Blackmagic capture, no dropped frames?

[durian]

Hi all,down to my last 20 tapes to transfer. workflow jvc9600u-pvw2800 - decklink 4k extreme 12g- bmd media express, windows 10, 10900k 32 gigs ram 1080ti nvme drive. resolve for deinterlace and upscale.

have seen previous posts suggesting that black magic capture cards were bad with lots of dropped frames and audio sync issues also to stay clear of windows 10. happy to report that everything worked great maybe things are getting better at bmd or with windows or computers in general.

majority of my captures were vhsc tapes with some hi 8. the hi 8 is straight out of the camcorder no tbc. captured everything no problems.before i got my jvc deck tested a 1.5 hour capture using a go-video no tbc standard vhs deck and had no issues if the source was clean (pro recorded commercial tapes) for camcorder vhsc tapes the 9600u was needed . fingers crossed i get through the last 20 hi8 tapes with no issues .

[timtape]

Quote:

Originally Posted by durian

... fingers crossed i get through the last 20 hi8 tapes with no issues .

Well done. With another 20 tapes to transfer I would have the tape path of the Hi 8 player manually and thoroughly cleaned as some sort of insurance against problems including irreversible tape damage.

[lordsmurf]

No issues with a non-TBC deck? Samples needed.

[durian]

did a quick 5 min capture for you uploading original res and interlaced to yt now . here is a video from my ipad as i was capping to show you the workflow https://www.youtube.com/watch?v=RjCpXqJfhPQ this is a 10$ vhs i got from goodwill yesterday playing a tape from the same good will captured off someones vhs 20 years ago heres deinterlaced version of cap https://youtu.be/chDDeLf4CTQ a cap from a betacam sp deck https://youtu.be/Xb-dFSD2kf0 a cap from hi8 on digital 8 camcorder svhs out https://youtu.be/-RE7lwtg3gs

[lordsmurf]

- "bush vhs test deinterlaced" looks awful. Wiggly, wiggly, wiggly. This is lack of line TBC.
- "haouli test 1080" isn't useful. All camera shake.
- "Jay Real cheats death" not great values, but everything else seems fine. Lots of motion there, hard to tell for certain.

Erratic motion and overt line timing errors can mask dropped frames issues.

[hodgey]

It's always possible that this specific blackmagic is set up differently to e.g the intensity shuttle ones and doesn't drop to the extent that those do.

The pvw2800 has a built in tbc (I'm not sure if it buffers full frames or not but probably more than sufficient on a betacam tapes), so one would expect that one to be stable. the signal from the sony hi8/d8 camcorders with tbc is generally stable outside of very major errors on the tapes and imperfect between recordings. The vhs one does indicate that it's not giving black frames to nearly the extent that some blackmagic cards do at least.

[durian]

the bush vhs was specifically captured from a 10$ goodwill vhs with worn heads with a composite cable the worst case scenario i could come up with .if i played one of my vhsc tapes it would have been wiggle lines all over the place. the point was the card did not drop any frames and just keeps recording if there is a signal on the screen of my camcorder for example there will be an image on the computer. the rest was just better sources beta and hi 8. I would do any specific test you guys like to try to see if this card is any better then previous BMD stuff. would rewinding and ffwding during a capture be a good test to check for drops ? I agree 100 % a TBC would have helped I do most of my captures with a jvc9600 i have passed the signal through the pvw2800 but currently dont use it. jvc or camcorder straight to card.. here is an old vhs bodyboard video from jvc to decklink card upscale is with resolve to 1080 https://youtu.be/6mgW6lubGfU . I have seen the decklink clean up snow i think there is some form of tbc on it . thanks for keeping an open mind guys i needed the decklink for hdr color grading in resolve anyway so i was happy to give it a try as a capture card. the jvc was an expense but i trusted the advice you guys gave on what to get and am very happy i did .

[latreche34]

Some of the BM analog to SDI and analog to PCI are indeed decent, You are not the first one to report them, members here and at VH have seen success using them, Jwillis just posted a thread over at VH about the analog to SDI converter. What is the exact model number to look up the user manual?

Anyway, the key to a successful capture with no dropped frames or audio sync problems is drivers and port bandwidth, BM with their MediaExpress took care of the driver issue under any OS platform and their devices work either as expansion cards or USB 3.0, So they don't have the USB 2.0 and its drivers issues.

There is two problems with your captures though, levels are all over the place and you have too much black borders around the frame, I know the decklink captures at 486 but that's more than 6 lines, So I don't know what went wrong, a lossless sample from the raw capture will help figure out what is going on.

[durian]

Thanks Latreche34. this is the model i am using https://www.blackmagicdesign.com/pro...specs/W-DLK-25 .what would be the ideal length, size of the sample ,subject matter preferred. and are the levels something i can change or is that related to the source material. Lordsmurf also mentioned the "values" not being great i am unclear as to what is being refereed to. i am guessing it is the brightness black levels etc. do we need a source thats stable like filming a test chart? should i upload as an attachment here or is there a preferred Dropbox ? can you link to the jwillis thread i am unfamiliar with "VH" so i do not know where to go to check for it . preferred file format for the sample avi or quicktime rgb 10 bit or yuv ?

[latreche34]

Regardless the source level you can always tweak it in the proc amp, BM desktop software should have a tab where you can see all the controls such as luminance, chrominance, hue ...etc. You can also capture with vdub 1.9 it has a nice tool for levels called histograms. I hope you didn't pay $895 for it, Most of that premium price is for the 4K option which is not needed for capturing analog into SD.

Samples of 20 to 30sec, MediaExpress 8bit YUV, use vdub2 to make a quick losslessly compressed HuffYUV AVI 4:2:2 YUV2. Dropbox is fine if the sample is over 99MB, You can always post at videohelp and link it here, they have 500MB upload cap.

https://forum.videohelp.com/threads/...uct-with-a-TBC

[durian]

i uploaded to "video help" https://forum.videohelp.com/attachme...e3%20vdub2.avi this was filmed/recorded with digi8 camcorder i am using for transfers then captured in media express. the lines on the bottom are not on the border. so i will make another small sample from svhs. just wanted to make sure i got the codecs right

[latreche34]

D8 recordings are not analog, therefore they are always better captured using a DV workflow, Digital camera, firewire, WinDV or Sclive. And they are not the right source to stress test analog workflows.

[durian]

here are 2 samples off the jvcsvhs with the tbc on https://forum.videohelp.com/attachme...in%20tones.avi https://forum.videohelp.com/attachme...a%20adjust.avi i sent the signal out to my shogun external monitor that has tools and used false color to set luma off the skin tones for the first sample

[dpalomaki]

Quote:

...and are the levels something i can change...

The BM Desktop Video utility does allow some level settings for analog captures. For s-video inputs you can set luma and chroma gain a you can specify set-up as 7.5 or 0 IRE. (Not full proc amp adjustment capability.) The BMD devices I've seen will crush ultra blacks (below setup) and may clip ultra whites above somewhere between 100 and 110 IRE, both of which can happen with analog signals from home recordings and VCRs.

MediaExpress can be set to stop capture on detected dropped frames, which may or may not detect all dropped frames.

What capture format are you using? M-JPEG?

[latreche34]

Quote:

Originally Posted by durian

here are 2 samples off the jvcsvhs with the tbc on https://forum.videohelp.com/attachme...in%20tones.avi https://forum.videohelp.com/attachme...a%20adjust.avi i sent the signal out to my shogun external monitor that has tools and used false color to set luma off the skin tones for the first sample

Yep, Perfect. That's how a pro device capture looks like, Nice and straight vertical frame edges, extra top 6 lines for caption/teletext acquisition, Bottom head switch signal band, You could still tweak luma and chroma levels scene by scene if you want to devote the time to it otherwise these would be your typical master files, All processing should be done from files like these.

[durian]

those were both using avi 8 bit in media express then converted to Latreche34s instructions i have set it to stop capture if it detects dropped frames thank you

[lordsmurf]

Quote:

Originally Posted by durian

i have set it to stop capture if it detects dropped frames thank you

This is the main issue with Blackmagic cards. The detection is bad to not there. That's a main reason BM cards are not usable for more serious users. Newbie users just assume no drops, and ram through their VHS project without paying it any close attention. Far too many learn of the problems later, sometimes years later.

[durian]

Lordsmurf is there a way to detect dropped frames . i just changed the setting so i have no idea how well it will work. did you see any dropped frames in my samples ? or is it not something you can see with your eyes. i am a newbie but i dont want to be "the newbie" who finds out years later.

[lordsmurf]

Quote:

Originally Posted by durian

Lordsmurf is there a way to detect dropped frames . i just changed the setting so i have no idea how well it will work. did you see any dropped frames in my samples ? or is it not something you can see with your eyes. i am a newbie but i dont want to be "the newbie" who finds out years later.

Not really. There are ways to see dupes, dropout frames, but not really drops. Not until watching, or paying attention while editing -- which is when it always get noticed. Nobody sees it realtime in their tiny 4" preview screen on the computer, but they will on a large HDTV, or non-realtime editor (NLE).

Don't assume "no dropped frames".
Assume = ass-u-me

For example, VirtualDub can essentially be set to not report drops, and it has a counter that will then be static as "0 drops" (but it's BS).

Verify.
On verification, many people recant (or disappear ).

[durian]

thank you, will check all my footage for drops when i am editing on 4k monitor frame by frame.