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Really confused about DSLR bitrate/quality...

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Josh Smith
Really confused about DSLR bitrate/quality...
on Nov 10, 2012 at 12:58:23 am

Hello everyone,

I am wondering if someone could please clear something up for me. I have a Canon 550D that I use to film video only (always 1080p25), and I'm wondering if I've got the settings right. Thing is, the quality of the footage is, well... rubbish. The colours aren't that vivid/sharp, and the detail/quality of the video is really quite poor. It's stuffed with artifacts and is generally just pretty grainy. I've got in on the RAW setting, although I'm not even sure that makes a difference, because I thought that was a still photo setting. But that's how I've got it. I've tried other settings and can't seem to make a difference.

Looking at the file information of the .MOV clips form the SD card, it tells me that the footage is heavily compressed with .H264 right on the camera, and I'm getting a bitrate of between 3-5Mbps. And it shows. I mean, HD YouTube clips should be at least 5-8Mbps, right? So am I really doing it right by getting sub-YouTube quality footage straight off my 550D? Comparing this to my friend's XH-A1, the raw footage from that is far superior. I understand that this is a much better camera, of course, but it makes my footage look really bad! When I look at the info of the XH-A1 footage, it's showing a bitrate of 25Mbps, so it's no surprise of course.

What confuses me even more is that I hear about the 5D and 7D being used for BROADCAST productions. If my 550D is anything to go by, the quality of the footage from DSLRs is nowhere near good enough for broadcast, surely? I thought broadcast cameras such as XDCAMs have a Mbps of 50+, so how do they get away with using DSLRs in broadcast situations?

One thing I do have a good-ish understanding of is colourspace - I understand that the 550D probably encodes in 4:2:0? I know that XDCAMs and the like have a colourspace of 4:2:2, which dramatically improves the quality of the colours. But still, why is my 550D footage so terrible? How do they use 5Ds and 7Ds for broadcast? I wouldn't have thought the footage would even meet the network requirements?

Many thanks for your help!


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Peter Burger
Re: Really confused about DSLR bitrate/quality...
on Nov 10, 2012 at 3:06:37 pm

[Josh Smith] "I've got in on the RAW setting, although I'm not even sure that makes a difference"

Setting your camera to RAW or JPEG won't affect video at all.

[Josh Smith] "Looking at the file information of the .MOV clips form the SD card, it tells me that the footage is heavily compressed with .H264 right on the camera, and I'm getting a bitrate of between 3-5Mbps."

Yes, the H.264 compression is very heavy, but the bitrate of the Canon DSLR videos is around 40 Mbps which is really quite good.
When I output for Youtube I use bitrates around 25 Mbps (H.264 compressed), not sure though, what Youtube does to the clips...

You'll definitly can get broadcast quality out of the Canons.

[Josh Smith] " I understand that the 550D probably encodes in 4:2:0? I know that XDCAMs and the like have a colourspace of 4:2:2, which dramatically improves the quality of the colours"

True. Color-subsampling is 4:2:0 which is not... well... ideal for postproduction. 4:2:2 would be much better.

[Josh Smith] "But still, why is my 550D footage so terrible? How do they use 5Ds and 7Ds for broadcast? I wouldn't have thought the footage would even meet the network requirements?"

Indeed, bitrate and color-subsampling are very important factors, but even more important (especially with heavy compression codecs) is proper exposure. Underexposed pictures will get grainy. So you'll need a lot of light and/or a fast lens.

What settings did you use (ISO, aperture, framerate, picture style, ... etc)? What lens are you using? Could you post a clip or a still and tell us which settings where used?

I shoot a lot with the 550D (T2i) and I find the quality amazing.

It's no secret, that the 550D tends to be noisy in low-light. I find everything above ISO 400 unusable.
I'm talking about the 550D WITHOUT Magic Lantern. When using the Magic Lantern "hack" you'll be able to use ISOs with multiples of 160 which are much cleaner. I'd even say ISO 640 has less noise than ISO 400 (at least with my 550D).

------------------------------------------
"Tragedy is a close-up; comedy, a long shot." - Buster Keaton

Me on Twitter (english/german)
http://twitter.com/FastFoodVideo


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Josh Smith
Re: Really confused about DSLR bitrate/quality...
on Nov 10, 2012 at 3:50:04 pm

Thanks for your reply, Peter!

I didn't think the RAW setting woud make any difference, so thanks for confirming that.

Perhaps I don't fully understand what bitrate means, then... why do people say that the 550D records in 40Mbps (I also read that the 7D records in 48Mbps), but when I look at the footage, it shows only about 3-5Mbps? How do I get clean 40Mbps footage from the camera using an SD card? It certainly does not look like 40Mbps quality when I watch it on my iMac! When I compare it to XH-A1 footage (25Mbps), or footage from an XDCAM (50Mbps), it looks far, far poorer quality. There is much more detail in the other footage, even in very good light and perfect ISO settings. So are you saying that the 550D records more Mbps than an XH-A1, and nearly as much as an XDCAM? Is that right...? Because that's not what I'm getting.

I didn't think that DSLRs could record in such high Mbps - surely that is what the bigger TV cameras are for? I would have thought that DSLR bodies just don't have enough "power" in their system to record in high Mbps.

Am I missing something here?

(Also, I don't usually upload to YouTube in more than 8Mbps for HD - see here: bit.ly/v35c5y)

Thanks again.


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Peter Burger
Re: Really confused about DSLR bitrate/quality...
on Nov 10, 2012 at 7:14:05 pm

[Josh Smith] "why do people say that the 550D records in 40Mbps (I also read that the 7D records in 48Mbps), but when I look at the footage, it shows only about 3-5Mbps?"

How do you "look at the footage"? "MediaInfo" tells me "30 - 50 mbps". And you can look up the techspecs on the Canon site too..

Maybe you confuse mbps with MB/s. mbps = MegaBits/Second, MB/s = MegaBytes/Second...

[Josh Smith] "So are you saying that the 550D records more Mbps than an XH-A1, and nearly as much as an XDCAM? Is that right...? Because that's not what I'm getting."

The 550D does about 48 mbps. The XH-A1 is an HDV camcorder, isn't it?

If so, then yes: the 550D has a higher bitrate than any HDV camcorder. HDV has a bitrate of 25mbps in MPEG2. The 550D has a bitrate of about 48mbps in H.264.

H.264 even is a far superior codec than MPEG2 plus you record in a higher bitrate, so there *has* to be a difference.

I have a Sony HDR-V1 (HDV) and if I compare the Sony-footage to the Canon-footage, I see quite a huge difference in quality on the DSLR side.

Can't compare to XDCAM though

[Josh Smith] "I didn't think that DSLRs could record in such high Mbps - surely that is what the bigger TV cameras are for? I would have thought that DSLR bodies just don't have enough "power" in their system to record in high Mbps."

Well, they do... No difference between the "smaller" Canons and the "bigger" ones like the 5DMkII (Can't speak for the 5DMkIII). We shot a couple of videos with the 7D, the 550D and the 5DMkII. There *is* a bit of a difference (mostly in low-light capacity), but not much.

[Josh Smith] "Also, I don't usually upload to YouTube in more than 8Mbps for HD - see here: bit.ly/v35c5y"

If I read the info in the link correctly, 8mbps is recommended for "standard quality 1080p" uploads, for "high quality" even 50mps is recommended, so I'm somwhere in the middle ;)

------------------------------------------
"Tragedy is a close-up; comedy, a long shot." - Buster Keaton

Me on Twitter (english/german)
http://twitter.com/FastFoodVideo


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