10-09-2007, 09:49 PM

Ok I am stuck. Any thoughts would help...

I am having some kind of playback issue with many but not all videos on my powerbook 15inch 1.5ghz. Running OSX 10.4.1.

These are files I have moved to a external hard drive and back to my powerbook at some time in the past. I have moved files back and forth before without issue.

I use a western digital external firewire harddrive in a generic casing.

I have worked with these files (for years in some cases) without problem before now. I use FCP 4.5 and occationally iMovie to edit them.

When I attempt to play the videos in both Quicktime player and the FCP timeline (from the files on my powerbook) I am getting some kind of dropped frame/artifacts in the image and audio.

The strange thing is that when I play copies right off my external harddrive they play fine but as soon as I copy them to my powerbook and then play those local copies i get the problems.

I have done the toss the FCP pref thing, fixed the permissions and restarted. I ran MacJanitor to run my maintanence scripts.

I assume that my hardware is ok since the playback does work when I play back from the external drive and because other video files I have on my powerbook, which I have never moved to the external harddrive, play fine and show no sign of the corruption.

I can recover the raw video from tape but I lose all the editing time.

My bigger concern is whether I can trust the external drive at this point. Or maybe there is a softwhere or hardware issue I am missing.

Thoughts?

not

10-14-2007, 01:27 AM

Nothin?

I have you stumped too?

10-14-2007, 02:26 AM

Something is sluggish somewhere. I try not to use external drives since they love to spin down, but I don't think that is your issue. It might be a firewire issue somewhere. I'd really have to see the problem myself, I guess. What format are these videos in? Are they compressed? What format? How large (resolution)? Laptop hard drives are usually pretty slow in an effort to save space and power.

10-17-2007, 05:44 PM

Thanks for the reply Joe,

Do you think it could be something in Final Cut? I feel like the issue started after I reconnected some media and linked some of it to the external drive. I thought I would do it temporarily for a couple edits and then later work off my local drive for more important stuff.

The external hd was a pretty good generic set up when I bought it several years ago...120gb oxford chip, western digital brand...I got the highest speeds available at the time, I think it is 7200rpm with a 8mb cache. I don't know how to check that.

The video is off of mini-dv tape in NTSC usually put out to Quicktime format in 720x480 resolution.

Here is the stats of one typical video:
DV, 720 x 480 (640 x 480), Millions
16-bit Integer (Big Endian), Stereo, 48.000 kHz
frame rate: 29.97

Thanks for taking the time to reply.

10-17-2007, 06:09 PM

ok and here is even more strangness.

So I tried log and capturing new video from my camera in to final cut and that worked fine.

I again tested a video from the external hd. It played fine on the external hd but when copyied to my local hd I get the issue. I tried plugging the firewire cable into both the sockets on the external hd, both gave me the same issue when I copied.

But then I did find a couple work arounds of sort. I found if, working in FCP, I copy a source file into a new project sequence and either export it to my local drive or use Media Manager to copy the source files to a new folder on my local drive, I end up with good copies on my local drive.

Strange. I still can't figure why I am getting corruption just when I try a simple drag and drop copy process when I can make a transfer work in these more complicated ways.

10-17-2007, 09:08 PM

You can use Terminal to see if you have corruption. Open it from the Utilities folder.

At the prompt type the letters 'cksum' (excluding the quotes), and a space and then from the finder, drag the file name of interest from the external drive to the Terminal window, then hit return. You'll see a long number, the cksum number, to the left of the file name. Now that do for the copy of the file on your local drive. The numbers should be identical.

10-18-2007, 12:28 AM

Thanks xstep,

I tried it and got:
1476400909 727762287 (external drive copy)
487887161 727762287 (local drive copy)

They don't match, what do you think could cause the corruption?

not

10-18-2007, 05:16 AM

First, did you do that with an original and copied file that you have not touched in any way? The size suggests you did, but I like to check. It would have been best to make the copy just before running the cksum tests.

Another command similar to chksum is md5 which gives a similar long number but at the end of the line that it prints.

Next up is to check the internal drive. Open Disk Utility found in the Applications-->Utilities folder.

Select the drive not by name, but by disk. The line that displays the gigabytes just above the drive name which is indented. Then, I'm not sure the Powerbook has this line, but you are looking for

"S.M.A.R.T. Status : Verified"

If the "S.M.A.R.T. Status" line is available and does not say Verified (or unsupported I think), then you need a new drive.

If that line does not exist or is Verified, then you want to click on the "Verify Disk" button. If it comes back with problems, the only way to fix that is to boot into the install CD and run Disk Utility from that and choose Repair Disk. Backup what you can before you repair.

Here is another copy test you can do, again from the Terminal.
Type the letters 'cp' (which means copy) and a space, then drag the filename from the external drive to the terminal window, type another space, then drag a folder name from the internal drive to the terminal window, and hit the return key. Finally do the cksum or md5 tests on both copies of the files.

OK. Now here comes some wild speculation, because without being at the scene there isn't much I can do to narrow it all down.

As for why you can get the copy to work via the FCP tools, I don't know. Perhaps they are doing some extra checking during the copy process or using a different tool than the Finder does. It is almost like the Finder itself is having an issue. I've never heard of that. I would actually expect a total failure rather than corruption.

To possibly test the Finder you could make a copy by dragging a copy from the external drive to another folder on the external drive. To do that, during the drag process, also hold down the Option (Alt) key while dragging the file and release the mouse button first.

If we end up thinking the Finder is having a problem, then you have two issues. The first is how to backup your internal drive, as you would not want to use that Finder. Second is you would want to do a total reformat and reinstall. After all, we would wonder what else may be wrong.

10-19-2007, 02:24 AM

thanks. it is going to take me a bit to get to those checks.

I may have access to another mac this weekend and I am going to see what happens when I copy off the external hard drive on to that computer.

danke