All posts by 3DM

Recording direct to disk from a Firewire equipped camcorder

There are mini-disk products that you can connect directly to your Firewire equipped camcorder to record direct to disk. But then tend to range in price from about $600 to $1800 depending on used vs new, capacity and vendor.

An alternative is to record direct to your notebook computer.

If you have a Macbook or Macbook Pro, a very easy way to record direct to disk is to connect the Firewire output of your camcorder to the notebook computer and then run iMovie and import from the camera.

The camera should be in its “camera” mode but does not need to be recording to tape. Whatever the camera sees will be recorded direct to disk.

This works with my Canon HV30 in HD mode and I’ve done it using both iMovie 8 and the older iMovie HD (version 6) connected to a Macbook.

On Windows, there are several software utilities available that will enable you to do the same thing. While I am typing this on a Windows desktop, I do not have a Windows notebook on which to test this out!

The main advantage to doing this is to overcome the occasional tape dropout problem that tends to plague HDV format.By recording direct to your notebook computer disk, who cares about tape dropouts! (Caution – you may want to use a longer Firewire cable to keep the notebook away from your camera mic, especially if the fan kicks on to keep the CPU cool. Not all cameras have sufficient drive signal to use a longer cable, though. So be sure to test out your configuration first!)

On SD recordings, a video dropout typically lost a single 1/30th of a second frame. If you even noticed, you could always copy an adjacent frame and no one would notice.

With HDV you can lose up to 1/2 second per dropout – and I guarantee, everyone will notice!

Two other steps to avoiding dropouts are to clean your video heads in the camera every 5 to 10 hours of recording – I use a Canon cleaning tape for about 10 seconds but I’m told most any cleaning tape is fine. The other important step is tape quality – I used to use TDK tape all the time on my SD camera with excellent results – but the SD tapes always had dropouts when recording HDV on standard TDK tape.

I switched to Panasonic AMQ (HDVM63AMQ) tapes and have now recorded probably 75 hours with excellent results on that tape. I buy mine from TapeStockOnline.com. They have consistently quick order fulfillment and decent prices. If you are used to buying standard miniDV tapes at the local discount store  you’ll find that high quality tapes for HDV are more expensive – currently $5.25 in a minimum order of 10 units.

There are other brands that cost both more or less than these but I’m sticking with what has worked well for me. Hopefully this note provides some idea for you to try if you are plagued by video dropouts!

Why does my 30p video show up as 60i?

I’ve seen some confusion on the online forums regarding shooting in 30p (or 24p) and then importing into a video editor.

Why does my 30p video show up as 60i in <name your editor>?

In an interleaved 60i video (normal old fashioned video), the image is scanned 60 times per second, producing one half frame at each scan (say the odd scan lines, followed by the even scan lines in the next half frame). Because movement can occur between the two half frames, you some times see interlaced jagged edges.

A better way is to take 30 still pictures per second of the entire image.

When your camera records at 30p video, it takes a single image – but splits it into two half frames and stuffs those into two 60i half frames (without any jaggies since its splitting one image in to two pieces whereas 60i creates one image from two separate pieces taken 1/60th of a second apart).

Consequently, a 30p video is stored as a 60i video. And two consecutive half frames, put together, become 30p. Your video software can’t tell the difference between between 60i and 30p.

So why do we have these strange 60i half frames? Historic reasons. The earliest TVs were not able to scan the full image top to bottom before the next image would arrive. The solution then was to draw only half the lines in each interval. Thanks to the persistence of the phosphor image of old TVs, the first lines remained glowing while the TV then scanned the alternate lines.

No one would design a TV like that today – but we’ve lived with it for many decades and it is still supported for compatibility reasons.

I can import 24p video into iMovie (or other editor) but it plays weird – why?

This depends on the camera. But it is common to store the 24p image in half frames, similar to 30p. But since 24 does not evenly divide into 60, the sequence of half frames is a little different.

In 30p, the sequence is basically 2:2:2:2:2:2 and so on where the 2 signifies 2 half frames.

In 24p, the video may be stored in various combinations such as:

2:3:3:2 or 2:3:2:3

In this way, the 24p mode uses up more half frames – consider 2 half frames and then 3 half frames. This slows down the video frames to match the 60i storage of the tape. Consequently, 24p gets mapped into a funky sequence of half frames on the 60i tape.

To a program like iMovie, this 24p footage looks just like 60i. But unfortunately, iMovie (And many other video editors) have no way of knowing that it is not really 60i footage with some frames appearing 3 times. So play back and edits produce strange artifacts.

If you want to convert this to proper 24p footage and then edit in an editor that supports 24 frames per second see these instructions.

Youtube adds 1080p capability

HD videos uploaded in 1920 x 1080/p will – probably – be transcoded by Youtube into 1080p videos. This represents an upgrade from Youtube’s 1280 x 720p maximum HD resolution.  (“Probably” because Youtube says not all videos will be converted just yet.)

The 1080p videos, however, are useless for most computer displays as few have 1920 x 1080 sized displays. The main advantage, probably, is that in a near future world, we will be watching streaming videos over the Internet – on our real HDTVs, arriving via a set top box.

Worse, you’ll need a very fast processor to watch the new 1080/p HD videos. I can’t watch them on a 3.2 Ghz Windows OS computer – and I can watch them on my quad core Mac Pro only if I wait for the video to download entirely, first. The problem is the video stutters badly as the processor cannot keep up with the Flash video decoding.

Recommendation: Upload the HD video but don’t select the HD option during play back.  It looks like the new “normal” is 1280 x 720 – so you don’t need to select HD.

youtube Failed (upload aborted)

uploading Failed upload aborted – YouTube Help.

Just an FYI – this is happening to me, also. It has been impossible to upload videos to YouTube the past couple of days. Actually, I can upload short videos, say 30 seconds long – YouTube gives an error but processes the video anyway. Longer videos, such as 5 minutes, always fail. I suspect this is due to YouTube’s new 1080p upgrade not working.

Nothing changed on my end – or for the many others experiencing this problem. Today is Saturday, November 21, 2009 for reference.

There is a work around, apparently: Use the multi-video or bulk video upload option. This does work for me and others.

Canon XH A1 and soft focus issue

A handful of online comments have asked about a “soft focus” issue with the Canon XH A1, a professional HD camera noted for its sharp lens! Only a few people seemed to encounter the soft focus problem – and usually dealt with it by manually focusing instead of using the auto-focus. But no one seemed to identify the root cause problem and the correct solution.

Until now.

Yesterday, I encountered soft focus and it took quite a bit of testing today to locate the cause of the problem and to identify a solution.

I was video taping a marching band competition (mostly in the rain – such fun) and noticed that the camera, which was set to auto focus, was usually slightly out of focus. Even when I manually set the focus and then turned auto focus back on, the camera would shift back out of focus just enough to produce a soft image appearance.

In the interim, I set focus to manual and peaking and magnification on and manually set the focus. But when I offloaded to the computer and blew up the images, I could see that the images were still not sharp.

What was going on?

After shooting a bunch of test images on both an XH A1 and an HV30  – and finding the little HV30 to have sharper images, I knew something was not right.

After a few hours of experimenting, I found the problem – and its even mentioned on page 39 of the manual. Sigh.

Here goes – yesterday, I was shooting an outdoor event, under cloudy skies in 24F mode at 1/48th of a second in Tv mode. I had the AGC set to off and gain manually set to 0 db to avoid adding any noise to the image. Previously I had shot similar events in 30p at 1/60th or 1/100th of a second exposure.

The problem turned out to be caused by not using neutral density (ND) filters resulting in a high f-stop setting auto selected by the camera.

What I did not realize is that when the AGC is set to off, the XH A1 does not advise you when the neutral density (ND) filters should be selected. Consequently, I never thought to use an ND filter.

Further, I did not have the exposure information visible on the display and did not realize the camera was trying to shoot at f-9.5 – where the lens sharpness is degraded. (I didn’t have my reading glasses on and for some reason I thought it said f-19.)

Two problems occur at a tiny aperture:

  1. The auto focus mechanism basically does not work at higher f-stops. In fact, it probably doesn’t work well above f-5.6 or so. If the camera is in full auto mode, it generally chooses excellent settings and you don’t need to worry about this.
  2. The lens sharpness is severely degraded at tiny apertures like f-9.5.

Consequently, there were two problems happening at the same time – one was the poor auto focus and the second was shooting at an f-stop where the lens produces soft images.

The solution is that when shooting in manual mode with AGC turned off, check the f-stop being set by the camera! Set the ND filter and shutter speed as required. Or, I suppose, shoot in Auto mode, with the AGC set to Auto/On as well. Then you’ll get an ND filter warning as required. You can also test your setting by turning AGC back on and see if the camera warns you to enable the ND filter. Set the ND filter and then turn AGC back off.

In my test shots, once I set the ND filter and dropped my exposure to f3.4 – from f-9.5 – the blurriness went away and sharpness was returned.

I have not yet determined the f-stop having the maximum sharpness but have seen some blog posts indicating f-4 is quite sharp.

Why shoot at 24 fps? When uploading online, this provides the highest quality image for a given bit rate. Although it may not make that much difference due to compression across frames.

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Update: July 2010

I recently ran across the same problem with my older Panasonic AG-DVC 30 SD camera.  The DVC 30 has a fake progressive mode for taking a “frame” like image versus an interlaced image. The problem is that in this particular camera, there is a resolution drop  when using the “30F” frame mode due to how Panasonic scans the pixels to create the frame. If I understand the situation correctly, this could result in a 33% resolution drop in Frame mode.  ( To my eye, it depends on the image because it typically seems less than this – and on some test shots, the 30F mode definitely looked better than a high quality de-interlace of the 60i video).

There are two possible work arounds. One is to shoot in normal 60i and get full resolution – and then use DV Film Maker in post to deinterlace the 60i to either 30p or 24p. This works quite well, although its not as good as shooting native progressive to start with.

The second method is to use the camera in 60i but manually set the shutter to 1/30th of a second. This actually produces a true full frame progressive image and is fine as long as you can use the low shutter speed. So far so good.

However, if shooting in bright light, the DVC 30 will push the f-stop as high as it can go – and sure enough, the auto focus fails and the camera is unable to obtain a clean focus.

Consequently, I’d say this problem is probably common across many cameras. The main issue with the XH A1 is that in manual gain setting mode, we no longer see the warning about the need for a neutral density filter.

In the case of the DVC 30, a simple solution would be to use an external ND filter.

Update November 2010

I shot an event, outdoors, under stadium lighting, at night. For some of this event, I used f1.6 aperture and 0 db gain. The image looked fine in the viewfinder. However, after watching on the computer, I discovered some of the shots did quick small jumps out of focus and then back in focus. Really ugly stuff. What’s going on?

In low light conditions, the “Instant Auto-Focus” feature often starts doing a hunt and seek. Therefore, DO NOT use I.A.F. mode in low light. Either use the standard through-the-lens autofocus, or use manual focus.

Some of the event I shot at +6 db gain and I did not seem to have the focus problem there. Again, in low light:

– don’t use I.A.F., use standard auto focus or manual focus

– if you use auto focus, probably best to add sufficient gain

The problem with gain is that it adds some noise, although nothing to worry about at +6 db.

Bottom line

Focus on the XH A1 is a complicated affair!