Android 相机视频为空白，带有白线

Posted 2023-04-17

【中文标题】Android 相机视频为空白，带有白线

【英文标题】：Android Camera Video is blank with white lines

【发布时间】：2021-04-12 02:45:52

【问题描述】：

我已经使用MediaRecorder 实现了android 的Camera2 API 来从摄像头录制视频。相机预览工作正常，视频文件也成功创建，没有任何错误。但是，输出的视频是空白的，并且有白色闪烁的线条。

这是我得到的输出视频。

准备MediaRecorder的代码

val surface = MediaCodec.createPersistentInputSurface()
surface.release()

val outputFile = createFile(applicationContext,"mp4")
val mMediaRecorder = MediaRecorder()
mMediaRecorder.setAudiosource(MediaRecorder.AudioSource.MIC)
mMediaRecorder.setVideoSource(MediaRecorder.VideoSource.SURFACE)
mMediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4)
mMediaRecorder.setOutputFile(outputFile.absolutePath)
mMediaRecorder.setVideoEncodingBitRate(10_000_000)
mMediaRecorder.setVideoFrameRate(30)
mMediaRecorder.setVideoSize(matchedResolution.width, matchedResolution.height)
mMediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.H264)
mMediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC)
mMediaRecorder.setInputSurface(surface)

创建会话。

val previewSurface = surfaceView2.holder.surface

val captureCallbackVideo =
    object : CameraCaptureSession.StateCallback() 
        override fun onConfigureFailed(session: CameraCaptureSession) 
        override fun onConfigured(session: CameraCaptureSession) 
            // session configured
            val previewRequestBuilder =
                cameraDevice.createCaptureRequest(TEMPLATE_RECORD)
                    .apply 
                        addTarget(previewSurface)
                        addTarget(surface)
                        set(CaptureRequest.CONTROL_AE_TARGET_FPS_RANGE, Range(30,30))
                    
            session.setRepeatingRequest(
                previewRequestBuilder.build(),
                null,
                Handler  true 
            )
        
    

cameraDevice.createCaptureSession(mutableListOf(previewSurface, surface), captureCallbackVideo, Handler  true )

开始录制

mMediaRecorder.prepare()
mMediaRecorder.start()

为了停止

mMediaRecorder.stop()
mMediaRecorder.release()

【参考方案1】：

我想通了。问题出在MediaRecorder 的输入表面上。显然，Google 在 GitHub 上的代码camera2 的方式在正确设置Surface 为MediaRecorder 时是不对的。

解决方案是我们不应该提供Surface 作为MediaRecorder 的输入，而是提供prepare 不带MediaRecorder 的Surface，然后将其内部Surface 用于我们的CaptureRequest

mMediaRecorder = MediaRecorder()
mMediaRecorder.setVideoSource(MediaRecorder.VideoSource.SURFACE)
mMediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4)
mMediaRecorder.setVideoEncodingBitRate(10_000_000)
//Uncomment on physical device, comment on emulator
//mMediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
mMediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.H264)
mMediaRecorder.setVideoSize(matchedResolution.width, matchedResolution.height)
mMediaRecorder.setVideoFrameRate(30)
mMediaRecorder.setOutputFile(outputFile.absolutePath)
try 
    mMediaRecorder.prepare()
 catch (e: java.lang.Exception) 
    e.printStackTrace()
    return

用于创建会话

val previewSurface = surfaceView2.holder.surface

val captureCallbackVideo =
    object : CameraCaptureSession.StateCallback() 
        override fun onConfigureFailed(session: CameraCaptureSession) 
        override fun onConfigured(session: CameraCaptureSession) 
            // session configured
            val previewRequestBuilder =
                cameraDevice.createCaptureRequest(TEMPLATE_RECORD)
                    .apply 
                        addTarget(previewSurface)
                        addTarget(mMediaRecorder.surface)
                        set(CaptureRequest.CONTROL_AE_TARGET_FPS_RANGE, Range(30,30))
                    
            session.setRepeatingRequest(
                previewRequestBuilder.build(),
                null,
                Handler  true 
            )
        
    

cameraDevice.createCaptureSession(mutableListOf(previewSurface, mMediaRecorder.surface), captureCallbackVideo, Handler  true )

开始录制：

mMediaRecorder.start()

停止录制：

mMediaRecorder.stop()
mMediaRecorder.release()

【参考方案2】：

您可以使用下面的代码，我认为 setVideoEncodingBitRate 可能存在问题

recorder.setVideoSize(640, 480);
recorder.setVideoFrameRate(16); //might be auto-determined due to lighting
recorder.setVideoEncodingBitRate(3000000);
recorder.setVideoEncoder(MediaRecorder.VideoEncoder.H264);// MPEG_4_SP
recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);

【讨论】：

这不是问题。我已经尝试过不同的比特率。