Author Topic: Can we build a hardware solution for the sd card based cameras' write speed?  (Read 31444 times)

ItsMeLenny

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Is this anything like a possibility?  ;D

And is there anything I can do to be helpful?

See above!!

Can

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See above!!

Actually, I was referring to the notion of using the USB interface as a supplement to the SD...should have been more specific, sorry.

ItsMeLenny

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Actually, I was referring to the notion of using the USB interface as a supplement to the SD...should have been more specific, sorry.

The usb is really far too slow to be of any help to anything.
But I have no idea. Can't help you with that one sorry.

Schmeknicolor

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I know this is almost dead but i found a bigger picture of the SD Board if anyone is still interested 

600duser

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Catching the Unicorn

1) there is probably a bandwidth bottleneck....as in data can only be SENT so fast to the SD card slot/port anyway

2) LiveRam....imagine a stick of DDR3 ram, powered by a battery, aka liveram

3) Create a high speed data cable that terminates in the shape of an SD card ( with appropriate protocol and ID )

In theory data could be sucked out of the camera at several Gigabytes (not bits) a second.

Perhaps a simpler way is to RAID up 2,3,or 4 SD cards....have them suck out the data alternately  in parallel


List of device bit rates
http://en.wikipedia.org/wiki/List_of_device_bit_rates




LiveRam is the ultimate bandwidth  solution. It would be like a class 10,000 SD card :-p

ItsMeLenny

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Catching the Unicorn

1) there is probably a bandwidth bottleneck....as in data can only be SENT so fast to the SD card slot/port anyway

2) LiveRam....imagine a stick of DDR3 ram, powered by a battery, aka liveram

3) Create a high speed data cable that terminates in the shape of an SD card ( with appropriate protocol and ID )

In theory data could be sucked out of the camera at several Gigabytes (not bits) a second.

Perhaps a simpler way is to RAID up 2,3,or 4 SD cards....have them suck out the data alternately  in parallel


List of device bit rates
http://en.wikipedia.org/wiki/List_of_device_bit_rates




LiveRam is the ultimate bandwidth  solution. It would be like a class 10,000 SD card :-p

There is the bottle neck in the sd card controller, the bit that communicates between the camera and the sd card. But the idea was to totally pass the sd card controller and build a new one, whether the data being passed to the sd controller is faster than the data from the controller to the card, nobody knows.

600duser

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Ive been looking into camera hardware. I know next to nothing about digital cameras apart form the fact they suck to the power n but i know a great deal about computers,  imaging and physics related stuff. They are complex tricky devices for sure. A lot to squeeze into a small space. Engineering / repairman's nightmare but id so love to do a kick starter campaign 'Digital photography solved'  cos there is a huge gulf between where we are at now and where 'we could and should be', as a consumer, designer and engineer, its driving me bonkers !

You cant make a silk purse out of a sows ear, so despite the large number of owners of camera X advances in the hardware tech is likely to outpace most hardware hackers efforts. Software hackers having an easier time in general.

canon 600d disassembly
http://ghonis2.ho8.com/600Dreinstallsteps1a.html

Point of interest, i actually bought  a 100mbs class 10 U1 SDHC card before i decided what camera to get, there are faster cards than that.  A fast card you buy today would solve many speed issues. Very high frame rate video still going to be an issue though if its also at high resolution.


Panasonic Lumix DMC-GH3 . The GH1 and GH2 were hacked. Probably worth reading up on for those interested in the topic.
http://en.wikipedia.org/wiki/Panasonic_Lumix_DMC-GH3

"It is the first MILC that can record videos with a bit rate of up to 72 megabits per second. That is significantly higher than the specification of AVCHD 2.0 of up to 28 megabits per second, which was released in July 2011 and is used for similar cameras and camcorders.[3]"


Digital movie camera
http://en.wikipedia.org/wiki/Digital_cinematography_cameras

http://en.wikipedia.org/wiki/DVCPRO#DVCPRO






SD Host Controller. SD Standards Some cameras now have 2 SD card slots.
https://www.sdcard.org/developers/overview/host_controller/



Q what kind of speeds are needed, reliable and burst speeds ?...solve one bottle neck and you quickly find the next !








Fast Communications.

http://www.astronomiser.co.uk/helpcanon.htm


This is important for a couple of different reasons. If imaging using a PC or laptop and downloading shots as you go, it's preferable to allow the camera a reasonable cool-down time between shots - a warm sensor means an increase in electro-thermal noise or noise caused by heat due to the electronics of the camera. A lot of electronic components heat up when in use (including sensors themselves) and a good idle time between shots (between 30 and 45 seconds depending on ambient temperature) can improve the quality of shots significantly. If a camera's communication electronics is running for half of this time, then heat inside the camera does not dissipate so readily. Secondly, if saving shots to a CF card then later downloading them to your PC, then download can take considerably longer.

The difference between the models is that some use USB1.1 and others use USB2.0. The speed difference is 12Mbps (Mega bits per second) vs 480Mbps - this is 40 times faster, but is a maximum measure of the speed available under the standard and note a true measure of the speed difference. A lot of other factors come into play - other devices attached to the USB bus (even some devices internal to the PC or laptop), the connected device's true maximum (i.e., flash drives have a maximum of about 240Mbps). The whole speed thing is a bit of a minefield - MBps is not the same as Mbps (Mega Bytes vs Mega bits - 8 bits in a Byte so multiply MBps by 8 to give Mbps) and Full-Speed USB is not the same as Hi-Speed - Full-Speed is 12Mbps USB 1.1 and Hi-Speed is USB 2.0. Also 'USB 2.0 Compatible' does not mean that it is USB 2.0. Anyway - this page - http://www.everythingusb.com/usb2/faq.htm - should answer some of your questions.

So, importantly, which camera is what?

    D60 - USB 1.1
    300D - USB 1.1
    10D - USB 1.1
    350D - USB 2.0
    400D - USB 2.0
    450D - USB 2.0
    1000D - USB 2.0
    20D - USB 2.0
    30D - USB 2.0
    40D - USB 2.0

ItsMeLenny

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Point of interest, i actually bought  a 100mbs class 10 U1 SDHC card before i decided what camera to get, there are faster cards than that.  A fast card you buy today would solve many speed issues. Very high frame rate video still going to be an issue though if its also at high resolution.
Have you actually read any of this post. You could have a kabillion MB/s card and it won't help, there's a bottle neck in the SD controller in the camera that limits it to 20MB/s

Q what kind of speeds are needed, reliable and burst speeds ?...solve one bottle neck and you quickly find the next !
If it is found how to overcome the sd card controller bottle neck then the next bottleneck would be the SD card. Speeds that are needed at 100MB/s, whatever the fastest SD speed there is to come along.

You should probably go back and read the posts first.

600duser

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Fast SD cards will help, but we are only talking by a few % if the bottleneck is further upstream and if the SD card is already twice the speed

Cache sizes are also important

Found this link
http://a1ex.magiclantern.fm/bleeding-edge/raw/raw-chart.png

Not an easy hack-around if there is no drop in physical substitute for the bottleneck controller.

Hardware to Hardware handshaking and protocols might be inflexible...bit stuffed in that case.

Need a detailed schematic of the data chain in order to have a more meaningful discussion, schematic of the specific hardware in question.

Over volting and overclocking can squeeze a double digit % increases if they are applicable. Heat and reliability can be an issue.

ItsMeLenny

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Yes. All already realized facts.

Fast SD cards will help, but we are only talking by a few % if the bottleneck is further upstream and if the SD card is already twice the speed
A card that can manage 40MB/s write speed won't be any faster than a card that can manage 30MB/s, the bottleneck is 21MB/s.


The idea was to take out the SD card and SD controller in general. Replace with anything else, whether it be an SATA SSD to a magnetic tape (obviously not magnetic tape, just something faster than the 21MB/s controller). Nothing is known about the hardware though.

600duser

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With video becoming a must have feature, or at least a top selling point this will drive the need for much faster processors and bandwidth pipelines.  Its a bit like how computer games drove the development of graphics and sound cards.

Talking of bandwidth i actually crashed my computer yesterday BSOD trying to play a 4k video taken by a Smart phone.

Things are moving fast, give it another 5 years and most of the video related kinks will be ironed out....bit frustrating but i guess thats just the way it is. Solving 'Video' is an order of magnitude more difficult than solving Still pics. Start saving the pennies i guess.

 


ItsMeLenny

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With video becoming a must have feature, or at least a top selling point this will drive the need for much faster processors and bandwidth pipelines.  Its a bit like how computer games drove the development of graphics and sound cards.

Talking of bandwidth i actually crashed my computer yesterday BSOD trying to play a 4k video taken by a Smart phone.

Things are moving fast, give it another 5 years and most of the video related kinks will be ironed out....bit frustrating but i guess thats just the way it is. Solving 'Video' is an order of magnitude more difficult than solving Still pics. Start saving the pennies i guess.

Yes but if you've seen, they still sell really shitty computers that can't run games. They will continue to sell shitty cameras which limit themselves in hardware for the sake of making people spend more money. They even limit the hardware via the software, there's hardware out there with twin siblings but they put worse software on one, and if you pay the 1000 dollars extra to upgrade all you're getting is the extra features that already existed and should've been unlocked in the first place.

I do believe the processor in some of these cameras, 550D, 600D, have the ability to do faster writing, the bottle neck is elsewhere, so this post is in some regards to do some reverse engineering, which people have put their hands up, but I guess gotten no results, or not been able to do what they were planning.

Here's an example of something else in the camera. The 550D actually has a stereo audio chip thingy, they only put in one mic tho, with a bit of soldering one could install a second mic and get in camera stereo, but then again, who would want to when one can just by a rose stereo mic or the like.