Open Broadcaster Software (OBS) on Mac Open Broadcaster Software (or OBS) is a free, multi-platform (Windows and Mac) program available from: https://obsproject.com/. As there are slight differences between the versions for each operating system, this guide is specifically for Mac. This program was primarily designed for streaming/recording video games as they are being played, a common practice on sites such as Twitch (http://www.twitch.tv/) and YouTube (https://www.youtube.com/). As such it includes extra features when compared to other streaming software. Further, as it is an open source project it is enhanced by the community supporting it, and this results in plugins and modifications either currently available or being made, which will further expand the potential. This guide will outline the important features of OBS, detailing the various steps necessary to start your broadcast. Connecting to Streaming Wizard: Navigate to your Streaming Wizard login page (either http://nasta.streamingwizard.com/ or http://sra.streamingwizard.com/) and enter your username and password. The following screen will appear. Set the Stream name to something relevant but remember it, as it will be required later. Leaving the Width and Height at the default setting (320x240) is fine, though you can change it at any time if necessary, for example if you later find out that black bars are appearing around the image. Setting the Height to 30 will remove the video box, which can be useful if you are planning an audio-only broadcast. Finally decide if you will allow viewers to watch in Full Screen mode, and if the broadcast will automatically start when a viewer views the site. Setting Automatic Start as true will mean that the stream will begin playing as soon as the site is accessed, whereas false means the player will not begin until the viewer tells it. If Full Screen option is set to true, there will be an icon on the toolbar of the video which when pressed will cause the video to stretch to the full size of the viewers’ screen. If it is set as false then this option will not be available. Once all the options are set as best suits your needs for the stream, click the button “Create code using above details”. A version of this page will be displayed: Make note of the FMS URL displayed at the top of your page, as well as the Stream name. The Stream name will be the same as was chosen on the previous page. These will be required later for setting the OBS stream. Also note the preview at the bottom of the screen. In this example it shows what an audio only stream (with a height set at 30) would look like. The screenshot below shows what a full video preview would look like: The buffering circle is there because we are currently not streaming anything to this address. It will keep spinning until you pause it, or have finished setting up OBS and have started streaming, at which point it will display your stream. Streaming Settings: Open OBS. Click the button Settings, in the bottom right hand side. In the window that opens click “Stream” in the column on the left. Under Stream Type choose “Custom Streaming Server”, and then enter the FMS URL Streaming Wizard gave into the URL section. The Stream key is the name of the stream (this is what you chose in Streaming Wizard). For example: Output: Below stream, in the left had column, is the Output options. This is where OBS is told the Bit Rates of the audio and video components of your stream. You will need to use this screen in conjunction with the individual audio and video settings in order to properly set-up the stream. The Bit Rate settings are very important as this balances the quality of the stream with the streaming capabilities of the Internet. Depending on what you are streaming, these settings may need to be altered for the best results, however the default settings (video at 2500kbps and audio at 128kbps) are very respectable. One of the main things you need to consider when setting your Bit Rate is the strength of your audience’s Internet. For example, if the average viewer has an internet speed at around 4Mbps, you need to set your bitrate to be low enough to fit within this, and account for any other traffic that may be present (therefore the OBS default of a total bandwidth of 2628kbps could work perfectly at the right resolutions). Here are some rough figures to help you understand what the bit rate represents, and where it may be at a suitable level for your stream. The video bit rates in particular are not an exact figure, but give a useful starting point for your tests before you stream. For audio: • 24 – 32kbps = good for talking • 48 – 80kbps = decent for music • 92 – 128kbps = CD quality, great for music • 192 – 320kbps = better than CD quality. For video: • 400 kbps = output 320x240 • 700 kbps = output 480x270 • • • 1500 kbps = output 1024x576 2500 kbps = output 1280x720 4000 kbps = output 1920x1080 If you find you need to cut back on the bit rate, audio can be an easy place to start, as you can cut back quite a bit from 128kbps without it being too noticeable, especially if the stream is mainly comprised of speech. Also on the output window is options for recording your broadcast, in case you wish to save for a historical archive. Just set the folder location you wish to save the stream to, and when you click the “Start Streaming” button, also click, “Start Recording”. Audio settings: Below the Output icon is Audio. Set the Sample Rate as 44.1khz (this is a standard sample rate for nearly all circumstances). The channels can be either Stereo or Mono. Stereo is usually better, unless the source is only in mono, in which case putting the stream in stereo will have no benefit. Now pick the audio inputs. This will depend entirely on the source material. There are options in this menu for up to 5 audio inputs. This is far more inputs than other programs (e.g. Flash Media Live Encoder) because the original design of the program was for streaming competitive video games, where audio would need to be captured from the game, as well as the microphones of the commentators. This also means that OBS has the capability to capture audio being played on the computer, assuming the source is compatible. This can be an incredibly useful feature, depending on what you plan to broadcast. For each audio input that is selected, an extra bar will appear on the main screen under the mixer. This will give you individual control over the volume, as well as a visual cue as to which audio stream is playing, and how loudly. Video: This window will allow you to set the video settings, such as the resolution of the stream. This will alter depending on the video source resolution, as well as how the stream resolution will match up with the bit rate allowed in the output settings earlier. Plugins: One of the major strengths of the OBS software is the open-source nature, including the freedom to add plugins and other modifications to enable extra features within the program. Plugins are currently only possibly with the Windows version, as this was the version originally released, the Mac version being very recent the functionality still needs to be added. As OBS is still being constantly updated, plugins will become more widely accessible. Scenes and Sources: At the top of OBS is a large preview screen. In order to place something into the preview screen you have to create a Scene. You can name this anything you want to help make it memorable for future use. Each scene can have multiple Sources, and you can swap between scenes with a simple mouse click. Create a new Scene by either clicking the green plus sign at the bottom of the Scenes box, or right clicking the box, and selecting it from the menu that appears. The other icons are: • Red “-”sign = remove scene • White box with lines = options/settings for that scene • Up/down arrows = move the scene up/down. For the sources box, this can impact whether the source is in the background or foreground, therefore if it is visible or not. Sources can be set up in the same way. Many different options are available as sources, including a desktop capture, or something simpler such as just an image or text. It is then possible to move these sources around on the preview screen, and swapping the levels of them, bringing them above or behind other sources.