Newsletter #110 - July 1, 2006

Re-Capturing a 'Lost' DV-AVI File

Maybe you deleted one in a cleanup process like I did a while ago. Or moving one from one drive to another left you with a corrupt file. Or the audio that you hear on the tape in the camcorder stops playing mid-way through the project. There are many reasons you might find yourself needing to re-capture a 'lost' or unusable DV-AVI source file.

I'd tested the re-capture process before to see if and how it would work, but I hadn't really needed to do it until last week when I started the DVD phase of the Renaissance wedding project. I cleaned up hard drive space by deleting one too many files... a DV-AVI source file was gone and all I had was the project file and low quality movies for the website.

The re-capture process worked. Recovery was quick and easy, and the experience led to a newsletter topic.

Instead of using my real world example, in which the alignment of the replacement source file isn't really critical, I'll create a sample project that is... it'll be like using a magnifying glass to see how well the recaptured file fits into the original project position.

For some good practice following something with your camcorder, try doing a bee gathering pollen. Here's a frame snapshot from MM2 to get a good benchmark. I took it from the clip in the collection to get a full size 640x480 picture.

The bee wasn't in the same spot twice, and I slowed the clip playing speed down by a factor of 8 so it'll be easy to see if the replacement file fits... we just need to check the location of the new bee.

... before getting into it further, a few short notes...

Notes...

Vista Corner... I gave DVD Maker the 14 videos of the Renaissance wedding project and made a couple DVDs.

Here's the opening screen of the DVD as it's playing on my XP laptop in InterVideo's WinDVD.

My first for-sale video on Google Video... submitted on May 3... still has the status of "Video is verified; stay tuned - it will be live shortly"... that's almost 2 months now of it being in the queue.

Now I'm taking bets as to whether or not it ever gets to the next step.

My copies of the MaximumPC issue with the Photo Story 3 tutorial should be coming next week... as they head toward bookstands on July 18th.

.... back to the main topic...

the Capture Sessions - Using WinDV

I'll do both the original and the 'recovery' capture sessions right after each other... capturing to different drives, with different folder paths and file names. And I'll start and stop the captures at different points of the tape.

Setup

I plugged my camcorder in with a firewire cable, rewound the tape to the beginning, and did some capturing, using my current standard method... the WinDV utility.

Press the Config... button in WinDV, set the discontinuity threshold to 1 second and select a type 2 file.

The one second setting results in the capture session starting a new file whenever there's at least a one second pause between frames.

Type 2 files are more universally accepted by video software apps.

First Capture Session

The tape started with some footage of flowers and bees in a Saugatuck, Michigan garden, and was followed by some beach scenes of lapping waves.

I used one of my external USB 2 hard drives as the file destination... my 'E' drive. I created a new folder named Newsletter 110 - 1st Capture, pointed WinDV to it, and told it to name the captured file(s) Saugatuck.

I let the capture run until I started seeing waves instead of flowers, then paused and stopped the capturing.

Second 'Recover' Capture Session

I turned right around and did the recovery capture...

For this one, I didn't start at the beginning of the tape... maybe 20 or 30 seconds into it.

I used a different external USB 2 hard drive for the file destination... my 'I' drive, with the captured file going to I:\Testing\DVCapture\2nd Capture for Newsletter 110 folder. I told WinDV to name the file(s) Flowers.

The recovery capture session started later in the tape than the first one, and I let it run a bit further into the tape before I paused and ended the session. WinDV reported no frames dropped in either session.

Captured Files

Let's use Total Commander to look at the sets of captured files, those from the 'original capture' at the left, and the 'recovery capture' at the right... a few comments:

I told WinDV to name the original capture files Saugatuck with the date and time stamp info added automatically. I renamed the files at the left after the capture to add descriptive info about the scenes.
The original capture session started at the beginning of the tape, so the first file on the tape comes in with the date and time of 06-06-20_17-08.00. June 20th was our anniversary and we went to Saugatuck to celebrate. The date is embedded in the tape's files. The time that the first clip was taken was 5:10 pm or 17:10. WinDV automatically adds the combo of the date and time to the name I give it.
The recovery session started a little bit into the 2nd segment on the tape. It missed the first one entirely and picked up most of the second one (108+ MB file on the recapture versus 121+ MB file on the first).
4 of the files are identical in date, time and file sizes... great clues that the frames in them are identical.

The sample project uses the 6th file from the original capture, the larger 670+ MB one with the 06-06-20_18-31.00 date/time stamp info. The recovery file aligns with it.

After making the project from the original file, we'll delete it and see if the recovery file can be used in it's place. It's currently on a different drive, in a different path/folder, and with a different file name. But we know from the clues that the file is the same, so we shouldn't have to do anything more than resolve the big red-X in Movie Maker after it notices the source file is missing.

the Movie Maker Project

I took a snapshot of a frame and then split the clip... in the collection to get the higher quality JPG (640x480). You saw the frame snapshot on the way into the newsletter.

The project has only a few clips

the first part of the split clip... trimmed and slowed down by 8x
the snapshot
a copy of the snapshot turned into a painting by a VirtualDub filter.
another copy of the snapshot
the second part of the split clip... trimmed and slowed down by 8x

Here's a link to the one minute rendered movie...

Sample Project

It's time to delete the original DV-AVI source file and see what it takes to use its replacement from the recovery session.

the Missing File

With the big red X showing up in the project, we have to work with the info included in the project file.

You don't need notes about the name of the file or its location. Open the properties of the missing clip, linger over the source file's location, and read the tool-tip. It'll show you the drive, path and file name of what it's looking for.

Double-click on the red X and browse to the replacement file... from the recovery capture session. You know from the clues that it's the same.

But it's in a different place with a different name. When you tell Movie Maker to show all the files in the folder, and you select the right one, you get this error message.

The tool tip tells us the file name, so let's rename it to that one. The dialog box which is looking for the file has the file name in it, easy to copy, and paste it into the renaming of the recovery file.

Got 2 problems this time.... the rename says the file name has an illegal character and points to what looks like a period after the word Saugatuck.... added automatically by WinDV. But it continued on to finish the renaming after closing the error message??

But it didn't work... got the same error as the first attempt. It had the right name, but it's in a different location.

Let's re-create the folder if needed, and copy/move the renamed replacement file to it.... BINGO!!! double-clicking the red X results in the linking being fixed in a second, without having to browse to the folder.

I rendered the movie to see how the new bee fits into the project... the snapshots and painted frame are from the original bee. The new movie uses

the new bee file

It fits right in.

the Capture Sessions - Using Movie Maker 2

Before concluding that WinDV is needed to recapture a file, after having used it to create the initial file, let's explore doing the recovery capture with Movie Maker 2. WinDV made a type II DV-AVI file and MM2 will make a type I... but the differences shouldn't be in the visual. Maybe we can be equally successful.

Using the auto-clip splitting feature of MM2, the first step looks promising... comparing the MM2 split clips at the left to a recapture set of split clips at the right, we see the same as we saw when looking at the initial and recovery captures using WinDV.

Again the 4 clips align in date, time and duration. See that the date and time is identical to the files captured with WinDV, just in a different format.

With WinDV we were looking at individual files and file sizes... with MM2 it's clips within a single file, and clip durations. Let's take a closer look.

Comparing MM2 clips to WinDV files

Here's an interesting comparison... I put the 4 clips captured with Movie Maker on the video track of the timeline, and 4 of the files captured by WinDV on the audio/music track... to see how they aligned in durations.

I didn't expect them to align as perfectly as they did. The 4th file from WinDV was the one I split for the project and took the snapshot of the bee. When I went to that point of the timeline I was looking at the new bee in the exact position as the original. Things seemed to be in sync.

As MM2 shows you every other frame, I might have nudged it to the frame to satisfy myself... we'll take the comparison a big step further by using the MM2 clip as a replacement for the WinDV file and look at the rendered movie.

Replace the WinDV file with the MM2 Clip

I left just the 4th clip from MM2 on the timeline and rendered a DV-AVI file... I was thinking about the dropping 27th frame in such a file moving the bee one frame to the left... would it be noticeable?

I slipped the newly rendered DV-AVI file into the original folder and opened the project in Movie Maker. It didn't blink at the new type I file in either the collection or project. No red-X to be resolved.

The rendered movie looks pretty good. Here's the link to the last of the sample clips for this issue... see if you can spot the effect of the missing frame when the bee freezes for a bit, and then takes off again.

WinDV File Replaced by a Clip from a Recapture by MM2

The recovery MM2 clip effectively replaced the lost WinDV file... with no need to make any changes to the project file.

Conclusions and Closing

It turned out easier and more successfully than I thought it might be.

The recapture was for a file initially captured by WinDV with the option of breaking the capture session into several files. If I had captured originally to one big file with either WinDV or MM2, it would probably be much more difficult to recover. More studying would be needed...

Use WinDV with settings such that you get multiple files as your routine method of capturing DV-AVI files from your camcorder... if you want the insurance of being able to do a recapture to replace a corrupt, deleted, or lost source file.

Date and time code data is used by MM2 to initially name the auto-split clips. I explored that area a bit more and found something interesting.

Friendly Clip Names versus Date/Time Names

If you capture a file with MM2, naming it something friendly such as 'Our Vacation in Maine', it won't include the date/time stamp info as part of the file name. And if you then import it into your MM2 collection without auto-splitting, the clip name will be the same friendly one... but the date/time info is still there, and can be obtained as you'll see in a second.

If you import the same file with auto clip generation turned on, the sub-clips are named with the date/time info.

If you select a clip in a collection with a friendly name, and use the option to 'Create Clips'... even if there are no sub-clips to split it into, Movie Maker will change the file name from the friendly one to the date/time stamp info... recovering the date/time stamp info for the selected clip.

But if you rename the clip in the collection to a friendly one, and then copy it into a project, the name will only be the friendly one, as you can't rename a project clip. Your ability to recover the clip's date/time info is gone.

Friendly clip names in projects are good for easy editing, but not for a source file recovery.

Have a great week...

PapaJohn