SDHC vs CF vs P2 vs SXS

gint12b

gint12b

Member
Alright, please help my math out here but I'm just throwing this out there...

Shouldn't you be able to record P2 HVX200 footage (100Mbps) onto an SDHC card which can transfer at speeds up to (240Mbps)...

Now I know P2 has an advantage with a RAID built in and I'm sure it has other features but for the price difference. I hope we are given the choice in the future to get higher bitrates on SDHC. I think this is only the beginning and the less proprietary the format (P2 and SXS) the better.

Why is AVCHD limited to only 24Mbps? It seems like we could use some more data (especially in the 1080 mode) and receive 4:2:2. I guess this is what AVCIntra solves but why not offer it on SDHC cards instead of P2 cards and stick it in prosumer cameras?

Lastly what are some advantages of SDHC to CF? It seems like still cameras switch from CF in pro (D3) to SDHC in prosumer (D90).

I know I've asked a lot of questions in this thread but overall, what are your predictions for the future of tapeless media?
 
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Just to quickly compare the 4:

SxS = 800Mbps (100MBs)

P2 = 640Mbps (80MBs)

CF = 368Mbps (46MBs)

SDHC = 240Mbps (30MBs)
 
Just to go through the math on the cards...

SDHC Class 4 = 4 M Bytes/second x 8 bits to the byte = 32 M bits per second.

Notice that upper case "B" = Bytes and lower case "b" is bits. There are 8 bits to a Byte.

SDHC Class 6 = 6 MB/second x 8 = 48 Mb/second

CF 20 MB/second x 8 = 160 Mb/second


Keep in mind that I'm giving common speeds, there are faster chips that higher rates, but these are typical rates.


Bob Diaz
 
gint12b said:
Now I know P2 has an advantage with a RAID built in and I'm sure it has other features but for the price difference. I hope we are given the choice in the future to get higher bitrates on SDHC. I think this is only the beginning and the less proprietary the format (P2 and SXS) the better.
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Speeds will only increase, so time will tell. There is going to be some time before common consumer cards can reliably do 100Mbps. For now, the capacities are increasing much faster than the speeds.

Why is AVCHD limited to only 24Mbps? It seems like we could use some more data (especially in the 1080 mode) and receive 4:2:2. I guess this is what AVCIntra solves but why not offer it on SDHC cards instead of P2 cards and stick it in prosumer cameras?
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It's a consumer codec that is already pretty difficult to process at 24Mbps. It is a pretty damn impressive consumer format, but you can get more from pro codecs. As mentioned above, AVCIntra would not work with current SD speeds... but you also need to spend a lot of money to get a camera that can encode it.

Lastly what are some advantages of SDHC to CF? It seems like still cameras switch from CF in pro (D3) to SDHC in prosumer (D90).
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Mainly size, and it is becoming the standard that won with consumers (like blu-ray over hd-dvd). I've read that CF is good with burst speeds whereas SD is better at sustained speeds (needed for video).

I can't predict any major tapeless media changes in the near future other than sizes doubling (and doubling again) and speeds climbing. Solid state cards and drives are finally reaching capacities that can replace the need for tapes and (non-massive) hard drives, so I would expect to see this takeover continue its path.
 
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I must have glanced at your numbers too quickly (I saw 100MBps thinking you were referring to P2 writing 100Mbps with current codecs, and the SDHC rate didn't look familiar, etc). So your math IS correct, I just wasn't sure where you were getting some of those rates.

On that note though, I'm pretty sure those really high rates that are being advertised are maximum data transfer rate. Video requires a sustained minimum transfer speed, so those numbers come down quite a bit (not to mention they need to leave some headroom and use common cards). I haven't heard of cards above "class 6", but if they don't already exist, I'm sure they will soon enough. Everything will be possible in the future, but I don't see P2 leaving the pro cameras anytime soon. I've seen talk of expresscard to SDHC adapters that work for the EX-1, maybe a similar option for P2 will come about.

AVCHD is capped at 24Mbps though, so it can't go any higher. Someone could make a variant of it that allows for more down the road similar to how XDCam HD expanded on HDV. This is a prosumer camera that uses consumer media/codec just like DVX did, the massive savings outweigh the few setbacks in this class. :) Since these cameras don't do much above 720, I don't think it's an issue right now, but might be thirsty for some more bandwidth if/when the sensors are improved.
 
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"Video requires a sustained minimum transfer speed, so those numbers come down quite a bit"

I actually just came across this amazing article describing how Redcode RAW is transferred to CF Cards and it pretty much goes all the way up to the maximum data transfer rate of these cards without any fault:

http://provideocoalition.com/index.php/mcurtis/story/red_one_geekery_real_world_info_on_redcode/

You can't get much more professional than RED and if they are shooting to CF cards successfully, one mode RC28 with a maximum data rate of 28MB/s (224 megabits), and one RC36 with a maximum data rate of 36 MB/s (288 megabits), I don't see the real need for all that extra bitrate that SxS and P2 offer...

I think what upsets me the most is that it seems completely possible to record P2 to CF cards or even SDHC cards at a fraction of the cost to the customers but these big camera companies won't allow it because they can make over 1000 dollars per P2 or SxS card...

Technology is rapidly changing, I just predict that P2 and SxS won't last. Just my humble opinion...
 
Sony and Panasonic gulped down a bitter pill with the onset of digital production and the loss of business from declining tape deck sales. My 2 SVHS editing decks cost close to $9,000. back in the day. So with proprietary products like SXS they can hold on to some profitability. Panasonic is not likely to offer AVCHD Intra in a prosumer product anytime soon, or until a company like RED forces their hand.

That's why I like to see products like RED come along and shake the ground under these powerful companies
 
"That's why I like to see products like RED come along and shake the ground under these powerful companies"

Well Said!!! :)
 
I have to say I do agree that a lot more IS possible (whether or not it is feasible). I have thought about and wished for the same features you brought up as I love hi-tech toys at a price I can actually afford. It seems that the companies have to draw the line somewhere between pro and prosumer features/price (and another line for consumer) to help make a profit. That line keeps getting narrower every year, even the consumer cams are really impressive for a lot less. If Red's Scarlet delivers as promised, it will def stir things up at this level. What we have to realize is that the 150 (like the DVX) is tailored to a slightly different market and is meant to be more consumer friendly. I do wonder if AVCIntra will ever make it down to the hpx170 or even hpx500 level pricing.

There are some threads on P2 that mention how there are a lot of people/companies bought into it that it wont be going away anytime soon at the pro level. They could offer cams with both drives to transition though, it would just be questionable if they would spend money developing this feature to lose out on earning money for the cards (like you pointed out). For "us", we would just have to hope for a new codec that can be used on our cheap cards, I just wouldn't hold my breath until things get sorted out with the current one.
 
Of the four, my favorite is CF. It passes the "drug store test" (is available at your local drug store) and is bigger than the SD card, which is too small for my tastes.

Actually, even the CF is too small. The ideal size for professional media is the P2 or SxS (easier to handle, write labels on). But those fail the drug store test.
 
combatentropy said:
Actually, even the CF is too small. The ideal size for professional media is the P2 or SxS (easier to handle, write labels on). But those fail the drug store test.
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Well,

When you insert your SDHC into your expresscard adapter, it becomes a nice professional size, it passes the Best Buy / Circuit City test, and it's cheap.

:)
 
accelv said:
So with proprietary products like SXS they can hold on to some profitability. Panasonic is not likely to offer AVCHD Intra in a prosumer product anytime soon, or until a company like RED forces their hand.
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I'd hardly call expresscard proprietary. Nearly every new laptop can read and write from them. And the current KxS solution proves that you can stick a common SDHC card in an Expresscard adapter and use that just fine.

The battleground question is whether Sony will step up to the plate and try to sell more cameras by pushing this nice solution, or whether it will try to shut down the process and force everyone back to SxS from them and Sandisk.

I know I just cut my media costs by 9/10ths this week.
 
PerroneFord said:
I'd hardly call expresscard proprietary. Nearly every new laptop can read and write from them. And the current KxS solution proves that you can stick a common SDHC card in an Expresscard adapter and use that just fine.

The battleground question is whether Sony will step up to the plate and try to sell more cameras by pushing this nice solution, or whether it will try to shut down the process and force everyone back to SxS from them and Sandisk.

I know I just cut my media costs by 9/10ths this week.
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I completely agree and I just read this article you are talking about yesterday when it showed up on FreshDV. http://www.freshdv.com/2008/10/kxs-replacing-costly-sony-sxs-media-with-cheap-sd-cards.html

Very interesting times indeed... Things are changing monthly.

Just like you said though, lets HOPE that Sony doesn't cut off this solution with their next firmware update... MiniDV tapes were always open to competition so I don't understand why any other new media should be proprietary like P2.
 
My total cost was under $100 shipped for a 16GB card and a reader. I ordered two readers though, just in case. I'll probably get 2 more readers and then 2 32GB cards when they come out.

When I put the card in the camera, it formatted it in about 3 seconds and then showed 58 minutes of recording time at HQ 1920x1080.

An hour of recording for under $100. I know three years from now, we'll look back at this and laugh at how much we're paying as SHDC cards are going to fall in price quite quickly. But if Sony is smart, they'll get on board FAST with this, and produce these units themselves, certify them with the camera, and make money.

I'm looking at having nearly 4 hours of uninterrupted recording time on 2 32G card by Christmas for about $350. My original SxS cards can stay with me for overcranking purposes.

By the way, stocks of the Kensington 7 in one cards are down in the US, UK, and elsewhere according to reports. I wonder if the plant manager at the place who makes these is wondering why his production estimates are suddenly not meeting market demand! LOL! Somewhere there is a business manager trying to figure out what the heck happened this month with the sales spike!
 
HMC 150 is a game changer. Expensive tapeless media will soon be gathering dust on the shelf unsold.
 
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