Video Saver, how to Turn OFF Video AGC?

Steve-Mahrer wrote on 1/16/2023, 5:32 PM

HI, I purchased a Magix Video Saver to dub off old VHS tapes. It works, rather clunky menus, and settings default to 25 frames ( I'm in the US!!). My question however relates the USB video interface, can I disable the Video AGC? It's blowing out the video and the AGC varies wildly with content.. I'm a retired production guy, so I had hoped to some options here. Thanks! Steve

Comments

AAProds wrote on 1/17/2023, 6:24 PM

@Steve-Mahrer

Steve, I'm not sure you can disable AGC. I have other capture dongles and I haven't come across an AGC switch.

Regarding the "blowing out", you should be able to go into the "Hardware and Drivers" area and hopefully find the Image Settings section. On the VideoProcAmp tab, you'll be able to adjust the Brightness and Contrast. I don't actually have a Magix dongle and am only going on the typically poor PDF manual; if you have access to that, it's on page 21.

If that doesn't work, there is a free, third-party program that will give you access to the procamp while the video is playing/capturing.

All my forum comments are based on or refer to my System 1.

My struggle is over! I built my (now) system 2 in 2011 when DV was king and MPEG 2 was just coming onto the scene and I needed a more powerful system to cope. Since then we've advanced to MP4 and to bigger and bigger resolutions. I was really suffering, not so much in editing (with proxies) but in encoding, which just took ages. A video, with Neat Video noise reduction applied, would encode at 12% of film speed. My new system 1 does the same job at 160% of film speed. Marvellous. I'm keeping my old system as a capture station for analogue video tapes and DV.

System 1

Windows 11 v23H2 severely modified by Openshell and ExplorerPatcher

Power supply: 850W Cooler Master (should have got modular)

CPU: Intel i7 13700K running at 3400mhz, cooled by a Kraken 2x140mm All In One liquid cooler.

RAM: 64gb (2x32gb sticks) G.Skill "Ripjaws" DDR4 3200Mhz

GPU 1: iGPU UHD 770

GPU 2: NVidia RTX 3060Ti Windforce 8gb

C drive: NVME 500gb

Various other SSD and HDDs.

Monitor: 27"/68cm Samsung, 2560 x 1440, 43 pixels/cm.

MEP 2021 version 20.0.1.80

Movie Studio 2023 version 22.0.3.172

Magix Video Easy version 7.0.1.145

System 2

(Still in use for TV and videotape capture)

Windows 10 v22H2

CPU: i5-750 at 2670mhz with 12gb RAM

Onboard IEEE1394 (Firewire) port

GPU: ATI Radeon HD 4770 (512mb) which is ignored by MEP

Hard drives: C Drive 256gb SSD, various other HDDs.

Monitor: Dell 22"/56cm, 1680x1050, 35 pixels/cm

MEP 2021 version 20.0.1.80

Movie Studio 2023 version 22.0.3.172

VPX 12

Steve-Mahrer wrote on 1/17/2023, 6:49 PM

Thanks for the response, much appreciated. I think I’m facing the reality of the limited options on the USB dongle video interface. The AGC works on ingest, so the MPEG master file gets blown out…badly. I used a variable attenuator on its input to try and drop levels…. The AGC appeared to fix the attenuation! My videos from 1990 looks like they’re 2 or more stops overexposed, yet it varies with video content. The procamp style controls work, alas however, they work after the damage is already done. i may try to reverse engineer the dongle, try to lock the gain. I’m retired and a geek, it’s a challenge, which is fun.

 

cheers!

 

steve
 

 

AAProds wrote on 1/17/2023, 7:19 PM

@Steve-Mahrer

Steve, out of interest, the Panasonic ES-15 I use as a cheap-charlie TBC raises the whites too much also.

I used a variable attenuator on its input to try and drop levels….

What actual device are you using as an attenuator? It might be handy for lowering the levels from the ES15 prior to the capture stick.

All my forum comments are based on or refer to my System 1.

My struggle is over! I built my (now) system 2 in 2011 when DV was king and MPEG 2 was just coming onto the scene and I needed a more powerful system to cope. Since then we've advanced to MP4 and to bigger and bigger resolutions. I was really suffering, not so much in editing (with proxies) but in encoding, which just took ages. A video, with Neat Video noise reduction applied, would encode at 12% of film speed. My new system 1 does the same job at 160% of film speed. Marvellous. I'm keeping my old system as a capture station for analogue video tapes and DV.

System 1

Windows 11 v23H2 severely modified by Openshell and ExplorerPatcher

Power supply: 850W Cooler Master (should have got modular)

CPU: Intel i7 13700K running at 3400mhz, cooled by a Kraken 2x140mm All In One liquid cooler.

RAM: 64gb (2x32gb sticks) G.Skill "Ripjaws" DDR4 3200Mhz

GPU 1: iGPU UHD 770

GPU 2: NVidia RTX 3060Ti Windforce 8gb

C drive: NVME 500gb

Various other SSD and HDDs.

Monitor: 27"/68cm Samsung, 2560 x 1440, 43 pixels/cm.

MEP 2021 version 20.0.1.80

Movie Studio 2023 version 22.0.3.172

Magix Video Easy version 7.0.1.145

System 2

(Still in use for TV and videotape capture)

Windows 10 v22H2

CPU: i5-750 at 2670mhz with 12gb RAM

Onboard IEEE1394 (Firewire) port

GPU: ATI Radeon HD 4770 (512mb) which is ignored by MEP

Hard drives: C Drive 256gb SSD, various other HDDs.

Monitor: Dell 22"/56cm, 1680x1050, 35 pixels/cm

MEP 2021 version 20.0.1.80

Movie Studio 2023 version 22.0.3.172

VPX 12

Steve-Mahrer wrote on 1/17/2023, 7:44 PM

It’s funny, here am I trying to salvage VHS tapes of my kids from 1990, and my source deck is an old $100 VCR, from maybe late 1990s, no TBC, just the usual RCA jack with a badly heterodyned Y /C video OP. The dongle’s AGC appears super responsive, and the result isn’t clipping, it’s more of a soft “gamma” / video knee crushing effect… my attenuator is from my RF lab, 0-60dB in 1dB steps… in pause, it looks good until you record the footage, and then the AGC “ fixes it!”. Just FYI viewing the tapes native on my 60” plasma shows much better video quality.

My previous life was 4K cine cameras, post work flows, color science etc… I miss access to those toys!

I’m just trying to capture the VHS content, “as is”. Then export that as a file format / codec that using Black Magic Resolve I can grade for posterity. The USB video dongle appears to be “helping too much”.. trying to fix very varied lighting…
 

The supplied software is interesting as to export options, the MP4 codecs are interesting and quite clever, CABAC, GOP options etc. I just wish they’d encode a fixed level video.

again, I appreciate the interest and suggestions!

steve.

 

 

 

johnebaker wrote on 1/18/2023, 3:20 PM

@Steve-Mahrer

Hi

. . . . my attenuator is from my RF lab, 0-60dB in 1dB steps… in pause, it looks good until you record the footage, and then the AGC “ fixes it!” . . . .

The attentuator should not be necessary. The VCR should be outputting Composite video at the standard signal level of 1.0v peak to peak into a 75 ohm load.

Video converters expect this signal level, any attentuation will make the AGC compensate for this and can introduce undesirable effects.

John EB
Forum Moderator

VPX 16, Movie Studio 2025, and earlier versions 2015 and 2016, Music Maker Premium 2024.

PC - running Windows 11 23H2 Professional on Intel i7-8700K 3.2 GHz, 16GB RAM, RTX 2060 6GB 192-bit GDDR6, 1 x 1Tb Sabrent NVME SSD (OS and programs), 2 x 4TB (Data) internal HDD + 1TB internal SSD (Work disc), + 6 ext backup HDDs.

Laptop - Lenovo Legion 5i Phantom - running Windows 11 23H2 on Intel Core i7-10750H, 16GB DDR4-SDRAM, 512GB SSD, 43.9 cm screen Full HD 1920 x 1080, Intel UHD 630 iGPU and NVIDIA GeForce RTX 2060 (6GB GDDR6)

Sony FDR-AX53e Video camera, DJI Osmo Action 3 and Sony HDR-AS30V Sports cams.

Steve-Mahrer wrote on 1/18/2023, 3:36 PM

Hello John.. That's true, the VCR is fine, the composite video OP is fine, as seen on a WFM / scope or TV.

The issue appears to relate to the USB Dongle's AGC, it reacts to the "averge scene" video content and "adjusts" the levels dramatically. The Attenuator (2-3dB) was an attempt to drop the video level in the hope of getting a less crushed "recording". For the money paid, it works, alas it's just not the quality I was hoping for. I can post some screen shots of VCR OP vs Dongle ingest if needed. As I commented, its not clipping per se, its just applying some sort of soft crushing / gain boost and increasing the video APL by a large amount. Thus anything light, ex a white shirt or a face gets desaturated and often looks overexposed. I'll be travelling overseas, I'll update when I'm back and had a chance to look at the issue again. Cheers!