我使用MetadataRetriever从视频中提取了帧，并将所有图像存储在ArrayList<Bitmap>中。我想将所有这些存储在SD卡上（仅用于测试目的）。
但是当我从模拟器中取出一个文件夹并查看保存的图像时，所有图像都只是视频的第一帧。
这就是我从视频中提取帧的方法：
File videoFile=new File(Environment.getExternalStorageDirectory().getAbsolutePath()+"/videos","sample_mpeg4.mp4");
Uri videoFileUri=Uri.parse(videoFile.toString());
MediaMetadataRetriever retriever = new MediaMetadataRetriever();
retriever.setDataSource(videoFile.getAbsolutePath());
ArrayList<Bitmap> rev=new ArrayList<Bitmap>();
//Create a new Media Player
MediaPlayer mp = MediaPlayer.create(getBaseContext(), videoFileUri);
int millis = mp.getDuration();
for(int i=0;i<millis;i+=100){
Bitmap bitmap=retriever.getFrameAtTime(i,OPTION_CLOSEST_SYNC);
rev.add(bitmap);
}
这就是我如何保存它们（我正在调用此方法并传递位图ArrayList）：
public void saveFrames(ArrayList<Bitmap> saveBitmapList) throws IOException{
Random r = new Random();
int folder_id = r.nextInt(1000) + 1;
String folder = Environment.getExternalStorageDirectory()+"/videos/frames/"+folder_id+"/";
File saveFolder=new File(folder);
if(!saveFolder.exists()){
saveFolder.mkdirs();
}
int i=1;
for (Bitmap b : saveBitmapList){
ByteArrayOutputStream bytes = new ByteArrayOutputStream();
b.compress(Bitmap.CompressFormat.JPEG, 40, bytes);
File f = new File(saveFolder,("frame"+i+".jpg"));
f.createNewFile();
FileOutputStream fo = new FileOutputStream(f);
fo.write(bytes.toByteArray());
fo.flush();
fo.close();
i++;
}
Toast.makeText(getApplicationContext(),"Folder id : "+folder_id, Toast.LENGTH_LONG).show();
}
当我拿出一个文件夹来查看所有帧时，所有图像都是第一帧视频。有人可以向我解释发生了什么事吗？
更新
我尝试过另一个视频。我发现我没有得到空白图像，但它总是只返回第一帧。
MediaMetadataRetriever.getFrameAtTime(long timeUS)仅返回第一帧，但我想检索所有帧。我应该做些什么改变？
我该如何解决这个问题？
答案 0 :(得分：37)
MediaMetadataRetriever的{{1}}方法以微秒（1/1000000秒）而非毫秒为单位，因此在您的情况下，它总是向下舍入到第1帧。
答案 1 :(得分：8)
只需将毫秒转换为微秒，因为getFrameAt以毫秒为单位获取数据
1 miliseconds have 1000 microseconds..
for(int i=1000000;i<millis*1000;i+=1000000){
Bitmap bitmap=retriever.getFrameAtTime(i,OPTION_CLOSEST_SYNC);
rev.add(bitmap);
}
那么你的问题就解决了..
我是根据自己的需要创建的。
public class MainActivity extends Activity
{
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
File videoFile=new File(Environment.getExternalStorageDirectory().getAbsolutePath()+"/screenshots/","myvideo.mp4");
Uri videoFileUri=Uri.parse(videoFile.toString());
MediaMetadataRetriever retriever = new MediaMetadataRetriever();
retriever.setDataSource(videoFile.getAbsolutePath());
ArrayList<Bitmap> rev=new ArrayList<Bitmap>();
//Create a new Media Player
MediaPlayer mp = MediaPlayer.create(getBaseContext(), videoFileUri);
int millis = mp.getDuration();
for(int i=1000000;i<millis*1000;i+=1000000)
{
Bitmap bitmap=retriever.getFrameAtTime(i,MediaMetadataRetriever.OPTION_CLOSEST_SYNC);
rev.add(bitmap);
}
}
}
答案 2 :(得分：3)
替代Android getFrameAt的{{1}}方法的替代解决方案。 AV_FrameCapture 使用MediaCodec解码视频帧，并使用MediaMetadataRetriever将视频帧转换为RGB位图。由于Android OpenGL不能保证在调用MediaMetadataRetriever时返回结果，因此该getFrameAtTime可用于提取具有准确性的视频帧。
请按照以下步骤实施AV_FrameCapture
1。将以下课程添加到您的项目中。
类别列表：AV_FrameCapture，AV_GLHelper.java，AV_GLUtil.java，AV_TextureRender.java，AV_FrameCapture.java，AV_VideoDecoder.java
2。使用方法
我们以两种方式提供了视频的捕获快照。如果要使用AV_BitmapUtil.java进行捕获，请使用MediaMetadataRetriever；否则它将使用USE_MEDIA_META_DATA_RETRIEVER = true捕获。
最后使用OpenGL，captureFrame和VIDEO_FILE_PATH，SNAPSHOT_DURATION_IN_MILLIS调用SNAPSHOT_WIDTH函数。它将自动捕获该帧的屏幕截图。
SNAPSHOT_HEIGHT课程列表。
1。 AV_GLHelper.java
private AV_FrameCapture mFrameCapture = null;
boolean USE_MEDIA_META_DATA_RETRIEVER = false;
private void captureFrame(String VIDEO_FILE_PATH, long SNAPSHOT_DURATION_IN_MILLIS, int SNAPSHOT_WIDTH, int SNAPSHOT_HEIGHT) {
// getFrameAtTimeByMMDR & getFrameAtTimeByFrameCapture function uses a micro sec 1millisecond = 1000 microseconds
Bitmap bmp = USE_MEDIA_META_DATA_RETRIEVER ? getFrameAtTimeByMMDR(VIDEO_FILE_PATH, (SNAPSHOT_DURATION_IN_MILLIS * 1000))
: getFrameAtTimeByFrameCapture(VIDEO_FILE_PATH, (SNAPSHOT_DURATION_IN_MILLIS * 1000), SNAPSHOT_WIDTH, SNAPSHOT_HEIGHT);
String timeStamp = new SimpleDateFormat("ddMMyyyy_HHmmss", Locale.getDefault()).format(new Date());
if (null != bmp) {
AV_BitmapUtil.saveBitmap(bmp, String.format("/sdcard/read_%s.jpg", timeStamp));
}
if (mFrameCapture != null) {
mFrameCapture.release();
}
}
private Bitmap getFrameAtTimeByMMDR(String path, long time) {
MediaMetadataRetriever mmr = new MediaMetadataRetriever();
mmr.setDataSource(path);
Bitmap bmp = mmr.getFrameAtTime(time, MediaMetadataRetriever.OPTION_CLOSEST);
mmr.release();
return bmp;
}
private Bitmap getFrameAtTimeByFrameCapture(String path, long time, int snapshot_width, int snapshot_height) {
mFrameCapture = new AV_FrameCapture();
mFrameCapture.setDataSource(path);
mFrameCapture.setTargetSize(snapshot_width, snapshot_height);
mFrameCapture.init();
return mFrameCapture.getFrameAtTime(time);
}
2。 AV_GLUtil.java
public class AV_GLHelper {
private static final int EGL_RECORDABLE_ANDROID = 0x3142;
private static final int EGL_OPENGL_ES2_BIT = 4;
private SurfaceTexture mSurfaceTexture;
private AV_TextureRender mTextureRender;
private EGLDisplay mEglDisplay = EGL14.EGL_NO_DISPLAY;
private EGLContext mEglContext = EGL14.EGL_NO_CONTEXT;
private EGLSurface mEglSurface = EGL14.EGL_NO_SURFACE;
public void init(SurfaceTexture st) {
mSurfaceTexture = st;
initGL();
makeCurrent();
mTextureRender = new AV_TextureRender();
}
private void initGL() {
mEglDisplay = EGL14.eglGetDisplay(EGL14.EGL_DEFAULT_DISPLAY);
if (mEglDisplay == EGL14.EGL_NO_DISPLAY) {
throw new RuntimeException("eglGetdisplay failed : " +
GLUtils.getEGLErrorString(EGL14.eglGetError()));
}
int[] version = new int[2];
if (!EGL14.eglInitialize(mEglDisplay, version, 0, version, 1)) {
mEglDisplay = null;
throw new RuntimeException("unable to initialize EGL14");
}
// Configure EGL for pbuffer and OpenGL ES 2.0. We want enough RGB bits
// to be able to tell if the frame is reasonable.
int[] attribList = {
EGL14.EGL_RED_SIZE, 8,
EGL14.EGL_GREEN_SIZE, 8,
EGL14.EGL_BLUE_SIZE, 8,
EGL14.EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
EGL_RECORDABLE_ANDROID, 1,
EGL14.EGL_NONE
};
EGLConfig[] configs = new EGLConfig[1];
int[] numConfigs = new int[1];
if (!EGL14.eglChooseConfig(mEglDisplay, attribList, 0, configs, 0, configs.length,
numConfigs, 0)) {
throw new RuntimeException("unable to find RGB888+recordable ES2 EGL config");
}
// Configure context for OpenGL ES 2.0.
int[] attrib_list = {
EGL14.EGL_CONTEXT_CLIENT_VERSION, 2,
EGL14.EGL_NONE
};
mEglContext = EGL14.eglCreateContext(mEglDisplay, configs[0], EGL14.EGL_NO_CONTEXT,
attrib_list, 0);
AV_GLUtil.checkEglError("eglCreateContext");
if (mEglContext == null) {
throw new RuntimeException("null context");
}
// Create a window surface, and attach it to the Surface we received.
int[] surfaceAttribs = {
EGL14.EGL_NONE
};
mEglSurface = EGL14.eglCreateWindowSurface(mEglDisplay, configs[0], new Surface(mSurfaceTexture),
surfaceAttribs, 0);
AV_GLUtil.checkEglError("eglCreateWindowSurface");
if (mEglSurface == null) {
throw new RuntimeException("surface was null");
}
}
public void release() {
if (null != mSurfaceTexture)
mSurfaceTexture.release();
}
public void makeCurrent() {
if (!EGL14.eglMakeCurrent(mEglDisplay, mEglSurface, mEglSurface, mEglContext)) {
throw new RuntimeException("eglMakeCurrent failed");
}
}
public int createOESTexture() {
int[] textures = new int[1];
GLES20.glGenTextures(1, textures, 0);
int textureID = textures[0];
GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, textureID);
AV_GLUtil.checkEglError("glBindTexture textureID");
GLES20.glTexParameterf(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_MIN_FILTER,
GLES20.GL_NEAREST);
GLES20.glTexParameterf(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_MAG_FILTER,
GLES20.GL_LINEAR);
GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_WRAP_S,
GLES20.GL_CLAMP_TO_EDGE);
GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_WRAP_T,
GLES20.GL_CLAMP_TO_EDGE);
AV_GLUtil.checkEglError("glTexParameter");
return textureID;
}
public void drawFrame(SurfaceTexture st, int textureID) {
st.updateTexImage();
if (null != mTextureRender)
mTextureRender.drawFrame(st, textureID);
}
public Bitmap readPixels(int width, int height) {
ByteBuffer PixelBuffer = ByteBuffer.allocateDirect(4 * width * height);
PixelBuffer.position(0);
GLES20.glReadPixels(0, 0, width, height, GLES20.GL_RGBA, GLES20.GL_UNSIGNED_BYTE, PixelBuffer);
Bitmap bmp = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
PixelBuffer.position(0);
bmp.copyPixelsFromBuffer(PixelBuffer);
return bmp;
}
}
3。 AV_TextureRender.java
public class AV_GLUtil {
/**
* Checks for EGL errors.
*/
public static void checkEglError(String msg) {
boolean failed = false;
int error;
while ((error = EGL14.eglGetError()) != EGL14.EGL_SUCCESS) {
Log.e("TAG", msg + ": EGL error: 0x" + Integer.toHexString(error));
failed = true;
}
if (failed) {
throw new RuntimeException("EGL error encountered (see log)");
}
}
}
4。 AV_FrameCapture.java
class AV_TextureRender {
private static final String TAG = "TextureRender";
private static final int FLOAT_SIZE_BYTES = 4;
private static final int TRIANGLE_VERTICES_DATA_STRIDE_BYTES = 5 * FLOAT_SIZE_BYTES;
private static final int TRIANGLE_VERTICES_DATA_POS_OFFSET = 0;
private static final int TRIANGLE_VERTICES_DATA_UV_OFFSET = 3;
private final float[] mTriangleVerticesData = {
// X, Y, Z, U, V
-1.0f, -1.0f, 0, 0.f, 1.f,
1.0f, -1.0f, 0, 1.f, 1.f,
-1.0f, 1.0f, 0, 0.f, 0.f,
1.0f, 1.0f, 0, 1.f, 0.f,
};
private FloatBuffer mTriangleVertices;
private static final String VERTEX_SHADER =
"uniform mat4 uMVPMatrix;\n" +
"uniform mat4 uSTMatrix;\n" +
"attribute vec4 aPosition;\n" +
"attribute vec4 aTextureCoord;\n" +
"varying vec2 vTextureCoord;\n" +
"void main() {\n" +
" gl_Position = uMVPMatrix * aPosition;\n" +
" vTextureCoord = (uSTMatrix * aTextureCoord).xy;\n" +
"}\n";
private static final String FRAGMENT_SHADER =
"#extension GL_OES_EGL_image_external : require\n" +
"precision mediump float;\n" + // highp here doesn't seem to matter
"varying vec2 vTextureCoord;\n" +
"uniform samplerExternalOES sTexture;\n" +
"void main() {\n" +
" vec2 texcoord = vTextureCoord;\n" +
" vec3 normalColor = texture2D(sTexture, texcoord).rgb;\n" +
" normalColor = vec3(normalColor.r, normalColor.g, normalColor.b);\n" +
" gl_FragColor = vec4(normalColor.r, normalColor.g, normalColor.b, 1); \n"+
"}\n";
private float[] mMVPMatrix = new float[16];
private float[] mSTMatrix = new float[16];
private int mProgram;
private int muMVPMatrixHandle;
private int muSTMatrixHandle;
private int maPositionHandle;
private int maTextureHandle;
public AV_TextureRender() {
mTriangleVertices = ByteBuffer.allocateDirect(
mTriangleVerticesData.length * FLOAT_SIZE_BYTES)
.order(ByteOrder.nativeOrder()).asFloatBuffer();
mTriangleVertices.put(mTriangleVerticesData).position(0);
Matrix.setIdentityM(mSTMatrix, 0);
init();
}
public void drawFrame(SurfaceTexture st, int textureID) {
AV_GLUtil.checkEglError("onDrawFrame start");
st.getTransformMatrix(mSTMatrix);
GLES20.glClearColor(0.0f, 1.0f, 0.0f, 1.0f);
GLES20.glClear(GLES20.GL_DEPTH_BUFFER_BIT | GLES20.GL_COLOR_BUFFER_BIT);
if (GLES20.glIsProgram( mProgram ) != true){
reCreateProgram();
}
GLES20.glUseProgram(mProgram);
AV_GLUtil.checkEglError("glUseProgram");
GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, textureID);
mTriangleVertices.position(TRIANGLE_VERTICES_DATA_POS_OFFSET);
GLES20.glVertexAttribPointer(maPositionHandle, 3, GLES20.GL_FLOAT, false,
TRIANGLE_VERTICES_DATA_STRIDE_BYTES, mTriangleVertices);
AV_GLUtil.checkEglError("glVertexAttribPointer maPosition");
GLES20.glEnableVertexAttribArray(maPositionHandle);
AV_GLUtil.checkEglError("glEnableVertexAttribArray maPositionHandle");
mTriangleVertices.position(TRIANGLE_VERTICES_DATA_UV_OFFSET);
GLES20.glVertexAttribPointer(maTextureHandle, 3, GLES20.GL_FLOAT, false,
TRIANGLE_VERTICES_DATA_STRIDE_BYTES, mTriangleVertices);
AV_GLUtil.checkEglError("glVertexAttribPointer maTextureHandle");
GLES20.glEnableVertexAttribArray(maTextureHandle);
AV_GLUtil.checkEglError("glEnableVertexAttribArray maTextureHandle");
Matrix.setIdentityM(mMVPMatrix, 0);
GLES20.glUniformMatrix4fv(muMVPMatrixHandle, 1, false, mMVPMatrix, 0);
GLES20.glUniformMatrix4fv(muSTMatrixHandle, 1, false, mSTMatrix, 0);
GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4);
AV_GLUtil.checkEglError("glDrawArrays");
GLES20.glFinish();
}
/**
* Initializes GL state. Call this after the EGL surface has been created and made current.
*/
public void init() {
mProgram = createProgram(VERTEX_SHADER, FRAGMENT_SHADER);
if (mProgram == 0) {
throw new RuntimeException("failed creating program");
}
maPositionHandle = GLES20.glGetAttribLocation(mProgram, "aPosition");
AV_GLUtil.checkEglError("glGetAttribLocation aPosition");
if (maPositionHandle == -1) {
throw new RuntimeException("Could not get attrib location for aPosition");
}
maTextureHandle = GLES20.glGetAttribLocation(mProgram, "aTextureCoord");
AV_GLUtil.checkEglError("glGetAttribLocation aTextureCoord");
if (maTextureHandle == -1) {
throw new RuntimeException("Could not get attrib location for aTextureCoord");
}
muMVPMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uMVPMatrix");
AV_GLUtil.checkEglError("glGetUniformLocation uMVPMatrix");
if (muMVPMatrixHandle == -1) {
throw new RuntimeException("Could not get attrib location for uMVPMatrix");
}
muSTMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uSTMatrix");
AV_GLUtil.checkEglError("glGetUniformLocation uSTMatrix");
if (muSTMatrixHandle == -1) {
throw new RuntimeException("Could not get attrib location for uSTMatrix");
}
}
private void reCreateProgram() {
mProgram = createProgram(VERTEX_SHADER, FRAGMENT_SHADER);
if (mProgram == 0) {
throw new RuntimeException("failed creating program");
}
maPositionHandle = GLES20.glGetAttribLocation(mProgram, "aPosition");
AV_GLUtil.checkEglError("glGetAttribLocation aPosition");
if (maPositionHandle == -1) {
throw new RuntimeException("Could not get attrib location for aPosition");
}
maTextureHandle = GLES20.glGetAttribLocation(mProgram, "aTextureCoord");
AV_GLUtil.checkEglError("glGetAttribLocation aTextureCoord");
if (maTextureHandle == -1) {
throw new RuntimeException("Could not get attrib location for aTextureCoord");
}
muMVPMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uMVPMatrix");
AV_GLUtil.checkEglError("glGetUniformLocation uMVPMatrix");
if (muMVPMatrixHandle == -1) {
throw new RuntimeException("Could not get attrib location for uMVPMatrix");
}
muSTMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uSTMatrix");
AV_GLUtil.checkEglError("glGetUniformLocation uSTMatrix");
if (muSTMatrixHandle == -1) {
throw new RuntimeException("Could not get attrib location for uSTMatrix");
}
}
private int loadShader(int shaderType, String source) {
int shader = GLES20.glCreateShader(shaderType);
AV_GLUtil.checkEglError("glCreateShader type=" + shaderType);
GLES20.glShaderSource(shader, source);
GLES20.glCompileShader(shader);
int[] compiled = new int[1];
GLES20.glGetShaderiv(shader, GLES20.GL_COMPILE_STATUS, compiled, 0);
if (compiled[0] == 0) {
Log.e(TAG, "Could not compile shader " + shaderType + ":");
Log.e(TAG, " " + GLES20.glGetShaderInfoLog(shader));
GLES20.glDeleteShader(shader);
shader = 0;
}
return shader;
}
private int createProgram(String vertexSource, String fragmentSource) {
int vertexShader = loadShader(GLES20.GL_VERTEX_SHADER, vertexSource);
if (vertexShader == 0) {
return 0;
}
int pixelShader = loadShader(GLES20.GL_FRAGMENT_SHADER, fragmentSource);
if (pixelShader == 0) {
return 0;
}
int program = GLES20.glCreateProgram();
AV_GLUtil.checkEglError("glCreateProgram");
if (program == 0) {
Log.e(TAG, "Could not create program");
}
GLES20.glAttachShader(program, vertexShader);
AV_GLUtil.checkEglError("glAttachShader");
GLES20.glAttachShader(program, pixelShader);
AV_GLUtil.checkEglError("glAttachShader");
GLES20.glLinkProgram(program);
int[] linkStatus = new int[1];
GLES20.glGetProgramiv(program, GLES20.GL_LINK_STATUS, linkStatus, 0);
if (linkStatus[0] != GLES20.GL_TRUE) {
Log.e(TAG, "Could not link program: ");
Log.e(TAG, GLES20.glGetProgramInfoLog(program));
GLES20.glDeleteProgram(program);
program = 0;
}
return program;
}
}
5。 AV_VideoDecoder.java
public class AV_FrameCapture {
final static String TAG = "AV_FrameCapture";
private HandlerThread mGLThread = null;
private Handler mGLHandler = null;
private AV_GLHelper mGLHelper = null;
private int mDefaultTextureID = 10001;
private int mWidth = 1920;
private int mHeight = 1080;
private String mPath = null;
public AV_FrameCapture() {
mGLHelper = new AV_GLHelper();
mGLThread = new HandlerThread("AV_FrameCapture");
mGLThread.start();
mGLHandler = new Handler(mGLThread.getLooper());
}
public void setDataSource(String path) {
mPath = path;
}
public void setTargetSize(int width, int height) {
mWidth = width;
mHeight = height;
}
public void init() {
mGLHandler.post(new Runnable() {
@Override
public void run() {
SurfaceTexture st = new SurfaceTexture(mDefaultTextureID);
st.setDefaultBufferSize(mWidth, mHeight);
mGLHelper.init(st);
}
});
}
public void release() {
mGLHandler.post(new Runnable() {
@Override
public void run() {
mGLHelper.release();
mGLThread.quit();
}
});
}
private Object mWaitBitmap = new Object();
private Bitmap mBitmap = null;
public Bitmap getFrameAtTime(final long frameTime) {
if (null == mPath || mPath.isEmpty()) {
throw new RuntimeException("Illegal State");
}
mGLHandler.post(new Runnable() {
@Override
public void run() {
getFrameAtTimeImpl(frameTime);
}
});
synchronized (mWaitBitmap) {
try {
mWaitBitmap.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
return mBitmap;
}
@SuppressLint("SdCardPath")
public void getFrameAtTimeImpl(long frameTime) {
final int textureID = mGLHelper.createOESTexture();
final SurfaceTexture st = new SurfaceTexture(textureID);
final Surface surface = new Surface(st);
final AV_VideoDecoder vd = new AV_VideoDecoder(mPath, surface);
st.setOnFrameAvailableListener(new OnFrameAvailableListener() {
@Override
public void onFrameAvailable(SurfaceTexture surfaceTexture) {
Log.i(TAG, "onFrameAvailable");
mGLHelper.drawFrame(st, textureID);
mBitmap = mGLHelper.readPixels(mWidth, mHeight);
synchronized (mWaitBitmap) {
mWaitBitmap.notify();
}
vd.release();
st.release();
surface.release();
}
});
if (!vd.prepare(frameTime)) {
mBitmap = null;
synchronized (mWaitBitmap) {
mWaitBitmap.notify();
}
}
}
}
6。 AV_BitmapUtil.java
public class AV_VideoDecoder {
final static String TAG = "VideoDecoder";
final static String VIDEO_MIME_PREFIX = "video/";
private MediaExtractor mMediaExtractor = null;
private MediaCodec mMediaCodec = null;
private Surface mSurface = null;
private String mPath = null;
private int mVideoTrackIndex = -1;
public AV_VideoDecoder(String path, Surface surface) {
mPath = path;
mSurface = surface;
initCodec();
}
public boolean prepare(long time) {
return decodeFrameAt(time);
}
public void startDecode() {
}
public void release() {
if (null != mMediaCodec) {
mMediaCodec.stop();
mMediaCodec.release();
}
if (null != mMediaExtractor) {
mMediaExtractor.release();
}
}
private boolean initCodec() {
Log.i(TAG, "initCodec");
mMediaExtractor = new MediaExtractor();
try {
mMediaExtractor.setDataSource(mPath);
} catch (IOException e) {
e.printStackTrace();
return false;
}
int trackCount = mMediaExtractor.getTrackCount();
for (int i = 0; i < trackCount; ++i) {
MediaFormat mf = mMediaExtractor.getTrackFormat(i);
String mime = mf.getString(MediaFormat.KEY_MIME);
if (mime.startsWith(VIDEO_MIME_PREFIX)) {
mVideoTrackIndex = i;
break;
}
}
if (mVideoTrackIndex < 0)
return false;
mMediaExtractor.selectTrack(mVideoTrackIndex);
MediaFormat mf = mMediaExtractor.getTrackFormat(mVideoTrackIndex);
String mime = mf.getString(MediaFormat.KEY_MIME);
try {
mMediaCodec = MediaCodec.createDecoderByType(mime);
} catch (IOException e) {
e.printStackTrace();
}
mMediaCodec.configure(mf, mSurface, null, 0);
mMediaCodec.setVideoScalingMode(MediaCodec.VIDEO_SCALING_MODE_SCALE_TO_FIT_WITH_CROPPING);
mMediaCodec.start();
Log.i(TAG, "initCodec end");
return true;
}
private boolean mIsInputEOS = false;
private boolean decodeFrameAt(long timeUs) {
Log.i(TAG, "decodeFrameAt " + timeUs);
mMediaExtractor.seekTo(timeUs, MediaExtractor.SEEK_TO_PREVIOUS_SYNC);
mIsInputEOS = false;
CodecState inputState = new CodecState();
CodecState outState = new CodecState();
boolean reachTarget = false;
for (; ; ) {
if (!inputState.EOS)
handleCodecInput(inputState);
if (inputState.outIndex < 0) {
handleCodecOutput(outState);
reachTarget = processOutputState(outState, timeUs);
} else {
reachTarget = processOutputState(inputState, timeUs);
}
if (true == reachTarget || outState.EOS) {
Log.i(TAG, "decodeFrameAt " + timeUs + " reach target or EOS");
break;
}
inputState.outIndex = -1;
outState.outIndex = -1;
}
return reachTarget;
}
private boolean processOutputState(CodecState state, long timeUs) {
if (state.outIndex < 0)
return false;
if (state.outIndex >= 0 && state.info.presentationTimeUs < timeUs) {
Log.i(TAG, "processOutputState presentationTimeUs " + state.info.presentationTimeUs);
mMediaCodec.releaseOutputBuffer(state.outIndex, false);
return false;
}
if (state.outIndex >= 0) {
Log.i(TAG, "processOutputState presentationTimeUs " + state.info.presentationTimeUs);
mMediaCodec.releaseOutputBuffer(state.outIndex, true);
return true;
}
return false;
}
private class CodecState {
int outIndex = MediaCodec.INFO_TRY_AGAIN_LATER;
BufferInfo info = new BufferInfo();
boolean EOS = false;
}
private void handleCodecInput(CodecState state) {
ByteBuffer[] inputBuffer = mMediaCodec.getInputBuffers();
for (; !mIsInputEOS; ) {
int inputBufferIndex = mMediaCodec.dequeueInputBuffer(10000);
if (inputBufferIndex < 0)
continue;
ByteBuffer in = inputBuffer[inputBufferIndex];
int readSize = mMediaExtractor.readSampleData(in, 0);
long presentationTimeUs = mMediaExtractor.getSampleTime();
int flags = mMediaExtractor.getSampleFlags();
boolean EOS = !mMediaExtractor.advance();
EOS |= (readSize <= 0);
EOS |= ((flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM) > 0);
Log.i(TAG, "input presentationTimeUs " + presentationTimeUs + " isEOS " + EOS);
if (EOS && readSize < 0)
readSize = 0;
if (readSize > 0 || EOS)
mMediaCodec.queueInputBuffer(inputBufferIndex, 0, readSize, presentationTimeUs, flags | (EOS ? MediaCodec.BUFFER_FLAG_END_OF_STREAM : 0));
if (EOS) {
state.EOS = true;
mIsInputEOS = true;
break;
}
state.outIndex = mMediaCodec.dequeueOutputBuffer(state.info, 10000);
if (state.outIndex >= 0)
break;
}
}
private void handleCodecOutput(CodecState state) {
state.outIndex = mMediaCodec.dequeueOutputBuffer(state.info, 10000);
if (state.outIndex < 0) {
return;
}
if ((state.info.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0) {
state.EOS = true;
Log.i(TAG, "reach output EOS " + state.info.presentationTimeUs);
}
}
}
答案 3 :(得分：1)
long time;
String formattedFileCount;
FileOutputStream fos;
BufferedOutputStream bos;
NumberFormat fileCountFormatter = new DecimalFormat("00000");
int fileCount = 0;
File jpegFile;
ArrayList<Bitmap> bArray = null;
Bitmap lastbitmap = null;
bArray = new ArrayList<Bitmap>();
我在微秒内花费时间，从媒体播放器获取持续时间，如：
time = mp.getDuration()*1000;
Log.e("Timeeeeeeee", time);
bArray.clear();
MediaMetadataRetriever mRetriever = new MediaMetadataRetriever();
mRetriever.setDataSource(path);
int j=0;
我的帧速率为12帧/秒，所以我将1/12 = 0.083333分开，这是帧的第二部分，而不是我将帧秒转换为微秒，因此它变为83333
for (int i = 833333; i <= time; i=i+83333) {
bArray.add(mRetriever.getFrameAtTime(i, MediaMetadataRetriever.OPTION_CLOSEST_SYNC));
formattedFileCount = fileCountFormatter.format(fileCount);
lastbitmap = bArray.get(j);
j++;
// image is the bitmap
jpegFile = new File(Environment.getExternalStorageDirectory().getPath() + "/frames/frame_" + formattedFileCount + ".jpg");
fileCount++;
try {
fos = new FileOutputStream(jpegFile);
bos = new BufferedOutputStream(fos);
lastbitmap.compress(Bitmap.CompressFormat.JPEG, 15, bos);
bos.flush();
bos.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
} catch (Exception e) {
}
答案 4 :(得分：1)
@Navneet Krishna
视频具有关键帧（有时称为“同步”帧）。问题可能是：使用OPTION_CLOSEST_SYNC ...
尝试替换此行：
Bitmap bitmap=retriever.getFrameAtTime(i,OPTION_CLOSEST_SYNC);
使用此方法（它将获得与给定时间最接近的帧）：
Bitmap bitmap=retriever.getFrameAtTime(i,OPTION_CLOSEST);
阅读以下内容：CLOSEST和CLOSEST_SYNC。
下面的代码未经测试，但是是“如何...” 的一般概念，因此，如果有帮助，请让我现在...
结果应为视频时长每秒一幅图片。用简短的视频进行测试。
//Create a new Media Player
MediaPlayer mp = MediaPlayer.create(getBaseContext(), videoFileUri);
int millis = mp.getDuration();
for (int i = 0; i < millis; i += 1000)
{
Bitmap bmp = retriever.getFrameAtTime( i * 1000, MediaMetadataRetriever.OPTION_CLOSEST );
if (bmp != null) { rev.add( bmp ); }
}
retriever.release ();
答案 5 :(得分：0)
使用MetaData Retriever我能够获得视频的截图
答案 6 :(得分：-1)
在for / loop上试试这个：
Bitmap bitmap = retriever.getFrameAtTime(
TimeUnit.MICROSECONDS.convert(i, TimeUnit.MILLISECONDS),
retriever.OPTION_CLOSEST_SYNC);