Captured huffy AVI, convert to mpg poor.

[davexnet]

My Avermedia capture card has an built-in mpeg encoder, but today I wanted to see how well it did using
Huffy.
I captured abut 30 seconds of a cartoon today. When I look at the file in virtualdub, it looks OK.
I split the fields and it looks pretty clean.
I tried encoding it to mpeg, but when I look at the fields in Virtualdub, there is some ghosting or artifacts.
Here's a shot of frame 2 from the source and frame 2 from the mpeg. You can easily see problems in the split fields.
Any thought appreciated.








Uploaded with ImageShack.us

[sanlyn]

Not enough information. What software did you use to capture the video? Did you copy directly to AVI? What is the capture's frame size? What kind of MPEG are you making (MPEG-1, MPEG-2 for DVD? SVCD?). What software was used to encode MPEG? Why are you splitting the fields?

[davexnet]

Hi Sanlyn, it was a quick and dirty test just to see how my capture card works with various software.
The capture utility is called Stoik, a very simple to use tool downloaded from Videohelp.com/tools section

I captured directly to Huffy AVI. Frames size capture is 720*480. I encoded the mpeg from this AVI
in two tools: HCenc (via avisynth avisource)
and Tmpgenc 2.5 - both had problems . The reason I split the fields? Because I could see the
mpeg playback looked fuzzy compared to the source. Splitting the fields and looking at them allows
you to see the problems easier (I didn't use split fields in encoding it's just a diagnostic tool).

The source is quite good quality for an analog capture, while the mpeg looks poor in comparison.
I'm trying to figure out if I'm doing something wrong in the encode? Looking for suggestions.

[poisondeathray]

Virtualdub doesn't handle interlaced YV12 mpeg2 correctly . See this post.

https://forum.videohelp.com/threads/307116-8mm-film-and-the-msu-old-color-restoration-f...=1#post1890833

another non-anime example
https://forum.videohelp.com/threads/322848-Scripts-and-filters-for-an-Opera-(sample-vid...=1#post2000643

Do you see the same artifacts in vdubmod ? or use an avs script to open in vdub . This may or may not be the issue, but your 2nd set of screenshots isn't valid

Was your Huffyuv an RGB capture? What was your avs script ? If you did colorspace conversion did you remember to specify interlaced=true ?

[davexnet]

poisondeathray, thanks for mentioning the Vdub problem. I had heard of t before, but didn't know it manifested like this.
I opened the mpg in Virtualdubmod and it looked much more like the source AVI.

The settings I had in the Huffy codec prior to capture (and I must admit I'm not that familiar with it and I'm not sure what
the ramifications of these settings are)
yuy2 compression manager=predict left (fastest)
RGB conversion method = <- convert to yuy2
Always suggest RGB format for output (this was checked)

Why do you say the 2nd screenshot is invalid ? Because of the Virtualdub problem?
The script I used (to open the source in HCenc) was very simple:
avisource("file.avi")
assumefps(29.97)

Perhaps I should try a colorspace conversion here and specify interlaced=true, or does HCenc do that under the covers?
It certainly accepted the script as-is.

[poisondeathray]

Why do you say the 2nd screenshot is invalid ? Because of the Virtualdub problem?

Yes, it's invalid because of your screenshot method (i.e vdub usage with interlaced YV12 MPEG2)

The way you have it set, your huffyuv settings looks like it's capturing in YUY2. You only need to specify interlacd=true when you do the colorspace conversions e.g. if you were converting interlaced RGB => interlaced YUY2 you would use ConvertToYUY2(interlaced=true). You don't need to do that in this case. But you do have to indicate that it's interlaced in HCenc encoding settings , but it sounds like you've done that

If it looks ok (like the source) in vdubmod, then there isn't a problem

[sanlyn]

The VirtualDub problem is hard to see with real-world video, but somehow it flares up with animation or line art. I recall doing some silly once (once?), telling my encoder the field order was bottom field first. Made a mess.

If you're going to do any processing with VirtualDub, you might consider capturing with huffyuv to RGB24 instead of YUY2.

[davexnet]

Thanks again..I'll have to look to see if I can tweak anything in HCenc to optimize the encode - at least I know now it's handling the
interlacing correctly. Didn't HCenc used to only accept yv12? Now it seems as if it accepts yuy2 also.

Does the developer @ Virtualdub know about this problem?

[manono]

Thanks again..I'll have to look to see if I can tweak anything in HCenc to optimize the encode

You can probably tweak your script to IVTC it. I seriously doubt this thing is pure interlaced 29.97fps.

To find out the colorspace, add Info() at the bottom of the script.

[poisondeathray]

You could probably use some filters too, the source looks like it could be cleaner (for anime)

Maybe a custom matrix like a MANONO matrix ... heh . Actually I don't use custom matrices, so I'll let manono explain if that's a good idea or not. But I noticed there were some named matrices after him the other day

Does the developer @ Virtualdub know about this problem?

yes he does

[davexnet]

sanlyn, poisondeathray & manono - thanks for your continuing suggestions. This Scooby Doo cartoon clip was just something that happened to be on - a live broadcast,
my daughter was watching it, I was just playing around and only captured about 30 seconds. Here is the route it took.
Cablebox to vcr (s-video), vcr to capture card (composite). So you can see, it's already somewhat compromised; I'm surprised it's as good as it is.

It's not pure interlaced- there are many progressive frames. Regarding using IVTC - I assume you mean reduce it to 23.96 and encode the mpeg2 with pulldown?
Would there be a generic AVisynth script, or does it have to be adaptive to catch any change in the pattern ?

A couple of weeks ago, I did something similar. Once again, my daughter was watching TV - one of her tapes, an old off the air animation recording,
recorded in the ep speed. Quite fuzzy and a lot of color noise. I captured about 5 minutes of it in my cards native mpeg-2. I was quite surprised to see that the card
had cleaned up the signal somewhat. The image look much improved compared to what I saw on the TV.
In this case I was wondering how to convert it to a progressive AVI. I ended up with a script that looks like this:
LoadPlugin("J:\dgmpgdec157\DGDecode.dll")
MPEG2source("F:\DG-nimh4.d2v")
TFM(d2v="F:\DG-nimh4.d2v")
TDecimate(mode = 1) ############### mode 1 for animation
spline16resize(640,480)

I'm not a script expert by any means, but the above came out quite well.

[Gavino]

You only need to specify interlacd=true when you do the colorspace conversions e.g. if you were converting interlaced RGB => interlaced YUY2 you would use ConvertToYUY2(interlaced=true).

interlaced=true is only relevant to conversions to and from YV12, so it's not needed for RGB<->YUY2.
It's not a colorspace (RGB/YUV) issue, it's a (sub)sampling issue.

[manono]

It's not pure interlaced- there are many progressive frames. Regarding using IVTC - I assume you mean reduce it to 23.96 and encode the mpeg2 with pulldown?

Yes, that's exactly what I mean. And using TIVTC as in your example is also what I had in mind. The encoding will be much more efficient resulting in much better quality for the same file size given that you'll be encoding all progressive frames and many fewer of them as compared to encoding for interlaced 29.97fps.

[poisondeathray]

interlaced=true is only relevant to conversions to and from YV12, so it's not needed for RGB<->YUY2.
It's not a colorspace (RGB/YUV) issue, it's a (sub)sampling issue.

Thanks, I didn't know that it wasn't required for YUY2<=>RGB .

[davexnet]

I did some test encodes with HCenc 024 using the built-in default matrix, the "notch" matrix, and the cg/animation matrix from Tmpgenc 2.5
I also tried to see if there was any difference in allowing HCenc to do the yuy2 > yv12 conversion, or coding "converttoyv12(interlaced=true)" in the script.

The Tmpgenc matrix seemed to give the best result, but there wasn't much in it. In general, the mpeg didn't seem as vibrant as the source.
For now, I haven't attempted IVTC, but left it at 29.97.
Here's 10 seconds of the source if you'd like to give it a try (199 MB) :
http://www.mediafire.com/download.php?yz1nwqutnfdwboz

[jagabo]

Your black level is too high it could probably use a little more gain too. Hence the loss of "vibrance".

Also be careful how you compare before and after videos. You usually can't compare by opening both in media players side by side. Only one player can use Video Overlay which has different proc amp settings than the Desktop. Even if both players are viewing the same file they will look different unless you've calibrated Video Overlay and the Desktop to look the same.

You should also consider turning down the temporal filter on your caps. There is ghosting between frames. Although, that could be from the broadcaster.

[davexnet]

Hello -
I always thought the temporal filtration was fixed in the HW of the capture card,
but I assumed it only applied when the HW assisted mpeg encoding was selected.
Since this was Huffy, and presumably encoded without HW support, where is the temporal
filtering coming from? Maybe related to the HW analog
comb filter or other processing . Bottom line, I don't know if it's adjustable.

I can change brightness, contrast, sharpness, hue & saturation - that's the only adjustments I see.

I had noticed the black was too high - I had previously adjusted the brightness down a little to
compensate, but reinstalling the SW the settings were lost. I'll recheck it.

[jagabo]

If your card/driver is doing it, the temporal filtering probably works even when capturing uncompressed YUY2. All the cards I have are like that.

You may be able to control more features of the card/drivers by adding the capture filter in Graph Studio, right clicking on it, and selecting properties. VirtualDub may also give yo access to them. Sometimes there's a Registry setting you can modify.

[lordsmurf]

Rooby roo!
Is this a new show?

[davexnet]

Rooby roo!
Is this a new show?

My daughter knows far more about these shows than I ever would, so I'll have to consult with her!

Regarding the ghosting, I see it, but I never would have noticed it unless I was looking at it quite closely.
This was recorded from the s-video/composite it.

My cable feed also has the local analog channels for those with analog TV's and no cable box.
The quality of them is very poor. I do have the cable split and one of the feed plugged into this
analog input. Not really sure why I did it, they're all redundant, bar none.
Either I can pick up the same ATSC equivalent from the roof antenna, or I can watch the digital version
via the cable box.

I tried a short capture of these analog channels, and the smearing is absolutely unbelievable.
"Ghosting" would be too kind a word for it. Is the capture card's noise reduction confused by the
poor signal? In any event, the capture is almost worthless.

Perhaps I'll post a short clip later.