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Uncompressed hdmi from canon 5d Mark 2???

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Robert Floutier
Uncompressed hdmi from canon 5d Mark 2???
on Oct 26, 2012 at 11:00:41 am

I am an independent film maker starting out. I have used a mark II for about 18 months and understand much of the technical side of the camera. However I have a big hole in my knowledge.

uncompressed HDMI. I understand that the camera compresses video footage in order to keep it manageable for editing on lesser powered computers, however i'd like to learn about uncompressed footage.

What do larger file sizes bring you? Am I right in saying fundimentally it will allow you to view your footage on large screens and have much less detail loss?

Also I have heard that the mark 2 cannot output a full hdmi signal? If so what exactly can it output?

still a newby. appreciating everyones help, hopefully i will be able to do the same 1 day.


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David Eaks
Re: Uncompressed hdmi from canon 5d Mark 2???
on Oct 26, 2012 at 2:32:28 pm

[Robert Floutier] " I understand that the camera compresses video footage in order to keep it manageable for editing on lesser powered computers"

Actually it just the opposite. Compressed video files from an HD camera are difficult even for decent editing systems to deal with, which is why we convert to Prores etc. The camera compresses the video so that the file size can fit on the recording media.


[Robert Floutier] "Am I right in saying fundamentally it will allow you to view your footage on large screens and have much less detail loss?"

Somewhat, but not necessarily. With good compression you might not notice much, if any, difference visually. It's just that there is less "information" in compressed video, information that is needed for green screen, grading etc. There is a lot to be learned in this area of video.


[Robert Floutier] "Also I have heard that the mark 2 cannot output a full hdmi signal? If so what exactly can it output?"

Not exactly sure of the current situation with the 5D MII but I think the problem is simply that the HDMI outputs the on-screen display, which ruins the video for most recording purposes. There may be a Magic Lantern update that fixes it though. "Uncompressed HDMI" is just that the video signal is bypassing the cameras internal compression, coming right from the sensor and out the HDMI. This "uncompressed video" coming live from the sensor is not the same as playing back a recorded clip, because the recorded clip has been compressed to fit on a tiny memory card. The live uncompressed HDMI has not yet lost the information that the compressed recording has lost. Although, the actual HDMI signal itself is not compressed.

I hope to be corrected, if anything I said is inaccurate.


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Al Bergstein
Re: Uncompressed hdmi from canon 5d Mark 2???
on Oct 26, 2012 at 4:50:19 pm

Hey Bob, as you might tell from my other post, I've also been looking carefully at the 5D Mkiii. Apparently, the Mkiii cannot do a 'clean' HDMI out at this point, and is waiting for a ROM update in April of next year for that. I believe that Magic Lantern will allow you clean HDMI out right now for your Mk ii, but don't see it listed on the ML web site as such.

Canon was quoted as saying, "When shooting video, HDMI Output makes possible the recording of high-definition uncompressed video data (YCbCr 4:2:2, 8 bit) from the EOS 5D Mark III to an external recorder via the camera's HDMI terminal. This, in turn, facilitates the editing of video data with minimal image degradation for greater on-site workflow efficiency during motion picture and video productions. Additionally, video being captured can be displayed on an external monitor, enabling real-time, on-site monitoring of high-definition video during shooting."

It's this 4:2:2 video data that is really going to improve your picture quality. But it comes at a cost in both storage and your workflow. The uncompressed files will be significantly larger. I would say that it's only for those who are doing 'theatrical' level work. I for one, have not found it worth dealing with on my documentary work, nor for my stage work. I shoot for the web or DVD. The "normal" 4:2:2 out of the Canon XF series of cameras is fine. And the new C300 is also the same.

Philip Bloom's review of the 5D Mark iii comes to the conclusion it's worth the price of updating, especially if you have the lenses to go with it. My POV is that if are thinking of doing theatrical work, wait and see what the C100 is going to be like, (still 4:2:0 but HDMI clean out) or just buy the C300 if you have the money.

Al


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Robert Floutier
Re: Uncompressed hdmi from canon 5d Mark 2???
on Oct 26, 2012 at 5:23:18 pm

David and Al, thank you.

I think I will enter some smaller online festivals before I try for theatrical releases and by that time, I may be able to upgrade to a c100 or c300.

Do you know of any good articles or forum related pages regarding 4:2:2 because much like my previous question, its a subject I have heard about briefly, but could not hold a conversation about.

For myself I am at a bit of a crossroads, because I now feel I have mastered the 5d mii and also eager to learn. Image quality is paramount to most videographers and improving my image quality inch by inch is my next step. After that it is down to my style and knowledge of film.

Have either of you ever had any troubles with magic lantern? and do you know of a website or article which talks about its features? Because whilst I enjoy making films, I do rely on my camera for part of my income.

Thanks again.

still a newby. appreciating everyones help, hopefully i will be able to do the same 1 day.


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Al Bergstein
Re: Uncompressed hdmi from canon 5d Mark 2???
on Oct 26, 2012 at 6:06:49 pm

I can't remember anymore where I did my original reading on 4:2:2 but there are some good overviews out there. Barry Green has a good overview here:
http://www.dvxuser.com/articles/colorspace/

As I have a 7D, I have not yet used ML. It's still in "beta" and having worked in software development, I know what that can mean. I intend on buying it as soon as it is considered 'shipping'.

But there are thousands of happy users of it out there on other cameras. There is a low possibility of 'bricking' your camera with it, meaning essentially making it unuseable, but I don't think that is a huge concern, or people wouldn't be using it.

Be sure to donate 'something' to their cause if you use it. It keeps the development cycle going.

Al


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Brian Crawford
Re: Uncompressed hdmi from canon 5d Mark 2???
on Apr 18, 2013 at 2:35:35 pm

So this thread is relatively old, yet still relevant, so I thought I'd add my two cents.

I'm also a 5D mk ii owner, and have been considering wether to upgrade to a large censor camcorder (like the FS100 or AF100) or whether to try and exploit the 5D's HDMI with a field record like the Ninja or DeckLink.

However, if you dig through Magic Lantern's site about HDMI output on the 5D, you'll find this little bit of important information:

"While these devices are capable of recording 1080p 422 signals, the HDMI output from the Canon HDMI is limited to 1620x1080 (3:2) while the camera is not recording. This requires the user to crop the footage from the external recorder to 1620x910 (16:9) and then resize it to either 1280x720 (79%) or 1920x1080 (119%).

When the camera is recording, HDMI output resolution is limited to only 720x480 (effective image resolution is 640x388, which represents a stretched 3:2 frame)."

You can read more here: http://magiclantern.wikia.com/wiki/HDMI_Output

Anyway - certainly makes me reconsider the whole proposition. Please keep in mind though that this information pertains to the mk ii, and I cannot speak to the quality that is sent from a mk iii.


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