| Updated: April 19, 2023 |
The mm-stream configuration lists and configures the plugins used by clients for accessing the server, and by the server for reading input, processing media content, and delivering output.
Typically, the JSON object that configures a plugin is named for the shared object (.so) file that implements the plugin. The JSON object name may also contain a string that hints at how the plugin is configured. This is because you can define multiple configurations of the same plugin, to support multiple concurrent mm-stream instances. For example, if your target system has both a 360p and a 720p encoding processor, you can define separate configurations of the media-processing plugin to encode video at different rates suitable for each display type.
Each configuration is specified as a distinct JSON object. The sections below provide tables that describe the JSON objects and fields used in the configurations.
Configures the input plugin that reads media files
| Field name | Type | Description | ||
|---|---|---|---|---|
| uuid | Hexadecimal string | Universally Unique Identifier (UUID) for the plugin | ||
| file | path | String | Absolute path of the input file | |
| file | blitter_buffers | Number | Number of source buffers to use for blitting, which entails copying pixels between buffers to convert formats, scale the image, etc. | |
| file | audio_settings | JSON object | Defines how audio content read from the file is formatted for delivery to the processing plugin | |
| file | audio_settings | channels | Number | Number of audio channels |
| file | audio_settings | samplerate | Number | Frequency of the audio sampling, in Hertz (Hz) |
| file | audio_settings | bitspersample | Number | Number of bits in each sample |
| file | audio_settings | codec | JSON object | Codec to use for formatting the audio delivered to the processing plugin. This object can contain fields that configure codec settings. |
| file | video_settings | JSON object | Defines how video content read from the file is formatted for delivery to the processing plugin | |
| file | video_settings | width | Number | Width of the video, in pixels |
| file | video_settings | height | Number | Height of the video, in pixels |
| file | video_settings | rotation | Number | Angle by which the video is rotated, in degrees. Positive values indicate clockwise rotation; negative values indicate counterclockwise. |
| file | video_settings | framerate | Number | Frame rate (Hz) |
| file | video_settings | codec | JSON object | Codec to use for formatting the video delivered to the processing plugin. This object can contain fields that configure codec settings. |
Configures the input plugin that reads audio using libasound
| Field name | Type | Description | ||
|---|---|---|---|---|
| uuid | Hexadecimal string | Universally Unique Identifier (UUID) for the plugin | ||
| audio | device_name | String | Absolute path of the audio device | |
| audio | fragment_size | Number | Size of each audio data fragment delivered by libasound, in bytes. All processing occurs on individual audio fragments (rather than the whole buffer). | |
| audio | audio_settings | JSON object | Defines how audio content read from libasound is formatted for delivery to the processing plugin | |
| audio | audio_settings | channels | Number | Number of audio channels |
| audio | audio_settings | samplerate | Number | Frequency of the audio sampling, in Hertz (Hz) |
| audio | audio_settings | bitspersample | Number | Number of bits in each sample |
| audio | audio_settings | source_filter_method | Number | Sample rate conversion method. This setting can be 0, to make libasound use the basic linear interpolated SRC algorithm, or 1, to make it use the basic anti-aliased SRC filter (or 7-point Kaiser windowed). |
| audio | audio_settings | codec | JSON object | Codec to use for formatting the audio delivered to the processing plugin. This object can contain fields that configure codec settings. |
Configures the input plugin that reads video using Screen
| Field name | Type | Description | ||
|---|---|---|---|---|
| uuid | Hexadecimal string | Universally Unique Identifier (UUID) for the plugin | ||
| screen | type | String | Display type | |
| screen | swap_interval | Number | Number of vsync (refresh) periods between content postings | |
| screen | screen_format | String | Pixel format | |
| screen | blitter_buffers | Number | Number of source buffers to use for blitting, which entails copying pixels between buffers to convert formats, scale the image, etc. | |
| screen | display_buffers | Number | Number of destination buffers for storing pixels copied during blitting so they can be rendered onto physical displays | |
| screen | source | JSON object | Defines settings for the blitting source buffer | |
| screen | source | x | Number | X-coordinate of the upper left corner of the source buffer |
| screen | source | y | Number | Y-coordinate of the upper left corner of the source buffer |
| screen | source | width | Number | Width of the source buffer, in pixels |
| screen | source | height | Number | Height of the source buffer, in pixels |
| screen | destination | JSON object | Defines settings for the blitting destination buffer | |
| screen | destination | x | Number | X-coordinate of the upper left corner of the destination buffer |
| screen | destination | y | Number | Y-coordinate of the upper left corner of the destination buffer |
| screen | destination | width | Number | Width of the destination buffer, in pixels |
| screen | destination | height | Number | Height of the destination buffer, in pixels |
| screen | video_settings | JSON object | Defines how video content read from Screen is formatted for delivery to the processing plugin | |
| screen | video_settings | width | Number | Width of the video, in pixels |
| screen | video_settings | height | Number | Height of the video, in pixels |
| screen | video_settings | rotation | Number | Angle by which the video is rotated, in degrees. Positive values indicate clockwise rotation; negative values indicate counterclockwise. |
| screen | video_settings | framerate | Number | Frame rate (Hz) |
| screen | video_settings | codec | JSON object | Codec to use for formatting the video delivered to the processing plugin. This object can contain fields that configure codec settings. |
Configures the input plugin that reads video using the Camera Framework
| Field name | Type | Description | ||
|---|---|---|---|---|
| uuid | Hexadecimal string | Universally Unique Identifier (UUID) for the plugin | ||
| camera | unit_id | Number | Logical camera unit | |
| camera | buffers | Number | Number of buffers in the viewfinder window that are allocated for the user application (i.e., the program configuring mm-stream) | |
| camera | video_settings | JSON object | Defines how video content read using the Camera Framework is formatted for delivery to the processing plugin | |
| camera | video_settings | width | Number | Width of the video, in pixels |
| camera | video_settings | height | Number | Height of the video, in pixels |
| camera | video_settings | rotation | Number | Angle by which the video is rotated, in degrees. Positive values indicate clockwise rotation; negative values indicate counterclockwise. |
| camera | video_settings | framerate | Number | Frame rate, in Hertz (Hz) |
| camera | video_settings | codec | JSON object | Codec to use for formatting the video delivered to the processing plugin. This object can contain fields that configure codec settings. |
Configures the media-processing plugin that uses OpenMAX AL to decode and encode media streams
| Field name | Type | Description | ||
|---|---|---|---|---|
| uuid | Hexadecimal string | Universally Unique Identifier (UUID) for the plugin | ||
| plugins | Array | UUIDs of source plugins to link in | ||
| plugins | uuid | Hexadecimal string | UUID for a particular source plugin | |
| priority | Number | Priority level for the thread in which the library runs | ||
| ts | JSON object | Defines the settings used for multiplexing audio and video input streams into an output container based on the MPEG Transport Stream (TS) format. | ||
| ts | audio_settings | JSON object | Defines how audio streams are transcoded for output. This nested object needs to be present when you're using the audio or file input plugin to read a file with audio content. | |
| ts | audio_settings | bitrate | Number | Rate at which to output audio stream data, in bits per second (bps) |
| ts | audio_settings | channels | Number | Number of audio channels to output |
| ts | audio_settings | samplerate | Number | Sampling rate (in Hz), which means how often to read PCM data from the input plugin |
| ts | audio_settings | bitspersample | Number | Number of bits to provide in each sample |
| ts | audio_settings | codec | JSON object | Codec to use for encoding the audio in the output container. This object can contain fields that configure codec settings. |
| ts | video_settings | JSON object | Defines how video streams are transcoded for output. This nested object needs to be present when you're using the Screen or Camera Framework input plugin or the file input plugin to read a file with video content. | |
| ts | video_settings | width | Number | Width of the video, in pixels |
| ts | video_settings | height | Number | Height of the video, in pixels |
| ts | video_settings | rotation | Number | Angle by which to rotate the video, in degrees. Positive values indicate clockwise rotation; negative values indicate counterclockwise. |
| ts | video_settings | framerate | Number | Rate at which to output video frames (in Hz) |
| ts | video_settings | bitrate | Number | Rate at which to output video stream data, in bits per second (bps) |
| ts | video_settings | codec | JSON object | Codec to use for encoding the video in the output container. This object can contain fields that configure codec settings. |
Configures the plugin that encapsulates TS content into RTP packets and outputs them
| Field name | Type | Description | |
|---|---|---|---|
| uuid | Hexadecimal string | Universally Unique Identifier (UUID) for the plugin | |
| plugins | Array | UUIDs of source plugins to link in | |
| plugins | uuid | Hexadecimal string | UUID for a particular source plugin |
Configures the plugin that provides clients with RTP access to mm-stream
| Field name | Type | Description | |
|---|---|---|---|
| uuid | Hexadecimal string | Universally Unique Identifier (UUID) for the plugin | |
| plugins | Array | Contains objects that describe the source plugins to link in | |
| plugins | uuid | Hexadecimal string | UUID for a particular source plugin |
| plugins | address | String | IP address and port number used by clients for accessing a specific RTP stream |
| plugins | peer_address | String | IP address and port number that the RTP stream is sent to; this can be unicast or multicast |
Configures the plugin that provides clients with RTSP access to mm-stream
| Field name | Type | Description | ||
|---|---|---|---|---|
| enabled | Boolean (true or false) | Whether the server initially listens for RTSP commands. If this field is false, the instance must be explicitly enabled before clients can start streaming content through RTSP. | ||
| uuid | Hexadecimal string | Universally Unique Identifier (UUID) for the plugin | ||
| address | String | IP address and port number used by the mm-stream server to receive RTSP commands | ||
| streams | Array | Contains objects that define the URLs for accepting RTSP commands and the source plugins that output the RTP packets in response to those commands | ||
| streams | url | String | URL specifying a server path to which RTSP commands can be sent; the URL must be appended to the IP address and port defined in address | |
| streams | plugins | Array | UUIDs of source plugins to link in | |
| streams | plugins | uuid | Hexadecimal string | UUID for a particular source plugin |