Dear readers!
You can help Vitaly Kiselev to collect some money for an appropriate and independent NAB coverage: http://www.personal-view.com/talks/discussion/2466/nab-2012.
As you may know the biggest surprise for the m43 system could be the new Super 35mm Micro Four Thirds camcorder. It may will anticipate some of the new video features of the GH3 too!
20 Responses
Wtf is NAB? New American Bible? Nerf Arena Blast?
I have a question for all of our video enthusiasts who strive for ever higher bit-rates through hacked cameras, and it’s really for my own education: What’s the point?
Say you record your video at 30Mb/s (I don’t know if this is even considered high enough). But at some point you have to show your work to others. Unless you record a blue-ray disk (uncommon), the other solutions are much more limited. DVD is only SD, and with 4.7GB you can only store mere minutes (20 minutes at 30Mb/s) of 1080p with high bit rate on it. Streaming options are all limited, whether you’re looking at Vimeo (5MB/s), youtube HD (3.5MB/s) or others all compress your video.
So, why bother going after ever more bit rates and less compression?
I was genuinely asking myself this question last week while multicam-filming an event. Given that our goal was to share the video online as high def, we decided to shoot at 720p and not worry about bit rates. But I wonder what you guys do with all the crazy bitrates that Vitaly’s hacks brings to the table.
I dont think the high,higher, highest bitrate result in better visual quality when playback directly, but its really important for the editing stage and re-encoding to the final product, as your headroom is better.
@Reza, the point is that the camera’s compression encoder has to work in real time with limited power, and so is nowhere near as efficient as a high-end offline encoder that can take seconds to minutes for each individual frame. So a higher bitrate compensates for that. The difference is highly visible.
Note that the most popular 24H hack bitrates start at 44mbps and go up well over 100mbps (I think I even saw over 200 mbps once, but I don’t use those ‘intra’ type patches, I average about 50mbps with I-frames using up to 100).
Thanks gl, I have not experienced it. So your saying that in practice, streaming two videos from vimeo, one from an unhacked GH2 and one from a hacked GH2, there is visible difference and a clear advantage? Even though vimeo’s bitrate is about 5Mb/s?
High bit-rate video recording is an ACQUISITION format, NOT a DELIVERY format. When you are capturing an event you want as much image information recorded as possible, which will then be edited in post production, with the final DELIVERY format exported from your video project.
Virtually every film / video you’ve ever watched was produced this way…
I admit that I’m a newbie to high def video, but if the final delivery method masks all the high def niceness, why bother? It takes much much more storage space and you need very powerful workstations to work with them (my dual core macbook pro with 6GB RAM totally cringes even for 720p video in final cut pro). You go through all this trouble, and eventually your content delivery method will ruin it anyway.
@ Reza, as I said, the encoding quality of a slow offline encoder (like from an NLE) is much better for a given bitrate, that’s why you may want to capture at a much higher rate to preserve as much detail and flexibility as possible.
As was said, that’s even more important if you do colour grading or denoising later – for example, the camera will throw out shadow detail early because it’s not so visible. But if you shoot to preserve highlights, you want to lighten the image in post – if the shadow detail was already thrown out, it won’t look good lightened. The camera will also smear out fine grain at lower bitrates – smeared grain is much harder to remove than the original fine grain. Then there are high detail shots and/or high motion (running water or fine foliage are good stress tests) which will look blocky and smeared with low bitrates.
In the end it depends what you shoot, how you process it and where it’ll end up. If you’re happy with the stock image that’s fine and you’ll save a lot disk space.
It is the same reason why people shoot RAW instead of jpeg, more flexibility to do what you want with it.
@Reza… in photographic terms is the same as saying one can take professional photos on a point’n’shoot as the final usage will be internet.
But the thing is that for photographs you have other viable means of delivery, super large prints, books, magazines, high res monitors, etc.
But for video there is no other feasible means of delivery.
If your camera cannot capture fine details, just imagine how will be the output?
The more cleaner you acquire the image, more cleaner it will be when recompressed. If your captured footage is smeared or have compression blocks, they will appear even worse when recompressed for output. So the principle is the same as photography. But we are talking about MB per second not per inch. Today I deliver my videos (captured at 42 or 88 mbps) at 5 or 10mbps and they look amazing. Very different from GH1 days (before tester13) when the maximum bitrate was 17. Take some test/comparison videos on the web and you’ll see the difference. 😉
I see your point and I concur.
But this few percentages of quality improvement (10%, 20%? It’s subjective and can’t be more than this) doesn’t come at a cheap price. 3 to 4 times larger files, which means more storage, more RAM and beefier CPUs required to process them.
Those high bit rates really help when you are shooting in very low light – EOSHD had posted some work a few months back that is quite illuminating (no pun intended!!).
Panasonic owes Vitaly a first-class trip to NAB (at least), but then he couldn’t be independent. So, yes we should stump up to help him. He is the one, together with Andrew Reid, who really put the the GH1 and GH2 on the videography map.
Panasonic has approved VK’s work:
http://www.eoshd.com/content/6810/panasonic-talk-gh2-hack-committed-to-video-on-gh3#c2
What on earth is NAB? I thought it must be National Australia Bank. they get far more than their share of anyones money but its just the sort of stunt a bank would pull.
Who or what is NAB? Just give generously. It must be a Republican fund raiser if its so secret.
Please have the decency to explain what is the subject of the begging request.
NAB: When you know what we are talking about then you will KNOW. Until then you will just be another outsider looking in…wanting in…trying deperately to get in. TFB for you.
you guys must be kidding… anyway.. here it goes:
National Association of Broadcasters
http://www.nabshow.com/2012/about/about_nab.asp
Are these russians, chinese, german, japanese or what?
35mm Micro Four Þirds makes absolutely no sense. Four Þirds is ðe sensor size (diameter in inches), as Olympus has stated.