50/60P Versious 25/30P - AVS Forum
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post #1 of 14 Old 08-01-2013, 11:55 PM - Thread Starter
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It has been mentioned to me that the resolution of 25P may be better than 50P due to more data per frame,resolution may well be determined by the cams sensor,so what is the gain in 50/60P,it uses a lot more space on cards is harder to edit,i had to find a software that would edit 50P on my pc setup,if slow motion is its only dubious benefit my previous thoughts may well be correct.
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post #2 of 14 Old 08-02-2013, 02:57 AM
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The advantage is more fluid motion when an object is moving rapidly. With slower frame rates, especially on a monitor that doesn't extrapolate between frames, that motion appears jerky.

So, if you are shooting some sort of sport for example, or cars moving in the background, you will want to use 50/60 fps if you can. With more static shots a slower frame rate would look ok.

My understanding is that the resolution doesn't change, but higher frame rates deal with motion better while lower frame rates give you more color depth (hence fewer artifacts after editing) at the same data rate.
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post #3 of 14 Old 08-02-2013, 04:14 AM - Thread Starter
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Originally Posted by Tugela View Post

The advantage is more fluid motion when an object is moving rapidly. With slower frame rates, especially on a monitor that doesn't extrapolate between frames, that motion appears jerky.

So, if you are shooting some sort of sport for example, or cars moving in the background, you will want to use 50/60 fps if you can. With more static shots a slower frame rate would look ok.

My understanding is that the resolution doesn't change, but higher frame rates deal with motion better while lower frame rates give you more color depth (hence fewer artifacts after editing) at the same data rate.

The better color depth and fewer artifacts outway the the gains for me,plus more card space and easier editing i am going back to 25P
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post #4 of 14 Old 08-02-2013, 10:29 AM
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25p does not mean better color depth than 50p. All consumer camcorders are 4:2:0 (60Hz DV cams are 4:1:1). Even GH3 with its 72 Mbit/s mode is still 4:2:0. 50p gives higher image rate, which is - surprise! - is also a sort of a resoluiton metric, called "temporal resolution".

50p is the ultimate format as you can get 720p50 for BD, 576i25 for DVD, 576PsF25 for DVD, 1080p25 for film look, you can slow it down to to 0.5 speed without faking frames and insert into 25fps timeline. 50p gives a whole slew of opportunities that you cannot get with 25p. 50p is even better than 60p, because with 60p you cannot go down to 24p, but with 50p you can: conform to 25p and slow down 4%.

At least Digital Cinema mode is usable in its 25p guise because it is 25PsF, not a stupid 3:2 pulldown that the U.S. models have.
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post #5 of 14 Old 08-02-2013, 02:09 PM
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Ungermann, how much color information can you recover from a 4:2:0 file? Is this information limited by the 8-bit format? Is this information limited by the compression algorithm? Or both? Will converting an 8-bit video to a better format increase the color info?
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post #6 of 14 Old 08-02-2013, 02:34 PM - Thread Starter
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So 50p gives higher image rate, which is - surprise! - is also a sort of a resoluiton metric, called "temporal resolution".but not visible to the naked eye,for that you get less card space and need better pc specs and software rolleyes.gif,pal 25P seems the better option for me.
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post #7 of 14 Old 08-02-2013, 03:20 PM
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Quote:
Originally Posted by thedest View Post

Ungermann, how much color information can you recover from a 4:2:0 file? Is this information limited by the 8-bit format? Is this information limited by the compression algorithm? Or both? Will converting an 8-bit video to a better format increase the color info?
Chroma subsampling is not related to quantization bit depth (also, don't forget different gamma profiles, as 8 bits are not enough to reproduce anything similar to real-life image without gamma correction).

A great article about chroma subsampling and notation: http://dougkerr.net/pumpkin/articles/Subsampling.pdf Check wikipedia too.

HDV and AVCHD are 8-bit 4:2:0. XDCAM HD422 and XF Codec are 8-bit 4:2:2. AVC-Intra is 10-bit 4:2:2. HDV and lower-bitrate AVCHD and some XDCAM EX variants use 1440 pixels across not 1920, so they actually have even less color info per full scan line (and less luma info as well). Red is 12 or 14 bits, I don't remember, and AFAIK Red RAW does not use gamma correction because apparently they have enough bit depth to do without it.
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post #8 of 14 Old 08-02-2013, 04:25 PM
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humm... nice info

I saw in one of zacuto's shootouts someone saying that an 8-bit video has X tones of a color (eg: brown), and a 10-bit has more browns and so on

If I convert an 8-bit video to a format with more latitude, can I recover those "lost" (or hidden) informations?

another question: considering the same camera. If I record in that camera a video with 28Mbps and do the same shot with 200+Mbps, will I be able to recover more info and increase the dynamic range, even if its hidden and cranked in a bad codec (because I may be able to recover that info)?

thanks a lot for the free classes smile.gif
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post #9 of 14 Old 08-02-2013, 04:38 PM
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"I saw in one of zacuto's shootouts someone saying that an 8-bit video has X tones of a color (eg: brown), and a 10-bit has more browns and so on" - 2^8 = 256, but then in broadcast video black is not 0, it is 16. Also white is not 255, it is 235. So you have less gradations, and these are not that many. 10 bits gives 2^10 = 1024. Simple math which you can calculate, you don't need Zacuto to tell you that.

"If I convert an 8-bit video to a format with more latitude, can I recover those "lost" (or hidden) informations?" - No. You cannot get information if it is not there. But a good interpolator can smooth up rough edges and reduce banding.

"another question: considering the same camera. If I record in that camera a video with 28Mbps and do the same shot with 200+Mbps, will I be able to recover more info and increase the dynamic range, even if its hidden and cranked in a bad codec (because I may be able to recover that info)?" - Higher bitrate mainly affects tiling a.k.a. macroblocking and therefore, how much detail you see. I guess more detail may affect contrast.
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post #10 of 14 Old 08-02-2013, 07:38 PM
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Quote:
Originally Posted by Ungermann View Post

25p does not mean better color depth than 50p. All consumer camcorders are 4:2:0 (60Hz DV cams are 4:1:1). Even GH3 with its 72 Mbit/s mode is still 4:2:0. 50p gives higher image rate, which is - surprise! - is also a sort of a resoluiton metric, called "temporal resolution".

You are forgetting that local color depth is affected by compression. That is what produces the visual artifacts one tries to avoid, such as pixellation and banding. The color depth the camcorder is capable of recording is not the same as what it actually records on a specific area of the frame. A higher frame rate means more choices the encoder has to make, and the greater the probability of "wrong" places being truncated (usually areas of interest to the eye with low contrast detail).
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post #11 of 14 Old 08-02-2013, 08:08 PM
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Quote:
Originally Posted by Tugela View Post

Quote:
Originally Posted by Ungermann View Post

25p does not mean better color depth than 50p. All consumer camcorders are 4:2:0 (60Hz DV cams are 4:1:1). Even GH3 with its 72 Mbit/s mode is still 4:2:0. 50p gives higher image rate, which is - surprise! - is also a sort of a resoluiton metric, called "temporal resolution".

You are forgetting that local color depth is affected by compression. That is what produces the visual artifacts one tries to avoid, such as pixellation and banding. The color depth the camcorder is capable of recording is not the same as what it actually records on a specific area of the frame. A higher frame rate means more choices the encoder has to make, and the greater the probability of "wrong" places being truncated (usually areas of interest to the eye with low contrast detail).
Again, color depth for all consumer formats is 8-bit and chroma subsampling is 4:2:0. I don't know where did you get "local color depth".
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post #12 of 14 Old 08-02-2013, 11:55 PM - Thread Starter
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So is the answer that i should just as well use 24mbps or try Mpeg4, i can load Mpeg4 clips but only via camcorder usb connection and again see no better performance than 24Mbps.
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post #13 of 14 Old 08-03-2013, 06:44 AM
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post #14 of 14 Old 08-03-2013, 12:21 PM
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Quote:
Originally Posted by Ungermann View Post

Again, color depth for all consumer formats is 8-bit and chroma subsampling is 4:2:0. I don't know where did you get "local color depth".

It is called compression, which is what you are forgetting about. What the camera CAN record is not what it WILL record.

If bandwidth is limited compression converts similar adjacent pixel colors to the same pixel color so it will fit. That is local color depth. If you run out of bandwidth compression will remove that for you at a local level, typically in areas of low contrast detail. That is what causes the pixellation and banding you see in some footage, particularly if you edit and re-render it.

Have you never worked with bandwidth limited footage?
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