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AVCHD Format Discussion
Inexpensive High Definition H.264 encoding to DVD, Hard Disc or SD Card.

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Old October 5th, 2007, 03:20 AM   #1
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nobody shoots indoors with video, it seems!

Does it seem that *all* video clips posted, and sample shots are shot in bright conditions?
I am deciding on a little HD cam to buy for an upcoming trip, and I enjoy shooting in more difficult lighting conditions. Anybody have a second or two of indoor lighting conditions, or even dimmer ?

It still amazes me that there are no testing web sites for video cameras that do more than talk.
Still cams have http://www.imaging-resource.com/ , and http://www.dpreview.com/ for excellent comparisons including some noise analysis and sample images to compare the same lighting conditions for different cameras.

I'm not looking for amazing low light results, but would, as many others do, like to get an idea of 'how bad' the video looks in somewhat dim conditions. The proverbial kid blowing out the birthday cake candle shot.

In particular, the Panasonic SD1 vs SD5 with the 1/4" vs 1/6" sensor would be a very interesting mystery to solve. Panasonic claims the 1/6" sensor does better low light. I doubt it. But they did scale up the sub 1K sensor to 1920, to improve the marketing hype! Shades of the inkjet DPI wars!
-Les
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Old October 5th, 2007, 08:58 AM   #2
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Lots of pixels on a little tiny chip will always have a hard time when the lights go down. CamcorderInfo shoots test charts under different lighting conditions:

http://www.camcorderinfo.com/d/Revie...h%20Memory.htm

Its not the same as video, but you can see how color and noise change as the lights go down. You might find it useful to look at the equivalent charts for the Sony VX2100, which is excellent in low light conditions, and maybe the Canon GL2, which has a harder time in low light, to give you some comparison points.

I suspect, for every HD camera in this price range (and even most SD cameras), you should plan on using an on camera light for the birthday party shots.

-Terence
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Old October 5th, 2007, 11:25 AM   #3
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Camcorderinfo does have some charts they shot at low light ( Pana SD1 ) , but they are scaled to thumbnail size. I can't see much in that, other than color fidelity.

I used the classic 'birthday party cake shot' as an example of the light I want to see in. I can't use a light, as in the situations I shoot in won't allow it. For example, in a Temple, a shopping area, a crypt, a Brazilian salon, a Japanese tea house. I don't use flash for stills either, it looks artificial ( and is ).

I know that all of the small HD cams will be poor in low light, I just want to select the least poor one ;).
-Les
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Old October 5th, 2007, 12:13 PM   #4
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This is a great site (actually, there are several blogs dedicated to different cameras): http://www.fxsupport.de/index.html No HG10 yet but I am sure he will get one.
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Old October 5th, 2007, 12:47 PM   #5
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Hi Les -
Take a look at the Sony CX7 - rated to 2 lux, and it's not bad. Shot my 3 yr old "blowing out candles", looks pretty good to me in the LCD, haven't had the chance to try edit and big screen yet, but so far this little guy is pretty impressive. I'll try to post a capture when I get around to editing.

FWIW, I've not had very good luck reproducing camcorderinfo's results, in fact I've found my results to directly contradict them sometimes in "real world" type conditions - they seem to really bag on the Sonys - they panned the HC7, yet I got excellent low light results once I learned to use the camera, the CX7 also got panned, yet I'm seeing it do amazingly well in low light so far.

For it's size the CX7 is pretty impressive, and I still love the HC7.

Can't speak to the Canon other than the bulid quality of the HV20 ultimately led me to sell it... just didn't inspire confidence, but maybe I was just paranoid... nice picture though!
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Old October 5th, 2007, 01:49 PM   #6
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Quote:
Originally Posted by Les Dit View Post
But they did scale up the sub 1K sensor to 1920, to improve the marketing hype! Shades of the inkjet DPI wars!
-Les
With the 3 CCDs, the SD1 was already processing everything at full 1920X1080 but got compressed to H.264 at 1440X1080. With the SD5, everything stays at 1920X1080 so you’re supposed to get a better picture even though the Mbps is still 13. I think the only way you’ll see a difference is by hooking it up to a 1920X1080 TV screen. Hopefully future consumer models will be higher than 13Mbps.
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Old October 5th, 2007, 05:51 PM   #7
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Panasonic is not 1920

The sensors in the 3 chip SD1 and SD5 are around 900 pixels across. Even considering the pixel shift technology to squeeze a bit more resolution out of it, it is in no way 1920 across. I fully believe that the 1440 compressed size of the SD1 did more than adequate job of getting all of the detail, but marketing wanted bigger numbers so they now waste bit rate on the fake 1920 compressed size.
What is going to be a dilemma for them is when they *do* get more image resolution from the sensors, they are going to be stuck at 1920 'full res' marketing hype already, so they will have to come up with some other jargon to show off the increased quality. Sad, really.
-Les


Quote:
Originally Posted by Paulo Teixeira View Post
With the 3 CCDs, the SD1 was already processing everything at full 1920X1080 but got compressed to H.264 at 1440X1080. With the SD5, everything stays at 1920X1080 so you’re supposed to get a better picture even though the Mbps is still 13. I think the only way you’ll see a difference is by hooking it up to a 1920X1080 TV screen. Hopefully future consumer models will be higher than 13Mbps.
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Old October 5th, 2007, 05:58 PM   #8
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Quote:
Originally Posted by Paulo Teixeira View Post
Hopefully future consumer models will be higher than 13Mbps.
Yes, consumer models...AND prosumer models.
It seems like this is the main obstacle everyone would like to see overcome within the year for AVCHD, but after a higher bitrate is achieved, people will still likely be looking for other improvements from the codec. Not to mention the arguments over how each manufacturer decides to implement it into their cameras.
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Old October 5th, 2007, 06:46 PM   #9
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Les Dit,

I think you misunderstood what I was trying to say meaning if it starts at 1920, it should end that way and since the encoder is much newer and better, I’d expect the picture quality of 1920 to be better even if its only slightly. Besides, there are other ways Panasonic can promote their future camcorders such as a higher bit rate that I mentioned already and a focusing ring around the lens.

If your trying to purchase a camcorder and willing to wait then it might be your best bet because I predict we will start seeing much better camcorders within the next few months. I’m only guessing with no inside knowledge at all but an example would be a replacement for the Panasonic DVC30 with 1/3.5” chips, a replacement for the A1u with a ½” chip and lest not forget the long awaited replacement for the GL2.
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Old October 5th, 2007, 07:43 PM   #10
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Quote:
Originally Posted by Paulo Teixeira View Post
With the 3 CCDs, the SD1 was already processing everything at full 1920X1080 but got compressed to H.264 at 1440X1080. With the SD5, everything stays at 1920X1080 so you’re supposed to get a better picture even though the Mbps is still 13. I think the only way you’ll see a difference is by hooking it up to a 1920X1080 TV screen. Hopefully future consumer models will be higher than 13Mbps.
1920x1080 contains 25% more information than 1440x1080. Well, it SHOULD contain 25% more if not for MPEG compression. How do you expect to get 25% more from the same bitrate with the same codec? In any case, whether MPEG4 is objectively or subjectively better than MPEG2, I don't think that it is two times better, and 25Mbps is barely enough for HDV. I am sure that HDV has only 1440 horizontal pixels not because it was not possible to create "Full HD" (I hate this term) 5 years ago, but because there was not enough bandwidth.

One would expect that with better codec (if we agree that MPEG4 is better than MPEG2) the solution would be easy: take the same storage media, be it tape or disk or something else, use the same bitrate as MPEG2 and receive instant gratification if form of better image. But AVCHD creators chose the HD-lite path, the same path that has been chosen by DirecTV and in lesser extent Dish Network, that is to reduce bitrate.

HD-lite can be explained in case of satellite providers, it allows to create more channels in the same bandwidth, but it is absolutely inexplicable for camcorder manufacturers. They had a simple and clear solution: use DV tapes, preserve the same 25Mbps bitrate, replace MPEG2 with MPEG4 and voila! Why they chose a different path? Why MPEG4 is not available in tape-based camcorders? Why limiting it with 13-15Mpbs? The reasonable answer is: to ensure that AVCHD does not compete with HDV and does not come close to professional HD equipment. In fact, HDV is already BETTER than broadcast-quality HD, but is not good enough for video masters, for professional editing. 25Mbps AVCHD could be good enough for editing. Heck, even HDV is not that bad when transcoded to losless format.

I am not sure that 20-25Mbps AVCHD will ever be implemented in a camcorder, at least in a consumer camcorder, because the quality of such video will trump 1280x1080 10-12Mbps HD-lite and will be on par with XDCAM HD.

Last edited by Michael Jouravlev; October 5th, 2007 at 09:11 PM.
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Old October 5th, 2007, 08:50 PM   #11
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If your TV is 1920X1080 then the 1440 will be scaled to 1920X1080 anyway so having 1920 to begin with shouldn’t be a problem.

Here is an article I read awhile back explaining the differences between the SD1 and the SD3 concerning 1440 and 1920. http://techon.nikkeibp.co.jp/english...070404/130166/

As far as any company using the higher bitrates, Panasonic has already showed us a prototype shoulder mounted AVCHD camera that is going to compete against the Sony HVR-HD1000U. I do believe that Panasonic will also use higher bit rates in much smaller cameras and we don’t know what Canon has up its sleeves. As for Sony, it’s true that’s its unlikely since it would be competing against the XDCAM.
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Old October 5th, 2007, 09:20 PM   #12
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Quote:
Originally Posted by Paulo Teixeira View Post
If your TV is 1920X1080 then the 1440 will be scaled to 1920X1080 anyway so having 1920 to begin with shouldn’t be a problem.
No this should be a problem, because you are not scaling to 1920, you are transferring 1920, which requires more bandwidth.
Quote:
Originally Posted by Paulo Teixeira View Post
Here is an article I read awhile back explaining the differences between the SD1 and the SD3 concerning 1440 and 1920. http://techon.nikkeibp.co.jp/english...070404/130166/
Panasonic can claim whatever it likes, but I will never believe that it is possible to compress proper 1080i into 13Mbps, even if it is MPEG4 instead of MPEG2. They can sent 1920 or 3840 to the codec, but if there is no bandwidth, all the codec will do is create macroblocks. Do you have experimental results of effective resolution testing? Maybe it can achieve 1080i on smooth scenes with few colors, but I am sure anything that looks Sunday football will break apart.
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Old October 5th, 2007, 10:19 PM   #13
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I may believe that the picture quality of the SD3 and SD5 are better than the SD1 and you guys may believe that the SD1 looks the best but one thing that I know we all agree on is that the bit rate should be much higher no matter if is your compressing to 1440 or 1920 and I really hope we will see those camcorders soon.
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Old October 5th, 2007, 11:58 PM   #14
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The above referenced Japanese article says of the SD1: "However, this camcorder downconverted the video signals shot at 1920 x 1080p into 1440 horizontal pixels, compressed them in H.264 and recorded the video in AVCHD format."

Someone explain to me how taking a signal from a sub 1K sensor and making it 1440 across is considered 'down converting'. That's crazy talk, I tell ya.

Back to my original complaint/observation: Please show 12 frames of video on these test reports, as you can tell, you can't trust any of what these testers say or parrot.

-Les
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