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Posted by Dave Martindale on 01/08/07 21:09
"Jim S" <Jim S@jimsplace.com> writes:
>"Dave Martindale" <davem@cs.ubc.ca> wrote in message
>news:ensm33$qbr$1@swain.cs.ubc.ca...
>> Rick Merrill <rick0.merrill@NOSPAM.gmail.com> writes:
>>>Better, get a camcorder with a hard drive to record DV25 files then you
>>>can edit it without waiting for ingest time.
>> That's a great idea, but do any such camcorders exist? All the hard
>> drive camcorder's I've looked at record MPEG, and boast about the long
>> recording times they are capable of (at very low quality). Nobody seems
>> to provide DV25 recording for quality, even as an option.
>> Dave
>Have you studied the new AVCHD format, see for example:
>It says here that:
>"The increased 18Mbps bit rate of the AVCHD format will likely impress
>prosumer users who have been disappointed with the quality of DVD video. At
>more than double the current 8.5Mbps rate, the new bit rate is very close to
>tape-based standard definition, and it is likely that AVCHD video will be of
>a much higher quality than existing DVD camcorders.
First, this seems like a step in exactly the wrong direction. DV25 data
storage for standard definition (SD) images looks pretty good because it
uses only modest spatial compression and no time-dimension compression.
If you applied the same compression technique to HD video, then the data
rate would rise above 100 Mbps because there are 5X more pixels per
second per second. At 18 Mbps, the camera is using *much more*
compression.
Yes, 18 Mbps is reasonably close to 25 Mbps, but can you even use that
data rate to record SD video? Crummy HD video is not an adequate
substitute for good SD video.
And saying something is "likely ... much higher quality than existing
DVD camcorders" is not exactly a high standard of comparison. It would
be much more interesting to know how the images compare to a SD
camcorder in the same price range.
>So because the AVCHD format is said to have a bit rate that is "very close
>to tape based standard definition", doesn't this improve the appeal of hard
>drive and DVD camcorders that record in this format?
Not unless it allows you to record high-quality SD video, which I doubt.
It certainly doesn't give high-quality HD video, as other readers
have attested.
Dave
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