Etiquette, expectations, entitlement...@autoexec_bin | #magiclantern | Discord | Reddit | Server issues
Started by nikfreak, January 15, 2015, 12:22:15 AM
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Quote1080p 60fps, 2K, 4K, RAW video...The best we could do was 1080p 35fps on 60D and 600D. If you request this, you are a 4K troll Custom codecsCodecs are not implemented on the general-purpose ARM processor. Only MJPEG might be technically possible, since the camera already saves JPEGs.
QuoteYour 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 DCTLets 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 -> StorageIf 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 fps3. 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.
Quote from: ShootMeAlready on March 09, 2016, 08:09:34 PMClearly IPB bit rates are less CPU than All-I. So if the existing pipe-line can handle All-I at 720p / 60 fps,then when we switch to IPB some of the cpu and pipeline is not used/free. I seem to recall IPB is about 1/3 the data as All-I.So the cpu power & pipeline has some untapped capacity in IPB.
Quote from: ShootMeAlready on March 09, 2016, 08:09:34 PMThe question becomes in 720p IPB compression, how can we trick the camera into using 1080p?Or the converse question in 1080p IPB compression, how can we trick the camera into going 60fps?
Quote from: ShootMeAlready on March 09, 2016, 08:09:34 PMThere is some potential here.
Quote from: nikfreak on March 12, 2016, 06:37:15 PMNo need to duplicate questions in 2 threads. DotTune works on 70D. Better read through the dottune thread again for instructions. Screen going black rather sounds like powersave. If you are in doubt then reset cam settings and retry.
Quote from: lozw on March 12, 2016, 06:03:51 PMAnyone got dotTune working on their 70D?Couldn't get this working on mineNightly.2016Mar08.70D111AFollowing the instructions,I focus manually in LVStart DotTune AMFA Scan.It gives a couple of messages about perfect focus and keeping the camera still.Then it shows the dotTune 'range' across the top of the menu screen.But then the screen goes blank.I leave it for 10+ minutes, and it is still blank and the camera controls are inoperative.So I have to switch off.
Quote from: swardet on March 15, 2016, 09:48:23 PM@xsghostanyway, i think ml is amazing and still contend canon should buy the guys and turn this into a full fledged officially supported product offering to really exploit the canon hw.
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