To change the settings of a dynamic movie, such as its audio and video codecs or quality settings,
You can change the following settings in a dynamic movie
Usually the frame rate is set when creating a composition or is determined by the base video you select. For certain output formats, such as a GIF animation, you can set the frame rate to a different (lower or higher) setting.
NoteWhen you change the frame rate, you must consider the implications for the audio track (if any). Any calculations that are based on the number of video or audio frames, must be adjusted to reflect the new frame rate
The choice of video codec determines the video formats you can generate. For example, a MP4 video requires the H.264 video codec, whereas WebM videos must be encoded with the VP8 codec. If you need both video formats, you must create a copy of the dynamic video with two different video codec settings.
When you change the video codec, you also affect the choice of audio codec. Not all combinations of video codec and audio codec work for all video formats.
Everything in the above paragraph about the video codec is also valid for audio codecs. Choosing a video codec will affect the hoice of audio codec and vice versa.
Video coding is to find a compromise between file size, quality and encoding speed. You can instruct the video encoder to emphasize a constant quality or to limit the bitrate and therefore file size. Both methods have advantages and disadvantages:
|Contstant Quality||Predictable quality even in fast-moving scenes||Large fluctuations of bitrate can affect playback|
|Constant Bitrate||Predictable size allows for smooth playback for bandwidth-limited clients||Fast-moving scenes appear blocky with visible artifacts|
The rate factor is a number between 15 and 51, with lower numbers mean higher quality and vice versa. A good default is 22, and the usable range is between 18 and 26. Higher number will result in smaller videos, but the encoding artificats will be visible.
Choosing a bitrate is more complicated, as you need to factor in the size of the video. A HD video requires at least 2 times more bandwidth than a SD video. A good default for a SD video is 900kbps, and 2000 kpbs for a HD video.
For a given encoding method (quality or bitrate) the encoder can be given more time to encode the video to a smaller size or a better quality in exchange for more time. If you do batch processing or do not have realtime requirements, you can increase the CPU Effort. For real-time applications or fast encoding, 20% is the lowest usable level.