1. CIS 136 Building Mobile Apps
Media Capture
CIS 136 Building Mobile Apps

2. Multimedia
Camera
Media
Media Capture

3. Media-Capture API
Provides access to the device's audio, image, and video capture capabilities
Assigned to the navigator.device.capture object
therefore has global scope but not available until deviceready
Three methods:
navigator.device.capture.captureAudio(success,error,options)
navigator.device.capture.captureVideo(success,error,options)
navigator.device.capture.captureImage(success,error,options)

4. SUCCESS CALLBACK FUNCTIONS
Invoked upon a successful media capture operation
Each successful callback passes back a mediaFiles object which may be a list(array)
Each MediaFiles object describes the captured media file
Properties
name: The name of the file, without path information. (DOMString)
fullPath: The full path of the file, including the name. (DOMString)
type: The file's mime type (DOMString)
lastModifiedDate: The date and time when the file was last modified. (Date)
size: The size of the file, in bytes. (Number)
Method
getFormatData(): Retrieves the format information of the media file.

5. ERROR CALLBACKS Examine error.code for one of these constant values:
Failure scenarios include
when the capture application is busy
a capture operation is already taking place
the user cancels the operation before any media files are captured
Examine error.code for one of these constant values:
CaptureError.CAPTURE_INTERNAL_ERR
The camera or microphone failed to capture image or sound
CaptureError.CAPTURE_APPLICATION_BUSY
The camera or audio capture application is currently serving another capture request
CaptureError.CAPTURE_INVALID_ARGUMENT
Invalid use of the API (e.g., the value of limit is less than one)
CaptureError.CAPTURE_NO_MEDIA_FILES
The user exits the camera or audio capture application before capturing anything
CaptureError.CAPTURE_PERMISSION_DENIED
The user denied a permission required to perform the given capture request.
CaptureError.CAPTURE_NOT_SUPPORTED
The requested capture operation is not supported

6. capture.captureAudio
Starts an asynchronous operation to capture audio recordings using the device's default audio recording application
allows the user to capture multiple recordings in a single session
capture operation ends when either the user exits the audio recording application, or the maximum number of recordings is reached
navigator.device.capture.captureAudio(success,fail,options);
captureAudio(…) takes three arguments:
the name of the function to run when audio is successfully recorded
the name of a function to run when an attempt to record audio fails
some optional arguments
Limit: maximum number of recordings (default:1)
Duration: maximum number of seconds for audio/video recording

7. capture.captureImage
Starts an asynchronous operation to capture images using the device's camera application
allows the user to capture multiple images in a single session
capture operation ends when either the user closes the camera, or the maximum number of recordings is reached
navigator.device.capture.captureImage(success,fail,options);
captureImage(…) takes three arguments:
the name of the function to run when the image is successfully taken
the name of a function to run when an attempt to take the image fails
some optional arguments
Limit: maximum number of image recordings

8. capture.captureVideo
Starts an asynchronous operation to capture video recordings using the device's default video recording application
allows the user to capture multiple recordings in a single session
capture operation ends when either the user exits the video recording application, or the maximum number of recordings is reached
navigator.device.capture.captureVideo(success,fail,options);
captureVideo(…) takes three arguments:
the name of the function to run when video is successfully recorded
the name of a function to run when an attempt to record video fails
some optional arguments
Limit: maximum number of recordings
Duration: maximum number of seconds for audio/video recording

9. Capture Audio Example
function captureAudio() { navigator.device.capture.captureAudio(captureSuccess, captureError, {limit: 2}); } function captureSuccess(mediaFiles) { var i; var len = mediaFiles.length; for (i = 0; i < len; i ++) { path = mediaFiles[i].fullPath; // do something interesting with the file and check if another file exists } function captureError(error) { var msg = 'An error occurred during capture: ' + error.code; navigator.notification.alert(msg);

10. Capture Image Example
function captureImage() { navigator.device.capture.captureImage(captureSuccess, captureError, {limit: 2}); } function captureSuccess(mediaFiles) { var I; var len = mediaFiles.length; for (i = 0; i < len; i += 1) { imgName = mediaFiles[i].name; // do something interesting with the file } function captureError(error) { var msg = 'An error occurred during capture: ' + error.code; navigator.notification.alert(msg);

11. Capture Video Example
function captureVideo() { var options = { limit: 3, duration: 10 }; navigator.device.capture.captureVideo(captureSuccess, captureError, options); } function captureSuccess(mediaFiles) { var I; var len = mediaFiles.length; for (i = 0; i < len; i += 1) { mediaFiles[i].getFormatData(successCallback,errorCallback); function captureError(error) { var msg = 'An error occurred during capture: ' + error.code; navigator.notification.alert(msg);

12. Mediafiles object method: Get Format Data
Retrieves format information about the media capture file.
Example:
mediaFiles.getFormatData(successCallback,errorCallback);
function successCallback(MediaFileData) {
var imgHeight=MediaFileData.height; }
MediaFileData properties
codecs: The actual format of the audio and video content. (DOMString)
bitrate: The average bitrate of the content. The value is zero for images. (Number)
height: The height of the image or video in pixels. The value is zero for audio clips. (Number)
width: The width of the image or video in pixels. The value is zero for audio clips. (Number)
duration: The length of the video or sound clip in seconds. The value is zero for images. (Number)