Question re bit rates and image quality - AVS Forum
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post #1 of 7 Old 01-07-2012, 01:13 PM - Thread Starter
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This is going to be a real rookie question but bear with me. I've been playing with the various hacks and patches for my Panasonic GH2 camera, some of which enable bit rates as high as 176 mbps.

The thing is, I'm not at all sure what this really accomplishes. It hasn't reduced the noise on footage shot in low-light conditions (or with high ISO speeds). It doesn't seem to expand the color palette, and I can't see how it enables anything when I do color correction.

But every time I read reports on the use of these higher bitrates, people insist that the image looks more film-like.

Is there a good FAQ that explains, with videos or examples, what higher bit rates accomplish, and how I can exploit them? Or am I eating up storage space for no real gain?
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post #2 of 7 Old 01-07-2012, 01:23 PM
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Make sure you are using a good Class 10 memory card too.

Tony
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post #3 of 7 Old 01-07-2012, 02:04 PM
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Quote:
Originally Posted by BrianSiano3 View Post

This is going to be a real rookie question but bear with me. I've been playing with the various hacks and patches for my Panasonic GH2 camera, some of which enable bit rates as high as 176 mbps.

The thing is, I'm not at all sure what this really accomplishes. It hasn't reduced the noise on footage shot in low-light conditions (or with high ISO speeds). It doesn't seem to expand the color palette, and I can't see how it enables anything when I do color correction.

But every time I read reports on the use of these higher bitrates, people insist that the image looks more film-like.

Is there a good FAQ that explains, with videos or examples, what higher bit rates accomplish, and how I can exploit them? Or am I eating up storage space for no real gain?

A higher bitrate will usually improve the quality of the video when there is a constant change between one frame and the next. For example, when you see a HD movie on TV and there is a fade to or from black, you often see pixellation ... the image becomes a bunch of squares, instead of a smooth image. The bitrate is too low.

Are you sure the bitrate you are talking about is 176mbps? If you divide by 8, you get 22 MBps. That is lower than regular AVCHD 108060P which is 28MBps.
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post #4 of 7 Old 01-07-2012, 07:08 PM
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Quote:
Originally Posted by W Jones View Post

Are you sure the bitrate you are talking about is 176mbps?

No, he is talking about 176 Mbps.
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Originally Posted by W Jones View Post

If you divide by 8, you get 22 MBps. That is lower than regular AVCHD 108060P which is 28MBps.

AVCHD 1080p60 is 28 Mbps.

Brian, all higher bitrate does is it reduces macroblocking or "tiling" artifacting and allows more details to be seen in a high-detail scene. It does not improve sensitivity or color.
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post #5 of 7 Old 01-08-2012, 06:05 AM
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[quote=Ungermann;21457918]No, he is talking about 176 Mbps.
AVCHD 1080p60 is 28 Mbps.

Ooops ... got my b's and B's crossed!!!
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post #6 of 7 Old 01-08-2012, 11:57 AM - Thread Starter
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Quote:
Originally Posted by Ungermann View Post

No, he is talking about 176 Mbps.
AVCHD 1080p60 is 28 Mbps.

Brian, all higher bitrate does is it reduces macroblocking or "tiling" artifacting and allows more details to be seen in a high-detail scene. It does not improve sensitivity or color.

Thanks. That explains it perfectly.

This kind of indicates that maybe I didn't need to buy a GH2. My normal camcorder's a Panasonic TM700, which shoots at 28 mbps, can do 24fps, 30fps, and 60fps at full hi-def, and looks gorgeous.

A GH2, using the latest firmware, does 24 mbps, and can't do 60fps at full hi-def. A hacked GH2 uses the older firmware, which is limited to only 24 fps at full hi-def. It appears that the only advantage to a GH2 is the ability to change lenses.
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post #7 of 7 Old 01-09-2012, 09:47 AM
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Quote:
Originally Posted by BrianSiano3 View Post

It appears that the only advantage to a GH2 is the ability to change lenses.

And this is the main trait people buy it for.
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