Help on end video quality!!

[Guest]

So hey, I made avi's from DVD's of a tv show to make a music video but when I
put them into WMM and make the actual movie into a movie, the quality sucks.
I've chosen High Quality Video (large) and the NTSC versions ((since it'll be
later burned onto a DVD for a fan no profit competition))

I mean, I guess it's not horrible, but there's this flat black shadow that
pops up and some bits are REALLY pixel-y. I just got this laptop with XP Pro
not even a month ago. So...yeah, there's no updates I'm possibly missing that
could help me keep the same video quality is there?

Another thing I think I should note, the clips I made are huge. There's like
4 episodes per avi and they're like 2 gigs each. Is there some sort of
compression thing I'm missing on WMM that'll make it be thatbad of quality?
Is there anything I could do to the original avi's to compress them and still
have everything look perfect?

ahhahaha....I'm probably confusing you all....I'm so sorry! T_T!

 

[RalfG]

Any video for TV other than HDTV is much lower resolution than your computer
monitor so once you stretch the video out to fill the monitor screen it will
look varying degrees of crappy. Probably worse looking on LCD monitors than
CRT. Nothing in the WMM or any other video editor settings will change that,
but the video should still look okay when viewed on a TV. Be aware that
every time you re-encode a video you will degrade its quality to some
extent. Converting from AVI to WMV degrades the video and converting again
from WMV to DVD format degrades it a bit more. How much degradation takes
place depends on the encoding settings you choose. It can range from hardly
noticeable to really, really awful.

Your large file size is caused by the encoding bitrate being used in WMM.
Higher bitrates mean better quality video (when viewed at the same size as
the actual video resolution) but it also means larger file sizes. To
decrease the file size without decreasing the resolution (ie. going from
720x480 down to 320x240 or some other dimensions) you can reduce the
encoding bitrate. WMM only offers a few default presets unfortunately. The
setting that you chose used a variable bitrate encoding method in which the
overall average bitrate can be quite high. It likely also increased the
dimensions of the video from that of the original AVIs, which along with
increasing the file size also degrades the image quality. You can try the
'local playback' or LAN presets to get a lower bitrate and smaller file
size. In the end the large file size shouldn't matter except if you are
short of harddrive space. The larger sized file should actually be better
quality than a more compressed smaller file. Working in a "lossless" format,
say DV-AVI or even uncompressed video should give you the best image quality
possible, though the file sizes will be huge. When you create the DVD the
video wll be converted again anyway into .VOB format and the final size
there will reflect the time length of the movie and the DVD video quality
settings.

I don't know what your 'black shadow' is, unless maybe your source AVIs are
at a different frame rate than NTSC uses and the conversion process caused
those glitches. The occasional blockiness you see in some scenes reflects
the quality of the original AVI video at those points and how much image
data was able to be detected and captured during the conversion to WMV. A
low bitrate AVI can have lots of video drop-outs or blank areas in
individual frames that you wouldn't neccesarily see when watching the video
but they would be captured and possibly emphasized in WMM. Capturing fast
motion can also be problematic if the encoding bitrate is too low.

 

[Guest]

uwah, thank you so much for replying! ^^!

yeah I understand you. I don't mind the large file size...I have enough
space for it, I just want the video to be the best it can possibly be. The
competition looks @video quality as one of the major judging points...they
shouldn't have said that. I'm a friggin' perfectionist...>.>;;!

Heres what I mean about the black shadow:

http://img266.imageshack.us/img266/4497/vidcomparisonexampwz6.jpg

The picture on the left is a screen taken from the avi I made from the
original VOB file from my DVD. The one on the right is a screen taken from my
video in WMM. I believe it's under the DV-AVI NTSC setting. See that black
shadow creeping on his cheeks? It's like that for him thus far in the entire
vid....though only in dark scenes. Sunlight/outdoor scenes aren't that bad.

Frame rate might be my problem. The original vid is like, @ 23 fps, the
video becomes 30 fps. Hmmm.

It's weird, but whatever the preview window shows in quality, that's exactly
what I get in quality. And oddly enough, its the same when choosing all the
NTSC and High Quality video settings. It's so weird.

((btw I don't know if I mentioned this already but the DVD I send off to
this competition has to be in NTSC format so that's why I kept thinking I
needed that option....if I don't necessarily need it please let me know!
heh!))

If you or anyone can think of anything I could do that'd be awesome.
Otherwise I think I might have to just bite my lip and not worry about it and
just get it done. heh!

Thanks again!!

 

[RalfG]

I had to put the screen capture into an image editor and brighten it up to
actually see what was going on.

Before doing that it just looked like the contrast was generally increased
in the second image. After brightening the whole thing though I could see
that what was a bit of a shadow below the fellow's eye in the original AVI
looked more like a black-eye in the second. There is an increase in contrast
in the second video but what isn't immediately obvious is that there was
also a colour shift towards magenta in all the dark areas... It probably
affects the overall image but there has been a definite shift from green
in the orginal to deep magenta in the new video. I don't have a convenient
upload site to show it, but when I lighten the colour tone of the darker
range, in the AVI side there are large blotches of solid green in the center
and left side of the man's chest and jacket, plus in the dark detail in the
left bottom corner of the picture. On the video side the image has been
completely altered, the green is almost entirely gone, replaced by flat
grey and deep magenta in all the shadow areas, plus in the formerly light
shadow under the man's eye and in his hairline. There is very little change
in any of the background, with just a few small areas shifting from greenish
to magenta.

 

[RalfG]

A couple of things I couldn't get around to mentioning yesterday...

There are 3 commonly used framerates in videos, 25fps for PAL, 30fps for
NTSC and 24fps (23.976) for movies. To change the framerate either extra
frames have to be added in (fudged in by the software) or frames must be
dropped from the original video, with the soundtrack (if any) adjusted
accordingly. If it is done well the video looks normal but there can be
visual artifacts like half-frames, jerkiness, or original soundtrack out of
synchronization etc.. Video frames have to be added to your video to bump
the frame rate up to 30fps. I don't know at what point WMM adds the extra
frames, before or after conversion to WMV format. I'm thinking that the
colour and contrast shifts are a result of WMM averaging the levels of the
assorted clips that you compiled together to make the video. Unfortunately
you don't have much control over that part of the process, but there are a
couple of video filters that could be used on individual clips to lighten or
darken them slightly. I would try lightening the clip your sample came from
(and possibly any others that appear to be on the dark side) and see what
that does to the final video.

If it was me doing the video I think I'd do the initial clipping and
splicing of video segments all in the original AVI format if possible. That
would mean using something other than WMM, like VirtualDub or some other
video editing software. It would give more control over the appearance
(colour, brightness, contrast, removal of problem frames etc.etc.), but
probably be a lot more work for you too, plus the initial learning curve
for the software.