Newsletter #156 - June 30, 2007
WMV is a 'Container' - Part 1


Q. What do you mean by 'Container'?
A. It's like a box delivered by UPS. If it's from Microsoft, you can bet that what's inside will work with Movie Maker. If it's from Apple, you can bet it won't. If it's from Jim's Online Conversion Service, you'll need to check it over carefully to see what's inside.
Q. What does 'Part 1' mean?
A. In this case, it means I got into the subject enough to finish the newsletter, but I didn't do much except muck around in the subject, with no real conclusion. I might come back to the subject someday and do Part 2.

We often use the word 'container' when someone has a problem with an AVI file in Movie Maker. Good advice includes telling the poster to use GSpot to look inside to see what codecs were used to make it.
But when users have similar issues with WMV files, we too often assume the files should work, so there must be something wrong with Movie Maker.
I think it's time we treat WMV files the same way we do AVI, assume nothing is wrong with Movie Maker and apply the same advice we give about AVI files, look inside the WMV container using GSpot to see how the file was compressed.
Two items in two days this week led me to write about it. I was studying two WMV files that acted strangely in Movie Maker, one from a poster who used a file conversion utility named Replay A/V 8 to make the file from a YouTube video, and the other I made from an MOV file downloaded by VeohTV using the Expression Media Encoder.

Item 1
The forum poster who used Replay A/V 8 had problems with the movie made with MM6. All was going well until he watched the rendered movie in Windows Media Player... where he saw alternating clips of content and blackness instead of a steady flow of content. I had him send copies of source and project files so I could help him dig deeper. Movie Maker doesn't provide codec info about a source file. WMP and GSpot in XP both said the compression was:
Here's the info about his file from GSpot, not on my Vista system, but on XP.
From Replay A/V 8
I was able to import the file in MM2.1 on my XP system, and save it to a new one with no intermittent black clips. My suggestion was it was a codec issue, not a problem with Movie Maker. Here's MP42 codec info on my XP system. 
The mpg4c32.dll that's associated with the MP42 codec isn't in my i386 folder from XP SP2. It's a vintage 2002 file.
Neither my Vista's Home Basic or Ultimate versions have a codec for MP42... GSpot says the codec status is undetermined. The mpg4c32.dll file isn't included in Vista, but the video plays on it.
I'm still studying the file... my status is like GSpot... undetermined. The poster was going to try making his project on an XP system instead of Vista, not a good conclusion.

Item 2
The other item was one I made myself, a WMV file that acted very strangely in MM2.1 on my XP laptop. I had installed the beta software for the new online VeohTV service, something I read about a couple weeks ago in USA Today.
My first download was a TV show, an Apple-format MOV file. My newest conversion app for MOV files is the Expression Media Encoder, so I used it to make a WMV file using Micorosoft's VC1 codec for compression. 
The WMV file plays fine online but acts very strangely in Movie Maker. Here's the link if you want to check it.
 Sample WMV File
Here's the info in GSpot.
From Replay A/V 8
I'll get into the details of the strangeness below.
Not all Veoh TV files are MOV.... the second one I downloaded is an WMV, a container I haven't looked into yet with GSpot.
Before getting into details, here are...
... a few notes...

Last week's newsletter closed on this thought...  "Don't add your background music until after the tweaking is over and everything should be fine".
I did some more testing after publishing it, and found it was the wrong conclusion.
The issue is the utility can unpack a large PS3 project file and tweak the xml settings, but it can't effectively put the project file back together if it's over 300 MB in file size. If you look at a project file that PS3 says is corrupt and can't be opened, and it's exactly 300 MB in size, it's a great chance it's a tweaked one.
It's pretty easy to have a story project of that size. The 300 picture limit of PS3 with 100 MB per picture gives you a 300 MB project. Our 5 megapixel camera saves JPG images of more than 1 MB average, and our newer 7 megapixel camera saves them at about 3 megapixels each. 100 pictures from our 7 meg camera would make a story project of that size, not counting files such as external music.
Vista Corner
Using my new low-end laptop with Vista's Home Basic for my evening sessions at Barnes & Noble... every other night... has been warming me up to Vista. The every-day basics are most important to me, not any particular app or wizz-bang super feature like aero-glass.
Library Classes
My classes at our library haven't been well attended. This fall we'll try changing the subject from the tool to the distribution methods. Instead of it being about Movie Maker to make videos for YouTube and other places, it'll be about YouTube and other online places and how to make videos for them using Movie Maker.
Software Reviews
The main reason this newsletter is later than usual in being published is that June 30th was my contracted date for submitting four software reviews that I did in June. I made the deadline. But then when digging into the topic of the week for the newsletter, I found myself fishing around more than I expected. So it's later and Part 1. But I enjoy the fishing and learning.
.... back to the main topic...

Two WMV Case Studies
Let's go back to the first case, the WMV file sent to me by a poster to Rob's forum.
From YouTube to Movie Maker
WMP played it fine and reported properties of
msmpeg4v2 for video (read it as Microsoft MPEG-4 version 2)
mp3 for audio 
I explored the Replay A/V 8 website for technical info but couldn't tell what choices the user had for compression. I wasn't ready to try downloading a trial version to look closer. 
My XP system has an MP42 codec and I didn't have the issues the poster had with his Vista system. And my two Vista systems don't have an MP42 codec.
I haven't tried using the file as a source one in MM6 and saving it to a new WMV file to see if my systems would show the same issues as the poster. With GSpot on my Vista systems not showing an MP42 codec but playing the file OK in WMP... it makes me wonder where one would get the msmpeg4v2 codec, why Vista doesn't automatically download it if it's a Microsoft codec (which it seems to be in XP).
Before I could dig deeper into this item, the second one came along. 

Veoh Full ClipFrom Online VeohTV to Movie Maker
I found this one very interesting... as it was totally unexpected, fully reproducible, and wouldn't have even been noticed if I didn't stop to divide the big clip in the collection and study the sub-clips there.
I had used the new Expression Media Encoder to select a 3-1/2 minute segment from 30 minute TV show... downloaded from VeohTV as an MOV file.
The full file played great in my Quick Time player and didn't exhibit any quirkiness in the Media Encoder, where I added an overlay image in the upper left corner and saved the selection as a WMV file. The encoder only uses the new VC1 codec, so that's the video codec.
After importing the WMV file into a collection in MM2.1 as a single clip, it previewed fine in the collection.
Using the right mouse click > Create Clips process in MM2.1 and MM6 produced totally different results.

MM2.1 in XP
Here's a picture of the 13 clips in MM2.1 after applying the 'Create Clips' feature.
Veoh Clip - Split in CollectionThe 1st, 5th and 10th clips previewed fine. The other clips sat there paused on their first frames. The first frames were typically not the images you see as the clip thumbnails.... close, a few frames different than the first one. 
The 3 clips that previewed fine were 17, 10, and 1 seconds in duration, not that it means anything. The durations of the other clips ranged from 1 to 40 seconds.
Putting all the clips on the timeline in sequence and previewing the project.... the full video looked and sounded good. That's all but the last sub-clip which turns to whiteness, shows my logo in the corner, and drops the audio part way through. 
Mixing the clips on the timeline and previewing the project.... again all previews fine.
Vista's MM6
On my new Vista Home Basic system the full clip previewed fine in the collection.
The 'Create Clips' process makes only 3 sub-clips... of 13 seconds, 3:02, and 11 seconds. The first two play fine and the 3rd one has the same issues with audio and whiteness as it did in MM2.1.
Clip splits by MM6 were at different points than those in XP... another difference between the two versions, one you wouldn't know unless you split the same clip on both systems.
I tried applying the Create Clips feature to the sub-clips in Vista and it wouldn't sub-divide them any further.
Remember MM1
It auto-divides the file into 17 clips, each of which previews fine in the collection. The thumbnail images are different than those of MM2.1, selected from different frames.
Rendering the Projects
The rendering and playing of new WMV files in WMP went along fine in both systems.
Again, a file with a number of things to ponder, with no conclusions at this point... just differences.

Assessing the Contents of a WMV Container
WMSnoop-VC1FileWe've used GSpot to look into AVI containers. The latest version of GSpot also covers, MPEG files, and we see that it can look into WMV files also.
GSpot tells us more about WMV files than Movie Maker (which says nothing about codecs) and Windows Media Player (which provides some info but not close to what GSpot provides). Besides, WMP should be too busy playing music from URGE to be used as a file assessment utility.... seriously. 

Here's the info it shows for the second item, the VC1 encoded WMV file.
I'm looking for something different about the beginning of the clips that played fine in the MM2.1 collections. Sub-clip #5 was one. The file properties of the clip goes finer than the list in the collection. The properties says the clip starts at 01:15:78.
That frame time in WMSnoop correlates with the taller blue frame to the right of the yellow keyframe I've marked below. The yellow one is the one of the newscast host in the studio. That's the frame I see when I go to the beginning of the clip in the collection.   
The thumbnail for that clip is the gal reporter in the field, which correlates with the taller blue frame a few to the right of the yellow one below. So the first frame is a guy but the thumbnail is a gal. We're learning, but I don't know what yet, other than MM2.1 doesn't use the first frame of a clip for the thumbnail.
Yellow Ones
The other 2 clips that played normally were #01 and #10, both of which show the same thing, the first frame being the picture at a yellow while the thumbnail is from a taller blueish bar a few frames to the right of the yellow.
What's a yellow one? It's a key frame, a full image rather than differential that is relative to a full one. If you want to see a well done Help file, take a look at the one in WMSnoop.
I'm not seeing enough correlation between split points and key frames to draw any conclusions.
All the split points in MM2.1 came at key frames except one. That's enough to do more checking.
Both of the Vista split points were done at keyframes. I didn't study those of MM1 yet.

Opening the WMV file made by Replay A/V 8 in WMSnoop shows
Seems that, for WMV containers, GSpot is the tool of choice when first looking in it.
WMSnoop shows lots of other info about the file, including the keyframes.  

Conclusion and Closing... and What's Next?
We have more to learn about how to examine the contents of a WMV container. This is enough for now.
Have a great week and enjoy your video work...