Magic Lantern Forum

Developing Magic Lantern => General Development => Topic started by: hirethestache on June 04, 2013, 10:10:58 PM

Title: 5D3/2 HDMI transfer speed?
Post by: hirethestache on June 04, 2013, 10:10:58 PM
I have done quite a bit of searching, but have not found a sure-fire answer. Is it known what the transfer write speeds of the HDMI interface from the 5D3 and 5D2 are? Do they surpass the CF write speed of 163/MBs?

If there could be a possibility of spitting raw data through HDMI, I already have a team of very skilled engineers I am financing to research an HDMI interface, as well as a CF-to-SATA interface with a minimum transfer rate of 500mb/s (for future cameras).

I would really like to have an official HDMI investigation started, but I am only a designer and investor, and have zero skills in development.
Title: Re: 5D3/2 HDMI transfer speed?
Post by: g3gg0 on June 04, 2013, 11:42:36 PM
already tried, but we can not transfer custom data via HDMI without it being modified by hardware.
Title: Re: 5D3/2 HDMI transfer speed?
Post by: hirethestache on June 05, 2013, 02:16:39 AM
Is the live-view preview downsampled? 1.2.1 was a software update that increased the HDMI capabilities--my feeble mind just assumed that the same methodology could be applied to the output of the live-view feed in conjunction with the raw information.
Title: Re: 5D3/2 HDMI transfer speed?
Post by: chmee on June 06, 2013, 10:36:43 AM
the hdmi-port (v1.3) as is - is able to transport around 8GBit, so ~1GByte/second. but:

(A) the hdmiport in the body is hardwired somewhere after the digic and somekind of data-to-tv-logic.
(B) the hdmi output is logically somewhere after the jpg-process
(C) its hardly nonsense to rewire the inbuilt hdmiport, sending data over it and then hoping, on the receive-side is any equipment understanding these data (and able to handle the datarate) - you have to build it as well.
(D) receiver - i guarantee its no fieldrecorder, but a raidbased datastorage..

(so far my assumings)

by now i m more interested how to lower the amount of data without losing its benefits. for example 10bit logarithmic. so, gently saying, forget this idea.

regards chmee
Title: Re: 5D3/2 HDMI transfer speed?
Post by: rudi on June 06, 2013, 11:44:37 AM
Hey chmee and others (nice CineDNG-Converter work by the way, i was also totally braindead after trying to sort these little/big endian shifts out -for some personal tests, tell you later).

Here are some personal findings to the theme:

As far as the community knows this HDMI Chip (or a very similar) seems to be build in:

http://www.analog.com/en/audiovideo-products/analoghdmidvi-interfaces/adv7523a/products/product.html

As far as we can see that means, that the  canons seem to be  limited to HDMI-1080i-Output, and the Chip can manage to process the Data with 80MHz. So we could assume, that the max possible data-throughput via HDMI is about 80 Mhz x 16 Bit data, which could mean max 80 Mio 16 Bit values. As the Raw Data from the sensor is 14 Bit/BayerPixel we could assume, that we could transfer about 80 Mio RAW Pixels per HDMI after hiding them in normal HDMI-data some way. 1920x1080@24fps with 16 Bit/RAW-pixel would mean about 50 Mio RAW-pixels. So there seems no hope for much higher resolutions.

The Magic Lantern Team can write the RAW-pixels to the HDMI-Chip, but the output will be modified to and HDMI-compliant output in hardware, like 16.235 conversion, sharpening color space conversion etc. But it could be possible to switch off some of these features in the HDMI-Chip. But still there will be probably coming modified data out the HDMI port.

Greetings

Rudi (from slashCAM)
Title: Re: 5D3/2 HDMI transfer speed?
Post by: hirethestache on June 08, 2013, 12:11:51 AM
I like your optimism, Rudi! My engineer and I are SO close to having a working CF-to-SSD solution--but that still only offers us a max of 160+/- output from the 5D3.

After we're done with the CFSSD interface, we are still going to work on adding a HDMI input to that same interface to act as a data recorder. I only hope that there is a HDMI development to follow suit!