Android视频和图像调整大小

Question

我正在寻找一种方法来降低图像和视频的大小，然后将其上传到服务器，此刻我发送的文件太大，我似乎找不到任何解决方案如何压缩这些文件，我知道像whatsapp和facebook这样的应用可以在几秒钟内压缩视频，并将它们剪裁成90％的大小，任何人都可以得到建议，我会很感激的。

谢谢。

Answer 1

我今天确实需要这么想这个代码。发送此函数一个位图，它将返回压缩图像的文件路径（本地）。然后创建一个与返回的文件路径的文件对象，并将其发送到服务器：

public File compressImage(Bitmap bmp) { 
     Bitmap scaledBitmap = null; 

     int actualHeight = bmp.getHeight(); 
     int actualWidth = bmp.getWidth(); 

//      max Height and width values of the compressed image is taken as 816x612 
     float imgRatio = actualWidth/actualHeight; 
     float maxRatio = logoMaxWidth/logoMaxHeight; 
//      width and height values are set maintaining the aspect ratio of the image 
     if (actualHeight > logoMaxHeight || actualWidth > logoMaxWidth) { 
      if (imgRatio < maxRatio) { 
       imgRatio = logoMaxHeight/actualHeight; 
       actualWidth = (int) (imgRatio * actualWidth); 
       actualHeight = (int) logoMaxHeight; 
      } else if (imgRatio > maxRatio) { 
       imgRatio = logoMaxWidth/actualWidth; 
       actualHeight = (int) (imgRatio * actualHeight); 
       actualWidth = (int) logoMaxWidth; 
      } else { 
       actualHeight = (int) logoMaxHeight; 
       actualWidth = (int) logoMaxWidth; 
      } 
     } 
     try { 
      scaledBitmap = Bitmap.createScaledBitmap(bmp, actualWidth, actualHeight, true); 
     } catch (OutOfMemoryError exception) { 
      logoUploadFaied(); 
      exception.printStackTrace(); 
     } 
     String uriSting = (System.currentTimeMillis() + ".jpg"); 
     File file = new File(Environment.getExternalStorageDirectory() 
       + File.separator + uriSting); 
     try { 
      file.createNewFile(); 
     } catch (IOException e) { 
      logoUploadFaied(); 
      e.printStackTrace(); 
     } 

     FileOutputStream fos = null; 
     try { 
      fos = new FileOutputStream(file); 
     } catch (FileNotFoundException e) { 
      logoUploadFaied(); 
      e.printStackTrace(); 
     } 
     try { 
      fos.write(getBytesFromBitmap(scaledBitmap)); 
      fos.close(); 
      //recycling bitMap to overcome OutOfMemoryError 
      if(scaledBitmap!=null){ 
       scaledBitmap.recycle(); 
       scaledBitmap=null; 
      } 
     } catch (IOException e) { 
      logoUploadFaied(); 
      e.printStackTrace(); 
     } 
     return file; 
    } 

Answer 2

可以使用的ffmpeg，一个开源的视频库，做压缩。

请注意，视频压缩的计算密集程度通常很高，所以除了小视频之外，不可能只需要“几秒钟”。

有许多方法可以在您的应用程序中包含ffmpeg。在这些“包装”项目看一看的例子醚的使用或帮助您构建自己的ffmpeg库：

• http://hiteshsondhi88.github.io/ffmpeg-android-java/
• https://github.com/jhotovy/android-ffmpeg

作为一个例子，下面的代码将压缩一旦您选择或构建了一个ffmpeg包装（此代码使用自定义ffmpeg库，但它应该给您一个概述，并且您应该能够替换上述示例之一）：mp4视频文件（默认压缩）：

public class VideoCompressionTask extends AsyncTask<String, String, String> { 
/* This Class is an AsynchTask to compress a video on a background thread 
* 
*/ 

@Override 
protected String doInBackground(String... params) { 
    //Compress the video in the background 

    //Get the the path of the video to compress 
    String videoPath; 
    String videoFileName; 
    File videoFileToCompress; 
    if (params.length == 1) { 
     videoPath = params[0]; 
     videoFileToCompress = new File(videoPath); 
     videoFileName = videoFileToCompress.getName(); 
    } else { 
     //One or all of the params are not present - log an error and return 
     Log.d("VideoCompressionTask","doInBackground wrong number of params"); 
     return null; 
    } 

    //Make sure the video to compress actually exists 
    if(!videoFileToCompress.exists()) { 
     Log.d("VideoCompressionTask","doInBackground video file to compress does not exist"); 
     return null; 
    } 

    //If the compressed file already exists then delete it first and let this task create a new one 
    File compressedVideoFile = new File(compressedFilePath); 
    if(compressedVideoFile.exists()) { 
     compressedVideoFile.delete(); 
    } 

    String argv[] = {"ffmpeg", "-i", videoPath, "-strict", "experimental", "-acodec", "aac", compressedFilePath}; 
    int ffmpegWrapperreturnCode = FfmpegJNIWrapper.call_ffmpegWrapper(appContext, argv); 
    Log.d("VideoCompressionTask","doInBackground ffmpegWrapperreturnCode: " + ffmpegWrapperreturnCode); 

    return(compressedFilePath); 
}