北上广程序员回重庆继续代码kotlin音视频解析六收藏

　　今天开始就讲解工具类的开发，AudioExtractor 音频的提取类，一个音视频包含了音频和视频，我们在拿到一个mp4文件过后，如果自己写一个播放器就需要解析里面的音频和视频。
　　这个工具类就是来解析音频里面的音频提取，需要用到的知识点有文件，文件异常IOException，FFmpeg 也是一个开源库，就是一个指令来提取视频里面的音频：val cmd = arrayOf(＂-i＂, video!!.path, ＂-vn＂, ＂-ar＂, ＂44100＂, ＂-ac＂, ＂2＂, ＂-ab＂, ＂192＂, ＂-f＂, ＂mp3＂, outputLocation.path)
　　有了这个工具类就很方便的把视频里面的音频给提取出来了class AudioExtractor private constructor(private val context: Context) {      private var video: File? = null     private var callback: FFMpegCallback? = null     private var outputPath = ＂＂     private var outputFileName = ＂＂      fun setFile(originalFiles: File): AudioExtractor {         this.video = originalFiles         return this     }      fun setCallback(callback: FFMpegCallback): AudioExtractor {         this.callback = callback         return this     }      fun setOutputPath(output: String): AudioExtractor {         this.outputPath = output         return this     }      fun setOutputFileName(output: String): AudioExtractor {         this.outputFileName = output         return this     }      fun extract() {          video?.let {              if (!video!!.exists()) {                 callback!!.onFailure(IOException(＂File not exists＂))                 return             }             if (!video!!.canRead()) {                 callback!!.onFailure(IOException(＂Can＂t read the file. Missing permission?＂))                 return             }              val outputLocation = Utils.getConvertedFile(outputPath, outputFileName)              //Create Audio File with 192Kbps             //Select .mp3 format             val cmd = arrayOf(＂-i＂, video!!.path, ＂-vn＂, ＂-ar＂, ＂44100＂, ＂-ac＂, ＂2＂, ＂-ab＂, ＂192＂, ＂-f＂, ＂mp3＂, outputLocation.path)              try {                 FFmpeg.getInstance(context).execute(cmd, object : ExecuteBinaryResponseHandler() {                     override fun onStart() {}                      override fun onProgress(message: String?) {                         callback!!.onProgress(message!!)                     }                      override fun onSuccess(message: String?) {                         Utils.refreshGallery(outputLocation.path, context)                         callback!!.onSuccess(outputLocation, OutputType.TYPE_AUDIO)                      }                      override fun onFailure(message: String?) {                         if (outputLocation.exists()) {                             outputLocation.delete()                         }                         callback!!.onFailure(IOException(message))                     }                      override fun onFinish() {                         callback!!.onFinish()                     }                 })             } catch (e: Exception) {                 callback!!.onFailure(e)             } catch (e2: FFmpegCommandAlreadyRunningException) {                 callback!!.onNotAvailable(e2)             }         }      }      companion object {          val TAG = ＂AudioExtractor＂          fun with(context: Context): AudioExtractor {             return AudioExtractor(context)         }     } }
　　上面就完成了音频的提取了完成了。
　　我是一个北上广回回重庆的程序员坚持在写代码，记得点赞，关注，转发，谢谢了。