User`s guide

Setting Encoder Presets
QuickTime Audio
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Wirecast User Guide | 104730
9. Enter the height of your broadcast video.
10. Select the quality of your broadcast by adjusting the slider between least and best.
Generally, encoders make a trade-off between higher quality (greater bandwidth)
and speed (CPU usage).
Note: If the Quality scale is greyed-out, quality is a fixed value.
11. Select the desired frames per second (FPS) of your broadcast. This is a target value
for the encoder and is not guaranteed.
12. Check Key Frame Every checkbox (optionally) and enter the number of frames. A
movie is a sequence of images and each image is called a frame. To compress video
data, most encoders take a frame and make it a reference (also known as a key). This
keyframe is sent as part of the broadcast, and all of the data after that keyframe is
relative to it. The benefit of this is that the compressor only needs to send what has
changed since the last keyframe. The main drawback of this is that over time it
becomes harder for the encoder to distinguish the frame-difference information,
especially if there is a lot of motion in the video. Another drawback is if your
viewer’s computer misses a keyframe, the video is distorted until the next keyframe
is sent. However, you can control how often the encoder makes a new keyframe by
setting the number of frames. The more keyframes you broadcast, the more
bandwidth required and less compression, but results in better quality video.
13. Check Average Bit Rate checkbox (optionally) and enter the average bit rate as a
target setting.
14. Check Limit Peak Bit Rate checkbox to request the encoder to limit the output to a
specific rate.
Note: Some encoders use this as a target value, not as an absolute value.
15. Click the Packetize button to modify how the QTSS packets are created. This is an
advanced feature for knowledgable users.
16. Click Save to save your settings.
QuickTime Audio
To modify a QuickTime audio preset, follow these steps:
1. Open the Encoder Presets window.
2. Select a QuickTime preset from the Encoder Presets menu.