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Posted by jerry on 10/12/06 05:43
1. http://tinyurl.com/eqnzu
"Motion, especially fast-moving and detailed motion as in sports
footage, presents quite a challenge for the real-time MPEG encoders in
standard HDV cameras."
"It's a challenge HDV can often meet, but not always."
"This is the downside of HDV's impressive MPEG compression
efficiency."
2. http://tinyurl.com/h6qwu
"Shooting with the Sony HDR-FX1, we noticed that the image quality,
although generally very good, becomes a bit noisy (or blurred) when we
panned with the camera."
"Actually, this is quite typical for MPEG-2 compression, even in HD
broadcasts, as we noticed in the Summer Olympics broadcasts."
"With the HDR-FX1, the blur/noise is more visible because it features a
less expensive codec."
"Using an HD-SDI converter, we then hooked up the camera with a
portable HDCAM deck (SONY HDW-250)."
"This let us bypass the MPEG-2 codec (with a transfer rate of 25 Mbps)
and, instead, record uncompressed HD (with a rate of 140 Mbps)."
"This resulted in a higher image quality with relatively clean pans."
"Based on our experience, we also recommend minimizing horizontal
movement (panning) as much as possible in order to maintain a clean
image."
"If you need to pan (and want to maintain the image quality), always
pan as slowly as possible!"
3. http://tinyurl.com/zn7c3
John Beale -- author of the famous Web site about the old Sony
DCR-TRV900 -- now uses HDV camcorders, but when he down-converts to
standard definition, he has to apply blur filters to the down-converted
HDV to overcome unique issues (click the preceding link to read about
those).
4. http://tinyurl.com/bedru
Wikipedia:
"Compared to more expensive HDCAM and DVCPRO HD equipment, HDV suffers
from significantly more spatial and temporal (motion) artifacts."
"As a consequence of interframe (temporal) compression, HDV editing is
more complex, and introduces greater distortion at the splice point
(due to the interdependence of adjacent video frames.)"
"Compared to conventional SD DV, HDV offers a much higher spatial
resolution, so most observers are willing to accept the artifacts in
exchange for a higher-definition picture."
5. http://tinyurl.com/ehcum (by DV MAGAZINE's Adam Wilt)
"HDV looks very good for scenes of low to moderate complexity and
unhurried motion."
"But a lot of high-frequency detail and/or abrupt, complex motions
cause noticeable degradation in the form of posterization, blocking,
and pseudo-random noise."
"Unlike DV, where the most noticeable artifact is localized 'mosquito
noise' around areas of high detail, HDV's artifacts can permeate the
entire frame, and are scene dependent in their characteristics."
"Furthermore, each frame's quality varies with the complexity of the
other 14 frames in its Group of Pictures (for 1080i; 720p uses a
6-frame GOP), so there's a time dependency to HDV's artifacts that's
absent in DV."
"After a couple of months of working with the HDR-FX1, I still get
surprised at how certain scenes react to HDV's compression."
"For the most part, an HDV camera original tape played back at 1 x
speed looks quite good, with artifacts adding a feeling of overall
noise rather than appearing as noticeable, localized defects."
"However, the 'noise' buildup on busy scenes is noticeable."
(The preceding comments are from Adam Wilt and I agree with him. - JJ)
6. http://tinyurl.com/guz3s
(Excerpt from Larry Jordan's Final Cut Pro Newsletter.)
Also, a great article about how AVCHD H.264/MPEG-4 compares:
http://tinyurl.com/nvvtd
Jerry Jones
http://www.jonesgroup.net
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