Video Assist audio problem

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jallen0

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Video Assist audio problem

PostSat Feb 27, 2021 8:35 pm

I am wondering if anyone else has experience an hour long video recording on the Video Assist 7" 12G HDR monitor drifting out of sync by 2-3 frames by the end of the program. I am just beginning to troubleshoot this issue and there are numerous places where the problem could be occurring from so I thought I would check here first.

Setup:
Sony A7sIII camera with a Deity S-Mic 2S attached to it. Frame rate is 30fps
Video Assist monitor attached via HDMI - Side note, frame rate recorded at 59.95
Resolve Studio version 17.0

If anyone had any thoughts that would be welcomed. Thanks.
2019 MacPro OS 11.4, 3.2GHz 16 Core, 160GB Mem, 4TB Drive, 8TB Internal Sonnet Raid, Dual Radeon Pro W5700X 16GB
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jallen0

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Re: Video Assist audio problem

PostSat Feb 27, 2021 10:09 pm

Update: I have been rendering the rest of the all-day event and it appears that it was only that one clip where the audio drifted. I have zero ideas as to why one of them would drift and not any of the others.
2019 MacPro OS 11.4, 3.2GHz 16 Core, 160GB Mem, 4TB Drive, 8TB Internal Sonnet Raid, Dual Radeon Pro W5700X 16GB
LG UF 5k, 27" Tbolt Display, 55" LG C8
Resolve Edit Keyboard, Mini Panel, US 4K Mini
Resolve Studio Ver. 17.2.1
Desktop Video 12.1
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rick.lang

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Re: Video Assist audio problem

PostSun Feb 28, 2021 12:25 am

With a recording I did recently, the audio and video recorded on the BMVA12G7 was always slightly delayed compared to the audio and video from the camera recorded video. I kept the audio and video linked for each device and brought them into proper alignment on the timeline.
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jallen0

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Re: Video Assist audio problem

PostSun Feb 28, 2021 12:45 am

Thanks Rick. In this case I did not record the video from the camera, just the VA Monitor. Mostly because the Sony A7sIII overheats when recording while being plugged into the USB port. Luckily this project was more a test of the system vs a real world client but I just got done telling my partner that there is a reason why you always want to have two copies of your data file...just to fix things like this.

I am curious however as to why it only happened on one file and not the others.
2019 MacPro OS 11.4, 3.2GHz 16 Core, 160GB Mem, 4TB Drive, 8TB Internal Sonnet Raid, Dual Radeon Pro W5700X 16GB
LG UF 5k, 27" Tbolt Display, 55" LG C8
Resolve Edit Keyboard, Mini Panel, US 4K Mini
Resolve Studio Ver. 17.2.1
Desktop Video 12.1
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rick.lang

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Re: Video Assist audio problem

PostSun Feb 28, 2021 1:06 am

Do you think the different frame rates between the camera and the Video Assist are a concern?
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jallen0

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Re: Video Assist audio problem

PostSun Feb 28, 2021 1:16 am

I did initially but the imported videos are normal looking and 10 out of 12 of them had no issues. Also, on the forum boards, there was a thread about how the VA monitor records in 59.98 regardless of the camera settings at times.
2019 MacPro OS 11.4, 3.2GHz 16 Core, 160GB Mem, 4TB Drive, 8TB Internal Sonnet Raid, Dual Radeon Pro W5700X 16GB
LG UF 5k, 27" Tbolt Display, 55" LG C8
Resolve Edit Keyboard, Mini Panel, US 4K Mini
Resolve Studio Ver. 17.2.1
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CptCurk

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Re: Video Assist audio problem

PostFri Mar 05, 2021 10:54 am

Hey

I got a synch problem using XLR input and HDMI over my X-T3. It's not synch, because I guess the HDMI is slow in my X-T3. I can clearly see a delay between my movement and the image in the VA. May be that's the cause of the problem.

I have an audio problem also :

no need to understand what I'm saying, just look at the levels. (the K6+ME66 is not made to be used as a handmic, that's the only important info I'm saying)

Do you have the same level issue ?
Because They comunique a lot about the fact that noise level is really low. But if recorging level is 30dB lower than it should be... You completly loose the benefic low noise level x)

best regards ! Hope I helped with your problem !
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rick.lang

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Re: Video Assist audio problem

PostFri Mar 05, 2021 11:37 am

When recording on the BMVA12G7 with HDMI fed from the BMPCC4K, there’s a typical 2 or 3 frame delay; all the frames are there as the total duration is the same as recording on the BMPCC4K.
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jallen0

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Re: Video Assist audio problem

PostFri Mar 05, 2021 12:26 pm

I can say that between the Sony A7sIII and 12G VA monitor over HDMI there was zero delay. Everything matched up great. I did encounter the following issues over a day of filming and using the Video Assist as my recording monitor

1) One hour long clip had an audio drift of 2-3 frames with it getting longer as the recording went on. Other hour long sets did not have this issue

2) 2 shorter clips for some reason error out when rendering for output. This clips play fine in Resolve, they just error out during rendering.

3)I did experience a delay when using the USB out from the Video Assist into the computer. Again, there was zero delay coming into the monitor but as soon as I hooked the USB out into the computer I experienced 3-5 frame delay on the incoming video. When plugging the camera directly into the computer there was no delay. Conclusion: The USB out of the Video Assist introduces delay.

4) I did not experience any audio sound level issues, everything seems fine on playback.
2019 MacPro OS 11.4, 3.2GHz 16 Core, 160GB Mem, 4TB Drive, 8TB Internal Sonnet Raid, Dual Radeon Pro W5700X 16GB
LG UF 5k, 27" Tbolt Display, 55" LG C8
Resolve Edit Keyboard, Mini Panel, US 4K Mini
Resolve Studio Ver. 17.2.1
Desktop Video 12.1
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CptCurk

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Re: Video Assist audio problem

PostWed Mar 10, 2021 9:32 am

Hey !

Okay great to know that all... I was think that was my X-T3 problem... That's quite sad actually x)
So for my other problem, the mic section was not good at all in the version 3.2.x, I updated to the 3.3 and it solve my issue. Just to let you know, I bought it with the 3.2 version on it ! So I never had audio working, now it is... Just software issue !

Hope the synching problem will be solve. Mine is clearly coming from my latency introduced by the X-T3 over the HDMI.

best regards !
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Re: Video Assist audio problem

PostWed Mar 10, 2021 12:12 pm

CptCurk wrote:Hope the synching problem will be solve. Mine is clearly coming from my latency introduced by the X-T3 over the HDMI.


I don't think they can solve the issue. I sold my 7" VA because of this problem. As far as I can see the VA is the only monitor recorder that doesn't have the ability to delay the video to allow syncing in the unit.
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rick.lang

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Video Assist audio problem

PostWed Mar 10, 2021 8:07 pm

But I find the delay is not a fixed amount. An option might be to delay a given amount, but that still might not be perfect. Unless I’m misunderstanding the problem. In tests I’ve done the video and audio are both delayed but easily synced by waveform (or timecode in post). Maybe VA Update 3.4 will address so I’ll need to retest.
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CptCurk

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Re: Video Assist audio problem

PostTue Mar 16, 2021 3:31 pm

Andrew HATFIELD wrote:I don't think they can solve the issue. I sold my 7" VA because of this problem. As far as I can see the VA is the only monitor recorder that doesn't have the ability to delay the video to allow syncing in the unit.


I agree that is a real problem in a professionnal recorder. As for me, the ability to do a pre-roll of 5 sec or even 3 sec. It's just logical to have a external recorder for those kind of function (with the "good" monitor of course)

For my latency, in photo mode, I finded that there is no latency ^^' but it's sending a bad quality through HDMI... Waiting for a firmware !
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Re: Video Assist audio problem

PostWed Mar 17, 2021 2:57 pm

I agree it's an easy fix in post but it's just something else to do, which shouldn't be necessary.

The Convergent Design and Atomos recorders all offer the facility to sync in the unit and even the ancient Video devices PIX-E5 can do it.

I would like to get another VA but until they sort this out I will stick with the Ninja V.
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CptCurk

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Re: Video Assist audio problem

PostTue Apr 27, 2021 9:19 am

Okay then no solutions for the moment.
I hope BM peoples did look into that topic for the next firmware. I also got that sound sync problem actually, and I can't use professionnaly my BM VA 7" 12G HDR and it's audio-port. The time to resync in post is just too long.

Best wishes folks! :D
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rick.lang

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Video Assist audio problem

PostTue Apr 27, 2021 2:39 pm

CptCurk, if you’re on the latest version of DaVinci Resolve 17, it’s a couple of mouse clicks to sync with either Timecode or waveform. You can sync on the Media Page or the Edit page Timeline. So when you have a post option, it’s a quick correction. If you are using your BMVA12G7 in live broadcast mode, then there are possible delay issues.
Last edited by rick.lang on Wed May 12, 2021 6:04 pm, edited 1 time in total.
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CptCurk

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Re: Video Assist audio problem

PostWed May 12, 2021 6:48 am

Little side by side. To show that what you're suggesting Rick, it's not possible. Synching somthing that's burn into the footage is not possible.
AND
If I want to use VA as proxy, there is a shift of 4 frames (take a look at the fifth line from bottom = Time code of the first frame)

VA vs X-T3.JPG
BM VA 7" 12G HDR versus Fuji X-T3 (externally FHD / internally UHD = same footage)
VA vs X-T3.JPG (433 KiB) Viewed 615 times


There's also a second probleme which is not only this audio problem but a color issue :

VA-XT3.jpg
BM VA 7" 12G HDR comparaison Fuji X-T3
VA-XT3.jpg (98.47 KiB) Viewed 614 times


Basicly, those issue (no manual delay + no pre-roll + color issue) make this "professionnal product" not usefull with a small gear and lightweigh stuff like Mirrorless camera :!: They should warn us.

SDI is just right and working, I had no issue with it.

Still hope a BM dev will pass by this post !
Best regards to all,

Florent "Cpt" CURK (for my full name !) 8-)
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rick.lang

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Re: Video Assist audio problem

PostWed May 12, 2021 6:10 pm

Never seen that ‘colour’ issue with what appears to be a different gamma on part of the screen. I’d call that a faulty video assist as I can’t think of how you would achieve that if you tried.

Back to the audio, I don’t understand why you simply don’t sync the video assist track with waveform in post if you have scratch or other good audio on your camera’s recording. Sorry if I’m a bit thick at the moment.
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CptCurk

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Re: Video Assist audio problem

PostTue May 18, 2021 2:38 pm

hey,

Synch the audio waveform is working only if I want to use my camera inbody H265 video.
But my purpose is to use the BMVA sound + image. And I don't sync anything there. I can just readjust manually each shot one by one on my timeline.

And actually, I'd like to use both sound and image, just because it's 4:2:2 10bit and there is 2 XLR ! ^^' so sync in post, not the solution
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rick.lang

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Re: Video Assist audio problem

PostTue May 18, 2021 5:14 pm

CptCurk wrote:…I can just readjust manually each shot one by one on my timeline…


If you have a scratch track with the video, I’ve used the manual syncing in post many times before it was supported recently to do this automatically to Timecode or Waveform. Agree sometimes the auto-sync to waveform doesn’t work and in that case it’s pretty quick and easy to manually eyeball the scratch and good track’s waveforms. Not good if you have a thousand clips but fine once in awhile. I always have scratch or other audio on camera as well as audio captured into the MixPre-6 II.

On one clip in a very important client shoot, there was a temporary glitch on the off-camera audio fed from a soundboard and I manually matched the waveform from my shotgun track on camera and masked the error. Camera audio isn’t ideal, but it saved that live shot which couldn’t be reshot.
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CptCurk

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Re: Video Assist audio problem

PostWed May 19, 2021 5:06 pm

May be I just explain badly the issue. There is the picture

TimecodeSync_Son&ImageLatency2.JPG
TimecodeSync_Son&ImageLatency2.JPG (84.34 KiB) Viewed 462 times


  • on top you see littles lines = 1 frames
  • first marker = sound of my external mic
  • second marker = the sound and frame clap in the X-T3 record
  • last marker = the clap on the frame of the VA
  • orange is my in-body recording (X-T3)
  • blue is my Video Assist recording

Btw, the clap of the X-T3 on the waveform is sync with the hand clap on the X-T3 inbody record.

Quite hard to understand. But there it is, if I'm using the X-T3 video and external VA sound, I can just sync with the waveform. But If i'm using the VA video and external sound, I have to do it manually.

I tried on Davinci to sync base on the waveform, but it's not working, it's doing the same than timecode...

Could be better to sync in the VA ! ^^'
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rick.lang

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Video Assist audio problem

PostWed May 19, 2021 6:00 pm

Very good picture. Does the orange Audio track 1 from the camera align within a frame of the visual of the clapper closing? If not you can manually shift any or all Audio tracks to align with the visual track.

Whichever track aligns with the video would be your starting track and then you can manually move the other Audio tracks to align with the starting track in the absence of timecode on all these Audio tracks. When automatic sync by waveform doesn’t work, I just use the manual workaround.
Rick Lang

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