Ken Burkstrum
Stunt Coordinator
- Joined
- Dec 19, 2003
- Messages
- 149
I fit it all in the title.
300Mbps sounds like a pixel or clock rate for a graphics chip
I'm confused, it doesn't look like any of your responses are directed towards my questions?
No I'm not getting 300Mbps confused, that's the bitrate it records at. Takes up about 2GB for a minute of footage.
In fact, what does uncompressed video mean? I'm not sure if there is video equivalent to PCM of audio.
Essentially. But there are many different kinds of uncompressed video just as there are many different kinds compressed. Uncompressed just means that it hasn't been MPEG2 or 4(usually) compressed. It could be any bit-depth, linear or non-linear,4:4:4 or subsampled, different framerates, etc etc.
That's very high, you're probably captured pretty high resolution, but into what file format? Because that's pretty high, HD is about 10gb/hour usually, that's MPEG2.
From what I've seen, thats alot lower than professionals use at 1280x720. Though I yet to get information on it, the most I've heard is somebody with 720p recordings at 500Mbps and 1080p at 1.2Gbps. AVI by the way.
From what I've seen, thats alot lower than professionals use
Yes, the 10gb/hr was for compressed OTA HD. Uncompressed stuff, or even subsampled but uncompressed D5 is going to be a great deal more than that.
I thought until recently that all DVDs were 720x480, but I seen alot of articles saying it's 640x480
Almost all DVDs are 720. There are two other allowed widths, 704 and 352. 640 is not one of them; those articles are wrong, oversimplifying, or talking about something else. You might end up watching a DVD at 640x480 because the aspect ratio is 4:3, and 640x480 is 4:3, while 720x480 is not. In fact, 720x480 is not 16:9 either. The key here is that DVD pixels are not square. The same grid of pixels can represent either a 4:3 or 16:9 picture. In either case, the pixels must be stretched, either taller or wider, and remapped so you get the right image on a display, almost all of which are square-pixel. (The notable exception being tube TVs and monitors, which have lines, but not pixels, per se.)
So for 4:3, you can take 720x480 and squeeze it slightly to 640x480. Or make it a little taller to 720x540. If you play it full-screen and your screen is 4:3, then it works itself out.
I don't know what kind of technology pro filmmakers with digital cameras like Lucas use, but I'm sure they record at the top of the latter so you could say I'm asking what is the bitrate those ridiculously expensive 1080p cameras they use record at? Or does lucas record even higher...2k? 4k?
Lucas uses the Sony Cinealta camera system that records to HD-CAM tape. In Clones, using the first-gen Cinealta, the compressor in the camera is a two-stage compressor.
Stage 1: resample the 1920x1035 image to 1440x1035.
Stage 2: MPEG-II I-frame only compress the image to tape. Somewhere in the neighborhood of 300MBits/second, I believe.
The Thompson/Philips VIPER camera, on the other hand, is a completely different animal, recording roughly 4k X 2k, uncompressed, to either a very large block of RAM, or to an external RAID-5 hard-drive box.
VIPER has another tremendous advantage in that it's something like 12bits/pixel, and apart from a minimal pixel-noise / pattern noise removal, it does no image processing, whatsoever, recording the data in telecine formats, suitable for a direct suck into a daVinci color tweaking box.
Uncompressed HD moves a whole lot of bits around; the 1.6GB/s for uncompressed HD isn't far off, but in my experience, most are, in fact, 8bit/channel.
Leo Kerr
I know you wrote this YEARS ago, but your info was soooo wrong.. even at the time.Steve Berger said:Well, let's see here. This is going to sound poor, but 480p and 1080p are monitor resolutions not video specifications while 720p could be either a broadcast spec or a monitor resolution. 480i, 720p, and 1080i are broadcast specs and are variable bitrate and are compressed by definition. The numbers refer to vertical resolution and don't even define the horizontal spec. 480i can be 704x480, 720x480, 352x480, 540x480, etc.What exactly are you trying to find the bitrate for? Camcorder capture, TV broadcast, DVDs?
Broadcast does not count VOD.David Dutton_286985 said:I know you wrote this YEARS ago, but your info was soooo wrong.. even at the time.
HD resolutions have always been: 480p, 720p, 1080i, and 1080p, and ALL are broadcast specs as stations, cable TV, and Sat TV "broacast" many things in 1080p. It just was not used for the longest time to the enormous bandwidth it took (and storage space) to run 24-30 FPS with a compression that didn't make things look lossy