The Audio Sample Rate of DV-AVI Files - 32kHz or 48kHz?
There was an interesting exchange of posts about audio issues on the Movie Maker newsgroup about a week ago. They were saying that audio issues result from Movie Maker 'up-sampling' audio to 48kHz. The posters agreed that MM2 does such a poor job of it that you should up-sample with other software before using the source file in a project.
I added the essence of the posts to my Problem Solving > Audio Issues page, and it seemed like a good subject for a newsletter. Lots of users including myself have regular or intermittent audio issues. They drive me more and more to saving as high quality WMV files instead of DV-AVI.
Maybe the posters are right about the up-sampling being the cause... let's take a look. The properties of a typical type I DV-AVI source file from my camcorder, as shown by MM2, has an audio sample rate of 32 kHz... when captured with MM2 or WinDV.
Rendering it to a new DV-AVI file in MM2 shows the sample rate of saved movies is 48 kHz. According to the posters, it's this part of the process that introduces significant audio artifacts because Movie Maker doesn't do it very well.
Let's use this newsletter to study it enough to see if the posters are right... and what we can do about it.
At the 11th hour toward the newsletter issue deadline, I got a clue that the audio sample rate being reported by MM2 in XP and Movie Maker in Vista might be in error, and there's really no up-sampling going on when the camcorder records the audio at 48 kHz.
Opening the files with other software such as VirtualDub (the screen shot at the right) shows them as being 48 kHz.
It appears to be a reporting issue by Movie Maker, not a resampling, and Microsoft is checking into it...
As the bottom line isn't conclusive yet, I'm issuing the newsletter with hopes that it raises your awareness of the audio sampling rate.
... before getting into it further, a few notes...
My first for-sale video on Google Video... submitted May 3... still has the status of "Video is verified; stay tuned - it will be live shortly"... it's been over 2 months in the queue to be online.
I've stopped checking it's status every day and now taking bets as to whether or not it ever gets to the next step of 'being live'.
The MaximumPC issue with the Photo Story 3 tutorial is on magazine stands in the US. The 7 page article starts on page 68 in the Special Summer 2006 edition....
You can automatically open a second video at the end of the first one... this item is too short for a full newsletter issue, but worth a mini-mini tutorial.
My latest Video Doodle is a 2-part one. The first part is a 10 second countdown Photo Story that ends by opening another story...
The first one opens the second by an embedded 'script command'.
Use the Windows Media File Editor included with the Windows Encoder software.
Open the story file (or .WMV movie), go to the frame where you want to embed the command, press the Script Commands button, then the Add button, and enter the full URL. In this case it's
for the 2nd story.
You can have it open a website page, a movie, a story, an image... any URL address you usually enter in a browser.
With the high quality of photo stories and the average quality of online videos, it might be a neat way to make a 1-2 combo without lowering the quality of the story by re-rendering it as a clip in the movie.
It's not for everyone, as a security setting in the Windows Media Player may need tweaking from its default. Details are included at the end of the first story... if the 2nd story doesn't automatically start.
Vista Corner... I was using it to cross-check the audio sampling rate of captured files for this newsletter. Its reports are consistent with MM2 in XP, but now looking to be consistently wrong.
.... back to the main topic...
The Audio Sample Rate
Real world audio waves are analog, not digital. The sample rate is like putting dots on the audio waves to approximate them... like pixels approximates visual images. Put 32,000 dots on the waves each second and you have a sample rate of 32 kHz. 48,000 dots gets you 48 kHz. Can you hear the difference?... probably not. Is it an academic discussion?... you hope... but it might depend on the quality of the process that's used to change from one rate to another.
I'll start with my digital camcorder, a Sony TRV80. The manual says the audio recording for 16 bit stereo (my normal setting) is at a 48 kHz sample rate.
Captured Files using various apps get you either 32 or 48 kHz, as reported by the properties in Movie Maker
- MM2 captures to 32 kHz files.... as type I DV-AVI
- MM1 captures to 48 kHz files.... as type II DV-AVI
- WinDV captures to 32 kHz when opting for type I files, and 48 kHz when type II
- Vista captures to 32 kHz files.... type I DV-AVI
Rather than having to rip the audio from the type I files and do the up-sampling with another app, maybe using MM1 or WinDV to capture to type II files gets you there easier and with better results. (I said that before finding that the reporting might be in error and the files are actually starting at 48 kHz)
Ripped or Re-rendered files from the captured files - using default settings
- TMPGEnc 2.5 rips audio from a type I DV-AVI file to a WAV file of 48 kHz
- Audacity imports the audio from a DV-AVI file as an MP3 file... and an export of it to a WAV file results in a 44.1 kHz sample rate.... BUT the duration is 5 times longer than the original video file. It got that way during the ripping to MP3 format by Audacity.
- MM2 rips the audio of a DV -AVI file to a High Quality WMA file with a sample rate of 44.1 kHz... but the WMA file is a frame shorter than the original DV -AVI file. This isn't an issue as we know the dropped frame is the last one, which won't effect the movie's audio/video sync.
- MM1 renders to type II DV-AVI files with 48 kHz.
- MM2 renders to type I DV-AVI files with 48 kHz.
I captured a one minute segment of a Christmas concert... the same segment 4 times, using MM1, MM2, and WinDV for each of types I and II. Here's the storyboard view of this simple project.
I rendered it to new DV-AVI files a number of times to check how the 'upsampling' from the 32 kHz source files makes it versus those that don't need upsampling. After each render I made the project a bit more complex to see if and when the audio starts to run into problems.
- 1st render - nothing done to any of the clips other than add title overlays to note which of the files was playing
- 2nd render - split each of the 4 one minute source clips into 6 parts... every 10 seconds on the timeline
- 3rd render - added a random effect to each clip
- 4th render - added an MP3 music file to the audio/music track... balanced it such that the audio of the video clips is prominent... to see if mixing DV-AVI and MP3 audio results in audio issues
- 5th render - added transitions between all clips... just using the standard fade one
- 6th render - changed the fade transitions to others, using a random assortment
- 7th render - added fade-in and fade-out to the audio track of each video clip
- 8th render - shifted the balance from the audio of the video clips to the MP3 music
Each of the rendered DV-AVI files sounded as good as the original. I couldn't hear any differences between the 32 kHz or the 48 kHz source file segments. I wasn't successful at getting the audio to breakdown, not even a hiccup or short blip.
That kind of supports the issue being one of reporting the sample rate, not one of actual differences...
Conclusions and Closing
I asked the other digital media MVPs and Microsoft for comments about this subject, digested their collective thoughts, and mulled things over for a day as I edited the issue for the final time after finding out about the reporting issue.
My conclusion was heading this way before the 11th hour finding...
- My Sony camcorder records 16 bit audio at a 48 kHz sample rate
- Type II DV-AVI capture processes maintain the 48 kHz rate... but type I captures convert it to 32 kHz
- Movie Maker 2 and Vista save DV-AVI files at the 48 kHz rate
Maintaining the sample rate at 48 kHz from camcorder tape to captured file to rendered movie seems preferable to going from 48 to 32 and then back to 48 kHz... because resampling processes can reduce quality or introduce audio artifacts.
I'll let you know next week or future issues what else is found.... now we're heading off to the Ann Arbor Art Fair to look at pictures and take some video... have a great weekend.
I look forward to comments and discussion about this and other newsletters on the forums at:
Windows Movie Makers.net
Have a great week...
Movie Maker 2 and Photo Story 3 - www.papajohn.org
Photo Story 2 - www.photostory.papajohn.org
Products and Services
I'm involved in many things that support users of Movie Maker and Photo Story, and adding more regularly. Some are free and others reasonably priced.
Radio and Podcasting
TheDVShow is the only weekly Podcast having more useful information about desktop video editing and production than anywhere else on the Web. Digital video editing, nonlinear editing, streaming media, software releases, tutorials, business tips, technical help, download of the day and news on the latest products to make everything easier. It's where professional and consumer desktop video users go to stay on the cutting edge.
Call the phone mail machine to get your technical question answered on the air... call (206)-203-3516
The radio broadcast is from Boston, and the website has downloadable podcast files. The June 19th 2005 podcast was the first 'bi-weekly' show with a segment about Movie Maker 2.
Books and Magazines
Movie Maker 2 - Do Amazing Things (with its online companion on www.papajohn.org), published by Microsoft Press...
Movie Maker 2 - Zero to Hero - with support on the publisher's forum - Friends of Ed
MaximumPC's winter 2005 quarterly special... had a 7 page tutorial 'Make a Killer Home Movie with Maker 2'. The special edition of the video made for it is now on my website as a file download.
The November 2005 edition of Maximum PC had a well done reworked 6 page reprint of the same article, starting on page 42 after the Happy 20th Birthday article for Windows.
My new 5 page tutorial about Photo Story 3 will be in the Summer Special edition of Maximum PC, on newsstands July 18th.... the sample story will be included on the magazine's disc.
Learning VirtualDub - published by Packt Publishing in April 2005, is the first book about VirtualDub software. I wrote the introductory chapter about downloading and setting up the software: VirtualDub, VDubMod and AVISynth.
Movie Maker 2 and Photo Story 3 - www.papajohn.org - the site's 3 goals are: Doing Amazing Things, a detailed tutorial for PhotoStory 3, and helping you solve Movie Maker 2 problems.
It's being expanded to include the new version of Movie Maker in Vista.
Online Support - Forums and Newsgroups
I'm a regular on many online forums and newsgroups, the key ones being:
Forums are open to all for viewing, but require registration of those who want to post. Moderators actively participate to ensure the forum discussions move forward and stay on track.
Movie Maker and Photo Story forums at Windows Movie Makers
Movie Maker 2 forum at SimplyDV.com
Newsgroups are wide open for all to view and post... moderation is collective by the participants.
Windows XP Movie Maker newsgroup - microsoft.public.windowsxp.moviemaker
Photo Story 3 newsgroup - microsoft.public.windowsxp.photos
Movie Maker 2/Photo Story newsletter. The subscription is $20 for 52 issues, and the link to subscribe is on the main page of my Movie Maker website at:
Topics for upcoming newsletters (always subject to change):
#114 - July 29 - open
#116 - August 12 - open
I'm planning on not issuing newsletters when we're on vacation from August 24th through the week that includes September 20th...
Newsletters issued more than 6 weeks ago are posted by Rob Morris to an Archive Site on his Windows Movie Makers' website. Links from my website pages to specific newsletters make it easier for viewers to see the content of both while browsing a topic.
Drop an email to suggest a newsletter topic... I can use more requests rather than fewer.
Add-On Transitions and Effects
Transition Maker 2 (TM2) is a utility for the ultimate in making your own personal and custom transitions for Movie Maker 2. It's a joint product from Patrick Leabo, the programmer, and myself.
I've beta tested some of the Pixelan packages and think very highly of their people and products.
ProDAD's Adorage packages for Movie Maker 2 are additional sources of very professionally developed transitions and effects. And here are the links
Package for Movie Maker - Volume 1
PapaJohn's Transitions - Volume 2
PapaJohn's Video Effects - Volume 3
With more info to manage, consider additional tools that help.
My personal database has been an ongoing project over many years, and is now available to others. A tutorial about using it is on the Managing > Personal Database page of my site, and more info is in the database package itself.
It's free for the asking to regular newsletter subscribers... send an email request and I'll return it with the zipped file, which is less than 1 MB.
To others it's $10. To order, use the button on the top of the Managing > Personal Database page.
An online gallery that fully aligns with the main priority of the website is the 'PapaJohn Expert Zone' at neptune.
Check it at Neptune and the Distributing > Neptune page of the website, where there's a developing tutorial about how to use the service.
In conjunction with the Portage, Michigan library, I offer two free training sessions about Movie Maker and Photo Story, an intro session and a workshop. Scheduled sessions are:
(Summer Break... will re-start in October)
The classroom has a large screen overhead projection system... and individual laptops for each attendee to use. You learn by doing, with a little guidance from me.
Other fee-based services
If you can't save a movie because your project has become too complex, e-mail a copy and I'll divide it into manageable sub-projects, and provide detailed instructions about how to render the parts and assemble them into your final movie. $49.95 (no cost if it's not the right solution or doesn't work) - for details, see the sidebar on the Problem Solving > Can't Save a Movie page of www.papajohn.org
Movie Maker 2/Photo Story training and support services start at $75 per hour - send an email - PapaJohn@CharterMi.net and I'll help you determine your needs, and work with you to plan and implement them.
Wedding combo website/video packages - check the bottom branch of the Movie Maker 2 website for a sample of what you can expect for the online portion of the package.
© 2006 - PapaJohn
Microsoft is a registered trademark of Microsoft Corporation in the United States and/or other countries.
About John 'PapaJohn' Buechler from Microsoft.com
John "PapaJohn" Buechler, of Kalamazoo, Mich., goes by PapaJohn
online. An avid user of Movie Maker since its first release, and
a regular supporter of the community of Movie Maker users, John
received a 2003 MVP award from Microsoft for that support. In March
2003, he started a comprehensive website about Movie Maker 2 at
He maintains the website, writes books and articles, teaches, and
provides support services - all for the community of Movie Maker
2 users. An engineer by formal education, John is a computer database
and multimedia expert by business and personal experience. He co-authored
the first book about Movie Maker 2 and is actively working on a
second one. You can find his advice in the
Windows XP Movie Maker newsgroup and in the
Windows Movie Makers Forums.
newsletter is republished with permission of John "PapaJohn" Buechler.
Please note that this is an archive of newsletters and some information
may become outdated. PapaJohn, and the webmaster of this site, provides
this information "AS IS" with no warranties.
Visit - PapaJohn's Movie Maker 2 and
Photo Story 2 Newsletter Index