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View Full Version : Shoot video in 3:2 aspect ratio - use 7D's full sensor.



sbarbellalandy
02-09-2010, 10:37 AM
One of the things I liked about shooting on a camera like the DVX was that it did not shoot in 16:9 (i'm talking about without stretching the image), and it took some getting used to but after a while doing that saved me a lot of shots where my subject moved irregularly, or i liked a higher framing, etc. It's like actual 35mm film, the frame is larger than 16:9, actually about 3:2 (a fact not many people care to comment on) - just in case the boom needs to be cropped out, etc... and in post a 1:85 matte is applied. Voila!

The Canon 7d does not have this feature and shoots in 16:9. In post, when a 1:85 matte is applied, there is but a sliver that is removed - and silghtly more but still not a lot when a 2:35.1 matte is added.

My question is as follows - is there a way to get the 7D to shoot with it's full sensor: in 3:2? (that might not be the actual aspect ratio, but I mean the same full frame as the camera uses in photos)

I doubt that there is a way to disable this on the camera outside of a hack, which I don't particularly want to do, but does anyone else feel this way? Wouldn't it be better to use the whole sensor when shooting?

Thoughts? Comments? Petitions? Any help would be greatly appreciated.

ydgmdlu
03-03-2010, 01:11 PM
It's not possible, sorry. There are many reasons, one of which being that the codec is specifically designed to encode at certain resolutions.

shaocaholica
03-03-2010, 01:18 PM
H.264 is not limited to a certain set of resolutions. You can use any resolution as long as the width and height are divisible by 16. The days of having a resolution locked codec should come to an end.

ydgmdlu
03-03-2010, 01:26 PM
H.264 is not limited to a certain set of resolutions. You can use any resolution as long as the width and height are divisible by 16. The days of having a resolution locked codec should come to an end.
I wasn't talking about the H.264 spec. I was talking about the codec built into the camera, whether it's a hardware codec or a software codec.

shaocaholica
03-03-2010, 03:32 PM
I wasn't talking about the H.264 spec. I was talking about the codec built into the camera, whether it's a hardware codec or a software codec.

But the camera uses H.264? Ok, if the H.264 compression happens at the hardware level and that was designed to be locked into 1080p, 720p and VGA then yes, it would be locked. However, that would be a highly unlikely design path.

ydgmdlu
03-03-2010, 04:08 PM
However, that would be a highly unlikely design path.
How would you know that? On what basis would you presume it? Designing an encoder with as many fixed parameters as possible is simpler and more cost-effective than supporting everything that's possible. The H.264 spec includes B-frames, but none of the Canon DSLRs encode them. The 5D is getting a 24p/25p firmware update, but no 720p of any sort. If it were really as simple as changing a number, then why would Canon not enable 720p (at frame rates of 24/25/30) in this update? Why is the encoder limited to 40-45 Mbps VBR, instead of multiple CBR (or VBR) options (like the GH1 offers)?

The more variables that there are, the more code or circuitry that is necessary to make the whole system work, because the developer has to include ways of handling different input values. It's a basic fact of programming and engineering.

ydgmdlu
03-03-2010, 04:16 PM
Similarly, consider AVCHD camcorders. AVCHD is a subset of H.264, fully compliant and yet with its own specific set of acceptable values. Are all AVCHD camcorders capable of the same resolutions, frame rates, bit rates, and scanning methods (i.e. interlaced and progressive)? Can AVCHD camcorders be firmware-hacked to behave just like the Canon DSLRs' H.264 codec?

Or how about good old HDV, which is fully-compliant MPEG-2? Can HDV camcorders be hacked to encode MPEG-2 streams with arbitrary parameters?

Box
03-03-2010, 04:56 PM
It's not possible, sorry. There are many reasons, one of which being that the codec is specifically designed to encode at certain resolutions.

How would you know that? On what basis would you presume it?

ydgmdlu
03-03-2010, 07:01 PM
How would you know that? On what basis would you presume it?
I gave some of my reasons. If you would like to argue that it is possible, then please explain why and how.

ydgmdlu
03-03-2010, 07:11 PM
The thing is that live view does seem to use the whole sensor, but the recorded video doesn't. This suggests that the encoder has something to do with controlling the video resolution.

You can record the live view stream via the HDMI-out, but then it has all of those overlays on the image. With enough hacking, one probably could disable all overlays in live view. In this case, the camera still is not able to record a 3:2 (or whatever AR the sensor is) image by itself, but you'd still be using the camera to get the image. In that sense, what the OP wanted might be possible. But I still think that no amount of hacking will get the camera to encode anything other than a 16:9 HD image or 4:3 SD image. It's like asking if the GH1's codec could be improved, by firmware update alone, to use B-frames.

Box
03-03-2010, 08:33 PM
I gave some of my reasons. If you would like to argue that it is possible, then please explain why and how.

Beep beep bloop bloop vbr tgif cbr h264 bleep beep bloop. What kind of lunch do they serve in the cafeteria at the Canon corporate headquarters? Namaste.

I don't know if they could do it or not, and neither do you. I like where your head's at sbarbellalandy. It'd be nice if they could implement this.:bath: