Panasonic DMR-E55H (pal) and E85H (pal) image from VCR is too bright

[Bartoloni]

I tried to use DMR panasonic as a passthru to reduce lateral skewing of old VHS tapes... this is done prefectly, but the brightness level is changed
i use as input a composite signal (from various VCRs) and as output , composite, or S-video.. or component (this has completely wrong colors)

i'm acquiring with 3 different cards (2 blackmagic and 1 osprey)with the same results... the input is taken too bright (or the output is too bright).. well one of them is incorrect

this is an image about, on the left, original-signal , on center the composite (svideo is same) on right the component.
i was thinking to reduce brightness of output on svideo adding a resistor... but before doing this i will wait for someone that maybe can help on this situation.


[Attachment 79838 - Click to enlarge]

so.. 2 different DRM, how is possible that panasonic has not spotted that issue? (tried also using SCART adapter.. without any success)
tried also unsing an S-video input from a panasonic AG7350 ... but same

[Bartoloni]

meanwhile i tried adding resistance on luminance out signal...


[Attachment 79846 - Click to enlarge]

looks like that the brightness details are lost directly on input....

...
on attachments 200 ohms 250 ohms and 300 ohms
300ohm on right is reddish... the 250 ohm looks better..but still to bright.


[Attachment 79849 - Click to enlarge]

here 267 ohms seems a little bit too much brighter


[Attachment 79848 - Click to enlarge]

on this one.. 284 ohm seems a little bit highter, image is again redish and maybe a little bit darker.. maybe with 278/280 ohms...
probably i need to reduce a bit the source signal and a bit the output signal... (both)

[Sharc]

In a first step you should tweak the proc amp settings (lower the darks) of your capture card(s) and then try some color adjustments rather than fiddling with external resistors which possibly just spoil the impedance.
Actually I don't see a levels problem other than elevated darks. The loss of details in the (over)brights is probably on the source.

[Bartoloni]

(fixed the issue on component output.. one of the connector was oxided)

tried with software arrangments (lowering Y by 0.18 / 0.20 ) on the Blackmagic cards (just to have same brightness)
but some details are completely vanished( on high brightness spots )


[Attachment 79865 - Click to enlarge]

look at the t-shirt....

using a fully recapped AVE5 from panasonic these detailes are grabbed correctly by the card... (but i hate the AVE5 because it cut edges of the signal making some sort of unwanted zoom)

[Sharc]

The Original looks like progressive video (?), while the component looks interlaced. A valid comparison is difficult. Also, the component has clipped BLUE which may result in some loss of details. In the original the BLUE is not clipped it seems.
(The dark level looks still elevated (too grey) to me).

[Bartoloni]

going crazy with these EUROPEAN DMR units....
just bought another DMR .. and still the same, connecting a VCR (any kind) to all the inputs of DMR , is making an output (passthrough) with a change on contrast (white spots become bigger... loosing some light-grey details around white)

searched for service manual.... but it's showing
just a 100 ohms resistor (R3038) and a transistor 2SB1218A0L (Q3007) before the VIN on the main C1AB00001918 ( also a cap C3017 0.01 )

basically the video signal is entering immediately on the IC3001 (C1AB00001918 ) and there is nothing to set on EUROPEAN firmwares to change the "amplification/contrast/brightness" of the video input.


[Attachment 80439 - Click to enlarge]

[Bogilein]

you have to reduce the brightness before the signal goes into the Panasonic DMR.

Here in german language:

https://gleitz.info/forum/index.php?thread/47744-tipp-digitalisieren-%C3%BCbersteuerte...eer#post464769

[Bartoloni]

you have to reduce the brightness before the signal goes into the Panasonic DMR.

https://gleitz.info/forum/index.php?thread/47744-tipp-digitalisieren-%C3%BCbersteuerte...eer#post464769

Just made the "attenuation" filter, the signal become darker (and a little bit reddish).. the details are now grabbed correctly, but also using the Blackmagic acquisition Luma change ( +0.39 ) i can restore the brightness , but due to the "hardware filter" there is also a missing contrast... the final result is lacking contrast.

[Bartoloni]

The Original looks like progressive video (?), while the component looks interlaced. A valid comparison is difficult. Also, the component has clipped BLUE which may result in some loss of details. In the original the BLUE is not clipped it seems.
(The dark level looks still elevated (too grey) to me).

i recently bought a PAL VCR (NV-sv121) from panasonic, a SuperVHS device with a minimal TBC .. for my surprise... the RCA output is STILL too bright! ( on S-Video output seems OK... maybe a little bit brighter BUT but details are not lost on very white zones )
how is possible that a VCR (not a DVD passthru) make an RCA output too bright? it's possible that are the "MODERN" acquisition cards the issue?

i don't think that 20 years ago a 400$ units can output a wrong brightness using RCA
very frustrated about this... yes now i can use the S-VIDEO in a decent way for capturing... but i doubt everything is ok.

[Sharc]

The Original looks like progressive video (?), while the component looks interlaced. A valid comparison is difficult. Also, the component has clipped BLUE which may result in some loss of details. In the original the BLUE is not clipped it seems.
(The dark level looks still elevated (too grey) to me).

i recently bought a PAL VCR (NV-sv121) from panasonic, a SuperVHS device with a minimal TBC .. for my surprise... the RCA output is STILL too bright! ( on S-Video output seems OK... maybe a little bit brighter BUT but details are not lost on very white zones )
how is possible that a VCR (not a DVD passthru) make an RCA output too bright? it's possible that are the "MODERN" acquisition cards the issue?
i don't think that 20 years ago a 400$ units can output a wrong brightness using RCA
very frustrated about this... yes now i can use the S-VIDEO in a decent way for capturing... but i doubt everything is ok.

What exactly do you mean by "too bright"? Compared to what (reference)? Elevated dark level? Or brights in the luma 235 ....255 range? If nothing is clipped you won't be loosing details, and the brightness etc. can be adjusted to taste in post processing. No clipping is the most important. Worst case you might have to legalize the YUV to ensure valid RGB upon YUV -> RGB conversion.

[Bartoloni]

What exactly do you mean by "too bright"? Compared to what (reference)? Elevated dark level? Or brights in the luma 235 ....255 range? If nothing is clipped you won't be loosing details, and the brightness etc. can be adjusted to taste in post processing. No clipping is the most important. Worst case you might have to legalize the YUV to ensure valid RGB upon YUV -> RGB conversion.

the RCA out is like the S-VIDEO central image of this: https://forum.videohelp.com/attachments/79838-1718198837/compare.jpg

nothing that can be fixed on post processing.

what i think is that seems impossible that on default composite output the brightness level is wrong... and i was assuming because the modern (pci epxress) acquisition cards are "different" (in some way) from old All-in-wonder, Matrox Marvel and voodoo3500 that (probably) can aquire correctly from the composite output

[Bogilein]

maybe my comparison of a few PAL video recorders a few years ago will help you:

https://www.digitalfaq.com/forum/video-capture/10658-luminance-clipping-capture.html

[Sharc]

The brights get crushed somewhere. EH55 input overload?

Original picture

[Attachment 83329 - Click to enlarge]

S-Video picture

[Attachment 83330 - Click to enlarge]

You may want to try with this attenuator between the VCR and the DMR-EH55:

[Attachment 83331 - Click to enlarge]

[Bartoloni]

attenuator on the Y signal of S-video? or youy are talking about the composite video?

[Bogilein]

depends on whether the video recorder is connected to the Panasonic DVD recorder with S-Video or composite

[Alwyn]

@Sharc, in your attenuator, assuming an SVideo connection, is the top path (with the 27ohm resistor) the luma, and the bottom path the Chroma?

And for a Composite connection, would the top path would be the centre pin of the cinch cable?

[Sharc]

@Sharc, in your attenuator, assuming an SVideo connection, is the top path (with the 27ohm resistor) the luma, and the bottom path the Chroma?

TOP: Luma (pin 3 of the 4-pole S-Video mini-DIN aka Hosiden connector, or pin 19 of the VCR SCART out)
BOTTOM: Luma return, aka "Ground/shield/screen", (pin 1 of the 4-pole S-Video mini-DIN aka Hosiden connector, or pin 17 of the VCR SCART out)

And for a Composite connection, would the top path would be the centre pin of the cinch cable?

Yes. For composite the value of the attenuation is more critical as luma and chroma are attenuated. One might have to increase it experimentally to say 6dB to "disable" the AGC of the DMR.

See also here
https://forum.videohelp.com/threads/403635-Panasonic-DVD-recorder-passthrough-settings...15#post2757188

[Alwyn]

Thanks. I've already made a box that has a rheostat on the Luma line but am curious about whether your gadget would be better.

[Sharc]

Main design aspects:
- It should be purely resisitve in the MHz S-video range
- It should be highly linear (to avoid nonlinear signal distortions)
- It should preferably present a 75 Ohms terminating impedance to avoid signal reflections

Added:
A "high impedance" termination at the VCR side may worst case drive the output of the VCR into the clipping (6dB voltage step-up, voltage doubling) which cannot be recovered by subsequent attenuation. Depends on the VCR design.

[Bartoloni]

tried with a "vivanco" video mixer VCR3046 (a small mixer for hobbyist ) to reduce brightness of the original source (this is what i do often in software post-processing)

on the results the details are present.. but i'm very worried about a quality loss... these units can change colors/contrast/sharpness/etc.,.etc.. and the signal is processed a lot.

here 2 images.. both from ES10... but on the second one the vivanco i present to reduce brightness.

can be possible to see the exact issue on BLACK SPOTS.

[Sharc]

It looks about correct to me now. The bright details are preserved now, no clipping. Maybe you want to increase the gamma slightly to expand the darks a little.

[Attachment 83665 - Click to enlarge]

[Bartoloni]

this is a medium brightness

[oln]

video mixers that can properly alter brightness also tend to mess with the vertical sync signal so might prevent the es10 from working if you put them in front. Fancier ones have frame stores and sometimes some tbc functionality themselves so will completely replace the sync signals. I seem to remember the vivanco mixer I have doing that but could be wrong (also those things are kinda budget low end stuff so might degrade the video in other ways.)

[Sharc]

this is a medium brightness

Looks ok to me as well, no clipping, no loss of details. It's all within personal preference.

[Attachment 83767 - Click to enlarge]

[Bartoloni]

is just me or everything is going to purple/pink using a resistive attenuator?
using a pulldown reisstor of 100 ohm details are appearing... but there is a way to have a spectral analysis of the image to udnersatand if the red is increasing?

the single second image is usign just a resistor from signal (composite) to GND

[Sharc]

Whatever, it is pink-purple anyway. Adjust the white balance. How should it look??

[Bartoloni]

do you think the original one and the 100ohm reduced signal purple/pink component is similar?