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-   -   xh-a1 downconverter vs shoot sd. (https://www.dvinfo.net/forum/canon-xh-series-hdv-camcorders/93505-xh-a1-downconverter-vs-shoot-sd.html)

Tom Cambridge May 8th, 2007 07:14 AM

xh-a1 downconverter vs shoot sd.
2 Attachment(s)
To begin with I have been shooting hd and using in camera down conversion for the time being until I uprate my computer to handle ample hd footage.

I have just shot some comparision footage of a Close up of a fence because it is an area of high detail. The reason being is to compare the down-converted clip to the standard sd clip and what I discovered is very dis-pleasing. (see attached stills, the first is the down-converted)

It would seem there is much detail loss in the down-converted clip and an overall loss in sharpness.

So now I am worried as to whether a down-coversion in final cut will be far superior to the nasty in camera downconverter.

You thoughts please.

Maksim Yankovskiy May 8th, 2007 12:35 PM

Capturing HDV

Is your current system capable of capturing DV? It sounds like it does. If so, I think it should be able to handle A1's HDV with the only caveat that you have to use a capture utility/NLE program that can natively edit HDV.

If your NLE supports HDV natively, like Adobe Premier Pro 2 and above, you can capture HDV just as DV - they are the same bitrate at 25Mbs/second.
If your NLE doesn't support HDV natively, it will need to decompress each arriving fram of HDV stream, which is MPEG2 by buffering the whole GOP (15frames?) - this will present problems for most systems.

I have a 3 years old laptop with 1G of memory and a 3GHz CPU (Pentium 4). It captures HDV without a single glitch. The only little nick in the wood is that when capturing with Premier Pro 2, the capture window does not show live image preview, so I pop open the LCD screen on camera.

Tom Cambridge May 8th, 2007 03:43 PM

Thankyou for the info Maksim. My system is infact far capable of capturing and storing plenty of sd footage, I have hundreds of clips stored already.

My main worry is this-

My project when finished is going to be in sd, however I have chosen to to shoot in hd and down-convert in post after reading that down converted material is of the same or superior quality to sd (with the added bonus of using the hd at a later time).

Now after comparing the sd to down-converted hd from the camera I am worried as to whether this is the best choice considering the clearly apparent lesser quality of the down-converted material, as can be seen in the stills above. So my main concern is whether this clearly poorer quality of the down-converted material is just the result of a poor down-conversion in camera rather than a better result from converting in final cut pro or similar.

Finally, are my finding's justified as to the apparent lesser quality of the in camera down-converted material? What are other peoples finding's on this matter? and is there an explanation for these finding's or maybe my camera is faulty.

To top this all off, I also have the nasty black line at the top of the screen with my in camera down-converted material which it would seem is becoming an unresolved universal matter for all A1 owner's.

James Miller May 9th, 2007 01:21 AM

Hi Tom,

If you are working on an older Mac, Capture the footage within FCP as HDV. Reveal captured file in the Finder and drop into Compressor, Down convert your footage to DV here adding in the filters tab about 10-15 in 'Sharpen Edge'.

The resulting file can be then edited within your normal DV timeline. Make sure the to constrain aspect to 16:9, frame size will be the 720 x 405.

This yields much better results than in camera conversion. When you upgrade your Mac later there will less to worry about as you can use FCP 6.

I should add this works best with the 25p setting.


Maksim Yankovskiy May 9th, 2007 02:22 PM

Does one always have to apply sharpenning to get better HD->SD downconversion?

I've produced a PAL DVD from NTSC clips that I shot over the weekend, and the image turned out a bit on the soft size, while the original HD was very sharp. I, howerver, attributed it to the frame blending, which is applied as part of NTSC->PAL conversion.

I am yet to work on converting HD video of the concert I shot last week to SD within the same domain - NTSC.

I can say one thing, though. The footage shot in HD NTSC and then converted to SD PAL looks way better than what used to come out when I did the same with my older SD camcorder.


Originally Posted by James Miller (Post 675370)
Down convert your footage to DV here adding in the filters tab about 10-15 in 'Sharpen Edge'.

James Miller May 10th, 2007 01:42 AM

I do apply a little sharpening on any down-conversion, just like if you resize a 40mb photoshop image down to web size, it will need sharpening to bring back the detail.

I suppose it's down to personal preference.

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