Amarec FPS issue

[Slothrop]

Hello! Long time lurker, first time poster!

So I've been capturing VHS tapes using the GV USB-2 as a capture device, and the capturing has been done in Amarec. I pass it through in UV ULY2 codec, no deinterlacing at 720x480.

My capture settings in Amarec are:

*w= 720, h= 480, fps=59.94, fcc=YUY2, bit=16

My questions are, have I already messed up? And my other is when I get my 59.94 fps avi, how do I deinterlace without doubling all of the frames again? What would you recommend as the next post processing step? Vdub or Avisynth? Thank you for your preemptive help.

[Alwyn]

Choose the "*w= 720, h= 480, fps=29.97, fcc=YUY2, bit=16" format.

To deinterlace to 29.97 frames/sec in VDub, choose one of the single-rate options such as on the top right: "Keep top field" or "Keep bottom field".

In AVISynth/QTGMC, add "FPSDivisor=2". That will give you the original frame rate.

That said, I prefer doubling the frame rate because it smooths the movement a bit.

[Slothrop]

Thanks for your response! I actually don't have a 29.97 fps option in amarec. I just have the 59.94 and 60 fps options listed. I've tried looking for a solution but couldn't find it!

As for the discard field options, that's for the preexisting 59.97 fps captures right?

[Alwyn]

I actually don't have a 29.97 fps option in amarec.

Oh that's weird. It seems the capture format options are determined by the digitiser and the GV-USB2 definitely captures at 29.97:


[Attachment 75465 - Click to enlarge]

I'm on the 1.1.0.93.5 driver (on Graph 1 Tab, click Device Setting).

As for the discard field options, that's for the preexisting 59.97 fps captures right?

Yep. I don't know the fineries of each, whether one is better than the other.

[Sharc]

I don't know the fineries of each, whether one is better than the other.

Depending on the mode and order settings it throws away one field and interpolates (synthesizes) the missing field spacially. Useful when there are quality differences between the 2 fields: Keep the sane field and drop the bad field, as recently discussed here:
https://forum.videohelp.com/threads/412482-What-kind-of-problem-exists-with-my-digitiz...eo#post2713905

Better than trying to describe: You can try out the various deinterlacing options with the attached file which contains 2 static distinct fields representing 2 individual pictures (no motion).

Having said this, I would discourage the OP from single rate deinterlacing unless he has a specific reasons to justify it. One throws away 50% of the temporal resolution. What a waste of a good capture

[lollo]

Nice example Sharc!

I just added the output of your files using a simple script to show the outcomes:

video_org=AviSource("0) 422i_.avi")

### de-interlacing
deinterlaced_dfr=video_org.AssumeBFF().QTGMC() 

deinterlaced_sfr=video_org.AssumeBFF().QTGMC(FPSDivisor=2).SelectEvery(1,0,0)

f_stackhorizontal(deinterlaced_sfr,deinterlaced_dfr,"deinterlaced_sfr BFF","deinterlaced_dfr BFF")

function f_stackhorizontal(clip c1, clip c2, string t1, string t2)
{
stackhorizontal(\
subtitle(c1,t1,size=20,align=2),\
subtitle(c2,t2,size=20,align=2)\
)
}

video_org=AviSource("0) 422i_.avi")

### de-interlacing
deinterlaced_dfr=video_org.AssumeTFF().QTGMC() 

deinterlaced_sfr=video_org.AssumeTFF().QTGMC(FPSDivisor=2).SelectEvery(1,0,0)

f_stackhorizontal(deinterlaced_sfr,deinterlaced_dfr,"deinterlaced_sfr TFF","deinterlaced_dfr TFF")

function f_stackhorizontal(clip c1, clip c2, string t1, string t2)
{
stackhorizontal(\
subtitle(c1,t1,size=20,align=2),\
subtitle(c2,t2,size=20,align=2)\
)
}

[Attachment 75475 - Click to enlarge]

Actually, the kell factor reduce the loss of temporal resolution below 50% for real world, but your example should explain a lot

[Sharc]

I developped this example some time ago to convince the devs of a well known NLE that the NLE doesn't handle interlaced YV12 properly.
It is not really a deinterlacer test because the motion between fields is taken out of the equation, but it helps to understand the fields manipulations and color space conversions.

[lollo]

It is not really a deinterlacer test because the motion between fields is taken out of the equation, but it helps to understand the fields manipulations.

Absolutely

[Slothrop]

Ah! I'm on the 1.1.0.93.8 driver, I downloaded it right from the iotku.pw link. Did you use the disc driver download? I reinstalled the drivers too and got the same options. I'm just puzzling over why this would be the case, especially if the driver is newer!

I do like understanding that halving is an option, but I'm definitely aiming for the best output possible, with proper deinterlacing, that is. I'd rather keep all the information I can squeeze from the tape!*Thanks for the tip on when that can be useful though. And for the visuals, I like pretty pictures even if i don't fully understand them!

EDIT: I can manually enter in the FPS in the text box, since this seems to be pretty "set it and forget it", I'm not going to fret if it captures the right information.

I do have a question about the baked in proc amp settings for the GV USB-2. Do any of you have experience fiddling with those pre capture or should i just leave them as is and correct in post? Thanks again!

[Alwyn]

Did you use the disc driver download?

No, when I first installed it, I used the 1.11 driver from the website after I put in my serial number. I'm not sure though what effect, if any, the serial number has on the download. Could simply be marketing data-capture.

You could try the 1.11 driver: get it here. You can change OS on the droplist.
https://www.iodata.jp/lib/software/g/1780.htm#Windows%208

It might also pay to reset AmarecTV: delete the AmaRecTV.ini file from the AmaRecTV folder and restart it.

[Sharc]

I do have a question about the baked in proc amp settings for the GV USB-2. Do any of you have experience fiddling with those pre capture or should i just leave them as is and correct in post? Thanks again!

Leave them alone to begin with. Then make a capture and post a sample here so someone will comment. Fiddling with the proc-amp settings is a subject of its own.
Firstly make the GV-USB2 up and running correctly. I seem to remember that someone had the framerate problem before. I just can't find the post and don't remember the remedy.
By the way I am using driver version 1.1.0.93.5, 2010.06.28 on Windows 10 and 11. No problems here.
If nothing helps make a capture with your 59.94fps and post a sample here.

[oln]

I could be misremembering but I think when testing the latest driver I had to use virtualdub and/or the bundled capture app and select the TV system to PAL in my case to make the 25 fps (in my case) option to show up (may need to chose NTSC for the 29.97 option). Think it may be under the "device setting" or "input setting" buttons in the amarectv menu. May have to restart amarectv as well after doing that.