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Does ARRI has been solved the "timecode freeze" when changing frame rates from higher to lower (50 > 25 as an example)?

On 12/30/2017 at 9:00 PM, CJRobertsIV said:

Hello everyone,

 

The Alexa Mini has given me a huge headache because I can not get it to jam with my 633 or betso lockit box for the life of me. Ive read through this entire thread and have seemingly tried everyone's suggestions but for some reason my gear will not sync with the two different Alexa mini's I've worked with. Even worse is that I hear from DP's that no other audio mixers have ever had this issue so I look like an idiot. This is the first time I've ever had a technical issue in the field that I was unable to troubleshoot by lunch time of day 1. 

    Any ideas what I'm doing wrong? I am suspicious of the Betso box since it's a word clock out but why wouldn't the camera jam from my 633 directly? 

 

Hi,

 

Look for answers here (as you started a new topic): 

 

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I've been making a fool of myself amongst the ACs on the last few jobs trying the JAM SYNC option with the Mini. The TC will read but it will keep flashing 9 times out of 10. Sometimes even an error message will appear saying the camera cannot jam to the external signal or that the signal is not valid (can't remember the exact wording).

What is the jam sync option for and what option should I be using for sync from an external box? The most recent crew says to stick with REGEN.

Sent from my SAMSUNG-SM-G891A using Tapatalk

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I did a commercial yesterday with ARRI Alexa Mini.

ARRI Alexa Mini Firmware: 5.2.17

Sound Devices 633 (latest firmware)

Free Run

25 FPS

 

At 08.00 morning we did a jam sync from 633 to Mini (REGEN).

After 35 minutes running (with REGEN setting), timecode decided to started from 00.00.00.00, again.

We decided to change from REGEN to PRESET (after jamming).

 

The good thing about the new firmware (5.2.17) is:

 

- From 100 FPS to 25 FPS there was no freezing (like older firmware). After FPS change, timecode was the same as 633.

 

- Break 30 minutes; camera off. After break time, timecode was there like 633 (ok, good camera internal battery).

 

Note: Project Frame Rate and Timecode Frame Rate must be the same (into camera).

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31 minutes ago, Patrick Tresch said:

I still wonder why Arri is still seen a reliable?

 

Because the "real" Alexa is reliable.

Btw I can't remember having any TC issues with Amiras or Minis either - as long as they are set to follow EXT TC from a sync box.

Keeping an eye on TC (which fortunately can be displayed in the video output too so everyone on set can see on their monitors if they are still in sync) is not much different from keeping an eye on battery level of my own gear.

 

The other camera common around here has so many issues that TC doesn't stick out. Thinking along the lines of heat issues, fan issues (or "sound issues" in producer-speak), card speed issues, proprietary data format issues, loss-of-metadata issues, and yes TC issues too. "Do you like tuna?"

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24 minutes ago, pkautzsch said:

 

Because the "real" Alexa is reliable.

Btw I can't remember having any TC issues with Amiras or Minis either - as long as they are set to follow EXT TC from a sync box.

Keeping an eye on TC (which fortunately can be displayed in the video output too so everyone on set can see on their monitors if they are still in sync) is not much different from keeping an eye on battery level of my own gear.

 

The other camera common around here has so many issues that TC doesn't stick out. Thinking along the lines of heat issues, fan issues (or "sound issues" in producer-speak), card speed issues, proprietary data format issues, loss-of-metadata issues, and yes TC issues too. "Do you like tuna?"

 

To bad for the fake Alexa then. I've never seen that on my (non Alexa) cameras but if you say so...

 

Ps: for your heat issue on the Epic (wich is an old body that Arri copied) did you test the Fanplate?

 

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Regen probably is the best mode, but the TC box should stay on the camera at all times. If it is removed, TC can veer off quickly. 

JamSync is the mode where you jam once, then remove the TC box. The Mini should then keep the correct TC for several hours. 

In either case it’s important that all relevant settings are correct. 

 

1 hour ago, Patrick Tresch said:

I still wonder why Arri is still seen a reliable?

 

Patrick, I don‘t understand why it’s so important to you that everyone here loves the Red camera as much as you do? Let it go. Most of us here care about sound and many couldn’t care less about the camera, except where it concerns sound. 

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2 minutes ago, Patrick Tresch said:

Ps: for your heat issue on the Epic (wich is an old body that Arri copied) did you test the Fanplate?

 

You're not saying Arri copied the Epic, are you.

Epic was the first "compact" cam body, yes, and that form factor proved to be handy in steadicam/gimbal/multicopter settings.

 

 

Being a production sound mixer, I don't decide what cam or accessories are used. However I do notice when cam dept needs time to solve some kind of issue. As I usually maintain good communication with AC and DIT (and all other crew), they also more often than not are glad to explain to me over a beer what the issue was. Seems they find a new surprise every time with non-Arris.

 

The Mini doesn't need additional accessories to keep cool.

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After just writing what I now realized is a flawed understanding of what Arri meant by Jam-Sync, I re-read their description of the mode, and feel like it's not the same definition I use for Jam-Sync. 

 

From the Arri sup manual 5.2

 

"The new jam sync mode not just samples the timecode from an external source, additionally the camera analyses the signal and tunes it’s internal oscillator to the source. This minimizes potential drift significantly. Please be aware that, different to the other (non Mini) ALEXAs, due to the analyses and tune mechanism the jam sync procedure might take up to 30 seconds. Drift of jam-synced timecode is below one frame over eight hours."

 

I use the term jam-sync to describe momentarily plugging in timecode to sync the current TC value, then removing the TC-Source and letting both clocks run concurrently.  Previously I have not used the Jam-Sync mode on the mini because when I removed the TC signal it constantly showed an error saying the TC signal is missing.  That was counter-intuitive to what I expected since I am used to most cameras jamming in a second or two.  However I never realized that in Jam-Sync mode it can take up to 30 seconds as the mini re-tunes their internal clock to match the TC Stream.

I mostly use an ERX on camera feeding TC and audio.  The newer firmware on the Mini, when fed constantly and in REGEN mode keeps perfect sync throughout the day, but sporadically throws up the info warning icon  and the error displays a message stating the incoming TC frame rate is incorrect.  On shoots when AC's don't mind that, we ignore the info icon and everything goes smoothly.  With AC's or DIT's who don't like seeing the error displayed all day I have been jamming the camera in REGEN mode, then switching to PRESET mode before removing the external TC.  If you remove TC in REGEN mode it shows the info warning that the TC signal is missing.  Jamming in REGEN then switching to PRESET seems to be the only way to avoid this.

 

Now realizing that the Jam-Sync option is designed to sync the main clock, and not just sync the current TC value, I will approach using it differently.  Although I've found the REGEN to PRESET method of jamming to generally be reliable for 6 hours at a time (jam after lunch), it seems like Jam-Sync would be a more accurate way to sync (even though they only claim accuracy up to 8 hours).  However I am a little cautious about using it with an ERX considering the following from the Arri sup manual.

 

"Syncing the sensor via LTC timecode requires a precision timecode generator A precision generator with low jitter is required when using an LTC timecode signal to genlock the camera. Devices that work without a problem as standard LTC timecode source may not work as LTC genlock source"

 

I believe the REGEN errors come from a jitter in the ERX TC stream (same reason I can't use auto frame rate on Denecke slates with Zaxcom) and therefore I don't know if I trust syncing the mini's clock via LTC from an ERX.  Testing an ERX and another generator in jam-sync is a test I would like to do, but may not use it in the filed into I do so.

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Yeah, on my most recent Alexa Mini shoot, the DP and AC had figured out that it could be left in Jam-Sync mode with a TC box on it. My skepticism prompted a test where we went back and forth between 23.98 and 60 fps. When switching back to 23.98, it was blinking for about 10 sec, then locked to the Tentacle. This was great since the Mini was on a StediCam rig and throughout the day went back and forth between slo-mo shots / shots with sound.

 

Thanks Wandering, for the info on Arri's definition of Jam-Sync. This explains why it takes 10 seconds for the camera to "lock" to incoming TC.

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15 hours ago, Constantin said:

Patrick, I don‘t understand why it’s so important to you that everyone here loves the Red camera as much as you do? Let it go. Most of us here care about sound and many couldn’t care less about the camera, except where it concerns sound. 

 

Your right, I'll stop bullying about Alexa.

See you.

 

15 hours ago, pkautzsch said:

 

You're not saying Arri copied the Epic, are you.

Epic was the first "compact" cam body, yes, and that form factor proved to be handy in steadicam/gimbal/multicopter settings.

 

 

Being a production sound mixer, I don't decide what cam or accessories are used. However I do notice when cam dept needs time to solve some kind of issue. As I usually maintain good communication with AC and DIT (and all other crew), they also more often than not are glad to explain to me over a beer what the issue was. Seems they find a new surprise every time with non-Arris.

 

The Mini doesn't need additional accessories to keep cool.

 

Yes, Arri did hack the RED CEO box-mail. They where bluffed how popular the small body form factor from the Epic was. All areals/steadycam/gimbal job where done with the Epic and then they decided to make the Mini version. It was never intended to be the A camera. As you know there are no "modules" (RED ecosystem) and you still have to put your battery plate on some rods or use velcro to have some kind of power for the Mini.

 

When the Mini launched there was the Weapon form factor and the fan noise was allready solved.  If you shoot on the Epic today, I think you can tell the DP to use the Fanplate. It's just another top plate he has to use anyway.

 

Arri is not pushing the industry, remember all the 2k is enough bullshit (they have been forced by the industry (from Netflix to GoPro) to make some 4k cameras (not yet there but they can stick the 4k logo if they want)) but they are putting all the efforts in taking the good job from the others (steadycam, gimbal, follow focus, camera form factor, lenses) and brand it with an Arri logo.

 

Ok enough said. The thread is about TC and the Mini...

 

Pat

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4 hours ago, Patrick Tresch said:

 

Yes, Arri did hack the RED CEO box-mail

 

Oh come on, rival companies sue each other all the time. What about Apple vs Samsung? That doesn’t prove anything. Besides, all three parties involved dropped the lawsuit and so the legal proof does not exist. 

Right after, RED sued Sony over the entire F-series. Again, as we know because the F-series cameras are still there, this was dismissed or RED outright lost it (I cannot remember and I can‘t be bothered to Google it). 

Right after that Sony sued RED... 

see where this is going?

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I think saying the red fan issue is solved is over stating the current state.  While the fan noise has been reduced (thankfully), I can still hear it, so I wouldn't consider it solved.

I have had lots of issues with getting various generations of red cameras to accept timecode, and the latest variations IME are less reliable than previous versions.  Usually fine by themselves, but have proven to me to be unreliable when external components are added, like teradecks and wireless focus, etc.  (The audio inputs also).   I have never seen that behavior on an Arri camera with external items connected.  

All systems have peculiarities, and knowing them is much more important than placing blame for any one.  To me that's what threads like this are about.

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Wireless focus problem due to he Red body? How do you do that? 

 

Your right. People have to know how to use their tools.

 

(ps: I callibrate the Weapon sensor to 47C so the camera can run hotter without fan noise).

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Not problems with wireless focus.  I have had issues with getting clean audio and reliable TC sync on bodies that have multiple external accessories attached, and I suspect ground loop or similar issues as being the cause.  That's what I was referring to.

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I worked with a Red Weapon a while back and had a major ground loop problem.  The on-camera wireless receiver couldn’t be run from the battery’s P-Tap without a massive amount of hum in both audio channels. I’ve not experienced this with any other camera rig, including Alexa Mini which, nonetheless, was really picky timecode-wise (see what I did there — back on topic). 

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On 18.3.2018 at 11:47 AM, Patrick Tresch said:

(ps: I callibrate the Weapon sensor to 47C so the camera can run hotter without fan noise).

 

This is something I'll definitely try to convince the next RED crew I'm working with to do. Thank you!

 

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