Author Topic: Half bitrate in h264 to enable 1080p@60fps or higher  (Read 15360 times)

TomasMascinskas

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Half bitrate in h264 to enable 1080p@60fps or higher
« on: April 22, 2014, 06:28:41 AM »
Hello, yes i asume most of you will say "no it wont work" (as i have read countless times) but could someone answer as to WHY, as i never read a proper answer

Heres my idea, since recording is all about data rates, how about we use the h264.ini to reduce data rate to say half or greater than half, say 40mbps, which is possible and i already done it, go on video mode, set resolution to 1080p, and FPS override, to 60, and theoretically it should be able to go even higher, but why wont the actual FPS go above 35, the only way i can do it is if i set the resolution through canon menus, 720p@60 fps, now i can override to 65, but how can we override the resolution now (like in camera raw)


TomasMascinskas

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Re: Half bitrate in h264 to enable 1080p@60fps or higher
« Reply #2 on: April 22, 2014, 10:04:36 AM »
great explanation...useless....

cannot be done...why, theoretically it makes sence and should be able to be done, i only ever read that the reason it is not able is due to the data rate at high bitrates, so if we reduce them then we can boost the fps...instead of calling people trolls and shit how about you explain why it cannot be done

TomasMascinskas

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Re: Half bitrate in h264 to enable 1080p@60fps or higher
« Reply #3 on: April 22, 2014, 11:50:49 PM »
no one? no one can at least give a reason?

dmilligan

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Re: Half bitrate in h264 to enable 1080p@60fps or higher
« Reply #4 on: April 23, 2014, 01:43:06 AM »
I suppose nobody wants to feed the trolls. No one is going to bother explaining it to you with an attitude like that.

nick.p

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Re: Half bitrate in h264 to enable 1080p@60fps or higher
« Reply #5 on: April 23, 2014, 01:45:59 AM »
It isn't about data rate, it's about sensor limitation. The fps override only works up to about 36fps at 1080p and obviously 60 when it switches to 720p mode. You can get higher resolution in raw at 60fps but it will be squished.

Audionut

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Re: Half bitrate in h264 to enable 1080p@60fps or higher
« Reply #6 on: April 23, 2014, 02:39:24 AM »
instead of calling people trolls and shit how about you explain why it cannot be done

There's a bunch of little worker men that pick the frames off the sensor, and carry it to the H.264 encoder.  With smaller sized frames, they can carry 60 of those suckers to the encoder, in 1 second.

However, due to constant bombardment from trolls, and losers, they simply don't have the strength to carry any more then 36 full hd frames, in a single second.

Every time a poster uses his 1st post, to ask a troll question, 1 of them dies.

TomasMascinskas

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Re: Half bitrate in h264 to enable 1080p@60fps or higher
« Reply #7 on: April 23, 2014, 12:55:34 PM »
There's a bunch of little worker men that pick the frames off the sensor, and carry it to the H.264 encoder.  With smaller sized frames, they can carry 60 of those suckers to the encoder, in 1 second.

However, due to constant bombardment from trolls, and losers, they simply don't have the strength to carry any more then 36 full hd frames, in a single second.

Every time a poster uses his 1st post, to ask a troll question, 1 of them dies.
you must feel so big right now

It isn't about data rate, it's about sensor limitation. The fps override only works up to about 36fps at 1080p and obviously 60 when it switches to 720p mode. You can get higher resolution in raw at 60fps but it will be squished.
thanks

Audionut

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Re: Half bitrate in h264 to enable 1080p@60fps or higher
« Reply #8 on: April 26, 2014, 04:07:04 AM »
No sense of humor hey!

TomasMascinskas

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Re: Half bitrate in h264 to enable 1080p@60fps or higher
« Reply #9 on: April 26, 2014, 08:49:16 AM »
not when youre bein a prick

Audionut

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Re: Half bitrate in h264 to enable 1080p@60fps or higher
« Reply #10 on: April 26, 2014, 11:15:54 AM »
Just a little reminder, that you sir, posted the troll question, despite it clearly being labeled a troll question in the FAQ, and clearly listed as a feature request, that is not possible.

nick.p

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Re: Half bitrate in h264 to enable 1080p@60fps or higher
« Reply #11 on: April 26, 2014, 02:40:07 PM »

No sense of humor hey!
Tbh I preferred your explanation. You said pretty much the same thing [emoji12].

TomasMascinskas

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Re: Half bitrate in h264 to enable 1080p@60fps or higher
« Reply #12 on: May 02, 2014, 07:58:40 PM »
Just a little reminder, that you sir, posted the troll question, despite it clearly being labeled a troll question in the FAQ, and clearly listed as a feature request, that is not possible.
it wasnt a feature request, it was a question of why it is not possible, as you all troll around how it aint possible but not give reasons (not any that ive found at least) least you couldve done was link to an explanation why it cant be done, (the only thing people stated was data rate limitations, which i clearly stated could be countered if we adjust the bitrate) rather than an insult which makes you look so far up your ass, enjoy your scent

dmilligan

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Re: Half bitrate in h264 to enable 1080p@60fps or higher
« Reply #13 on: May 02, 2014, 11:57:05 PM »
it wasnt a feature request, it was a question of why it is not possible, as you all troll around how it aint possible but not give reasons (not any that ive found at least) least you couldve done was link to an explanation why it cant be done, (the only thing people stated was data rate limitations, which i clearly stated could be countered if we adjust the bitrate) rather than an insult which makes you look so far up your ass, enjoy your scent

http://www.catb.org/~esr/faqs/smart-questions.html#not_losing
Quote
Exaggeratedly “friendly” (in that fashion) or useful: Pick one.

Remember: When that hacker tells you that you've screwed up, and (no matter how gruffly) tells you not to do it again, he's acting out of concern for (1) you and (2) his community. It would be much easier for him to ignore you and filter you out of his life. If you can't manage to be grateful, at least have a little dignity, don't whine, and don't expect to be treated like a fragile doll just because you're a newcomer with a theatrically hypersensitive soul and delusions of entitlement.

You really should read this entire article before posting anything else on this forum, but I have quoted the important/relevant parts. Personally, I think your attitude and words deserves you being banned from this forum.

Your logic as to why simply lowering the "bitrate" should allow "higher resolution" recording is very flawed. First of all from an information theoretical standpoint you're not actually recording or capturing more data or information, so even though it might be "1080p" there's not any more amount of information being recorded, which means there is very likely not much (or any) more perceived detail that will be captured in the footage.

Your question really boils down to this:
"Why can't I capture more information, by throwing away information?"

Now from a more practical standpoint:
Compression (what you refer to as "lowering the bitrate") is a difficult, computationally intensive task (it's also impossible). It is not a magical process where you throw some data in and it comes out smaller. The only way to get enough of an effective compression ratio for the incredibly huge size of a video data stream, is to just throw away some of it. The goal here being to throw out the least important information, but we are throwing away information nonetheless. The better an algorithm is at throwing away data (i.e. the better it is at figuring out what data is unimportant), typically the more complex it is. There are very easy ways to throw away data, such as reducing the resolution and line skipping, and there are very hard ways of throwing away data such as DCT

Lets now consider (a very oversimplified) pipeline that a video stream goes through in the camera:
Sensor -> Raw Data -> Image Processing (demosaic, wb, pic style, curves, etc.) -> H.264 Encoder -> Storage

When you talk of "bitrate" you are only talking about the bitrate at the very last step of this pipeline, the bitrate out of the encoder to the storage media. There are many other steps prior to this to consider. If you want a 1080p stream out of the encoder, you also need that 1080p stream to make it's way through the rest of that pipeline (at 60fps). That's where the limitation is, in fact there are probably many, I'll just go over some of the possible ones:
1. The H.264 encoder, can't handle 1080p of video data coming into it at 60 fps (remember it has to do something very complex and computationally intensive with the data and then spit out that result very quickly)
2. The image processing electronics can't handle 1080p of raw data at 60 fps
3. The internal buses that move the raw data from the sensor to the image processors can't handle that much data (1920*1080*14bit*60fps = 1.7 Gigabits per second)
4. The sensor itself isn't fast enough to sample 1080 lines at 60 fps (it takes some finite amount of time to read out each line, and they are read one by one)

I'm not saying that all of those are true, but at least one or more of them are, and that's why 60p mode is a lower resolution. Overcoming any of these obstacles is possible, but it would require more transistors (i.e. faster, more complicated electronics), which would make the camera more expensive. So without more expensive internal electronics, the only way to get enough "compression" to be able to even get our video data to the encoder, is to "compress" the data starting at the sensor itself, and what's the only way to do that? line skipping and reducing the resolution -> basically don't read in as many pixels.

This is actually pretty close to what audionut summed up with his analogy:
Quote
There's a bunch of little worker men that pick the frames off the sensor, and carry it to the H.264 encoder.  With smaller sized frames, they can carry 60 of those suckers to the encoder, in 1 second.
except that after that he got sarcastic, and then you probably just read the whole thing as sarcasm, and missed the fact that this was actually an explanation and answer to your question (in sarcastic analogy form).

I hope having answered your question that you will stop being rude and show some respect to the people who have done a tremendous amount of work creating and maintaining this project and website for free at no cost at all whatsoever to you. Even if you feel like they were being 'mean' to you.