to?

daverj · Post by **daverj** » Thu Jun 19, 2014 12:03 pm

How are you playing the video? Have you tried burning it to a DVD? Does a regular commercial DVD give a stable image when sent to the LZX?

arnoux · Post by **arnoux** » Thu Jun 19, 2014 12:30 pm

What kind of format is the still image rendered to?

We are just playing the clip from AE, the clip was recorded with the Intensity on the computer via their aquisition software.

How are you playing the video? Have you tried burning it to a DVD? Does a regular commercial DVD give a stable image when sent to the LZX?

We are going stright out through the Intensity..
We can't try a DVD player as our player is broken, but i.e. when filming with our Canon eos the immage is perfectly stable..

kjellb · Post by **kjellb** » Fri Jun 20, 2014 6:13 am

Have you tried to render out the still image as a sequence and then try to play the sequence back? It might be worth a try.

arnoux · Post by **arnoux** » Fri Jun 20, 2014 6:30 am

We tried to export/render the sequence and then playing back again from both AE and Final Cut, the footage is still unstable..

Thanks for your help, we keep trying!

Ty · Post by Ty » Fri Jun 20, 2014 11:51 am

Maybe it's a formatting/size issue? Since the LZX can only do SD, I would keep everything (AE composition and FCP Sequences) at the same resolution and test from there.

Can you describe what the unstable picture looks like?

arnoux · Post by **arnoux** » Mon Jun 23, 2014 6:23 am

Ty thanks for your reply, today we are going to try to keep everything SD, I'll let you know if it works.

Can you describe what the unstable picture looks like?

Using a gif or a footage of any kind the immage just shakes horizontally, fast..

Thanks again!

arnoux · Post by **arnoux** » Tue Jul 08, 2014 4:42 pm

LATENCY (?) TROUBLES TODAY!

Well the story is this, we performed live with our synth filming with a Canon eos the performance while capturing with the Intensity on our Mac the signal from the video-synth, audio was recorded on a portable Tascam.
When putting everything on Final Cut we discovered that the file captured with the Intensity was out of sync, I don't even know how to explain:
audio and the video from the Canon are perfectly in sync, trying to put the file of the video-synthesis in sync we noticed that the file was in sync in the first minutes of the video and then WTF in the end was 7 seconds late..
Very annoying situation after a lot of work!

Is it possible that the RAM of the computer failed some random frames here and there?

Ty · Post by Ty » Tue Jul 08, 2014 5:12 pm

Sounds like a frame rate issue.

Basically, its all in sync at the beginning but you are dropping a frame a second or so which adds up over a long time.

Try converting the out of sync source (to the framerate and format of the sync source) and then give it another go.

arnoux · Post by **arnoux** » Tue Jul 08, 2014 5:17 pm

Thanks Ty, we are trying now, anyway the video from the Canon was 50fps and the one captured was 25.. didn't know this could be so dangerous!

v8media · Post by **v8media** » Wed Jul 09, 2014 12:55 am

If it was a long event and both cameras were recording the whole time, it could just be that the clocks on the two devices were running at slightly different rates, even less than a frame rate difference. You see a similar thing sometimes in audio when you're using two audio interfaces at the same time. They'll start to get garbled over time.

Sometimes the only thing you can do is find a spot where it doesn't match, and fix that by moving some small amount to match it up, and again and again. If it's not too bad, you might only have to do this a few times.

arnoux · Post by **arnoux** » Wed Jul 09, 2014 7:26 am

Many thanks v8media, we are going to try to fix the problem like you suggested. Trying to match the frame rates unfortunately didn't work.

So the best way would be to have a "video" master clock like when you use multiple audio interfaces right?
But I can't see how to enslave none of these machines to a master clock..

Thanks for your time and your help!

v8media · Post by **v8media** » Wed Jul 09, 2014 4:23 pm

Exactly like that. A fair number of pro video equipment has features like this, but unfortunately, not any DSLRs that I know of. Even on some pro cameras, like the Red Epic, it sounds like you have to buy additional hardware to sync two cameras together (they can send, but not receive out of the box).

TV-OD · Post by **TV-OD** » Thu Jul 10, 2014 1:12 am

I purchased a Blackmagic h.264 Pro Recorder for work and it had some strange sync issues. It seemed to be dropping frames all over the place and the audio went right out of sync.

It is being fed HD-SDI with the audio embedded - so I was puzzled.

In the end it turned out to be the drivers - I upgraded to the latest from the web site and all was fixed. (note to self - never install the "supplied on CD" drivers)

Not sure if this is any help - but you may want to check you have the latest drivers for your device.

arnoux · Post by **arnoux** » Thu Jul 10, 2014 11:45 am

TV-OD thanks for your suggestion, right now we are putting in sync the two videos "by hand" but totally worth a try to check out the drivers, hopefully it will solve our problem!

Thanks!

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Sync troubles with Blackmagic capture (on page 2)