QtMultiMedia之CameraRecorder

QtMultiMedia 之 CameraRecorder

翻译： qyvlik


5.5.1

为

Camera

提供视频录制控制。

属性

actualLocation

:

string

audioBitRate

:

int

audioChannels

:

int

audioCodec

:

string

audioEncodingMode

:

enumeration

audioSampleRate

:

int

duration

:

int

errorCode

:

enumeration

errorString

:

string

frameRate

:

qreal

mediaContainer

:

string

muted

:

bool

outputLocation

:

string

recorderState

:

enumeration

recorderStatus

:

enumeration

resolution

:

size

videoBitRate

:

int

videoCodec

:

string

videoEncodingMode

:

enumeration

方法

record()

setMetadata(key, value)

stop()

详细描述

CameraRecorder allows recording camera streams to files, and adjusting recording settings and metadata for videos.

It should not be constructed separately, instead the videoRecorder property of a Camera should be used.

CameraRecorder

允许录制视频流到文件，为视频调整设置和元信息（例如 gps 等信息）。

CameraRecorder

不能直接创建，只能通过某个实例化的

Camera

的

videoRecorder

属性来使用。

[code]Camera {
    videoRecorder.audioEncodingMode: CameraRecorder.ConstantBitrateEncoding;
    videoRecorder.audioBitRate: 128000
    videoRecorder.mediaContainer: "mp4"
    // ...
}

There are many different settings for each part of the recording process (audio, video, and output formats), as well as control over muting and where to store the output file.

录制过程中有许多设置，例如音频，视频，输出格式等，也允许控制是否静音以及存储路径等。

属性文档

actualLocation

:

string

This property holds the actual location of the last saved media content. The actual location is usually available after the recording starts, and reset when new location is set or the new recording starts.

这个属性保存的是最后保存的媒体内容的本地路径。通常在录制开始后这个本地路径才有效，当开始新的录制时，这个本地路径就会更新。

audioBitRate

:

int

This property holds the audio bit rate (in bits per second) to be used for recording video.

这个属性设置了录制视频时音频的比特率。

audioChannels

:

int

This property indicates the number of audio channels to be encoded while recording video (1 is mono, 2 is stereo).

在录制视频时，这个属性表示音频的通道数。（1 是 单声道，2 是立体声）。

不过原文中单声道是 momo，momo 是什么鬼

audioCodec

:

string

This property holds the audio codec to be used for recording video. Typically this is aac or amr-wb.

录制视频时指定的音频格式，一般是

aac

或者

amr-wb

。

audioEncodingMode

:

enumeration

The type of encoding method to use when recording audio.

录制音频的编码模式。

Value	Description
ConstantQualityEncoding	Encoding will aim to have a constant quality, adjusting bitrate to fit. This is the default. The bitrate setting will be ignored.
ConstantBitRateEncoding	Encoding will use a constant bit rate, adjust quality to fit. This is appropriate if you are trying to optimize for space.
AverageBitRateEncoding	Encoding will try to keep an average bitrate setting, but will use more or less as needed.

值	描述
ConstantQualityEncoding	编码时将有一个固定的质量，自动调整比特率。这个是默认值，自行设置比特率的将会被忽略。
ConstantBitRateEncoding	编码时将有一个固定的比特率，自行设置质量值来调整。你可以适当的调整质量值来优化存储。
AverageBitRateEncoding	编码时将会试图保存一个平均比特率，一般很少使用。

audioSampleRate

:

int

This property holds the sample rate to be used to encode audio while recording video.

录制视频时用来编码音频的采样率。

duration

:

int

This property holds the duration (in miliseconds) of the last recording.

最近一次录制的时长（毫秒）。

errorCode

:

enumeration

This property holds the last error code.

Value	Description
NoError	No Errors
ResourceError	Device is not ready or not available.
FormatError	Current format is not supported.
OutOfSpaceError	No space left on device.

值	描述
NoError	没有错误
ResourceError	设备还未就绪或者无法使用。
FormatError	不支持当前格式。
OutOfSpaceError	没有足够的存储空间。

errorString

:

string

This property holds the description of the last error.

保存最后一次错误描述。

frameRate

:

qreal

This property holds the framerate (in frames per second) to be used for recording video.

录制视频的帧率。

mediaContainer

:

string

This property holds the media container to be used for recording video. Typically this is mp4.

媒体容器，其实就是后缀名。默认为

mp4

。

muted

:

bool

This property indicates whether the audio input is muted during recording.

outputLocation

:

string

This property holds the destination location of the media content. If the location is empty, the recorder uses the system-specific place and file naming scheme.

媒体内容的终点路径（其实是保存路径？）。如果这个路径是空的，将会使用系统指定的路径和文件命名方式。

recorderState

:

enumeration

This property holds the current state of the camera recorder object.

相机的录制状态。

The state can be one of these two:

Value	Description
StoppedState	The camera is not recording video.
RecordingState	The camera is recording video.

一般有两个状态：

Value	Description
StoppedState	没有录制。
RecordingState	正在录制。

recorderStatus

:

enumeration

This property holds the current status of media recording.

录制媒体的状态。

Value	Description
UnavailableStatus	Recording is not supported by the camera.
UnloadedStatus	The recorder is available but not loaded.
LoadingStatus	The recorder is initializing.
LoadedStatus	The recorder is initialized and ready to record media.
StartingStatus	Recording is requested but not active yet.
RecordingStatus	Recording is active.
PausedStatus	Recording is paused.
FinalizingStatus	Recording is stopped with media being finalized.

Value	Description
UnavailableStatus	相机不支持录制。
UnloadedStatus	相机支持录制，但是未加载。
LoadingStatus	相机录制器正在初始化
LoadedStatus	相机录制器完成初始化，可以开始录制。
StartingStatus	相机录制器请求录制，等待响应中。
RecordingStatus	相机录制器正在录制。
PausedStatus	相机录制器暂停录制。
FinalizingStatus	相机录制器停止录制。

resolution

:

size

This property holds the video frame dimensions to be used for video capture.

保存了视频帧的大小尺寸。

videoBitRate

:

int

This property holds the bit rate (in bits per second) to be used for recording video.

视频的比特率。

videoCodec

:

string

This property holds the video codec to be used for recording video. Typically this is h264.

视频的编码方式，默认

h264

。

videoEncodingMode

:

enumeration

This property holds the type of encoding method to be used for recording video.

录制视频的编码模式。

The following are the different encoding methods used:

Value	Description
ConstantQualityEncoding	Encoding will aim to have a constant quality, adjusting bitrate to fit. This is the default. The bitrate setting will be ignored.
ConstantBitRateEncoding	Encoding will use a constant bit rate, adjust quality to fit. This is appropriate if you are trying to optimize for space.
AverageBitRateEncoding	Encoding will try to keep an average bitrate setting, but will use more or less as needed.

有如下不同的模式可以使用：

值	描述
ConstantQualityEncoding	编码时将有一个固定的质量，自动调整比特率。这个是默认值，自行设置比特率的将会被忽略。
ConstantBitRateEncoding	编码时将有一个固定的比特率，自行设置质量值来调整。你可以适当的调整质量值来优化存储。
AverageBitRateEncoding	编码时将会试图保存一个平均比特率，一般很少使用。

方法文档

record()

Starts recording.

开始录制。

setMetadata(key, value)

Sets metadata for the next video to be recorder, with the given key being associated with value.

为下一个视频设置元数据。

stop()

Stops recording.

停止录制。