Android录制视频分段保存的探究

录制视频需要分段保存，可以从系统源码考虑，看了以下一些代码：

• framework/av/media/libstagefright/MPEG4Writer.cpp
• package/apps/Camera/src/com/android/camera/actor/VideoActor.java

主要从MPEG4Writer.cpp中的kMax32BitFileSize 和入手，如下，修改单个文件最大容量为56M（0x3800000），发现利用系统Camera录像时，到达阀值后会提示“已达到大小上限”，并自动停止，保存已经录制的视频。

static const int64_t kMax32BitFileSize = 0x3800000;//0x00ffffffffLL; // 2^32-1 : max FAT32
static const int64_t kMax32BitDuration = 0x007fffffffLL;

然后追踪到VideoActor的处理。有一个思路，就是停止的时候，进行文件保存后立即重新启动录像。

    public void stopVideoRecordingAsync() { // TChip ZJ
        // for snapshot
        stopObjectTracking();
        mStopVideoRecording = true;
        Log.d(TAG, "stopVideoRecordingAsync() mMediaRecorderRecording=" + mMediaRecorderRecording 
                + ", mRecorderBusy=" + mRecorderBusy 
                + ", isVideoProcessing()" + isVideoProcessing()
                + ", mStopVideoRecording =" + mStopVideoRecording);
        mVideoContext.getZoomManager().changeZoomForQuality();
        mVideoContext.setSwipingEnabled(true);
        mHandler.removeMessages(UPDATE_RECORD_TIME);
        mVideoContext.getShutterManager().setVideoShutterMask(false);
        if (isVideoProcessing()) {
            return;
        }
        if (mRecorderBusy) { // return for recorder is busy.
            return;
        }
        mRecorderBusy = true;
        mRecordingView.hide();
        if (mMediaRecorderRecording) {
            mVideoContext.getShutterManager().setVideoShutterEnabled(false);
            if (mStoppingAction != STOP_RETURN_UNVALID && mCallFromOnPause != true) {
               // mVideoContext.showProgress(mVideoContext.getResources().getString(R.string.saving)); // TChip ZJ : 去掉保存UI
            }
            mVideoSavingTask = new SavingTask();
            mVideoSavingTask.start();
        } else {
            mRecorderBusy = false;
            releaseRecorder();
            if (mStoppingAction == STOP_RETURN_UNVALID) {
                doReturnToCaller(false);
            }
        }
    }

先吃饭了，明天再看实现的可行性以及效果（是否漏秒）。