Unless quieted opusenc displays fancy statistics about the encoding progress.
In VBR mode this specifies the average rate for a large and diverse collection of audio. In CVBR and Hard-CBR mode it specifies the specific output bitrate.
Default for >=44.1kHz input is 64kbps per mono stream, 96kbps per coupled pair.
Outputs to a specific bitrate. This mode is analogous to CBR in AAC/MP3 encoders and managed mode in Vorbis coders. This delivers less consistent quality than VBR mode but consistent bitrate.
With hard-cbr every frame will be exactly the same size, similar to how speech codecs work. This delivers lower overall quality but is useful where bitrate changes might leak data in encrypted channels or on synchronous transports.
Either a filename for the artwork or a more complete specification form can be used. The picture is added to a METADATA_BLOCK_PICTURE comment field similar to what is used in FLAC. The specification is a string whose parts are separated by | (pipe) characters. Some parts may be left empty to invoke default values. Passing a plain filename is just shorthand for the "||||filename" specification.
The format of specification is [type]|[media-type]|[description]|[widthxheightxdepth[/colors]]|filename
type is an optional number describing the nature of the picture. Defined values are from one of:
0: Other
1: 32x32 pixel 'file icon' (PNG only)
2: Other file icon
3: Cover (front)
4: Cover (back)
5: Leaflet page
6: Media (e.g., label side of a CD)
7: Lead artist/lead performer/soloist
8: Artist/performer
9: Conductor
10: Band/Orchestra
11: Composer
12: Lyricist/text writer
13: Recording location
14: During recording
15: During performance
16: Movie/video screen capture
17: A bright colored fish
18: Illustration
19: Band/artist logotype
20: Publisher/studio logotype
The default is 3 (front cover). More than one --picture option can be specified to attach multiple pictures. There may only be one picture each of type 1 and 2 in a file.
media-type is optional. If left blank, it will be detected from the file. For best compatibility with players, use pictures with a media-type of image/jpeg or image/png. The media-type can also be "-->" to mean that filename is actually a URL to an image, though this use is discouraged. The file at the URL will not be fetched. The URL itself is stored in the metadata.
description is optional. The default is an empty string.
The next part specifies the resolution and color information. If the media-type is image/jpeg, image/png, or image/gif, this can usually be left empty and the information will be read from the file. Otherwise, you must specify the width in pixels, height in pixels, and color depth in bits-per-pixel. If the image has indexed colors you should also specify the number of colors used. If possible, these are checked against the file for accuracy.
filename is the path to the picture file to be imported, or the URL if the media-type is "-->".
Simplest usage. Take input as input.wav and produce output as output.opus:
Produce a very high quality encode with a target rate of 160kbps:
Record and send a live stream to an Icecast HTTP streaming server using oggfwd:
While it is possible to use opusenc for low latency streaming (e.g. with --max-delay set to 0
and netcat instead of Icecast) it's not really designed for this, and the Ogg container
and TCP transport aren't the best tools for that application. Shell
pipelines themselves will often have high buffering. The ability to set
framesizes as low as 2.5 ms in opusenc mostly exists to try out the quality
of the format with low latency settings, but not really for actual low
latency usage.
Interactive usage should use UDP/RTP directly.