1080p V 1080i ?

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Bob Aldis
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Joined: Mar 7 2001

I am in a camera upgrade mode at the moment and am looking at Panasonic SD800/900 camcorders. I have been following and participating in the TM 900 club thread but thought this needed a separate thread.

I have been working in HDV for a while now and so downloaded some 1080p clips made with a Panasonic 700 to see if my computer and Vegas studio could handle it.

While I was showing the results on my 46 inch plasma, my son commented that some of the action shots were not very smooth. As his eyes are better than mine I compared it to some of my HDV footage and I was surprised at the results as the HDV 1080i stuff was smoother.

I put it down to pilot error and assumed I had done something wrong. Later I found an article about Sony TVs having trouble with the BBC’s HD broadcast as the BBC were sending a mixture of 1080p and 1080i. The reason given was that some things were better on 1080i including the scrolling credits.

Now I am wondering do members use 1080i for moving shots and 1080p for slower stuff or is the lack of smoothness I am seeing due to the downloads?

It probably won’t influence my camera choice as 1080p is not an optional extra on decent cameras now but I think if I had to mess about from one to the other I would just plump for doing everything in 1080i.

Bob Aldis

Claire
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Joined: Apr 28 2001

Bob, you say 1080i or 1080P but what about the frame rate? 25P or 50P? Also, can you be sure you know the clips are unmodified? For instance I believe of all the TM700 and 900 clips on Vimeo only a select few that have been uploaded by some sort of "elite member" remain in the original format they were shot in and uploaded, the rest are dumbed down after a week or so and don't give a true impression of the smoothness.

Claire

Bob Aldis
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Joined: Mar 7 2001

That could be it Claire. When I eventually get a new camcorder I will find out for myself.

It was just reading the article about the BBC and knowing that they like to do sport at 720. I believe everything was 50p or 60p.

Do you use 1080p exclusively or are there some things that 1080i does better?

Bob Aldis

Bob Aldis
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Joined: Mar 7 2001

BTW does anyone use surround sound and is it practical with an onboard mike?

Bob Aldis

steve
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Joined: Apr 8 1999

All BBC HD (excluding experimental 3D) transmissons are broadcast as a 1080i 25 signal. Where programme material is originated as 24 or 25 fps progressive, (usually cinema films and some drama) the 1080i signal is flagged as 'psf (progressive segmented frame) to instruct the TV to reconstruct the interlaced fields as progressive. Some TVs will display this as intended, i.e. 24 or 25 fps, some TVs will try to convert the signal back to 1080i 25 or 1080i 30 which will look jerky as the video information only exists as 25 full frames per second. With 1080i 30, fields will be repeated which certainly will look jerky. More recent TVs will display progressive up to 50/60 frames per second, provided the incoming video is correctly flagged.
As far as Vimeo goes, be careful judging the smoothness with that. I have done some tests and it seems that video uploaded as 720p 50 gets converted to 720p 30 instead of 25 which would account for very jerky motion. 1080i 50 footage however gets converted to 720p 25. I suppose as 25 fps progressive is not a US standard (and wasn't included in the original ATSC spec), so they don't bother.

Steve

Alan Roberts
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Joined: May 3 1999

You'd be very unlucky (or careless) to have a TV set which accepted European HD and tried to show it at 30 frames/second.

Jerkiness in 'progressive' pictures is down to the low frame rate, 25Hz. This means that information has to be repeated to avoid display flicker, and it's this repetition that causes the jerkiness. 720p has completely dies for broadcast, it isn't used at all apart from special conditions (like having to shoot 'off-speed' to get speed-up or slow-down shots). Drama, wildlife and light music tend to be shot as 1080psf (progressive images, but handled as interlaced), while news, serious music and sport are shot interlaced. Documentaries fall in the middle and can go either way. Fortunately, both interlaced and psf travel via the normal interlaced transmission without modification, so everybody's happy.

Some of the newer breeds of cameras can shoot at 1080p/50, so there's no image repetition in the display, and motion is smooth. This is the final aim for broadcast, at least within Europe. The problem is in the tolling-up costs for the broadcasters. That said, the makers of drama will still want to originate in 25p and repeat frames, because they like the look, but I suspect most pro0gramme makers will eventually see the light and shift with the times.

1080p/50 is still in its infancy. Not all NLEs can handle it well, some not at all. It's a bit of a gamble at present.

Get my test cards document, and cards for 625, 525, 720 and 1080. Thanks to Gavin Gration for hosting them.
Camera settings documents are held by Daniel Browning and at the EBU
My book, 'Circles of Confusion' is available here.
Also EBU Tech.3335 tells how to test cameras, and R.118 tells how to use the results.

col lamb
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Joined: Jan 2 2010

Bob

Precisely where did you get the 1080p footage and how did you display it on your HD TV? If you downloaded a video from say Vimeo then that is not a true test as their data rate and resolution is way below the actuals from a 900

My TM900 produces great images in either mode with 1080p having the edge. I do keep the finished movie solid state and do not try to put 1080p onto a Blu-ray via Edius or CS5.5

The onboard mike is OK internally and outside in now wind conditions, with anything other than a gentle breeze I get it picked up on the mike that is why I now have a new Rode.

Col Lamb Lancashire UK ASUS P6X58D-E MOBO, 3.3GHz hex core i7 CPU, 12GB RAM, nVidia GTX580 GPU, W7 64bit, 500Gb boot, 1Tb RAID (Mirror) Store, 500Gb RAID (stripped), Edius 6.05, CS 5.5

Bob Aldis
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Joined: Mar 7 2001

Col I got the downloads from your thread "900 club" and Steve, Claire and Alan have pointed out the error of my ways :)

I have been playing them through my computer via HDMI but have always got better results with my WDTV(and surround sound) and I am on hold at the moment as my WDTV needs a new HDMI lead and I am waiting delivery (might have to cut some of the plug away to make it work).

I am sure that the 800/900 range will live up to my expectations and this thread is more about me trying to understand things rather than any concerns about the camera.
My only concerns about the camera will be price and size.

Bob Aldis

col lamb
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Joined: Jan 2 2010

Bob
The camera size is OK for me, my first AVCHD camcorder was a Sony TG3 which is miniscule.

If size matters then have a look at the Sony TG7 (I think that that is the latest model), the images are great in all but low light condidions and the sound is not as prone to wind noise as the Panny 900 mode the only other downside with the Sony is that it uses Memory Sticks instead of SD cards.

As a side issue I got one of the WD TV Hubs a month ago and it is a great piece of kit, all my movies and image slideshows are now on the unit's internal hard drive permanently.

Col Lamb Lancashire UK ASUS P6X58D-E MOBO, 3.3GHz hex core i7 CPU, 12GB RAM, nVidia GTX580 GPU, W7 64bit, 500Gb boot, 1Tb RAID (Mirror) Store, 500Gb RAID (stripped), Edius 6.05, CS 5.5

Bob Aldis
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Joined: Mar 7 2001

My last but one camcorder was a Sony PC55. Real slip in the pocket size but hopeless indoors my present camcorder is a Canon HV30 reasonable indoors but not slip in the pocket. I was looking at the Panasonic sd90 which would be as good as I need for picture quality but after reading advice on here it obviously wouldn't be any good in low light. That is why I am being driven to look at these huge :D 800/900 camcorders.

I just need to find a shop with a selection of them to compare for sizes. As a matter of fact I am going out now so will keep my eye out for shops.

Bob Aldis