WWDC2004 Session 701

Transcript

Kind: captions Language: en good morning and welcome to session 701 an introduction to digital media my name is Stephen tell and I'm a product manager on the QuickTime product marketing team and we thought this would be a great way to sort of kick off the entire quick time and digital media track by having sort of an intro course that explains you know just about everything you need to know about digital media from be interlacing 23 to pull downs everything you need to do to take that tape content you have and digitize it and make it look really good and so we have a special guest today we have hege Van Dyke from discrete who knows just about everything about quicktime he's even an old quicktime guy from apple and i'm here will be able to take you guys through for about an hour okay great thank you hi everybody first thing I'd like to say is thank you all for coming appreciate coming down here and talking about one of my favorite subjects which is digital media and also thanks to the QuickTime team for allowing me the opportunity to speak so let's get right into it if we can switch to the machine please i want to talk a little bit about what we're doing here today get this started okay so what I want to talk about today sort of digital media basics real simple stuff is how do we go from this which is our camera you know taking pictures of stuff very you know and I well what I will say used to be analog format but you know capturing pictures and assembling them putting them together in very creative ways this is what a lot of you are specialists at is really in producing this media so that's the next real level about it and then ultimately how do we get that what do we do with it and where's it going creasing lean more and more I could play the video to catch up here but we're starting to see that we need to take our media you know they used to say that editing touches every frame well now encoding really touches every frame and your media needs to be distributed in a variety of way so how do we sort of sort out all of the issues and logistics with our media as we take it from the camera where we collect those images sometimes in random haphazard any sort of format way produce them in exciting ways using great creative tools like this and ultimately get them down into formats that we might have in our pocket anytime anywhere that's the basic premise of my discussion today and again hopefully we'll have some fun and we will take questions at the end of people are interested we'll have some time for that as well so okay I'd like to switch to the slides please and we find my little switcher here okay we can that we've done that we've done that and now we're here okay so capture create output capture management deliver produced deliver how many folks have been to a trade show and seen these words somewhere in the last 10 15 18 years oftentimes them when we go to shows we see words like this on big banners above the convention center drawing us all in what does all this mean these are really terms that are used to describe the media workflow so in order what I'm trying to do today is give us a language that we can use to discuss digital media and hopefully that some of these basics will help bring value to you as you attend some of the other sessions here at WWDC 04 so again having these sort of catch phrases capture create output their stages in the production workflow we use these terms to describe that what I'm going to be doing is just using that as a frame of reference for our discussion today and kind of breaking up the media production process into those three categories capture creation and outputs and just to kind of screw things up a little bit i'm going to start in the middle with the create parts so create how do we create media well we're already on the desktop in the center thing and the way that we create media is using the very powerful QuickTime format so what is quicktime there's obviously one of the one of the reasons why I took this talk I'll have to admit this is that how often have you been on the receiving end or been the customer who said you know what kind of content are you using and you either said or heard I have a quick time okay some of you've got to have heard that before well that sort of the things it's like I'm speaking here in the United States there's not quite enough information in the QuickTime quicktime is so much more than that that again having other terms or a little deeper understanding of what it is will help us with this discussion so what is quicktime quicktime is system software so it's a core set of services that allow applications to treat media in a consistent fashion okay quicktime is a time-based a universal time base for multiple multiple synchronous event okay so what that means is that my computer over here I can play a movie my computer over there I can play a movie that movie has audio and video maybe few other kinds of tracks associated with it but they play back and think and then I can play them in different places now that's kind of a minor point is that we all take for granted but at one time we had a real time hard time making things synchronized up the fact that quicktime sort of handles this is a master for a time-based is again something that we might take for granted a little bit but the one that we really want to talk about today the thing that we're all focused on and the element that we all deal with is the QuickTime file format that's really again what we're talking about today so a QuickTime movie as it's known is a container for your media that's the most important thing to remember is that again quick time is the services and this timing references but it's a container for media and what I mean by that is it's a rapper that lets your video frame move through the production process and sometimes it's transcoded but that's the central ideas quicktime is a container it's not a codec in and of itself it has codecs and we'll get to that in just a second rather it's a container that wraps around your media and kind of protect it as it goes and is used by different applications in different ways it is traffic so again quicktime is a container of multiple tracks we're all familiar with an audio and video track the QuickTime has many other exciting traffic types including MIDI tracks texture text tracks sprite tracks we're always trying to get people to use these other track types because again quicktime is such a technically robust and truthful foundation for media we have all these track types so we're just not used to using them so it's always good to be aware of that and again obviously it's identified by the dot move file extension we're all used to what movies are let's talk about this a little bit what is a QuickTime movie I realize this is really obvious stuff but again it's good that we all sort of repeat it has the same perspective on it so video is framed sighs how tall and how wide it is that the actual frame is the reference there okay it's the frame rate how many frames are repeated one after another it's a codec or a compressor decompressor we'll talk about in a second and all that turns data rate so let's talk about these things first of all frame size measured in high spy with okay so DV the frame size here that I started with is 720 x 480 so that's pretty big size I think the resolution I'm here is 1024 x 768 pixel size okay a computer screen is made up of pixels those are called pixel elements that's what that short for a pixel so a computer display shows video by turning on basically a pixel and what they uses there's a value so already with digital video we have a resolution component how many colors do I see if we had a black-and-white monitor with the pixel on it pixel has two states that's white or black offer on and get a black and white image with a single pixel now if I take that fixed line I make it eight bit I multiply it get an 8-bit words that I'm using for that one pixel for a single color I get 256 shades of gray for that one color and color is made up on computer of red green and blue so we add those three colors together at 256 levels of gray for each of them put it all together and we get a few million colors that we're used to in our display okay but the main thing to realize is that again computer's display in pixels so the 720 x 480 that's the measurement that we're talking about then also switching to the audio here audio has the same thing audio has a sample size so much like the pixels at eight bit pixel that I just talked about which is determining the video resolution audio also has a sample size and that determines the dynamics for audio video quality is the difference in loud and softness and that again is controlled by your sample rate that should have been first so sample size rather so what I'm talking about is 16-bit audio 8-bit audio determining that dynamic there and then sample rate or frame rate a picture so we have a single frame and the movie is made up of multiple frames that playback in order ok and those frames playback at a specific rate so as pictures repeat again you get frame rate we have some common frame rates that the video works at my video camera here is ntsc that shoots at 29.97 or 30 frames per second in Europe they have a different electrical standard which relates to a different video standard in the video over there moves at 25 frames per second to get that tendon camera but what we're talking about right now as a container is just that video has a ray so these these repeat after each other in a certain rate okay so the last thing is we have our here we have a codec so it's interesting a codec is a concept that quicktime brought us it means a compressor decompressor okay before when we'd have a video frame we'd have to do with it its uncompressed form so if i just take a picture that picture is about a meg or the size of an old floppy disk it's going to bring a floppy disk today but i realized some of us wouldn't know what to do with it so i didn't bother but anyway floppy disk is one meg so at uncompressed video 720 x 480 one meg if i run that at 30 frames per second that 30 Meg's a second okay so that's starting to be a large amount of data now quicktime introduced this revolutionary concept when it came out 1992 called a codec or compressor decompressor what what a codex does for you is it take that data and shrinks it down often 10 times that original five it also decompresses it but because that codec is real time or you don't notice that it's there then if you store your media in a particular codec it essentially is ten times smaller now ok now we always have a trade-off with using codecs the trade-off is image quality we want to preserve image quality and so for that reason there's really two types of codecs two general categories for codecs and how they're used one of those is for the production of media high data rate codecs where I want to take high-quality images and combine them together what I want to do is use a high data rate codec for that then there's distribution where I want to take my media and I want to play it in as many places I as I can and get that media exposure those are distribution codex so there's two different times and again the beauty of QuickTime is quick time allows you to convert between those codecs very easily and efficiency efficiently because again it's all within the QuickTime architects doesn't let you to do that so the last thing about codec is again data rate or video size which is analogous to video quality again the amount of data that we can allocate for particularly for a particular movie would be considered its data rate that's measured by per second so data rates are usually talked about in megabytes per second for production or megabits per second much smaller unit when we're talking about distribution and again with audio so audio has a similar set of attributes again sample size determines its resolution sample rate really determined how sounds and the data rate is very much tied into that we use less codex it's really less codecs for audio do some more the Codex and audio either uncompressed for production then we have distribution codecs for audio all right now what I'd like to do i believe is show you just a quick demonstration of what i mean they're going to hide this and bring that in question so you'll have to excuse me because my little frame count got off there a little bit but just to demonstrate this a little bit so if I step through my movie here up there I got it back so what I'm doing is I'm just stepping through my movie obviously okay here so we have frames over time what that's doing is causing motion to happen so I'm now on frame 16 now if I take this movie and go here hoping to jump straight to perspective you but if I take this and then I pull out and I look to the side of it you'll see that I have a series of frames over time there so again let me go ahead now and play this just show you that and you have a series of movie so still image frame determine your frame rate and then over time again multiple frames so this is going to turn for us and show us that we have multiple frames so that's the basics of a movie again frame size frame rates kodak or format and data rain so ones do is bring up to stop this hi there what I want to do is just quickly bring up quick time and if i go to export this as though i have quicktime pro let's just take a look at the Codex available to us inside quick time so here i'm exporting inside quicktime pro i have video and audio settings and if i bring up the quick the standard compression dialogue to see that inside here quicktime has a lot of different codecs associated with them and so what are all of these things well these codecs are different ways of compressing media for different purposes so for instance if i'm doing DV i can select DB pro or dvd BBC pro ntsc that's a DV codec two runs at three point five megabytes per second to production kodak so i could take my media preserve the quality assemble it what's really important about production codex is often there what we say a fully kia they're all I frame or they're fully editable so as we start to get into distribution codecs what we do is we start to pull tricks that manipulate the image resolution and all the data isn't necessarily there in a codec that is used for distribution for production codecs what we do is usually try and preserve all of the image quality called an iframe and again iframe formats are what are used for production so again jpg or motion jpeg is a real popular format for production because every frame is fully editable and as we get into DV DV is a slightly compressed format but again it's always editable other choices that you see inside here I do have component video so again production codex i also have a few other ones in here i have mpeg-4 video and also have sorensen video so these are other codecs that are used for distribution again much lower data rate codex the two types of codex okay I think we can switch back to the other machine a please okay so that starts to get us into the create part of it how we create stuff again QuickTime movies now let's go back out into the real world and talk about how we capture stuff and the format's that we deal with when capturing video so i have a DV camera it shoots at 720 x 480 again if this was a pal camera it's also shoot set again 30 frames per second you've heard the term SD or standard resolution standard def standard definition what that means is that it's a four by three aspect ratio very common standard definition and again the size of that is 720 x 480 you can think of SD is like our television again our television is a 4 by 3 aspect ratio 640 by 480 the reason why this is 720 x 480 is because the pixels are not quite square again now i'm on the edge of going less than a little more than video basic so i'm going to stay a little bit away from pixel sizes but again just realize that you have SD 720 x 480 that's the size that we're used to now there's a new frame rate in town and there's been a lot of buzz over a format called HDTV everyone says you know come in come in soon HDTV so HDTV is a much larger size it's taking our SD sigh 720 x 480 and basically multiplying it by 4 so there's a variety of HD sizes the two main ones that were concerned about are the one called 720 which is 1280 by 720 in size and then 1080 which is again a huge frame which is 1920 x 1080 so a huge video frame now it's also interested about HD is that it's also higher resolution so again it can be up to 10 bits per pixel which means that we can't even display it on our computer screens all the color information at once because our computer screens are only a bit so dealing with HD has a whole bunch of interesting attributes to it it's very big frame size it has a lot of color information to capture and what's also interesting about HD is that we're back into a situation where with HD and HD production when you're building a system around that often your video quality is constrained by your data rate and a data rate for an HD signal is up around 160 megabytes per second so again a DV camera shoots a steady data rate of three point five megabytes per second and HD at 160 so again a lot more data what's really interesting about HD production is we get more and more into it that we start to learn a lot more about HD HD is you know technically a lot of resolution there but what we're starting to learn a lot is that there's a lot of issues associated with HD capturing so you want to go out and shoot an HD movie all of a sudden you need a better makeup person or a lot better makeup you need good life all of the details that film and DV cameras was so forgiving about because we're in the initial stages of HD production we're really suffering from that we have to blow a lot of smoke on stage to create a lot of depth the images tend to look very flat and again over time I'm sure that it will work with lenses and ways of softening that up so it's a little more useful but today HD is this huge frame size very hard to struggle with but once you get it obviously the quality is four times that now we also have frame rates that when you make a movie on your computer the frame rate can be any frame rate that you want again the idea of starting with the idea of a QuickTime movie as a frame size and a frame rate is just to let you know that those sizes are arbitrary and that you can make them whatever you need to but not in the real world sizes are dictated to you by the hardware so again my camera shoots full size that size happens to be 640 by 480 runs at 2997 now film and HDTV run at 24 frames per second so that's a little bit different a little bit slower and actually the difference between 24 frames per second and 30 frames per second is really enough that that matters about how the background looks that there's actually aesthetic considerations made to film shooting at 24 frames per second and how you can pan a subject on a camera and the way that that looks versus video which runs at 30 frames per second actually it's interleaved I'll get to that in just a second so it's actually showing you 60 images per second so video is much higher resolution than the 24 frame for film that's why again video is very popular for sports any sort of content where you need a lot of fast to action again video resolution at 30 frames per second allows you to capture that ok so again out in the real world we have different formats we have SD we have HD we bring those in so what we need to do at a certain point is capture that video now I used to say that this was an analog versus digital scenario and that it was real easy that our cameras were always analog and that we've just be digitizing that more and more though it's really portable versus not that increasingly our cameras digitized on site and already have converted that so this is a digital camera this DV camera it's a mini DV camera it's very old I props at about 14 times from places like this you can see I need a new one but the main thing again at so at 20 720 x 480 this is three and a half megabytes per second so the video comes in when I capture this ok it's digitize right on the camera so all I need to do when I capture this is I take as a firewire output what I'm doing is I'm moving that digital information between my camera and my computer so you can think of this as a hard drive again I can push the video back but I'm just taking visual information in digital format and pushing it back and forth with my camera so DV is very easy to use because the signal is already digital if you if you have an analog format we need to digitize that and again there's a variety of products to do that we have the i/o products from Asia again very high-end cards that lets you do component input if you have say producing on digital beta digital betacam has a digital output called an SGI SBI Jack and again that SGI Jack you can bring into a deck length black magic card again a naja box and bring that in but at some point you need to take the video from that outside world and bring it in and again that's where you capture and again what we're talking about there is that you have to be aware of the frame size the frame rate the codec and the data rate of all those different formats okay so we talked a little bit about capturing again variety of ways of capturing so once you've captured that video what do you do with it and again we showed the video of the different content there's a variety of applications what mainly happens in the production phase is that you're taking those QuickTime movies you're combining them all together either editing which is a temporal issue so you're you're combining the creative story where you're compositing them together the main point about production though the creation of content from a technical perspective is that you end up mastering that format at the same size again a common misconception is that I'm just going to output that video once i'm done to a small resolution and be done with it and the point really of having the discussion today is just to let everyone know that really increasingly you're going to go back to that content and want to deliver it in multiple formats so we must make a master version of that content that again can be used in many different places so the best way to do that is to produce it at full size and then to take that master file and start to convert it off to different formats also at some point down the road you're going to come back and want to make another version of it a DVD another CD or something like that so again having a full res master is really important so when you're producing your content again DVI output a 720 x 480 movie 30 frames per second using the DV codec so at a high again a distribution data rate our production data rate excuse me so once we've got in our video we've created the master now what we want to do is start to distribute that video what formats do we take to communicate our message out to multiple formats there's really a few different sizes there and again a few different things that happen with that video as we go through the production process the first thing is we want to make a DVD out of it that's the most popular kind of format or very accessible format for making video well DVDs are interesting if we take our little formula here frame size frame rate codec data rate the frame size of a DVD is set for us it's full size 720x480 so it's great about a DVD and why one of the reasons why it looks good is we've preserved that full frame size of our media now mpeg-2 is the codec so that is actually the compression scheme when we talk about mpeg-2 and peg to is is a compression sphere and that has a data rate associated with it and the data rate that we most commonly use for DVDs is 5.7 megabits again a DVD has a data rate choice of up to 10 megabits but I work with a lot of compression project products and what happens is a lot of times people have a short 20 minute movie they want to go ahead and make a DVD of that and we're all concerned about quality we want to get the highest possible quality from our media so if I have less than an hour and 15 minutes to put on my disc and I'm compressing that to DVD what I'll often do is turn the data rate quality up or what I would think is to turn the video quality all the way up to eight or nine megabits per second go ahead and encode that media and then go ahead and play it well there's a little bit of a problem with that and that what we've just what we've determined you know sort of extensive testing has found that if you have a real high data rate like that you're going to have an inconsistent playback experience between the different DVD players so increasingly when I talk with people about making DVD content I really urge them to try the data rate of 5.7 megabits and to try and use filtering or other processes to into him to preserve that video quality as much as possible because what we found is that a 5.7 megabit DVD really plays well in all places now as we move from DVD to other formats for instance web video the choices open up a lot more again with web video what we're trying to do is to get the video to play smoothly that's where the data ray comes in but the sizes are rather arbitrary and really when we're talking about compressing for video we're looking at those same trade off so I have uncompressed video that's full size the first trade-off that I can make is the frame size to reduce that data and again common web sizes is 320 x 240 what we're trying to do with web video is really get a theatrical experience whether or not we realize that we all want a theatrical experience from the web so we're really trying to get as full size codec as we can my work experience has been rather interesting I've been doing digital video for 18 years at this point and what we started off with was a technology called quick hon where everyone complains that they were little postage stamp movies and what we did was we worked really hard to with Hardware assist get that to be full screen full motion we achieve that in about 19 94 the variety of products to do that then what happened was about nineteen ninety-six the internet became more and more prominent and we started to get digital video happening on the web and there was once a time when Peter hottie who was the QuickTime architect asking me to make him a 60k movie no he wanted a 30k movie 30k bit movie and I said well Peter that's you know I'm going to be 60 x 90 and that looked too good he says I want to movie that played and oh I made the movie he used it for the demo but what was interesting about that was that we've now we went to a software world and then for after 1996 what happened was slowly we've been trying to get that frame to size to grow so it's in stretching that frame sizes in codecs developments and increasing the data rate can we actually stretch that size out to be full size and we've almost achieved that but there was an announcement yesterday very significant announcement for anyone making digital media which is that Apple is going to include a new h.264 codec in the next version of the OS in the tiger operating system now what's really exciting about that is that right now we can do a fairly good job of stretching mpeg-4 to full screen full motion it's pretty difficult to get it but if we increase the video by a factor of four that's going to look fantastic so we really look to mpeg-4 to deliver a software version of a codec that is full screen full motion now the interesting thing for me is just about the time right now that we're getting that together there's a new thing on the horizon and that is everyone's driving around in their car with their Wi-Fi we've been Hong Kong they're watching video on these portable formats so again it's kind of interesting about this is we work really hard to make it full screen full motion on software and they invent a new platform for us so this is a Klee a this is a pj 37 and what this is is a 200 megahertz CPU so again what they've done is they took my beige g3 or so and they shrank it but again the video quality on this is going to increase better and better than what we're going to see more and more of is video in these other portable formats and again what's the great thing about mpeg-4 and the upcoming h.264 codec is that it's going to increase the video look here by a factor of four so that's going to be very exciting and again just to get back to the size thing that often times when you're dealing with phones cell phones or palm OS devices such as this that again you're going down in size to 160 x 120 so you're able to compress that down a whole bunch so let's go ahead and switch to my machine for a second please go back to and so what this is just a picture of relative frame sizes for you so again the big white box is our 1920 x 1080 frame size the next box is our twelve eighty by seven ten eighty by seven forty seven twenty frames I excuse me here's our 720 x 480 here's our 320 x 240 standard website and again here's our 160 x 120 our cell phone side so again one of the ways we're reducing data is by stretching that frame size down we can do the same thing with frame rate but frame rate is a little more it's worth little less forgiving with frame rate because that has to do with temporal motion or motion over time and again what you want to be aware of about frame rate is that we have with really good eyes as far as seeing stuff like seeing deteriorated motion and motion resolution so what we really want to do is preserve motion wherever possible you have to really look at your content to see how how fast it's moving to determine whether or not you can switch the frame rate I kind of go back and forth on this and I'm currently in a personal phase where i try and keep my frame rates it's matching as much as possible so i will make my frame rates 2997 or 24 you can you can hit 215 or seven at lower bitrate but again the movie gets choppy but the nice thing about that is again with quicktime as the technology that choppiness will at least be consistent okay you won't get snappy video you'll get choppy video so that's what I'm an expert in choppy video okay so great we can go off of their back to okay so actually I want to do a little bit of a demo now and just talking a little bit about distribution there's going to be some seminars we can go actually back to my machine there's going to be some sessions during the week about about video distribution and video codecs and preprocessing so what I wanted to do is talk a little bit about again how we take our media and distribute it so you just cancel and close this cancel this I'm going to be using cleaner as an application to sort of talk for a minute about the process of distribution and how to get the most out of it the reason why I want to use cleaner here is because we're going to be talking about pre-processing when you spend your time creating your content you don't really want to think about color values things like that you really want to have a time when you're when you're being creative and assembling your media but at a certain level you have to come back and take a look at that media in terms of distribution and go okay now I need to distribute this I need to shrink this thing down many hundreds of times smaller than its original how do I do that and that's where compression applications offer you these pre-processing so the first thing again video when it's shot shot in the field so we talked about this before where you actually have alternating fields the reason for that is that when we started remember that a computers computer display has a pixel on it single pixel is going to shoot that on play always on when when you see that display on your computer well the television works a little bit different a little more arcane if you will television works by scanning every line it draws one line in the thirtieth of a second then it goes back and draws another line in the thirtieth of a second that's called interlaced video again field that's made up of these alternating fields they're scanned even and odd depending on your on your video format so DV is even odd even odd even odd again that alternating back and forth happens at the point of the camera so all of your video resolution is caught in that alternating field and when you digitize that video those alternating fields are also captured and if you produce your video and output it at full resolution those alternating fields are maintained through that process when you're doing video so what happens is when you get to the computer screen to view that video all of a sudden you have a problem because the computer video doesn't display that way it's always on and if you're going to show that frame with both of those you're going to see a difference there the interlace difference in the weather thought that motion is and if you're not careful with how you process that video all of that difference in motion is going to be interpreted by the computer which doesn't know what it is as noise it's going to create it giving you a very blotchy out outcome so again one of the things that we have to do we take video in and start to D interlace it or reduce that data down by taking away one of those fields and thus capturing that motion smooth and we're going to use cleaner to see that in just a second so again video alternating and D emulation is really critical to data reduction but it's also critical to getting a good look for your web video because again that those motion artifacts will be interpreted by as noise for you another thing is that if you're using film film is shot at 24 frames per second there's a problem with film though if I edit my film on video video runs at 29 97 so it's a different frame rate so there's a difference in the frame rate that film shot at 24 in the video at 2997 so how do we deal with that well there's a very standard process called teleson which is the process of of moving 24 frames per second video up to 30 so it's not like the video case where every field is to here is interlaced but basically habit of 60th of a field what's happening with telus in each video or video that originated on film is we get to progressive frame so so progressive frames the whole frame is captured we get two of those and then we get three interlaced frames to make up that difference and it's that difference of five over for overtime in the telus any process that makes up that 2997 so we've taken five frames mapped four frames map them to five frames and added three interlaced frames and to progressive frames that's where we hear that term three to pull up or pull again it can be 23 or 32 depending on where you start but the main thing to realize is that there you have to progressive frames and three interlaced frames now when you're in that situation and you apply at the interlaced filter what you're doing is only you're only doing the appropriate thing for those three frames because it's mixed up progressive and interlaced frames the interlacing all of that is going to cause a deterioration on those two progressive frames so what we need to do when we go back through web video is we need to do a process called intelli cine which is to remove that three to pull down back to that 24 frames per second so one of the really what I consider the pinnacle of web quality is the Apple trailer site the team in cupertino does a fabulous job encoding those and if you look at them they're all 24 frames per second and again the key to that was that those all those movies have gone through a nutella cine filter to restore that original frame rate never know where your media is going to come from today so again restoring that original 29 original 24 from your 2997 is important if you're doing stuff in pal it's just a one percent raise and lower so it's a little bit different they don't go through quite the intricate process the telus tinny process in tell city it's really only relevant to 2997 video ok so again as I was talking about the next thing is how to how to process the video so that it looks good we're taking uncompressed videos into this big and we need to run it through a hole that's too small so we want to do every single thing we can to preserve the quality of that video so again throwing off the frame rate making the frame size a lot smaller well that helps there goes half the data the interlacing that video takes away half that resolution actually helps us reduce that data but we're left with a variety of other techniques to preserve that video and that's where you're going to see some sessions on pre-processing because the key to good looking web video is pre-processing and what I'm really talking about now here is web video we talk about DVD we're not going to do a lot of processing to our DVD because it's already full size 720 x 480 the number one thing that I see people running into with a DVD production is they need to go from there interlace format to a progressive format they're going to be playing the DVD that will always be played back on a computer the only problem with that is that when you take your twin at your full size interlaced video and UD interlace it to make it progressive you've eliminated half the resolution vertically on that and you've softened that video so the one thing that you need to be aware of when you're making DVDs when moving from recive to influence moving from in relation to progressive as your videos can go soft now there is some tricks that you can do with the green channel and balancing that stuff out but just remember that again video goes soft when you're going down too much smaller data rates what you need to do is anything that you can do to to what we call this media mastering which is really a process of applying filters to preserve that data rate wherever possible so I want to walk through that now a little bit with cleaner and talk about what some of these pre processes and principles are and how you use them so I'm going to use my bubbles movie for this the reason why I'm going to use this movies because it has a whole lot of emotion in it so you see this is a TV movie it runs at again it's 3.5 megabytes megabits megabytes per second because it's on production codec and again this is just a little scuba trip that I had in them going down here and you're seeing a lot of these bubbles come up so just quickly how to use cleaner i have my quicktime movie is here in my batch window go ahead and remove this one because we're not going to use it i'm just going to bring up my settings dialog and apply settings for this and what's nice about cleaners that cleaner presents to you all of the parameters for quicktime movie and preprocessing right here in its settings window you'll see that i have the format at the very top here it says quick time and again I've my file suffix quick so how this cleaner works is basically I have these tabs that are going to list to me all of the output parameters and the pre processing parameters that I can apply to my video so again looking at the image size here the image size 320 x 240 let's see right here that again I have this deinterlace what's nice about this I'll see how this looks on this particular screen what I need to make it a little bigger that's okay okay so what I have here we find a little bit better frame cross so this is a before and after view of my movie the form before I actually compress it so let's look at that before view and again I've intentionally picked this piece of media because it's got a lot of motion so you see these sort of horizontal lines in my video in this before section what those are is because what we're seeing is a frame of video of a bunch of bubbles rushing up at us so the whole thing is moving and again all those interlace lines what those are is the difference in movement between that 60th of a frame so this is where I'm talking about de-interlacing your video in order to get the best possible look because again if I were just to compress this without deinterlacing it look what I'm feeding the encoder it's a mess it's never going to get both above this high level noise to get me any sort of picture of an image at all so again deinterlacing as the first step to creating a delivery for your media an output platform it's extremely critical because with all that otherwise you're going to get all that noise in there now cleaner is kind of interesting cleaner has a feature called adaptive there you see now if I go to the output also conversely notice how much that cleans up particularly this group right here in the center see how much just pulling away half of that field really clues that video up to get that started there so again be interlacing probably the most important filter when when pokémon making web video because again you're able to decrease that video but you're really preserving the size the look of this video adaptive deinterlacing if I have a Batman shot everything's at an angle has lots of diagonal lines in my video and I were to take a picture of that and in video and I were to be interlace it because I had diagonal lines in there and I take away that half every other line what I'm doing is starting to introduce jaggies into my output little jagged lines there well with an adaptive deinterlace your only be interlaced pixels that move so you're only going after these artifacts to get rid of that motion stuff again prepare your video for a distribution kodak so again adaptive deinterlace very important you'll notice that cleaner has a sharpen filter in there that sharpen filter is just to brighten things up again because codecs inherently doll our content so again having that sharpened codec in there is very helpful and what we have is a concept of noise reduction so with all of your video when you go down to lower data rates you're going to be using noise reduction noise reduction filters are very very cool what they do is they'll take the edges to preserve those edges and they'll apply blur to everything in between so the areas of less details that our eyes are much more forgiving for again can see this noise reduction filter it helps scale the video down very well so again how to use noise reduction is really keep it on mild or moderate and on how much motion you have and we'll do that ok the next filters just to talk about for image quality we have a few of them that you need to be aware of first thing is gamma that there's a difference in gamma between the mac and windows platforms i believe like gamma taco X right here so what I can there's a difference in gamma between the mac and windows so a mask computer is darker than a Windows display so if you're always producing your media on one platform on a Mac and you give it to your you play it for your windows friends they might say that it is a little bit dark for them the way that we handle that when producing content for the web is to add a gamma filter for that what a gamma filter does it just brightens up those mid-tones you can see here I'm just going to turn these off for a moment we go through this just update that so if I add just a little bit i'll turn the gamma filter off and again it's just going to take that and brighten that up just a little not not too much or the other way and again by raising the gamma we're able to make a movie that plays well in in a lot of different places now also with different encoding application jewellers you always have a brightness and contrast filter now color correction is one of the main things that we do when we're compositing media together because when have you ever had two pieces of video that were shot at the same place in the same time with the same line pretty much never so one of the things that I work a lot with people who produce visual effects is really in how to balance video with brightness and contrast in order to balance the different elements together well the same thing happens or a similar thing happens when you digitize your video and now I want to output it on to a variety of different formats in order to keep that video looking good you really want to take and think of it in terms of brightness so you have black and you have white as the two pillars of brightness here and so what you can do with this brightness and contrast filters is you can look at your video and you can reset what the black and the white level is so that when you're going into the process of encoding it you've given yourself really strong color values defined what the black and white level is and if you keep strong color values you're going to help reduce compression artifacts that's what use a brightness and contrast filter for so brightness is really used for finding the black level in your image you notice my image doesn't have a lot of black in it so it makes it a little bit hard to see but again you can tell that by bringing down that the brightness filter or just playing with the brightness filter in your compressor that you're able to again find a value that looks rich conversely contrast is what you use to adjust your white level so again you can move through enable your contrast filter and bring that up just a little bit you want to be careful because when you when you stretch your contrast too much you're actually reducing the range of pixels there so you're making your putting less color information in your video but again you're resetting that black and those white levels so again very good to be aware of your brightness and contrast cleaner has two other very important filters in it that are used for making the video really look the level of quality that we're talking about on the Apple trailer site and that is the concept of black and white restore so what these filters do in here for you is again they'll take and they'll actually regenerate those colors for black and white for you so this is significant because again it's going to really ground your York it's going to give your content good color values so you might say well there's not a lot of black in this video why would I use a black restore video on content like this well if we notice if we bring up the amount of black restore in the video image you'll see that this blue that's all over this this content really does have elements of black that there's a darkness associated with this whole background inside this video clip and that I can sharpen that up or increase the clarity if you will of that kind of stuff using a black restore filter so how you actually use these filters is you'll notice they have a smoothness control so if I just turn on the black restore and then turn this way up you're going to see that at a certain level it's going to start to get very blotchy so you notice in here starting to get so black is being added and just regenerated into all these areas but if i use a smoothness control here what I'm able to do is just get a little bit of softness and get a little bit of an edge and nice lift to that and really get those colors back so to get good contrast in that video I can go ahead with a lot of smoothness and softness and bring up that with that black hooker same is true for the white restore so again same principles apply that all colors have an element of white in them and that by regenerating this black end these white colors were able to really preserve those color values so that when you go ahead and compress that video you get the highest qualify output so we call this media mastering the other thing is to realize that when you do audio again for audio formats audio is an interesting case for a long time starting with quick times 3 we had audio codec called the cue design music codec so cute design was it was a very good codecs for reducing the data rate of our video but cute design did have an unfortunate artifact associated with it it would produce a phase shift at high at upper frequencies basically it would make sure your audio sounders so you get a swishing sound with the cue design codec now that was followed up by the very popular mp3 codec and mp3 you know it's available i believe quick time for came in and again mp3 very popular very portable format and mmm that's my mp3 impression so again mp3 is very good at planning they're just missing high end so mp3 doesn't have a lot of high end the other thing about mp3 that you should realize is that mp3 has really severe characteristics to it that change or your lower mid range so again if you're if you're in coding stuff to mp3 it's going to go through a tam bral shipper the quality of the sound will change a bit it's going to get a little lower mid-range e if you're if you have a jazz band with a saxophone the saxophone is going to be reduced in the ride cymbal is going to come up a little bit so you just want to be used to the fact that that mp3 while it's very small and portable does have like the cue design I'm some baggage associated with it that's where we have now of course what I always have to show here is the mpeg-4 audio or the AAC audio codecs this codec was pioneered or created by Dolby same folks that brought us that ac3 codec that is the standard for compression and DVDs the ac3 audio codec or the mpeg-4 audio codec as it's known is the best thing since sliced bread for video on the web this codec is the greatest what's nice about this is you get a full frequency there you get a full frequency dynamic so you get all of the frequencies associated with the video so no little high end stuff and you can do it at significantly lower data rates so again mpeg-4 really operates well for voice at 96 to 64k bit whereas with an mp3 we really would be up in the 164 range 128 range so you're able to reduce that a lot more you get a lot less artifacts now mpeg-4 audio is a compressed format and with you know four thousand dollars worth of speakers you will be able to hear a phase shift with it go ahead and say that but if you're in your car if you're in on a PC speaker that can't reproduce that range for ninety-eight percent of the uses that you will use it it sounds like a CD and and and and basically this whole concept that I said initially about a Kodak you have the technology that allows you shrink something and then decompress it in real time so that size is no longer the original size it's smaller now because you're using these codecs and again for your audio and just and distributing your audio and pay for audio codecs are really the key to that the few other things you can do with your audio such as normalize it that's just to bring the volume up so you don't introduce distortion and things like that okay now great so let's [Music] let's go back to back to the presentation please thank you okay so I'm starting to wrap up here and I'm really wanted to finish again where I started a little bit which is this concept of video what is digital video well digital video is quicktime movie or other formats but it has a frame size than a frame rate these frame rates are really a lot of the sizes controlled by the codec and ultimately that Kodak has a data rate associated with it and that data rate really is what determines the quality of your video great can we switch back to the demo machine please so I wanted to show you that again what we've talked a little bit about here we've introduced this idea of this great new h.264 codec and what's going to be happening there and really want to talk a little bit about some of the trends here in media so one of the exciting things that we have here inside cleaner we have the ability to go out using the kinoma exporter to the palm OS again palm OS devices are extremely good at playing video I have my little create hear that go ahead and play this and I think more and more what people are seeing is that our videos on our cell phones so we can take pictures with our cell phone now so it's just a matter of time before our cell phones will be able to actually display video moving pictures okay so we've got the single frame now we need to get multiple frames there's also really exciting component to this technology that well there's to a certain two other components first of all there's a thing called Wi-Fi 802 dot11 wireless technology that will be able to allow me to view this video anywhere and increasingly we're seeing more and more you probably have it at your house but increasingly you know down at starbuck you can go to places on just last week it was announced in Washington DC they're actually deploying Wi-Fi in a whole neighborhood under city blocks so more and more we're going to be able to take media wherever we want now if you capture a video on your cell phone realize that the resolution is this size it's going to be 160 x 120 so we're going to have an interesting period time when we try and take that video and scale it up to full size but again we're going to have very exciting codecs like a chat h.264 that will help us make that transition so again what's very exciting about that is what we're happening you know where this media is going and increasingly what we'll see is that you'll produce your video in these high-end format perhaps HD SD very high data rate a lot of creative stuff happening with that you get support where you need to distribute that media and oftentimes you're going to distribute it in multiple formats you'll make a DVD of it you'll make a web movie of it you'll make a cell phone version of it and again the idea here is that we're distributing this in multiple formats so you're going to make a master version of that and you're going to then from that derive all of these other versions at these lower data rates much smaller sizes okay we can go back to the to the demo machine are to the presentation machine please so again we've hit some basics today and just sort of discussed what quicktime was quick time is a container for your media that's extremely important that it's not just a codec it has codec attributes associated with it this is the reason why I have to draw that contrast as there's some other formats in the world where you don't have this level of technical complexity and dis amount of tools and really rich features to use where the codec is the name of the format so I shouldn't have to say what they are right thank you okay good so again quick time and to cook up really codec base so it really gives you that frame size that frame rate codec and data rate and that again data rates determine the plaza how you produce it how that image quality look and that we have different codecs for distribution than we have for production and again the codecs for distribution are very small the codecs for production are very high we have all these frame rates different sizes of videos that we collect from all over the world we bring those all into our we digitize those on our computers assemble those and then upload them it's still more smaller sizes in different format so again lots happening with the media I think that we're going to now take some questions people are interested in that and again what we do is we have first of all who to contact if you have any questions about the topics that we talked about today or just quicktime and quicktime technologies in general a few very important names you should know first up is Guillermo Ortiz he's a developer relations person for quick time and again wonderful key person to know for any of your questions you have regarding the QuickTime and the media track here in addition my colleague Stephen Stephen is available he's a product manager for QuickTime available for questions and follow-up and then myself I'm Hagee Van Dyke I'm available at here at discrete calm and my role is I'm a applications analyst so I'm really a person who works with all phases of media production and delivery and actually product development delivery I work for a company called the screen at a certain level we're known for a product called cleaner which is a kind of transcoding tool designed for compressing video from one format to another but discreet also has a real legacy and in history in high-end media production we have a product called via the flame which is an SGI based of real-time independent resolution system designed to give you very high quality motion effect and again what's interesting about the flame it does deal with still image formats so again large stuff and we're going to take some questions I believe