camerabin2

camerabin2 — CameraBin2

Synopsis

struct              GstCameraBin2;

Object Hierarchy

  GObject
   +----GstObject
         +----GstElement
               +----GstBin
                     +----GstPipeline
                           +----GstCameraBin2

Implemented Interfaces

GstCameraBin2 implements GstChildProxy and GstTagSetter.

Properties

  "audio-capture-caps"       GstCaps*              : Read / Write
  "audio-capture-supported-caps" GstCaps*              : Read
  "audio-src"                GstElement*           : Read / Write
  "camera-src"               GstElement*           : Read / Write
  "idle"                     gboolean              : Read
  "image-capture-caps"       GstCaps*              : Read / Write
  "image-capture-encoder"    GstElement*           : Read / Write
  "image-capture-muxer"      GstElement*           : Read / Write
  "image-capture-supported-caps" GstCaps*              : Read
  "image-filter"             GstElement*           : Read / Write
  "location"                 gchar*                : Read / Write
  "max-zoom"                 gfloat                : Read
  "mode"                     GstCameraBin2Mode     : Read / Write
  "mute"                     gboolean              : Read / Write
  "post-previews"            gboolean              : Read / Write
  "preview-caps"             GstCaps*              : Read / Write
  "preview-filter"           GstElement*           : Read / Write
  "video-capture-caps"       GstCaps*              : Read / Write
  "video-capture-supported-caps" GstCaps*              : Read
  "video-filter"             GstElement*           : Read / Write
  "video-profile"            GstEncodingProfile*   : Read / Write
  "viewfinder-caps"          GstCaps*              : Read / Write
  "viewfinder-filter"        GstElement*           : Read / Write
  "viewfinder-sink"          GstElement*           : Read / Write
  "viewfinder-supported-caps" GstCaps*              : Read
  "zoom"                     gfloat                : Read / Write
  "image-profile"            GstEncodingProfile*   : Read / Write
  "audio-source"             GstElement*           : Read / Write
  "camera-source"            GstElement*           : Read / Write
  "audio-filter"             GstElement*           : Read / Write
  "flags"                    GstCamFlags           : Read / Write

Signals

  "start-capture"                                  : Action
  "stop-capture"                                   : Action

Description

CameraBin2 is a high-level camera object that encapsulates gstreamer elements, providing an API for controlling a digital camera.

Note

Note that camerabin2 is still UNSTABLE and under development.

CameraBin2 has the following main features:

  • Record videos
  • Capture pictures
  • Display a viewfinder
  • Post preview images for each capture (video and image)

Usage

Camerabin2 can be created using gst_element_factory_make() just like any other element. Video or image capture mode can be selected using the "mode" property and the file to save the capture is selected using "location" property.

After creating camerabin2, applications might want to do some customization (there's a section about this below), then select the desired mode and start capturing.

In image capture mode, just send a "start-capture" and a picture will be captured. When the picture is stored on the selected location, a GST_MESSAGE_ELEMENT named 'image-done' will be posted on the GstBus.

In video capture mode, send a "start-capture" to start recording, then send a "stop-capture" to stop recording. Note that both signals are asynchronous, so, calling "stop-capture" doesn't guarantee that the video has been properly finished yet. Applications should wait for the 'video-done' message to be posted on the bus.

In both modes, if "post-previews" is TRUE, a GstBuffer will be post to the GstBus in a field named 'buffer', in a 'preview-image' message of type GST_MESSAGE_ELEMENT.

Customization

Camerabin2 provides various customization properties, allowing the user to set custom filters, selecting the viewfinder sink and formats to use to encode the captured images/videos.

GstEncodingProfiles are used to tell camerabin2 which formats it should encode the captures to, those should be set to "image-profile" and "video-profile". Default is jpeg for images, and ogg (theora and vorbis) for video. If a profile without an audio stream is set for video, audio will be disabled on recordings.

"preview-caps" can be used to select which format preview images should be posted on the GstBus. It has to be a raw video format.

Camerabin2 has a "camera-source" property so applications can set their source that will provide buffers for the viewfinder and for captures. This camera source is a special type of source that has 3 pads. To use a 'regular' source with a single pad you should use GstWrapperCameraBinSource, it will adapt your source and provide 3 pads.

Applications can also select the desired viewfinder sink using "viewfinder-sink", it is also possible to select the audio source using "audio-source".

The viewfinder resolution can be configured using "viewfinder-caps", these GstCaps should be a subset of "viewfinder-supported-caps".

To select the desired resolution for captures, camerabin2 provides "image-capture-caps" and "video-capture-caps", these caps must be a subset of what the source can produce. The allowed caps can be probed using "image-capture-supported-caps" and "video-capture-supported-caps". In an analogous way, there are "audio-capture-caps" and "audio-capture-supported-caps".

Camerabin2 also allows applications to insert custom GstElements on any of its branches: video capture, image capture, viewfinder and preview. Check "video-filter", "image-filter", "viewfinder-filter" and "preview-filter".

Example launch line

Unfortunatelly, camerabin2 can't be really used from gst-launch, as you need to send signals to control it. The following pipeline might be able to show the viewfinder using all the default elements.

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