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我有此命令使用ffmpeg運行以降低比特率。使用ffmpeg降低比特率
的ffmpeg -y -i input.mp4 -b：v 1024K output_1024k.mp4
，我們要採取輸入文件，只是降低它的比特率（只是1024K）。它在命令行中工作。 現在，我想通過Java降低比特率。我決定使用bytedeco/javacv FFmpegFrameGrabber和FFmpegFrameRecorder來執行相同的功能。下面是我的代碼：
FFmpegFrameGrabber grabber = new FFmpegFrameGrabber("input.mp4");
grabber.start();
FrameRecorder recorder = new FFmpegFrameRecorder("out.mp4", grabber.getAudioChannels());
recorder.setSampleRate(256);
recorder.start();
Frame frame;
while ((frame = grabber.grabFrame()) != null) {
recorder.record(frame);
}
recorder.stop();
grabber.stop();
但跟它以下錯誤：
org.bytedeco.javacv.FrameRecorder$Exception: avcodec_open2() error -22: Could not open audio codec.
at org.bytedeco.javacv.FFmpegFrameRecorder.startUnsafe(FFmpegFrameRecorder.java:732)
at org.bytedeco.javacv.FFmpegFrameRecorder.start(FFmpegFrameRecorder.java:351)
at com.goxhere.api.monte.resources.VideoResource.uploadFile(VideoResource.java:337)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.glassfish.jersey.server.model.internal.ResourceMethodInvocationHandlerFactory.lambda$static$0(ResourceMethodInvocationHandlerFactory.java:74)
at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher$1.run(AbstractJavaResourceMethodDispatcher.java:144)
at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.invoke(AbstractJavaResourceMethodDispatcher.java:161)
at org.glassfish.jersey.server.model.internal.JavaResourceMethodDispatcherProvider$TypeOutInvoker.doDispatch(JavaResourceMethodDispatcherProvider.java:247)
at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.dispatch(AbstractJavaResourceMethodDispatcher.java:99)
at org.glassfish.jersey.server.model.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:388)
at org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:346)
at org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:102)
at org.glassfish.jersey.server.ServerRuntime$2.run(ServerRuntime.java:337)
at org.glassfish.jersey.internal.Errors$1.call(Errors.java:271)
at org.glassfish.jersey.internal.Errors$1.call(Errors.java:267)
at org.glassfish.jersey.internal.Errors.process(Errors.java:315)
at org.glassfish.jersey.internal.Errors.process(Errors.java:297)
at org.glassfish.jersey.internal.Errors.process(Errors.java:267)
at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:280)
at org.glassfish.jersey.server.ServerRuntime.process(ServerRuntime.java:316)
at org.glassfish.jersey.server.ApplicationHandler.handle(ApplicationHandler.java:1084)
at org.glassfish.jersey.servlet.WebComponent.serviceImpl(WebComponent.java:418)
at org.glassfish.jersey.servlet.WebComponent.service(WebComponent.java:372)
at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:389)
at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:342)
at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:229)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:624)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:799)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:861)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1455)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:748)
基本上錯誤說我有音頻編解碼器的問題，但是當我試圖直接運行FFmpeg的命令行，它減少比特率就好了。我們是否缺少javacode中的一些設置？謝謝。