By >Daimaou - G.G-B
Xacti HD1, mediocre video quality maybe due to a bug
We wrote a small article on the Xacti DMX-HD1 two days ago, and the bottom line was not very flattering for this product. all videos we saw in the Japanese press or from the first owners displayed the same video quality. One of our readers delved into the subject and explained us the possible reason of the mediocre quality of the videos, so here’s his explanation (thanks Nightfly):
“As you can see clearly on the video, the borders that are oriented like a backslash (“\”) have a strange behaviour in the 720p videos of the HD1 whereas the ones oriented in the other way like a normal forward slash (“/”) are displayed correctly. Let me illustrate:
The subject:
\
_\
__\
___\
___/
__/
_/
/
Filmed with the HD1 in 720p, it is systematically displayed like this:
/
_/
__/
___/
___/
__/
_/
/
Affected zones like roofs, branches, … oriented in the “\” way get a heavily pixelated effect (3 or 4 pixels). If you look at it closely, it’s not really a pixelisation, but rather a bad orientation of these small pixel blocks, which creates jagged edges. This problem is unlike the blurring or loss of detail typically found in MP4 videos, and it also affects perfectly still images in a video. My best guess is that this is due to a bug in the HD1 when it comes to the encoding of certain DCT parameters, but we can imagine that it could also be done to save on the data stream (different components are encoded in an identical way in Huffmann… but that’s a bit out of my field of expertise).”
Let us give you a sample image…


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