我需要实现一个应用程序，其中视频正在视频视图中显示。用户从视频中选择特定范围的帧，并且帧速度减慢。基本上我已经完成了显示视频帧，用户也可以选择一组帧。接下来不知道如何降低所选帧的音频和视频速度。
问问题
1847 次
1 回答
0
使用Vitamio Api可以执行视频减慢（播放视频并改变播放速度）。出于测试目的，用户可以使用 GitHub Vitamio android sample上提供的 vitamio 示例。或者可以在 vitamio 示例中添加类 MediaPlayerDemo_Video avaialbe 到慢速视频。
这是 MediaPlayerDemo_Video 的代码
public class MediaPlayerDemo_Video extends Activity implements OnBufferingUpdateListener, OnCompletionListener, OnPreparedListener, OnVideoSizeChangedListener, SurfaceHolder.Callback {
private static final String TAG = "MediaPlayerDemo";
private int mVideoWidth;
private int mVideoHeight;
private MediaPlayer mMediaPlayer;
private SurfaceView mPreview;
private SurfaceHolder holder;
private String path;
private Bundle extras;
private static final String MEDIA = "media";
private static final int LOCAL_AUDIO = 1;
private static final int STREAM_AUDIO = 2;
private static final int RESOURCES_AUDIO = 3;
private static final int LOCAL_VIDEO = 4;
private static final int STREAM_VIDEO = 5;
private boolean mIsVideoSizeKnown = false;
private boolean mIsVideoReadyToBePlayed = false;
/**
*
* Called when the activity is first created.
*/
@Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
if (!LibsChecker.checkVitamioLibs(this))
return;
setContentView(R.layout.mediaplayer_2);
mPreview = (SurfaceView) findViewById(R.id.surface);
holder = mPreview.getHolder();
holder.addCallback(this);
holder.setFormat(PixelFormat.RGBA_8888);
extras = getIntent().getExtras();
}
private void playVideo(Integer Media) {
doCleanUp();
try {
switch (Media) {
case LOCAL_VIDEO:
/*
* TODO: Set the path variable to a local media file path.
*/
path = "";
if (path == "") {
// Tell the user to provide a media file URL.
Toast.makeText(MediaPlayerDemo_Video.this, "Please edit MediaPlayerDemo_Video Activity, " + "and set the path variable to your media file path." + " Your media file must be stored on sdcard.", Toast.LENGTH_LONG).show();
return;
}
break;
case STREAM_VIDEO:
/*
* TODO: Set path variable to progressive streamable mp4 or
* 3gpp format URL. Http protocol should be used.
* Mediaplayer can only play "progressive streamable
* contents" which basically means: 1. the movie atom has to
* precede all the media data atoms. 2. The clip has to be
* reasonably interleaved.
*
*/
path = "";
if (path == "") {
// Tell the user to provide a media file URL.
Toast.makeText(MediaPlayerDemo_Video.this, "Please edit MediaPlayerDemo_Video Activity," + " and set the path variable to your media file URL.", Toast.LENGTH_LONG).show();
return;
}
break;
}
// Create a new media player and set the listeners
mMediaPlayer = new MediaPlayer(this);
mMediaPlayer.setDataSource(path);
mMediaPlayer.setDisplay(holder);
mMediaPlayer.prepareAsync();
mMediaPlayer.setOnBufferingUpdateListener(this);
mMediaPlayer.setOnCompletionListener(this);
mMediaPlayer.setOnPreparedListener(this);
mMediaPlayer.setOnVideoSizeChangedListener(this);
setVolumeControlStream(AudioManager.STREAM_MUSIC);
} catch (Exception e) {
Log.e(TAG, "error: " + e.getMessage(), e);
}
}
public void onBufferingUpdate(MediaPlayer arg0, int percent) {
// Log.d(TAG, "onBufferingUpdate percent:" + percent);
}
public void onCompletion(MediaPlayer arg0) {
Log.d(TAG, "onCompletion called");
}
public void onVideoSizeChanged(MediaPlayer mp, int width, int height) {
Log.v(TAG, "onVideoSizeChanged called");
if (width == 0 || height == 0) {
Log.e(TAG, "invalid video width(" + width + ") or height(" + height + ")");
return;
}
mIsVideoSizeKnown = true;
mVideoWidth = width;
mVideoHeight = height;
if (mIsVideoReadyToBePlayed && mIsVideoSizeKnown) {
startVideoPlayback();
}
}
public void onPrepared(MediaPlayer mediaplayer) {
Log.d(TAG, "onPrepared called");
mIsVideoReadyToBePlayed = true;
if (mIsVideoReadyToBePlayed && mIsVideoSizeKnown) {
startVideoPlayback();
}
}
public void surfaceChanged(SurfaceHolder surfaceholder, int i, int j, int k) {
Log.d(TAG, "surfaceChanged called");
}
public void surfaceDestroyed(SurfaceHolder surfaceholder) {
Log.d(TAG, "surfaceDestroyed called");
}
public void surfaceCreated(SurfaceHolder holder) {
Log.d(TAG, "surfaceCreated called");
playVideo(extras.getInt(MEDIA));
}
@Override
protected void onPause() {
super.onPause();
releaseMediaPlayer();
doCleanUp();
}
@Override
protected void onDestroy() {
super.onDestroy();
releaseMediaPlayer();
doCleanUp();
}
private void releaseMediaPlayer() {
if (mMediaPlayer != null) {
mMediaPlayer.release();
mMediaPlayer = null;
}
}
private void doCleanUp() {
mVideoWidth = 0;
mVideoHeight = 0;
mIsVideoReadyToBePlayed = false;
mIsVideoSizeKnown = false;
}
private void startVideoPlayback() {
Log.v(TAG, "startVideoPlayback");
holder.setFixedSize(mVideoWidth, mVideoHeight);
mMediaPlayer.start();
}
}
布局代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<io.vov.vitamio.widget.CenterLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<SurfaceView
android:id="@+id/surface"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center" >
</SurfaceView>
</io.vov.vitamio.widget.CenterLayout>
</LinearLayout>
于 2016-04-11T12:55:02.250 回答