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(MPG4) Sanyo Xacti (all models)
A compact 720p MPEG4 digital media camera recording to SD Card.

 
 
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Old April 8th, 2006, 09:11 AM   #436
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Chris,

I know there is a wide latitude in GOP length in MPEG 2, and their appears to be an even wider latitude in MPEG4 - apparently as long as 300 frames. Determining how precisely you can edit would not necessarily tell you what the normal in-camera GOP is. It is entirely possible to have an I-frame followed immediately by another I-frame. As was mentioned earlier, the GOPs are re-constructed around the edit point, without disturbing the program as a whole. Each GOP has header information detailing the construction of that GOP. That's how frame accurate edits can be made in MPEG.

If you have TMPEG Author, you can see the GOP structure. Look at it around some edits. Of course that only works for MPEG2.
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Old April 8th, 2006, 09:20 AM   #437
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Quote:
Originally Posted by Bo Lorentzen
The issue with coporation between camera and software manufactures might be difficult. ;-)
Actually, I envision that the manufacturer themselves could supply a basic editing package with the camera that used this, even using somebody else's software. Basically, it is an extension of the in camera editing capability (hopefully filled out to all the essential stuff pro/sumers need). And provide a API/plug-in for NLE editing developers to use. It is really a on computer GUI interface to the in camera editing capabilities.


Steve,

The bus bandwidth is not a problem, all that the computer gets is display data, compressed or not, and the results codes (error codes). The camera can also pass back the rendered footage, and receive new footage. For 720p cameras, passing uncompressed is not too much a problem for USB2, though if your machine cannot handle mpeg4 decoding, it might also have trouble with a full USB2 data rate. For 1080/4(1440, got to call it something) I think it might fit (haven't calculated it). For true 1080 though, then you will be pushing, but lossless compression might help (If manufacturers set up cameras to support it). (I realise that most simple lossless solutions do around/or less, than 2:1, but we are talking about footage that has already loss a lot from Mpeg4, so hopefully it will compress even more.



We did a look into GPU, and the latest do 80 Gflop. or so, which is like an 8 core PC cpu. Programming is a problem, when they get used to it we might see a lot more. If people program it wrong, they bust all their performance, it has to be managed it's own way. We did some looking at it in the Digital Cinema stuff, and even the AGP back channel was more than fast enough. With PCI Express, we expect extra help. But, in the end, as much that can be done should be done on the cards, and the results passed back.

Direct X is moving towards a GPU that is much like a CPU, and Direct X 10 might deliver a lot more. Xbox360 is using more advanced direct x features, and I don't know how much of the 700+Glop (I can't remember how high it goes) will be available for processing enhancement. But Graphics manufacturers are enhancing their chip with more and more encoding/decoding features. I made a few posts on GPU enhancement for H264 in the news and alternative imaging forums. I spotted something very interesting in the diagrams, it was in an ATI chip, and seemed to be meaning, to take in analogue, or mpeg2 (not sure) and "transcode" it to h264.

For everybody here, the problem is that it is still far better to do it in camera instead (H264 will tax the CPU more). Some GPU's have the processing power, and all the features needed to get the max performance. But many are slow in places, and have features "emulated" by software routines, and don't deliver the goods. Many integrated graphics chips, and laptops, suffer from this problem. Also a number of the older/cheaper graphic cards also suffer more. To be certain you will have to see what the application that is using GPU acceleration suggests, as good choices for graphics.


Seriously, I think it is much better for camera manufacturers to explore this option, particularly in the next few years. It will stop people from being deterred by the though of buying expensive new editing hardware, just to get the most from cameras with new codecs.
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Old April 8th, 2006, 09:31 AM   #438
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A bit off subject:
Chris, did that guy in England get his amateur rocket into space a few years back?
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Old April 8th, 2006, 09:35 AM   #439
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Quote:
Originally Posted by David Kennett
I know there is a wide latitude in GOP length in MPEG 2, and their appears to be an even wider latitude in MPEG4 - apparently as long as 300 frames.
In fact, it doesn't matter here, because the HD1 use a fixed GOP too. An I-frame by second. So you have 1 I-frame followed by 29 P-frame.


@wayne : what you're talking about is just what you read around, and it's all PR talk and so one. Reality is MUCH MORE different...
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Old April 8th, 2006, 12:49 PM   #440
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I know. I also know that most people are just not good enough to milk a system for performance or efficiency, and then they whine about it, it's the systems fault is the usual whine, usually because they can't figure it out, then get the gullible to believe them. I've been around computing for nearly three decades, and it happens. Then after people with a real brain on their head figure it out, they find out that they could get many times more. I have come across, cynical, experts, out there, they seem to have a common problem, of turning out wrong, worth being skeptical of. Old story, stay tuned (and I am not saying that they will get everything GPU marketing promises, but most likely a lot more than the critics expect)!

I came across a thread tonight (to many threads) that was talking about a number of applications using GPU acceleration. It is not perfect. 80 Gflop peak sounds about right, it is not that crash hot. Not that you will get anywhere near it in most cases, but that is why it is called an accelerator, and not a encoder etc, but then you don't need too many Gflop to speed up encoding. I still don't think there is many GPUs that can actually deliver anywhere near 80Gflop, previous to 80Gflop being reached, performance was not anywhere near as good. So, most of this stuff is still expensive, and most systems out there won't hack it. And the stuff I quoted, is upcoming technology, which you can't judge on the basis of the results of previous/unoptimised technologies.

So, my head is screwed on straight, and what I say about using the custom specific in camera editing/encoding technology as a better solution then GPU still stands.

Now it is after 4am and I have to go to bed to clear my head.


Thanks

Wayne.
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Old April 8th, 2006, 05:48 PM   #441
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I am not sure about the guy in england. Dont recall it off hand. remember a name ? (google knows all Muahahahaha)

No RC car footage today. Fraking rain Grrrr

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Old April 9th, 2006, 06:45 AM   #442
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He was aiming for the first amateur rocket to breach the out atmosphere (over 100Km etc). I think it was a sugar powered rocket, or something, a big thing. Anyway, it doesn't matter.
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Old April 9th, 2006, 01:06 PM   #443
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hi and thanx Chris taylor for uploading samples, i'm gonna watch them now

by the way, i'm trying to follow that interesting discussion, but what GOP means ?

i'm too lazy to go back 5 pages before where i'm sure it has been explained
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Old April 9th, 2006, 01:46 PM   #444
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GOP is short for Group of Pictures. It's a concept that reduces temporal redundancy accross frames using a combination of I, B, and P frames(this is the compression you hear about, for example, in MPEG). GOP consists of one or more I images, followed by the B and P images.
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Old April 9th, 2006, 04:02 PM   #445
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ok thanx for the explanation !
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Old April 9th, 2006, 06:34 PM   #446
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I have some more clips - will have them online later tonight

http://www.nerys.com/sanyo

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Old April 10th, 2006, 01:35 AM   #447
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Chris,
Thanks for uploading more clips. Your clips exhibits much much less problem of jagged diagonal line. It is still there but not nearly as prominent as other sample clips I've seen. So far yours have been the best handheld examples I saw.
Did you use soft or softvivid setting?

I wonder if any of the HD1 owners on this thread is planning on some quality shooting setup. Tripod, good lighting, UV and polarizer filter, conversion lens.. whatever to get the best picture out of this camera.
I am seeing many reviews for this camera that almost dismisses HD1 as a camcorder, but I think it blows most consumer level DV camcorders. Even with heavy compression of mpeg, HD1's higher resolution and progressive scan feature makes it look pretty darn good when downconverted to 16x9 DV res or blown up to 1920x1080 res. I keep getting shocked to find out how bad DV compression really is when viewed on 1920x1080 size!

Anyway, thanks for sharing the test clips and please keep them coming! :-D
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Old April 10th, 2006, 02:02 AM   #448
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I agree, Euisung. People are spending too much time looking at resolution charts and diagonals. If you watch HD1 footage shot in decent light on a really good HDTV, DV is gone forever.
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Old April 10th, 2006, 03:12 AM   #449
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They were all shot iso 50 except the last 1 or 2 the turkeys was definately iso 400 (or 1600 whatever :-) it was prettymuch dark then.

The Jaggies are probably less visible because of normal hand held motion wobbles etc... I am really blown away just how amazing the quality is.

How it compares to a $2000 camera means nothing to me cause I aint got 2 grand. How it compares to my $500 DV Camcorder means I will never ever pick up the DV Camcorder again. :-)

I am going to have to figure out where to put these files. I want to keep them on longer but wow they are big :-) and recompressing would simply not do them justice.

The NEW vids are online (I made folders the 04092006 are what I shot tonight)

I cant WAIT till I have time to go to a rocket launch and shoot some vids !

IF I have enough to buy a second one by august I am definately putting one of these in a rocket and I'm gonna see how high I can send it :-)

I am trying to find an excuse to use a tripod but most of my shooting is spontaneous. ie most of the time when I use a tripod its a non moving subject and therfore I have no interest in using a video camera so much as my still camera.

I am going to build myself a steady cam rig and see if that helps a little. I also want to build a head mount for it with a 1:1 50mm scope sight. so what I see is what the camera see's I bet my head will prove to be a much more stable platform than my hands :-) this rig will also hopefully allow me to shoot rockets from ignition to ejection at full zoom. I just need to "align" the sight and the lens so what I see is what the camera see's

I will mess with that this summer. I have got to figure out a way to attach this to a telescope.

I DO have the Split Screen problem. its pretty nasty. basically it only happens in low light (so far) ie when I use flash and "so far" it wont do it if I am full wide or full telephoto only inbetween (so far) when I have time I am going to test this hypothesis more theoroughly. this is critical to me since though I never plan to use this as a normal camera (my casio is better at that) this camera does have 2 distinct advantages.

the macro is SICK. I am a macro whor. I LOVE macro and with this camera I CAN TOUCH something with the lens barrel and its still in focus !!! Insane ! (depth of field is EXTREMELY small doing this though)

10x Zoom and 5mp Wow makes otherwise impossible pictures possible. once I get the tele adaptor it will be 14x (assuming its stays crystal clear in focus)

I used the "VIVID" setting. I like sharp and I love saturation. the camear does tend to blow out the "brights" a little (neon colors red etc..) but not to the point of overly distracting but otherwise I like colors vibrant and colorful. the Malard Duck looks amazing ! it really came out nicely.

Hopefully today if time permits and I remember to bring all the pieces with me I will get some onboard RC Car footage. I have a large 4x4 hummer that can do 13-14mph (nice for a $70 toy !!) I am concered with "rolling" since the camera will significantly raise the vehicles center of gravity. I will have to make sure its VERY well padded from damage since at 14mph a roll will give it a rather nice (or not so nice) thunk but I think I have it figured out !

I just wish I could close the damned screen while recording (without exposing the LCD) its really bugging me since this things pretty much useless without the LCD)

Chris Taylor
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Old April 10th, 2006, 03:22 AM   #450
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Hey Tossed some stills up too (uploading right now done in under 2 minutes) one is an in camera crop of the moon 135 (not bad for 5mp)

128 is a nice closeup I got (was less than 1 inch from it when I shot that)

136 is the nasty split screen thing. OUCH horrible !!

129-133 are just some nice shots

I am not overly imoressed with the stills. my casio is better and my rather old nikon 5000 kills them both hands down. but in a pinch they are VERY usable and that macro is just insane !!

I will definately build a macro lighting rig for this thing !!

Chris Taylor
http://www.nerys.com/
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