Jump to content

To tri-level or not to tri-level...that is the question.


RPSharman

Recommended Posts

Hey all..... this sync thing is a real swamp of festering puss.  INMHO, all the professional sound recorders... Sound D, Deva, Fostex, Cantar and supporting devices like Ambient and Denecke have solid time bases +-fractions of frames over 4 hours.  Electronic cameras like  Sony, Panasonic, Red, Canon time bases are like a freeway maniac on the cell phone looking at a GPS,  a roadmap and cleavage in the Lexus,  or +-  full frames over 10 minutes....... the truth of the matter is that the Picture is indeed out of sync compared to a solid professional sound recorder, and of course the sound mixer will get the Oh Dark Forty call about their crummy sync. Add in the lack of clarity about Panasonic's 24PN frame rate in all the AVC Intra recordings that derive 23.9 TC from the 29.9 TC in (and is in sync only one frame a second), and Sony SRW recordings that Audio is in sync when the recorder is mounted on the camera but advanced by 2 frames when the recorder is detached from the camera, and advanced by 4 frames if the output of the SRW recorder is Pulled Down to 59.94 interlace..... eeeek.  Red has a mind of its own and Canon just flops around like a flounder with no timecode...3D is a syncing monster... Do NOT attempt.... the sound department has been shoveling shit against crummy Video time bases for years and has taken it personally when sync screws up.  Please don't.  The cameras are CRAP for time base.  Best options are: #1 Leave camera sync to a QUALIFIED Camera Technician. #2 Ambient/Denecke TC generator boxes will solve 90% of time base problems, but Test,Test,Test and  alert Production/Post that syncing uncertainties do exist with anything but a Tested workflow (do not take it personally... the syncing swamp is beyond all of us). #3 TC Slating that agrees with the sound recorder + 2 pieces of wood hitting each other + Say the slate Scene&Take # rather than "Marker" & that slate will serve everyone very nicely..... plus, it has a nice nostalgic rythymn......  Cheers from the swamp...... 

Link to comment
Share on other sites

  • Replies 57
  • Created
  • Last Reply

Top Posters In This Topic

" derive 23.9 TC from the 29.9 TC in and is in sync only one frame a second, "

more internet mis-information...

if they are in sync for one frame every second (the 00 frame), then they are in sync! the synchronized frames are just being divided into different fractions of a second.

Link to comment
Share on other sites

if they are in sync for one frame every second (the 00 frame), then they are in sync! the synchronized frames are just being divided into different fractions of a second.

Twew Twew..... the frame numbers correspond only once a second and yes the second is chopped into different intervals between frames....and, yes it is in sync.... however the first time i saw the  AVCIntra trick I was confused for a bit....... maybe that's the Polish Brain.  Also you are absolutly correct in calling attention to Internet crumbs of information........ most are Bogus.  I limit my statements to the knowledge I've learned in Battle....... thx for the clarification   

Link to comment
Share on other sites

Hey all..... this sync thing is a real swamp of festering puss.  INMHO, all the professional sound recorders... Sound D, Deva, Fostex, Cantar and supporting devices like Ambient and Denecke have solid time bases +-fractions of frames over 4 hours.  Electronic cameras like  Sony, Panasonic, Red, Canon time bases are like a freeway maniac on the cell phone looking at a GPS,  a roadmap and cleavage in the Lexus,  or +-  full frames over 10 minutes....... the truth of the matter is that the Picture is indeed out of sync compared to a solid professional sound recorder, and of course the sound mixer will get the Oh Dark Forty call about their crummy sync. Add in the lack of clarity about Panasonic's 24PN frame rate in all the AVC Intra recordings that derive 23.9 TC from the 29.9 TC in (and is in sync only one frame a second), and Sony SRW recordings that Audio is in sync when the recorder is mounted on the camera but advanced by 2 frames when the recorder is detached from the camera, and advanced by 4 frames if the output of the SRW recorder is Pulled Down to 59.94 interlace..... eeeek.  Red has a mind of its own and Canon just flops around like a flounder with no timecode...3D is a syncing monster... Do NOT attempt.... the sound department has been shoveling shit against crummy Video time bases for years and has taken it personally when sync screws up.  Please don't.  The cameras are CRAP for time base.  Best options are: #1 Leave camera sync to a QUALIFIED Camera Technician. #2 Ambient/Denecke TC generator boxes will solve 90% of time base problems, but Test,Test,Test and  alert Production/Post that syncing uncertainties do exist with anything but a Tested workflow (do not take it personally... the syncing swamp is beyond all of us). #3 TC Slating that agrees with the sound recorder + 2 pieces of wood hitting each other + Say the slate Scene&Take # rather than "Marker" & that slate will serve everyone very nicely..... plus, it has a nice nostalgic rythymn......  Cheers from the swamp......

DAVE IS THE MAN!!!

Philip Perkins

Link to comment
Share on other sites

in response to Senator's statement that a 23.9 second is exactly the same as a 29.9 second, that is correct.  However if a clapper is snapped at 00:00:00:10 in the 29.9 audio recording, the clapper snap will appear around 20% earlier in the 23.9 camera recording or at frame 00:00:00:08 thus appearing to be out of sync when the 2 time lines are compared.  if allowed to run for a second or more the sound will be in sync but the clappers will agree only when snapped at frame :00 (29.9) and frame :00 (23.9). Mentally challenging in my book and often needs to be dialoged with PostPro.  The ambiguity of all this is part of our festering puss swamp. My intent is not to clarify the behavior of any camera format but to weep with any technician, sound or video or editorial that has been through the sync chipper (think Fargo).  These techno landmines are deeply embedded in our professional lives and will not go away anytime soon.  Production will continue to throw the sound crew under the bus when sync is an issue. Our Technical role in Production is Humbling and requires a great deal of Courage.  Hats off to all of us that endured the Personal and Technical challenges in this Loved/Hated Business.   

Link to comment
Share on other sites

However if a clapper is snapped at 00:00:00:10 in the 29.9 audio recording, the clapper snap will appear around 20% earlier in the 23.9 camera recording or at frame 00:00:00:08 thus appearing to be out of sync when the 2 time lines are compared....

In dailies post, we just tell the client, "we have no ability to adjust sub-frames (less than a frame)," meaning they'll have to jig and jog the sound to get the clap closer. Although it's technically wrong, most assistant editors prefer for dailies to be a fraction of a frame early rather than late, I assume because of screen distance and/or a slight delay in the LCD displays used by most editors.

In 23.98 video dailies of film projects, sometimes there's a blur on the frame prior to the clap and a blur after the clap, and the camera literally did not have its shutter open to capture the actual frame of the clap. In this case, we can only fake it. We get as close as humanly possible in dailies, but those are the limits.

--Marc W.

Link to comment
Share on other sites

  • 1 month later...

David:

Great post! Just ran across it now. I'm going to print it out and send it to editorial the next time the issue comes around (and it will!).

I have had more than a few arguments with DIT's regarding the use of the Denecke boxes as well. Some techs insist that they don't need to genlock the cameras to the video sync output, but then the finger gets pointed at us when the sync starts drifting on long takes.

I would be very interested to hear how others are dealing with this, especially with low-end cameras like the 7D.

--Scott

Hey all..... this sync thing is a real swamp of festering puss.  INMHO, all the professional sound recorders... Sound D, Deva, Fostex, Cantar and supporting devices like Ambient and Denecke have solid time bases +-fractions of frames over 4 hours.  Electronic cameras like  Sony, Panasonic, Red, Canon time bases are like a freeway maniac on the cell phone looking at a GPS,  a roadmap and cleavage in the Lexus,  or +-  full frames over 10 minutes....... the truth of the matter is that the Picture is indeed out of sync compared to a solid professional sound recorder, and of course the sound mixer will get the Oh Dark Forty call about their crummy sync. Add in the lack of clarity about Panasonic's 24PN frame rate in all the AVC Intra recordings that derive 23.9 TC from the 29.9 TC in (and is in sync only one frame a second), and Sony SRW recordings that Audio is in sync when the recorder is mounted on the camera but advanced by 2 frames when the recorder is detached from the camera, and advanced by 4 frames if the output of the SRW recorder is Pulled Down to 59.94 interlace..... eeeek.  Red has a mind of its own and Canon just flops around like a flounder with no timecode...3D is a syncing monster... Do NOT attempt.... the sound department has been shoveling shit against crummy Video time bases for years and has taken it personally when sync screws up.  Please don't.  The cameras are CRAP for time base.  Best options are: #1 Leave camera sync to a QUALIFIED Camera Technician. #2 Ambient/Denecke TC generator boxes will solve 90% of time base problems, but Test,Test,Test and  alert Production/Post that syncing uncertainties do exist with anything but a Tested workflow (do not take it personally... the syncing swamp is beyond all of us). #3 TC Slating that agrees with the sound recorder + 2 pieces of wood hitting each other + Say the slate Scene&Take # rather than "Marker" & that slate will serve everyone very nicely..... plus, it has a nice nostalgic rythymn......  Cheers from the swamp...... 

Link to comment
Share on other sites

David:

Great post! Just ran across it now. I'm going to print it out and send it to editorial the next time the issue comes around (and it will!).

I have had more than a few arguments with DIT's regarding the use of the Denecke boxes as well. Some techs insist that they don't need to genlock the cameras to the video sync output, but then the finger gets pointed at us when the sync starts drifting on long takes.

I would be very interested to hear how others are dealing with this, especially with low-end cameras like the 7D.

--Scott

Long-term sync issues haven't come up w/ 5D and 7D because they will only roll for 11:54 min before autocutting (file-size limit).  Within that time period they hold sync perfectly, and we have done numerous tests of this to make sure.

Philip Perkins

Link to comment
Share on other sites

Plus, no external sync with the Canon EOS -- not yet. No news at the show on new EOS products that I saw.

I did just heard a rumor that the last episode of House was shot on this camera, which is stunning if true. I'm gonna be sure to tune in next month to see how it looks.

--Marc W.

Until they make the camera able to shoot a longer take than 12 min I don't think we need ext sync...  The continuous-roll-length limitation seems like what they should work on next.

Philip Perkins

Link to comment
Share on other sites

  • 1 month later...

I'm sympathetic, but the reality is that timecode, reference sync, and video are all related. If they aren't all in the right place at the same time, bad things can happen.

I just got off the phone with an engineer/friend of mine who told me that one place where this can really wreak havoc is with 3D video productions, where two cameras have to be 100% in sync with each other. When no genlock is provided with timecode, essentially what happens is that the video frames starts getting fractionally out of sync with each other -- not a full frame, but just a piece of a frame. If the frame starts drifting one way or the other, eventually the camera will "hiccup," and that's where the green flash hits.

--Marc W.

Timecode and sync do have a relationship. That is why sync from a SBT or Clockit should be fed to genlock on a RED while sending TC Jam, because when the camera starts its shutter it is locked to the frame TC being fed. If you are fractionally off - without genlock, it is hard to pick a frame that should be the sync mark, because you are seeing the transition of the Smart Slate LED. Also without genlock the shutter difference will be different every time the camera starts, random.

The sync is available on these boxes, my advice and that of the RED engineers I work with, is that you use sync-genlock with TC Jam whenever you can. It isn't like it costs more with a Clockit or SBT the outputs are there. When the 2 are set up properly on A RED One you get a gold chain symbol for TC and a padlock for genlock. TC Jam on a RED menu is System/Project/Timecode and Genlock is Sensor/Shutter.

If you are doing a 3D shoot you can use a BNC T to split the sync to 2 cameras on a rig. The Ambient Lockit has 2 TC outs one BNC the other Lemo so with the proper cables you can feed 2 RED Lemo inputs. I am not as familiar with the Deneke but I think it is similar. You absolutley need to use a TC/Sync box for 3D do not feed TC from one box and Genlock from another source as they have no relationship when separate. The tests have shown this to be a very stable system.

This probably is a camera tech responsibility, but at least you have a RED recommendation.

Brian Ferguson

RED Digital

audio tech support

Link to comment
Share on other sites

Timecode and sync do have a relationship. That is why sync from a SBT or Clockit should be fed to genlock on a RED while sending TC Jam, because when the camera starts its shutter it is locked to the frame TC being fed.

I've told this to the D.I.T.'s on the last three Red projects I've worked on, but have been overruled each time. Is this in the Red Camera manual? If not, perhaps it could be added to the Jam Sync instructions (page 72). We proceeded with just timecode for two 14-hour days on my last Red shoot and had flawless video throughout.

I just double-checked the build 30 manual, and the section on Genlock Input is kind of ambiguous (page 127). BTW, they should include the Denecke SB-T tri-level sync generator in their description as well; Ambient doesn't own this market.

--Marc W.

Link to comment
Share on other sites

I've told this to the D.I.T.'s on the last three Red projects I've worked on, but have been overruled each time. Is this in the Red Camera manual? If not, perhaps it could be added to the Jam Sync instructions (page 72). We proceeded with just timecode for two 14-hour days on my last Red shoot and had flawless video throughout.

I just double-checked the build 30 manual, and the section on Genlock Input is kind of ambiguous (page 127). BTW, they should include the Denecke SB-T tri-level sync generator in their description as well; Ambient doesn't own this market.

--Marc W.

Agreed, I always try to mention Deneke in my posts and not exclude them. Mike Deneke was a friend of mine, we worked on several jobs together, he was a great guy and to not include his legacy is not in me. We had a mutual friend in D.P. Ralph Young, they both did a lot with Chambers and Assoc. in the 80's. A Deneke slate was all I knew when I was an AC and as a DP. I was/am also a Director and Post Supervisor and then as Editor so I think I know this subject as well as anyone could.

RED may seem to have been Ambient centric because this was the direction our early features went. We test with the gear we have and when other situations occur we check those out. Other workflows have not really come up until recently. As much as I can tell until the SBT Deneke did not quite have a comparable device, correct me if I am wrong.

Brian Ferguson

Link to comment
Share on other sites

Well Robert,

Considering we met 2 years ago with my own RED camera, on the set of the short "Down & Out". I think you are very consistent. You did not listen to my advice then.

Brian Ferguson

I am very keen to listen to advice, and I recall this as being one of my first RED experiences a little bit more than 2 years ago, and honestly do not recall a discussion about whether or not supply tri-level sync to the camera.  I don't even remember using a lockit.  All I remember is running a cable to the camera for audio and having to train a very new and eager boom operator in front of DP Russell Carpenter.  Yikes!!

  Timecode and sync do have a relationship. That is why sync from a SBT or  Clockit should be fed to genlock on a RED while sending TC Jam, because  when the camera starts its shutter it is locked to the frame TC being  fed. If you are fractionally off - without genlock, it is hard to pick a  frame that should be the sync mark, because you are seeing the  transition of the Smart Slate LED. Also without genlock the shutter  difference will be different every time the camera starts, random.

 

This is HONESTLY the first time I recall being presented with this technical fact to support using tri-level on the RED.

But although this is the case, failure to provide tri-level will not cause any errors in the files or any dropped frames or any "green flashes", it will simply make it harder to "pick a frame that should be the sync mark".  Is that accurate?

Robert

Link to comment
Share on other sites

Honestly Robert.

What you provided worked out fine. There were no technical problems at all. You did not use a Clockit/Lockit. It worked fine. I asked you to provide a reference audio to the camera and you told me that was what assistant editors were for, and that you would not do it. The next day the editor went off on you, it was a no budget job, and the Director was Russ Carpenter's Assistant. They needed audio for dallies. After that you complied and it was no problem. I always say the most important thing is have a smart slate, with accurate audio TC on it it in front of the lens.  You were much easier on the next short installment, I am just saying you don't listen unless you think someone is an authority. I don't have time to tell you I have 25 years of film experience  before you started in the business.

At that time we did  "Down & Out" I was 3 months out of the ER for a burst appendix, I was done fighting those kind of battles. I already knew what dying was like and this was no biggie. You didn't want my advice then. So you were on your own. You did not want to send audio to the camera until the editor argued with you regardless of what I said.

And now you post you want a larger authority than my post. Listen to who you want. I was just giving you a heads up, like I was before. I didn't say you messed up before. It is degrees of perfection. It may not have been broke, it can be better.

I am just saying if you want to add one small cable to devices you are already using for better results, then you should do it. Why are sound guys so resistant to a little input? Soon this will be in the op's manual, l am sorry I gave it to you here - ahead of time, before everyone else. We are talking best practices, doesn't mean what you are doing now sucks.

Brian Ferguson

Link to comment
Share on other sites

" If you are doing a 3D shoot you can use a BNC T to split the sync to 2 cameras on a rig.  "

actually, for 3D, there is a lot of camera stuff to consider, as the cameras must be accurately synchronized --and this is not the sound departments responsibility!

Brian: may I inquire: you signed a post " Brian Ferguson, RED Digital, audio tech support  "; does this mean that what you said in that post is the official word from RED ?? what exactly does the title mean?? are you a paid, full time, technical staff in this position??  " with my own RED camera " and "  it was a no budget job, " + " People may see me on the set as a guy bringing a camera, " I'm getting confused... so you represent RED, and bring free cameras that belong to you (or RED??)... or ...??? are you RED representative, or a RED customer/follower ?? confusing...

Certainly genlock puts all the 'frame edges' in perfect alignment, but with independent camcorders being edited in post (vs. needing to be perfectly timed for glitch free live switching!) this may be, pardon the expression, a bit OC...(or is it AR??).

" They needed audio for dallies. " well, that is not new or unusual... been like that for decades! and assistant editors have been syncing up dailies for all of those decades!!

and a hotshot like " Russ Carpenter's Assistant " ought to understand this! (and ought to be able to pay for stuff, too, IMHO... or does he work for Mr. Carpenter without pay??  yeah, didn't think so...

" Why are sound guys so resistant to a little input?  "  why are RED guys so defensive??

Link to comment
Share on other sites

" If you are doing a 3D shoot you can use a BNC T to split the sync to 2 cameras on a rig. "

actually, for 3D, there is a lot of camera stuff to consider, as the cameras must be accurately synchronized --and this is not the sound departments responsibility!

Brian: may I inquire: you signed a post " Brian Ferguson, RED Digital, audio tech support "; does this mean that what you said in that post is the official word from RED ?? what exactly does the title mean?? are you a paid, full time, technical staff in this position??  " with my own RED camera " and " it was a no budget job, " + " People may see me on the set as a guy bringing a camera, " I'm getting confused... so you represent RED, and bring free cameras that belong to you (or RED??)... or ...??? are you RED representative, or a RED customer/follower ?? confusing...

Certainly genlock puts all the 'frame edges' in perfect alignment, but with independent camcorders being edited in post (vs. needing to be perfectly timed for glitch free live switching!) this may be, pardon the expression, a bit OC...(or is it AR??).

" They needed audio for dallies. " well, that is not new or unusual... been like that for decades! and assistant editors have been syncing up dailies for all of those decades!!

and a hotshot like " Russ Carpenter's Assistant " ought to understand this! (and ought to be able to pay for stuff, too, IMHO... or does he work for Mr. Carpenter without pay??  yeah, didn't think so...

" Why are sound guys so resistant to a little input?  "  why are RED guys so defensive??

I said that Genlock was probably a camera tech issue. I said it was a RED recommendation.

I work at Red as a consultant, I am paid on a retainer. I own a RED camera, I do freelance jobs. I have been at RED since it started.

I answer audio and time code questions there.

Matthew Mebane is one of Russ Carpenter's assistant cameramen who was directing this short film, "Down and Out". He is a friend of mine and they rented my camera. Russ was the D.P. on the film. There was very little budget on that film. The editor asked me to ask the mixer if he could run an audio reference to the camera, to make his job simpler. I asked Robert on the first day and he said no. He later complied.

I had a problem with Robert's attitude towards me on that job. I posted from that point of view, and I should not have. I will refrain from posting in the future.

Link to comment
Share on other sites

Brian,

I am sorry that your memory of that shoot and my memory of that shoot differs so greatly.  We have spoken and emailed since, as I have gone to you as a trusted RED expert when seeking advice and information on other RED shoots over the last couple of years.  I didn't realize you found me so combative.

At that time, it was the advice of EVERYONE to not use RED audio, including many RED owners/techs, and to resist running an audio feed that they could use for fear that they might use it.  "Treat it like film" was the advice for this new camera.  And while I respect your knowledge of the RED and filmmaking, there is a big difference between a camera technician asking a mixer to run audio to the camera and an editor asking the same.  My reluctance to run sound to camera was well founded, and assurances from the editor that he was ONLY going to use the camera audio for preview purposes while editing on set was what I needed to hear.  He did not "go off" on me.  We had a conversation about the challenge of my two-person crew running cables to the camera in difficult locations and 2-camera set-ups.  I felt that if were "treating it like film" then the sound would be synced using the TC slate by an assistant editor.  He did not have one and I did not have a 3rd, and the production environment is typically a harder place to make time compromises than an editing room.  He wasn't being paid to do the extra work, and neither was I, yet I complied.

I was called back by the producers for the next piece of the project some months later, so it couldn't have been all that bad.

Additionally, I am not looking for a "greater authority" to confirm what you have just shared with us on this forum.  I consider you to be a great authority on the RED camera.  I was just commenting on never having heard that piece on information before, not implying it was inaccurate.

Robert

Link to comment
Share on other sites

"  I will refrain from posting in the future. "

wow, someone has thin skin!

That is a poor attitude, and, if you actually are paid to dispense official RED information, you are a valuable resource to production sound mixers, among others...

I can confirm that there was, and still is, a general feeling among sound professionals that RED shoots, among others, should be treated as film shoots (and, after all, aren't RED followers largely of the belief that these camcorders are just like making films. In any case, professional sound crews generally are concerned with thei output being recorded on devices not under their control, most especially those with a proven history of sound  and/or SMPTE/EBU TC issues.

 I can also assure you that those of us who know Mr. Sharman do not consider him at all combative, disrespectful, or difficult to deal with! He is a knowledgeable, smart, sincere, professional, and nice person!

Link to comment
Share on other sites

When shooting with a RED Camera I always work as if it is a film shoot with a smart slate and a recorder. If production requests audio be fed to the camera I am happy to do it when practical. I explain to them that the quality of the sound devices recorder audio will be of a higher quality but they may use whatever audio they prefer as it is there project. I have had RED audio issues before and even though many operators claim the audio on the RED is now fine I personally cannot trust it. I will toggle to the RED Return occasionally but listen to my recorder 95 % of the time and treat my recorder as primary audio source and the camera as back up.

Brian, we all welcome your advice and answers to our questions but I agree with Senator Robert was just trying to cover himself and after talking to the editor everything worked out. Clearly his audio and work flow worked for production if he was rehired. I have had the same discussion with editors before.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...