Adjusting IRE Black Levels with Sony DV Camcorder Pass-Through Capture

[VideoDoc]

What is the best way to adjust the IRE black levels when doing a pass-through capture using a Sony Mini-DV camcorder? I have a Sony DCR-TRV38 that I know results in incorrect black levels when used in pass-through mode. Many scenes are washed out or too bright. I understand that that this is a common problem. Other than this, I am happy with the captures that I am getting. What is the least destructive way to adjust for this? I have considered buying a proc amp but the ones I have looked at are very expensive and appear to be overkill for what I want. Will adjusting for this after capture further degrade my video? I understand that the DV AVI file that I obtain is already lossy.

[Cornucopia]

Adjusting levels will entail further re-encoding. Re-encoding lossy will commit further loss. How much loss is objective, but the perception of it is subjective.

Best to do with proc amp in analog domain prior to passthrough, especially when digital is 8bit. Analog proc amps shouldn't be expensive, but due to scarcity (age?), and being bundled with other features (tbc, framesync, mixer?), it often is.

Scott

[VideoDoc]

Adjusting levels will entail further re-encoding. Re-encoding lossy will commit further loss. How much loss is objective, but the perception of it is subjective.

Best to do with proc amp in analog domain prior to passthrough, especially when digital is 8bit. Analog proc amps shouldn't be expensive, but due to scarcity (age?), and being bundled with other features (tbc, framesync, mixer?), it often is.

Scott

Thank you so much for your response. I kinda already anticipated that this was the likely answer but I thought I would check first. I have done an online search for proc amps but very little available. I assume I will have to buy something used? I found an Elite Video BVP4+ which I know is well regarded but it again seems like overkill. Anyone making anything that your can purchase new? I assume the answer is no.

[jagabo]

I believe it's possible to adjust DV levels without decompressing it. There is a program that does that but I don't remember what it's called.

<edit>

Found it: https://www.videohelp.com/software/Enosoft-DV-Processor

</edit>

[VideoDoc]

I believe it's possible to adjust DV levels without decompressing it. There is a program that does that but I don't remember what it's called.

<edit>

Found it: https://www.videohelp.com/software/Enosoft-DV-Processor

</edit>

Thank you so much for this info! If true, this would be fantastic. Does anyone else have any experience with this software? Is it really nondestructive? I found this thread from 2007 where the developer describes how to do this:

https://forum.videohelp.com/threads/259750-NTSC-IRE-levels-and-DV-camcorder-Pass-Throu...re#post1560272

Looking forward to giving this a try.

[Eric-jan]

DV has intra frame encoding,(Just like ProRes422) as long you encode back to DV loss will be minimal.

(MP4 = inter frame encoding.... that's the big difference)

What i now understand this black level "problem" is a NTSC problem, and it will not occur with PAL DV camera's ?

[Cornucopia]

Not "minimal", but less. IMO.

There is an issue w NTSC that doesn't exist in PAL, in that pedestal/blk setup could reference to 0IRE (Japan) or 7.5IRE (NorthAmerica). PAL always references to 0. Thus if you set your normal input black level wrong, error could be alleviated or exaggerated by how it is mismatched. However, that is just on top of the normal black and/or white level error you might be inputting, which you should use a proc amp with scopes in order to be as accurate as possible prior to digitization to avoid such errors.

Scott

[Eric-jan]

My question about that: here we had PAL, so would using the the composite or s-video connection to capture always be better then transferring by DV/Firewire in that case ?
Or, can the error's of the black levels be completely corrected in post ?
Also i thought of a setup with 2 ADVC100's with in between a "correction device" , using firewire "live" for correction
I have read a lot disaprovements using Firewire for transfering, or passthrough for "capturing" video, while Hi8 was one of the best quality of analog tape format, (shame about the drop-out's though..) is DV/Firewire just bad in general ?

[lordsmurf]

My question about that: here we had PAL, so would using the the composite or s-video connection to capture always be better then transferring by DV/Firewire in that case ?

The main reason not to capture DV is the colorspace compression
4:1:1 for NTSC is very lossy, unacceptable by modern standards (2000s, 2010s, 2020s).
4:2:0 for PAL is acceptable.

DV compression is 1990s technology.