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(MPG4) Sanyo Xacti (all models)
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Old March 18th, 2006, 11:37 PM   #1
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Sanyo HD footage vs HDTV?

I noticed, that the quality of local HDTV transmissions are so bad, that they are crawling with every sort of codec noise. Would most of the HDTV audience really notice much of a difference, in noise, if Sanyo HD1 footage was properly transcoded to HDTV? Of course, the average HDTV footage is shoot on a pro camera and will be much better in latitude, colour and sensitivity etc, but what about the noise itself?
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Old March 19th, 2006, 07:59 AM   #2
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When you consider the limitations of bandwidth on a cable feed, the fact that this bandwidth is usually split two or even three ways, and the compression algorithms, it is little wonder that there is so much artifacting to be seen. I presonally think HDTV around here is a fraction of what it's presented to be. Ours contains noise, high amounts of blocking... in truth I find it unacceptable.

I don't think comparing our output on HDTV to that of a cable feed is a reasonable measure of performance, nor do I think such measures are useful. If the video lacks notable artifacts when viewed on HDTV, has good saturation and contrast, and is smooth, I feel it is good output. I get this from my camera, though admitedly I have found this camera (or maybe HDTV in general) requires more skill to capture quality video. And I admit that I'm not getting the quality output that a $5000+ camera produces. I didn't pay for it and I don't expect it. I do, however, feel I am getting exceptionally close to it.

I noted in a prior post that our output looks better than an HDTV cable stream. In native 720p, sent straight from the camera, there was a notable improvement. I don't personally have a HDTV, but I have a friend with a Sony one and I've seen plenty of cable output on it; I've also seen several hours of footage from my HD1. Without question, there is notably lower artifacting with the HD1. In truth, I've yet to notice any from my camera at all.
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Old March 19th, 2006, 08:20 AM   #3
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Oh yes, to answer the noise question... there is visible noise on my HD1 videos, but it generally shows only in dark or shadow areas. Seen on a HDTV unit, this looks like static in the feed. I notice it, but I don't find it distracting. The noise is considerably less than digital cable contains. As a caveat to this, I must state that videos shot in substandard light are, of course, very noisy.

On a cable HDTV feed, I have noticed that the noise is more uniform in the image. All gradients seem to display noise in both light and dark areas. I think the compression used by cable broadcasters tries to achieve the lowest acceptable throughput at all times, instead of a stream at a steady speed. This makes sense, as it would reduce overhead on the network and deliver consistent quality. In contrast to this, our feed is a constant 9Mbps. What this appears to mean for us is that our videos contain less noise in the areas it is most noticeable, such as sky and colored walls. When the video is simple, when a large portion of the content is a constant or gradient color, our noise seems to vanish.
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Old March 19th, 2006, 03:56 PM   #4
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In the San Francisco Bay area we have excellent HDTV over cable most of the time. Over the air transmission can be very good as well -- I have an outdoor antenna that is little more than a coat hanger and get a few stations as clear as a bell.

The HD1 footage is not as good as the best of HDTV, but far better than DV and very attractive when carefully shot, which to me means: decent light, a steady hand or support and keeping the significant images big in the frame. Like early 35mm, it does not do well with small objects seen from a distance.
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Old March 21st, 2006, 09:52 AM   #5
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Sorry for the delay, we got hit by the biggest cyclone here in decades, approx 300KM winds. But, by the time it got closet to me it fortunately was only producing an occasional gust of probably 200KM wind, but mostly way below that, I think. Cleaned up one or two regional centers and a number of towns. Apparently George Bush was even offering some assistance even. If only I had a descent HD camera to film it ;).
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Old March 21st, 2006, 10:06 AM   #6
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I noticed something funny around here, digital TV footage is bad, pre-recorded or even live national/international sports events, but the occasional high end commercial comes out relatively clear. Is there something wing with the station's encoders, do the high end commercials come better encoded, or or are they shaping for the commercials?

They are extending the analogue cut off date around here, people are apparently not finding a substantial enough difference to warrant buying HDTV. There are people in the broadcast industry that want more channels to over come this, but what do they expect if it looks this bad and with HDTVs been so costly in the past (not to mention not even being HD and with no tuner).
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Old March 21st, 2006, 06:01 PM   #7
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I think what Wayne Morellini is pointing out is that HDTV broadcasts are poor enough that the average person familiar with HDTV image quality isn't going to percieve the HD1 output as a problem. Further to this, if the image is transcoded for playback on HDTV, it isn't likely to contain more visible noise than HDTV transmissions.

I think the first assertion is accurate... people that are satisfied with HDTV broadcasts are likely to be pleased as the HD1 output exceeds what they are familiar with. I think the only vital fact related to this is that the HDTV quality that the HD1 is being measured against in this process isn't an accurate measure of the 720p standard.

As far as noise if the HD1 output was transcoded, I would expect the quality to be similar to HDTV broadcasts if transcoded to smaller bandwidth, but that assumption takes much for granted. It is common knowledge that a higher grade original produces a higher grade copy... think of re-encoding MP3 files a few times... they get flat because too much data is lost in compression. Perhaps we are more safe is to say the noise will be, at most, only marginally higher.
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Old March 22nd, 2006, 06:01 AM   #8
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That is what I mean about properly transcoding, so as to take the cleaner Sanyo image to match the quality of the HDTV signals. I think, most ordinary transcoding is just going to loose the plot quality wise.

If, there is better quality to be had from broadcast HDTV then that is good, because what I am getting from broadcast here leaves me delusioned with the industry.
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Old March 26th, 2006, 08:37 PM   #9
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Time to chime-in. From what I'm reading here, the HD1 quality is all about ones frame of reference. That I can understand. If you plug this into a 40" LCD, and compare that with last years family events on VHS or MiniDV, it's a direct sell. Now if a few months from now, you were to compare the same image to say a wedding shot on an HD/HDV camera and burned to an HD-DVD disk, it would be a rip-off.

Point is, it's a consumer cam, and if all we have for less than $1500 in kit is a 1/4" 3chip mini-DV, then it still seems like a winner. After viewing the uploaded samples, I'm left with the impression that it's the same old noisy consumer look, but on a larger scale that fits the HD spec. That is, would I rather have juniors next birthday as an HD1 Mpeg4 clip, or some miniDV clip that I had to scale up in post? Which image would look better on an HDTV? Anyone tried to compare the same scene shot on a decent 3chip miniDV and scaled up for viewing on an HD monitor?
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Old March 26th, 2006, 08:51 PM   #10
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Lets put it this way: I judge everything on an excellent 60 inch Sony HDTV. I am more than happy with the Sanyo HD1, and my previous standard, the 3 chip Sony DCR PC1000, is for sale on eBay.

The Sanyo also fits into my pocket and takes 5MP stills that are also much better than those taken with the Sony. I'm also truly pleased to be done with tape in any form.
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Old April 4th, 2006, 05:08 PM   #11
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Quote:
Originally Posted by Chris Wells
I think the first assertion is accurate... people that are satisfied with HDTV broadcasts are likely to be pleased as the HD1 output exceeds what they are familiar with.
Agreed, Chis. I think HD1 output, when used within its limited operating "envelope," looks better than most of what is passed off to consumers as "HDTV." I like to say the big HDTV consumer sham is the industry is "Overutilizing bandwidth and underutilizing pixels!" By that I mean all of HDTV broadcasting is being carved up into sub channels--quantity over quality. Virtually no full-ATSC bandwidth feeds (19.4 mbps) are available anywhere (cable or satellite). Even when there are no shared sub channels, the bandwidth is often constrained by the primary feed so it WILL fit into a small pipe for the broadcasters that carve up their bandwidth into subs (consumers get the least common denominator in picture quality!) Even if the video stream bitrate appears to be worthy of the term HDTV (approaches 19.4 mbps) its is probably full of null packets that can be stripped losslessly (without transcoding) by the local affiliates or the cable companies in the sky to fit more channels in the pipe. They overutilize bandwidth! Lot's of channels to sell in brochures but nothing worth watching--quality wise.

On the other hand, take a look at how few programs contains sufficiently high spatial video frequencies to warrant the number of pixels provided by 1080i or even 720p. There are a few programs, but far less than half of what's aired as "HDTV" even justify such pixel resolution. But big screens with big pixel counts attract consumers.

Our local PBS affiliate boradcasts "HDTV" at about 10mbps, not counting null packets, of course. It's about the same as the maximum bitrate allowed for SD DVDs! Is that gonna work very well for 1080i? Gee, I don't think so! Even the ATSC maximum of 19.4 is pretty marginal and should've been made higher in the HD standard. Any scene changes or high motion produces blocks, even at 19.4 mbps, and broadcasters are trying to use far less than that.

I could rant on and on and I won't even get into the picture quality damage by broadcasting recompressed feeds with local watermark logos and other advertisements.


arrghhhh! Thanks for listening. ;)

Cal
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Old April 5th, 2006, 04:41 AM   #12
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Quote:
Originally Posted by Calin Brabandt
Virtually no full-ATSC bandwidth feeds (19.4 mbps) are available anywhere (cable or satellite). Even when there are no shared sub channels, the bandwidth is often constrained by the primary feed so it WILL fit into a small pipe for the broadcasters that carve up their bandwidth into subs (consumers get the least common denominator in picture quality!) Even if the video stream bitrate appears to be worthy of the term HDTV (approaches 19.4 mbps) its is probably full of null packets that can be stripped losslessly (without transcoding) by the local affiliates or the cable companies in the sky to fit more channels in the pipe
Eek, there should be a standard for the minimum bandwidth for a resolution, though I can't say who should do that here.

In Australia, they got into this massive fantasy land where we suddenly got cable providers and UHF TV (that gives worse reception, the opposite of what there promised) so we could have lots of new channels, like in America. But the truth is that with 20 Million people and five networks (that actually can fit in the VHF spectrum with the repeaters) there was no real room for new channels, even the few cable providers have had a hard time. Life is complicated enough with five channels, I imagine with the amount of channels I hear you have in America, things must be very confusing. Where is this going, it would have been better if they made a series of 38.8+ channels instead, with genuine minimums like 30Mb/s for 1080p, and 20 for 720p, and something like 8.8Mb/s for SD.

Quote:
On the other hand, take a look at how few programs contains sufficiently high spatial video frequencies to warrant the number of pixels provided by 1080i or even 720p. There are a few programs, but far less than half of what's aired as "HDTV" even justify such pixel resolution. But big screens with big pixel counts attract consumers.
In recorded content I agree, video tends to deal harshly with detail, but I like noticing the texture, grain (real grain, not "spotty film") and faces, on a theatre screen, and it would be good to have that on the HDTV.

Quote:
Is that gonna work very well for 1080i? Gee, I don't think so!
Hmm.. Ironically that sounds like something that doctor "house" would say, which is just about to start.

Quote:
arrghhhh! Thanks for listening. ;)

Cal
Understood, I'm with you. I hope they eventually go to h264 at least.
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