好吧，我正在使用 Android 版 LibVLC(与 Android Studio)来接收 IP 摄像机的实时 RTSP 流，因为 VideoView 不太支持实时流。我使用的是 VideoLAN 人员提供的示例代码，可以在此处找到:
https://code.videolan.org/videolan/libvlc-android-samples
我对代码进行了大量调查，以从我的相机输出的 4:3 宽高比中实现 19:6 宽高比。我尝试打破宽高比的原因是因为该 IP 摄像机记录 1280x720 像素，但通过其第二个流输出 640x480。问题是宽度没有被裁剪，而是从侧面拉伸(stretch)，所以看起来有点压缩。
我尝试在 SurfaceView 上将 4 个alignParent 选项设置为 true，但没有结果。还尝试将我在 JavaActivity 类代码中找到的一些宽度变量乘以 1.33333，理论上应该拉伸(stretch)宽度，但什么也没发生，甚至没有错误或异常。我还尝试创建一个扩展 SurfaceView 的新类并使用 onMeasure 方法进行调整，但没有成功。这是示例中的 JavaActivity 代码(当然，我已经调整了我的代码以与我的项目配合使用，但做了一些细微的更改)
package org.videolan.javasample;
import android.annotation.TargetApi;
import android.content.res.Configuration;
import android.graphics.PixelFormat;
import android.net.Uri;
import android.os.Build;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.SurfaceView;
import android.view.TextureView;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewStub;
import android.widget.FrameLayout;
import org.videolan.libvlc.IVLCVout;
import org.videolan.libvlc.LibVLC;
import org.videolan.libvlc.Media;
import org.videolan.libvlc.MediaPlayer;
import java.util.ArrayList;
public class JavaActivity extends AppCompatActivity implements IVLCVout.OnNewVideoLayoutListener {
private static final boolean USE_SURFACE_VIEW = true;
private static final boolean ENABLE_SUBTITLES = true;
private static final String TAG = "JavaActivity";
private static final String SAMPLE_URL = "http://download.blender.org/peach/bigbuckbunny_movies/BigBuckBunny_640x360.m4v";
// Not the actual RTSP Live Stream link but you know...
private static final int SURFACE_BEST_FIT = 0;
private static final int SURFACE_FIT_SCREEN = 1;
private static final int SURFACE_FILL = 2;
private static final int SURFACE_16_9 = 3;
private static final int SURFACE_4_3 = 4;
private static final int SURFACE_ORIGINAL = 5;
private static int CURRENT_SIZE = SURFACE_BEST_FIT;
private FrameLayout mVideoSurfaceFrame = null;
private SurfaceView mVideoSurface = null;
private SurfaceView mSubtitlesSurface = null;
private TextureView mVideoTexture = null;
private View mVideoView = null;
private final Handler mHandler = new Handler();
private View.OnLayoutChangeListener mOnLayoutChangeListener = null;
private LibVLC mLibVLC = null;
private MediaPlayer mMediaPlayer = null;
private int mVideoHeight = 0;
private int mVideoWidth = 0;
private int mVideoVisibleHeight = 0;
private int mVideoVisibleWidth = 0;
private int mVideoSarNum = 0;
private int mVideoSarDen = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final ArrayList<String> args = new ArrayList<>();
args.add("-vvv");
mLibVLC = new LibVLC(this, args);
mMediaPlayer = new MediaPlayer(mLibVLC);
mVideoSurfaceFrame = (FrameLayout) findViewById(R.id.video_surface_frame);
if (USE_SURFACE_VIEW) {
ViewStub stub = (ViewStub) findViewById(R.id.surface_stub);
mVideoSurface = (SurfaceView) stub.inflate();
if (ENABLE_SUBTITLES) {
stub = (ViewStub) findViewById(R.id.subtitles_surface_stub);
mSubtitlesSurface = (SurfaceView) stub.inflate();
mSubtitlesSurface.setZOrderMediaOverlay(true);
mSubtitlesSurface.getHolder().setFormat(PixelFormat.TRANSLUCENT);
}
mVideoView = mVideoSurface;
}
else
{
ViewStub stub = (ViewStub) findViewById(R.id.texture_stub);
mVideoTexture = (TextureView) stub.inflate();
mVideoView = mVideoTexture;
}
}
@Override
protected void onDestroy() {
super.onDestroy();
mMediaPlayer.release();
mLibVLC.release();
}
@Override
protected void onStart() {
super.onStart();
final IVLCVout vlcVout = mMediaPlayer.getVLCVout();
if (mVideoSurface != null) {
vlcVout.setVideoView(mVideoSurface);
if (mSubtitlesSurface != null)
vlcVout.setSubtitlesView(mSubtitlesSurface);
}
else
vlcVout.setVideoView(mVideoTexture);
vlcVout.attachViews(this);
Media media = new Media(mLibVLC, Uri.parse(SAMPLE_URL));
mMediaPlayer.setMedia(media);
media.release();
mMediaPlayer.play();
if (mOnLayoutChangeListener == null) {
mOnLayoutChangeListener = new View.OnLayoutChangeListener() {
private final Runnable mRunnable = new Runnable() {
@Override
public void run() {
updateVideoSurfaces();
}
};
@Override
public void onLayoutChange(View v, int left, int top, int right,
int bottom, int oldLeft, int oldTop, int oldRight, int oldBottom) {
if (left != oldLeft || top != oldTop || right != oldRight || bottom != oldBottom) {
mHandler.removeCallbacks(mRunnable);
mHandler.post(mRunnable);
}
}
};
}
mVideoSurfaceFrame.addOnLayoutChangeListener(mOnLayoutChangeListener);
}
@Override
protected void onStop() {
super.onStop();
if (mOnLayoutChangeListener != null) {
mVideoSurfaceFrame.removeOnLayoutChangeListener(mOnLayoutChangeListener);
mOnLayoutChangeListener = null;
}
mMediaPlayer.stop();
mMediaPlayer.getVLCVout().detachViews();
}
private void changeMediaPlayerLayout(int displayW, int displayH) {
/* Change the video placement using the MediaPlayer API */
switch (CURRENT_SIZE) {
case SURFACE_BEST_FIT:
mMediaPlayer.setAspectRatio(null);
mMediaPlayer.setScale(0);
break;
case SURFACE_FIT_SCREEN:
case SURFACE_FILL: {
Media.VideoTrack vtrack = mMediaPlayer.getCurrentVideoTrack();
if (vtrack == null)
return;
final boolean videoSwapped = vtrack.orientation == Media.VideoTrack.Orientation.LeftBottom
|| vtrack.orientation == Media.VideoTrack.Orientation.RightTop;
if (CURRENT_SIZE == SURFACE_FIT_SCREEN) {
int videoW = vtrack.width;
int videoH = vtrack.height;
if (videoSwapped) {
int swap = videoW;
videoW = videoH;
videoH = swap;
}
if (vtrack.sarNum != vtrack.sarDen)
videoW = videoW * vtrack.sarNum / vtrack.sarDen;
float ar = videoW / (float) videoH;
float dar = displayW / (float) displayH;
float scale;
if (dar >= ar)
scale = displayW / (float) videoW; /* horizontal */
else
scale = displayH / (float) videoH; /* vertical */
mMediaPlayer.setScale(scale);
mMediaPlayer.setAspectRatio(null);
} else {
mMediaPlayer.setScale(0);
mMediaPlayer.setAspectRatio(!videoSwapped ? ""+displayW+":"+displayH
: ""+displayH+":"+displayW);
}
break;
}
case SURFACE_16_9:
mMediaPlayer.setAspectRatio("16:9");
mMediaPlayer.setScale(0);
break;
case SURFACE_4_3:
mMediaPlayer.setAspectRatio("4:3");
mMediaPlayer.setScale(0);
break;
case SURFACE_ORIGINAL:
mMediaPlayer.setAspectRatio(null);
mMediaPlayer.setScale(1);
break;
}
}
private void updateVideoSurfaces() {
int sw = getWindow().getDecorView().getWidth();
int sh = getWindow().getDecorView().getHeight();
// sanity check
if (sw * sh == 0) {
Log.e(TAG, "Invalid surface size");
return;
}
mMediaPlayer.getVLCVout().setWindowSize(sw, sh);
ViewGroup.LayoutParams lp = mVideoView.getLayoutParams();
if (mVideoWidth * mVideoHeight == 0) {
/* Case of OpenGL vouts: handles the placement of the video using MediaPlayer API */
lp.width = ViewGroup.LayoutParams.MATCH_PARENT;
lp.height = ViewGroup.LayoutParams.MATCH_PARENT;
mVideoView.setLayoutParams(lp);
lp = mVideoSurfaceFrame.getLayoutParams();
lp.width = ViewGroup.LayoutParams.MATCH_PARENT;
lp.height = ViewGroup.LayoutParams.MATCH_PARENT;
mVideoSurfaceFrame.setLayoutParams(lp);
changeMediaPlayerLayout(sw, sh);
return;
}
if (lp.width == lp.height && lp.width == ViewGroup.LayoutParams.MATCH_PARENT) {
/* We handle the placement of the video using Android View LayoutParams */
mMediaPlayer.setAspectRatio(null);
mMediaPlayer.setScale(0);
}
double dw = sw, dh = sh;
final boolean isPortrait = getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT;
if (sw > sh && isPortrait || sw < sh && !isPortrait) {
dw = sh;
dh = sw;
}
// compute the aspect ratio
double ar, vw;
if (mVideoSarDen == mVideoSarNum) {
/* No indication about the density, assuming 1:1 */
vw = mVideoVisibleWidth;
ar = (double)mVideoVisibleWidth / (double)mVideoVisibleHeight;
} else {
/* Use the specified aspect ratio */
vw = mVideoVisibleWidth * (double)mVideoSarNum / mVideoSarDen;
ar = vw / mVideoVisibleHeight;
}
// compute the display aspect ratio
double dar = dw / dh;
switch (CURRENT_SIZE) {
case SURFACE_BEST_FIT:
if (dar < ar)
dh = dw / ar;
else
dw = dh * ar;
break;
case SURFACE_FIT_SCREEN:
if (dar >= ar)
dh = dw / ar; /* horizontal */
else
dw = dh * ar; /* vertical */
break;
case SURFACE_FILL:
break;
case SURFACE_16_9:
ar = 16.0 / 9.0;
if (dar < ar)
dh = dw / ar;
else
dw = dh * ar;
break;
case SURFACE_4_3:
ar = 4.0 / 3.0;
if (dar < ar)
dh = dw / ar;
else
dw = dh * ar;
break;
case SURFACE_ORIGINAL:
dh = mVideoVisibleHeight;
dw = vw;
break;
}
// set display size
lp.width = (int) Math.ceil(dw * mVideoWidth / mVideoVisibleWidth);
lp.height = (int) Math.ceil(dh * mVideoHeight / mVideoVisibleHeight);
mVideoView.setLayoutParams(lp);
if (mSubtitlesSurface != null)
mSubtitlesSurface.setLayoutParams(lp);
// set frame size (crop if necessary)
lp = mVideoSurfaceFrame.getLayoutParams();
lp.width = (int) Math.floor(dw);
lp.height = (int) Math.floor(dh);
mVideoSurfaceFrame.setLayoutParams(lp);
mVideoView.invalidate();
if (mSubtitlesSurface != null)
mSubtitlesSurface.invalidate();
}
@TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR1)
@Override
public void onNewVideoLayout(IVLCVout vlcVout, int width, int height, int visibleWidth, int visibleHeight, int sarNum, int sarDen) {
mVideoWidth = width;
mVideoHeight = height;
mVideoVisibleWidth = visibleWidth;
mVideoVisibleHeight = visibleHeight;
mVideoSarNum = sarNum;
mVideoSarDen = sarDen;
updateVideoSurfaces();
}
}
这就是现在的样子:
这就是我希望它显示的方式:
顺便说一句，我已经对第二张进行了 Photoshop 处理。
感谢任何帮助。如果您需要更多数据，请告诉我。
最佳答案
我遵循相同的示例并遇到了相同的问题。原来你需要在初始化VLC时添加一个参数。
final ArrayList<String> args = new ArrayList<>();
args.add("--vout=android-display"); // Add this line!
args.add("-vvv");
mLibVLC = new LibVLC(this, args);
mMediaPlayer = new MediaPlayer(mLibVLC);
信用归Alexander Ukhov在 videolan 论坛中指出这一点。
关于android - 适用于 Android 的 LibVLC - 在 SurfaceView 上将实时流 RTSP 拉伸(stretch)至所需的宽高比，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/47571241/