Canon 650D [OLD]

[nanomad]

A user made a module that downsamples the raw data on the fly from 14 to 12/10 bit so there's a bit of hope

About USB, it would probably have an impact on the CPU usage of the camera but it's worth investigating in the future.

[nanomad]

UHS-I can either support a clock of 100MHz writing 4-bits (1/2 byte) per clock = 50 MB/s or UHS104 specifies a 208MHz clock writing 4-bits per clock = 104 MB/s.  The SD controller in the T4i is a Macronix MX25L6436EM2I-10G with a clock speed of 104MHz.  The T4i will not support anything faster than 50MB/s. Slice and dice your video however you want.  That is the (theoretical maximum) hose you have to work with.

Actually, on a second inspection...that module does not look like a SD controller. It's just a 64Mb Serial flash

[En veritas]

http://www.flickr.com/photos/78309769@N08/8790349631/

dont know if this is actual write speed proof due to it being a H264 stream but quicktime reads the data rate at 64.27mbps on the file straight from the camera.

ignore the current size, thats just the size of the video in the window not the actual video size.

footage is HDR video from a high street, lots of chroma and luma variation plus switching ISO values between frames with CBR +1.4 active.

[VlastaS]

http://www.flickr.com/photos/78309769@N08/8790349631/

dont know if this is actual write speed proof due to it being a H264 stream but quicktime reads the data rate at 64.27mbps on the file straight from the camera.

ignore the current size, thats just the size of the video in the window not the actual video size.

footage is HDR video from a high street, lots of chroma and luma variation plus switching ISO values between frames with CBR +1.4 active.

That's Mb/s. It's quite different from MB/s. One byte contains eight bits so 64.27 megabits per second is not the same as 64.7 megabytes per second.
Cheers

[En veritas]

That's Mb/s. It's quite different from MB/s. One byte contains eight bits so 64.27 megabits per second is not the same as 64.7 megabytes per second.
Cheers

Sorry i wasnt clear on what i meant. I understand the difference between bits and bytes when it comes to write speed. i am now wondering if 64 megabits per second is the maximum speed supported?

[VlastaS]

No, that's just the data rate of the codec.

[En veritas]

No, that's just the data rate of the codec.

yes i realise it is the data rate of the decoded stream.

 I was just curious to know if that is the maximum data rate i will get from a H264 using ML on a 650D or if i need to increase the CBR settings or move into variable Q settings trials to get the best image quality.

thanks.

[1%]

I think you guys need to implement IPB and ALL-I/etc to squeeze the most out of this camera. The settings for all that stuff are in EOS-M (so here too)... I haven't bothered since the raw recording though. By default its like digic IV H264.

[En veritas]

all I frame recording would be most welcome to kill those annoying macroblocks.

RAW recording would also be great but to be honest just having a working pre alpha was more than i expected for the 650D with canon releasing a camera every 3 months!

[dngrhm]

Actually, on a second inspection...that module does not look like a SD controller. It's just a 64Mb Serial flash

... and that's why I'm not a HW guy   I'm still convinced 50MB/s is the max for pumping out to the SD card.  That still meets the UHS-I standard and that is what we are seeing on performance testing SD cards.

[1%]

No, you're right.. you just pulled the wrong? datasheet. Look at the datasheet the SD chip connects to as well. There is a max mhz and from lookin the firmware its SDR50/DDR50 for sure. The MHZ matches up.

[dngrhm]

Audio meter works on eos M while recording... it should work here too... but does not work at idle.

Is this currently in the M build or do you have to take out the #undef of AUDIO_METERS in features.h

[pemstudio]

I saw a version of video raw on forum. Is there anybody who can share it to me for testing? I know that it is unstable. I would like to ask about can a software destroy it?

[nanomad]

I've got weird stuff with RAW recording on the 650D, including a semi-brick of the camera with the latest source code. I wouldn't use it

[satriani]

I can confirm this. Played too much with it and thought my cam is gone 
Please be patient.

[scout72]

Few thoughts about RAW video:

1. Is it possible to use USB instead of SD card? Theoretically it is 60MB/s. Practically? And would PC or/and USB stick work?
2. One crazy thought: What about combining USB and SD card. For example odd frames would be stored on SD card and even through USB on USB stick or computer. And it would be combined in post-production similarly like HDR video.
3. Is it possible to shoot in RAW but only capture luminosity? Black & white picture would require lower bit rate.
4. Instead of using RAW would jpeg work better?

Thanks for your work. I am thankful user of pre-alpha 2.

Re: #4, what about implementing sRaw or mRaw for Raw video?

[lordgnagey]

Could we downsample the RAW to 8 - bit? Would that be too much for the CPU to handle in real time? It wouldn't be as glitzy as 10 / 12 bit... But most of us that have prior experience with canon cameras (I've been shooting DSLR since 2009 on the t2i) know that the sensor in this camera is only capable of so much. If I remember correctly the c100 shoots 8-bit hd video in avchd 4:2:0, so in theory it doesn't sound so bad. This is baring in mind the special 8.1 MP sensor on the c100.

In theory this would set raw at 8 - bit per pixel (I believe), it seems to me that would be much more likely to support (near or at) HD/2k sizes in a raw continous stream. My math figures it would be below 40 MB/s which would allow a cieling so that Global Draw can be enabled during recording. As a bonus this might offer some really high frame rates to 5D mark III RAW, and maybe open the feature up to older cameras.

I know we don't even have proof of concept for the 12 / 10 bit yet, and I know the 650d still burns strange AF artifacts into the images. So those will definitely be the first and most time consuming. But, can someone tell me if this is an option?

Maths:

1924 pixels by 820 pixels = 1577680 pixels per raw image
Which would work out to 8 - bits or 1 byte per pixel resulting in 1.5046 MB per frame or

36.2 MB/s for what could be 24 fps scaled at 1920 x 820 2.34 : 1

[Gorilla]

Could we downsample the RAW to 8 - bit? Would that be too much for the CPU to handle in real time?

I'm not too knowledgable on this stuff, but I think that would defeat much of the purpose of shooting in RAW. You might still get extra sharpness and such, but the real advantage of RAW is the extra bits. Right?

[jimmyD30]

I'm not too knowledgable on this stuff, but I think that would defeat much of the purpose of shooting in RAW. You might still get extra sharpness and such, but the real advantage of RAW is the extra bits. Right?

I believe the real advantage of RAW is increased post production capabilities. Of course the higher bit count would be more desirable, but RAW compared to compressed at any bit count gives greater control in post.

[lordgnagey]

Just based on numbers 36.2 MB/s is still way higher than any h264 compression would allow in terms of bitrate. Sharpness would not decrease dramatically as individual pixels are still being written into the raw. We might lose some dynamic range and some color depth (again I'm just theorizing here).

However, with the sensor in the t4i I feel 8-bit high res is better than 14 / 12 bit low res any day of the week. Not to mention it should cut down on the number of unusuable Magenta codec glitches that continue to appear in single frames. (some people say this is caused by a type of image buffer overrun?)

To bring back the main point, Nanomad and the rest of the ML team have some serious work ahead of them just trying to code out the af point burn in and making 650d raw video into a stable module.

[papkee]

The main reason I'm looking forward to RAW is dynamic range.

In the tests, what have you seen in terms of dynamic range? I've seen shots of the 5D3 and the range looks amazing, so how much of that trickles down to the 650d?

[midnite]

Hi,

I just installed this to my 650d but i couldn't make it to record hdr videos, is this feature disabled on alpha version?

http://ae.tutsplus.com/tutorials/production/a-simple-way-to-shoot-hdr-video-footage-using-magic-lantern/

i found this tutorial to record hdr vids, as you can see there, i need to change the firmware from noob mode to advanced mode. but it seems it is disabled on alpha right? no?

[nanomad]

That tutorial is way old. We don't have "hidden" features anymore. HDR should be in the alpha, look closer inside menus

[papkee]

Hi,

I just installed this to my 650d but i couldn't make it to record hdr videos, is this feature disabled on alpha version?

http://ae.tutsplus.com/tutorials/production/a-simple-way-to-shoot-hdr-video-footage-using-magic-lantern/

i found this tutorial to record hdr vids, as you can see there, i need to change the firmware from noob mode to advanced mode. but it seems it is disabled on alpha right? no?

It should be in the recycle bin menu under "Movie". Just press [Set] to enable/disable.

[midnite]

thanks for the answers, i just realized i need to set my iso setting manually. (it was set to auto) now i can record HDR videos. thanks all.