ApsaraVideo VOD:Terms

The short video SDK provides the Version class to obtain the SDK version information. You can use the variables that are defined in this class to obtain the SDK version information. Such information can help locate your issues.

public class Version {
    public static final String VERSION = "";
    public static final String BUILD_ID = "";
    public static final String SRC_COMMIT_ID = "";
    public static final String ALIVC_COMMIT_ID = "";
    public static final String ANDROID_COMMIT_ID = "";
}

You must activate the license of the short video SDK before you use the short video SDK. For more information, see Obtain and use a license for the short video SDK.

The resolution of a video indicates the effective horizontal and vertical pixels of the video. Generally, a higher resolution indicates a clearer video. However, a higher resolution indicates a larger file, which requires a longer processing time. Considering that the performance varies among different mobile devices, we recommend that you use 720P or a lower resolution. The following table describes the common video resolutions.

Resolution	1:1	3:4	9:16
480P	480*480	480*640	480*848
540P	540*540	540*720	540*960
720P	720*720	720*960	720*1280
1080P	1080*1080	1080*1440	1080*1920

• Recording module

  You can use the setMediaInfo(MediaInfo mediaInfo) method of AliyunIRecorder to set a resolution for the recorded video by setting the videoWidth and videoHeight attributes of a MediaInfo object.

• Cropping module

  You can use the setCropParam(CropParam param) method of AliyunICrop to set a resolution for the output video by setting the outputWidth and outputHeight attributes of a CropParam object.

• Editing module

  You can use the setVideoParam(AliyunVideoParam param) method of AliyunIImport to set a resolution for the output video by setting the mOutputWidth and mOutputHeight attributes of an AliyunVideoParam object.

The bitrate of a video indicates the number of bits that are transmitted per second. The unit is bit per second (bit/s). After you set a bitrate for a video, the video encoder compresses the video to the desired size. Within a specific range, a higher bitrate indicates a clearer video with a larger file size. The following table describes the recommended bitrates of different resolutions.

Resolution	Recommended bitrate
480P	1000000~2000000
540P	2000000~3000000
720P	2000000~4000000
1080P	2000000~6000000

• Recording module

  You can use the setVideoBitrate(int bitrate) method of AliyunIRecorder to set a bitrate for the recorded video.

• Cropping module

  You can use the setCropParam(CropParam param) method of AliyunICrop to set a bitrate for the output video by setting the mVideoBitrate attribute of a CropParam object.

• Editing module

  You can use the setVideoParam(AliyunVideoParam param) method of AliyunIImport to set a bitrate for the output video by setting the mBitrate attribute of an AliyunVideoParam object.

The frame rate of a video indicates the number of image frames that are displayed per second. The unit is frame per second (FPS). A higher frame rate indicates a smoother video with a larger file size. The recommended video frame rate is 25 FPS to 30 FPS.

• Recording module

  You can use the setMediaInfo(MediaInfo mediaInfo) method of AliyunIRecorder to set a frame rate for the recorded video by setting the mEncoderFps attribute of a MediaInfo object.

• Cropping module

  You can use the setCropParam(CropParam param) method of AliyunICrop to set a frame rate for the output video by setting the frameRate attribute of a CropParam object.

• Editing module

  You can use the setVideoParam(AliyunVideoParam param) method of AliyunIImport to set a frame rate for the output video by setting the mFrameRate attribute of an AliyunVideoParam object.

A group of pictures (GOP) is a collection of successive frames. A GOP starts with a keyframe, followed by a group of B-frames and P-frames. If the GOP size is too small, the number of keyframes increases in a video and the compression ratio decreases. If the GOP size is too large, seeking takes more time. In addition, reverse playback freezes because a GOP must be decoded for reversely playing the frames. In the short video SDK, the default GOP size is 5. We recommend that you set the GOP size to a value within 5 to 30.

• Recording module

  You can use the setGop(int gop) method of AliyunIRecorder to set a GOP size for the recorded video.

• Cropping module

  You can use the setCropParam(CropParam param) method of AliyunICrop to set a GOP size for the output video by setting the gop attribute of a CropParam object.

• Editing module

  You can use the setVideoParam(AliyunVideoParam param) method of AliyunIImport to set a GOP size for the output video by setting the mGop attribute of an AliyunVideoParam object.

The following table describes the scaling modes that are supported by the short video SDK.

Scaling mode	Solution
Cropping mode	Maintains the original aspect ratio and crops the material to display only the content in the middle area.
Padding mode	Maintains the original aspect ratio and displays the complete material by filling the blank area with a specified color.

• Cropping module

  You can use the setCropParam(CropParam param) method of AliyunICrop to set a scaling mode for the output video by setting the mScaleMode attribute of a CropParam object.

• Editing module

  You can use the setVideoParam(AliyunVideoParam param) method of AliyunIImport to set a scaling mode for the output video by setting the mScaleMode attribute of an AliyunVideoParam object.

The following table describes the encoding modes that are supported by the short video SDK.

Encoding mode	Description
Software encoding	Software encoding is completed by using the CPU. Compared with hardware encoding, software encoding allows you to set more parameters. At the same bitrate, a software-encoded video is clearer. However, software encoding is slow, the CPU load is high, and the mobile phone gets hot.
Hardware encoding	Hardware encoding is completed by other hardware instead of the CPU. Hardware encoding is faster, and the CPU load is low. However, the clearness of a hardware-encoded video is slightly lower than that of a software-encoded video. In addition, hardware encoding may fail on some Android devices.

Resources of the short video SDK include face recognition models, common filters, and animated filters. These SDK resources can be stored on the network or packaged into an Android package. Considering the size of the SDK resources, we recommend that you store the resources on the network and enable your application to download the resources when the application starts.

Type	Format
Video	MP4, MOV, and FLV
Audio	MP3, AAC, and PCM
Image	JPG, PNG, and GIF