In this issue, we will continue to build on the foundation we previously laid by taking the three technologies-downloads, progressive downloads and streaming-and discuss the tools and technologies required for each. We will also provide some tips and tricks along the way.
Encoding
There are three initial steps to digital media: Capture to a computer file format, compress the media data, and packetize data with hints or index. These three steps are included in the encoding process.
The encoding process takes full-bandwidth audio and video and compresses it into good quality audio and video that takes up less space. A compressor/decompressor referred to as a codec is the key component of encoding process. Compression is a math-intensive process, so it takes time to capture the video, reduce the size of the video, and then packetize it for transmission. The time it takes from source through the entire encoding process is called latency.
If you are encoding for a download or a progressive download, then latency is likely not a great concern because there is no time reference; however, you will want minimum latency with live streaming. In this case, dedicated encoding hardware should be considered because the process is done in the hardware and not with software running on a general computer where the OS is sharing processes with other software. Hardware systems are very expensive. Therefore, if you are not producing live content, and you can wait up to several hours to encode video, then encoding with software on general computing hardware is likely the most cost effective approach.
The video codec that is becoming (if not already) industry standard is the h.264. h.264 is also called mpeg 4 (part 10 more specifically) or AVC. As you produce content and set up live streams most professional devices list the codec as h.264. The two most popular audio codecs used in web-based applications are mp3 and AAC.
Ensuring Quality Encoding
Whether you are encoding for a download, progressive download or live streaming, there are several settings you should become familiar with to ensure that you get the best quality possible for your specific situation.
The encoding process is a struggle between bandwidth and quality. Even though hard drive sto-rage is getting cheaper, there is still a finite space available to store media. The same is also true for streaming media across the Internet-at some point you will reach a limit.
The most popular creative tools from Adobe, Apple, Avid and Sony have encoder programs as a standard feature of their respective production software suites. There are other great tools besides Adobe's Creative Suite and Apple's Final Cut Studio, but since they are the most common tool sets, I will cover the common quality settings you find when using these suites.
The codec is the first thing you need to understand and consider. You need to know what codecs have been used on your content, and what codec you need to use for your final delivery. You will also need to know the frame size, the frames-per-second, and the data-rate of your source material and destination.
In some of the settings menus you may be asked if you want a lossless or lossy compression. Lossless compression reduces the file size without any changes or distortion to the video. Lossy compression is the art and science of juggling between the smallest file size possible while main-taining as high quality video as possible. Most churches will want to select lossy compression. One production tip to note here is that lossy compression techniques are not suited for fast-moving, live-action programs. Fast camera zooms and high action close ups will likely cause unwanted artifacts in the compressed video.
You may see selections in the menus to choose between CBR or (Constant Bit Rate) or VBR (Variable Bit Rate). Most churches will want to choose VBR. Variable Bit Rate will allow you to change the bit rate to optimize the file size and quality of the video.
A video frame is made up of two fields: an odd field and an even field. The two fields are inter-laced to make a frame. Newer video cameras allow you to chose between shooting interlaced or progressive (non-interlaced). When encoding from a video camera that gives you an option, you will want to de-interlace the video. This is usually done by just selecting the de-interlace check box in the encoding interface menu. If you have an interlaced source video and it has horizontal line distortion in the compressed or streamed video, you are almost guaranteed that you don't have de-interlace checked in the encoder option menu.
Live Streaming
Not all encoders are designed for streaming media live, so first and foremost you will need to make sure that you have an encoder that supports live streams. In addition to the settings listed above, you will have a couple of additional settings in the live streaming encoder configuration menu to consider when setting up a live stream.
Live streaming requires three key components: a live streaming encoder, a streaming media server, and enough bandwidth to and from the server to supply a given number of concurrent us-ers or audience members.
This is where the difficulties start with anyone who wants to stream a live event, but it is espe-cially difficult for most churches. Servers can be expensive to purchase and even if you purchase the streaming server hardware and software, getting enough bandwidth to deliver more than a handful of concurrent users is often cost-prohibitive. Content Delivery Networks (CDNs) solve these issues. They not only provide live streaming servers but also provide the bandwidth need to support a large national and international audience.
There is no way of getting around it though, bandwidth isn't free. You will have to pay for it by either allowing the CDN to display advertising on your live stream, such as ustream.tv and live-stream.com, or pay for the bandwidth you will use and keep control of your content and what is viewed with it. By the way, both ustream.tv and livestream.com have free encoders with production features to make streaming just a click of the mouse away. You can also use other hardware and software encoders with these sites as well.
The bottom line is, you need to know three things: 1) know how much time you are going to stream per month, 2) know how many people will be watching simultaneously, 3) know what quality. Once you know these three things you will be able to determine what approach makes the most sense for your church.
There are several more requirements for setting up your live streaming encoder. First, you will need to know if you are going to push your content to the streaming server/CDN or will it pull from your encoder. If you or your provider wants to pull, you will need to set up your encoder with a static IP address. In most cases you will need to contact your ISP to determine if it is part of your plan or an additional cost. You will not need a static IP if you are going to push the con-tent to the server.
The last bit of information you will need to get is the location or network connection between your encoder and the server. Your CDN will provide you with this information and you will just copy and paste the information into the stream field and you will be set to go, barring no other technical glitches arise.
One last word on live streaming. There are some "studio-in-a-box" systems out there that claim you can just connect to the Internet and stream. In this scenario, you will need a static IP on the box, and the users will pull from this device. However, due to bandwidth issues, you may only be able to stream to a handful of users. If you need more than a half dozen or so watching your live event via the Internet, you will need to connect the studio-in-a-box to a CDN too.
Podcasting
Since Podcasting is historically audio-based, the two popular codecs used are mp3 and AAC. Mp3 is the oldest and, at the moment, still the most widely used. AAC provides higher fidelity audio and allows markers to be used in production so that images can be changed or sync'd with the audio during playback of the program. Older phones and mp3 players may not support AAC files or that added AAC features, so it is important to know your audience and their technology when selecting a podcasting codec.
The Final Connection
We have been discussion Internet-based technologies. This article focused on getting the content prepared, but the user can't access it until a web page with all of the right connections or links is created. Knowledge of HTML, Cascading Style Sheets (CSS), a scripting language, and profi-ciency with databases is also required at a minimum to create useful a dynamic and interactive website that uses all the Rich Media available for communication and intercommunication today. These and other topics will be covered in future issues.
