Android:是否可以显示视频缩略图？

Question

我用库对话框创建了一个视频录制应用程序.库对话框显示录制视频列表,其中每个项目包括图标,视频标题,标签和位置信息,方式如下:

有谁知道是否可以用视频缩略图替换图标(单帧预览)？

谢谢!

Answer 1

如果你没有或不能通过游标,如果你只有路径或文件对象,你可以使用自API级别8(2.2)公共静态位图createVideoThumbnail(String filePath,int kind)

Android文档

以下代码运行完美:

Bitmap bMap = ThumbnailUtils.createVideoThumbnail(file.getAbsolutePath(), MediaStore.Video.Thumbnails.MICRO_KIND);

Answer 2

如果您使用的是API 2.0或更高版本,则可以使用.

int id = **"The Video's ID"**
ImageView iv = (ImageView ) convertView.findViewById(R.id.imagePreview);
ContentResolver crThumb = getContentResolver();
BitmapFactory.Options options=new BitmapFactory.Options();
options.inSampleSize = 1;
Bitmap curThumb = MediaStore.Video.Thumbnails.getThumbnail(crThumb, id, MediaStore.Video.Thumbnails.MICRO_KIND, options);
iv.setImageBitmap(curThumb);

Answer 3

使用课程:

import android.provider.MediaStore.Video.Thumbnails;

我们可以从视频中获得两个预览缩略图尺寸:

Thumbnails.MICRO_KIND 为96 x 96

Thumbnails.MINI_KIND 适用于512 x 384像素

这是一个代码示例:

String filePath = "/sdcard/DCIM/Camera/my_video.mp4"; //change the location of your file!

ImageView imageview_mini = (ImageView)findViewById(R.id.thumbnail_mini);
ImageView imageview_micro = (ImageView)findViewById(R.id.thumbnail_micro);

Bitmap bmThumbnail;

//MICRO_KIND, size: 96 x 96 thumbnail
bmThumbnail = ThumbnailUtils.createVideoThumbnail(filePath, Thumbnails.MICRO_KIND);
imageview_micro.setImageBitmap(bmThumbnail);

// MINI_KIND, size: 512 x 384 thumbnail 
bmThumbnail = ThumbnailUtils.createVideoThumbnail(filePath, Thumbnails.MINI_KIND);
imageview_mini.setImageBitmap(bmThumbnail);

Answer 4

目前我使用以下代码:

Bitmap bMap = ThumbnailUtils.createVideoThumbnail(file.getAbsolutePath(), MediaStore.Video.Thumbnails.MICRO_KIND);

但我找到了更好的解决方案,使用Glide库和以下代码(它还可以缓存您的图像,并且比以前的方法具有更好的性能)

Glide.with(context)
                .load(uri)
                .placeholder(R.drawable.ic_video_place_holder)
                .into(imageView);

Answer 5

我真的建议你使用Glide库.这是为本地视频文件生成和显示视频缩略图的最有效方法之一.

只需将此行添加到您的gradle文件:

compile 'com.github.bumptech.glide:glide:3.7.0'

它将变得如此简单:

String filePath = "/storage/emulated/0/Pictures/example_video.mp4";

Glide  
    .with( context )
    .load( Uri.fromFile( new File( filePath ) ) )
    .into( imageViewGifAsBitmap );

你可以在这里找到更多的信息:https://futurestud.io/blog/glide-displaying-gifs-and-videos

干杯!

Answer 6

试试这个它对我有用

RequestOptions requestOptions = new RequestOptions();
 Glide.with(getContext())
      .load("video_url")
      .apply(requestOptions)
      .thumbnail(Glide.with(getContext()).load("video_url"))
      .into("yourimageview");

Answer 7

此解决方案适用于任何版本的Android。它已经证明可以在1.5和2.2中工作。这不是另一个“这是针对Android 2.0+”的解决方案。我是通过电子邮件留言板收集页面找到的，但是找不到原始链接。所有功劳归于原始海报。

在您的应用中，您可以通过以下方式使用此功能：

Bitmap bm = getVideoFrame(VideoStringUri);

在其自身功能的某个位置（在OnCreate等区域之外），您将需要：

private Bitmap getVideoFrame(String uri) {
        MediaMetadataRetriever retriever = new MediaMetadataRetriever();
        try {
            retriever.setMode(MediaMetadataRetriever.MODE_CAPTURE_FRAME_ONLY);
            retriever.setDataSource(uri);
            return retriever.captureFrame();
        } catch (IllegalArgumentException ex) {
            ex.printStackTrace();
        } catch (RuntimeException ex) {
            ex.printStackTrace();
        } finally {
            try {
                retriever.release();
            } catch (RuntimeException ex) {
            }
        }
        return null;
    }

在src文件夹中，您需要一个新的子目录android / media，该子目录将容纳该类（从android源本身复制），该类可让您使用此功能。此部分不应更改，重命名或放置在其他任何地方。MediaMetadataRetriever.java必须在您的源文件夹中的android.media下，才能正常工作。

/*
 * Copyright (C) 2008 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.media;

import java.io.FileDescriptor;
import java.io.FileNotFoundException;
import java.io.IOException;

import android.content.ContentResolver;
import android.content.Context;
import android.content.res.AssetFileDescriptor;
import android.graphics.Bitmap;
import android.net.Uri;

/**
 * MediaMetadataRetriever class provides a unified interface for retrieving
 * frame and meta data from an input media file. {@hide}
 */
public class MediaMetadataRetriever {
    static {
        System.loadLibrary("media_jni");
        native_init();
    }

    // The field below is accessed by native methods
    private int mNativeContext;

    public MediaMetadataRetriever() {
        native_setup();
    }

    /**
     * Call this method before setDataSource() so that the mode becomes
     * effective for subsequent operations. This method can be called only once
     * at the beginning if the intended mode of operation for a
     * MediaMetadataRetriever object remains the same for its whole lifetime,
     * and thus it is unnecessary to call this method each time setDataSource()
     * is called. If this is not never called (which is allowed), by default the
     * intended mode of operation is to both capture frame and retrieve meta
     * data (i.e., MODE_GET_METADATA_ONLY | MODE_CAPTURE_FRAME_ONLY). Often,
     * this may not be what one wants, since doing this has negative performance
     * impact on execution time of a call to setDataSource(), since both types
     * of operations may be time consuming.
     * 
     * @param mode
     *            The intended mode of operation. Can be any combination of
     *            MODE_GET_METADATA_ONLY and MODE_CAPTURE_FRAME_ONLY: 1.
     *            MODE_GET_METADATA_ONLY & MODE_CAPTURE_FRAME_ONLY: For neither
     *            frame capture nor meta data retrieval 2.
     *            MODE_GET_METADATA_ONLY: For meta data retrieval only 3.
     *            MODE_CAPTURE_FRAME_ONLY: For frame capture only 4.
     *            MODE_GET_METADATA_ONLY | MODE_CAPTURE_FRAME_ONLY: For both
     *            frame capture and meta data retrieval
     */
    public native void setMode(int mode);

    /**
     * @return the current mode of operation. A negative return value indicates
     *         some runtime error has occurred.
     */
    public native int getMode();

    /**
     * Sets the data source (file pathname) to use. Call this method before the
     * rest of the methods in this class. This method may be time-consuming.
     * 
     * @param path
     *            The path of the input media file.
     * @throws IllegalArgumentException
     *             If the path is invalid.
     */
    public native void setDataSource(String path)
            throws IllegalArgumentException;

    /**
     * Sets the data source (FileDescriptor) to use. It is the caller's
     * responsibility to close the file descriptor. It is safe to do so as soon
     * as this call returns. Call this method before the rest of the methods in
     * this class. This method may be time-consuming.
     * 
     * @param fd
     *            the FileDescriptor for the file you want to play
     * @param offset
     *            the offset into the file where the data to be played starts,
     *            in bytes. It must be non-negative
     * @param length
     *            the length in bytes of the data to be played. It must be
     *            non-negative.
     * @throws IllegalArgumentException
     *             if the arguments are invalid
     */
    public native void setDataSource(FileDescriptor fd, long offset, long length)
            throws IllegalArgumentException;

    /**
     * Sets the data source (FileDescriptor) to use. It is the caller's
     * responsibility to close the file descriptor. It is safe to do so as soon
     * as this call returns. Call this method before the rest of the methods in
     * this class. This method may be time-consuming.
     * 
     * @param fd
     *            the FileDescriptor for the file you want to play
     * @throws IllegalArgumentException
     *             if the FileDescriptor is invalid
     */
    public void setDataSource(FileDescriptor fd)
            throws IllegalArgumentException {
        // intentionally less than LONG_MAX
        setDataSource(fd, 0, 0x7ffffffffffffffL);
    }

    /**
     * Sets the data source as a content Uri. Call this method before the rest
     * of the methods in this class. This method may be time-consuming.
     * 
     * @param context
     *            the Context to use when resolving the Uri
     * @param uri
     *            the Content URI of the data you want to play
     * @throws IllegalArgumentException
     *             if the Uri is invalid
     * @throws SecurityException
     *             if the Uri cannot be used due to lack of permission.
     */
    public void setDataSource(Context context, Uri uri)
            throws IllegalArgumentException, SecurityException {
        if (uri == null) {
            throw new IllegalArgumentException();
        }

        String scheme = uri.getScheme();
        if (scheme == null || scheme.equals("file")) {
            setDataSource(uri.getPath());
            return;
        }

        AssetFileDescriptor fd = null;
        try {
            ContentResolver resolver = context.getContentResolver();
            try {
                fd = resolver.openAssetFileDescriptor(uri, "r");
            } catch (FileNotFoundException e) {
                throw new IllegalArgumentException();
            }
            if (fd == null) {
                throw new IllegalArgumentException();
            }
            FileDescriptor descriptor = fd.getFileDescriptor();
            if (!descriptor.valid()) {
                throw new IllegalArgumentException();
            }
            // Note: using getDeclaredLength so that our behavior is the same
            // as previous versions when the content provider is returning
            // a full file.
            if (fd.getDeclaredLength() < 0) {
                setDataSource(descriptor);
            } else {
                setDataSource(descriptor, fd.getStartOffset(),
                        fd.getDeclaredLength());
            }
            return;
        } catch (SecurityException ex) {
        } finally {
            try {
                if (fd != null) {
                    fd.close();
                }
            } catch (IOException ioEx) {
            }
        }
        setDataSource(uri.toString());
    }

    /**
     * Call this method after setDataSource(). This method retrieves the meta
     * data value associated with the keyCode.
     * 
     * The keyCode currently supported is listed below as METADATA_XXX
     * constants. With any other value, it returns a null pointer.
     * 
     * @param keyCode
     *            One of the constants listed below at the end of the class.
     * @return The meta data value associate with the given keyCode on success;
     *         null on failure.
     */
    public native String extractMetadata(int keyCode);

    /**
     * Call this method after setDataSource(). This method finds a
     * representative frame if successful and returns it as a bitmap. This is
     * useful for generating a thumbnail for an input media source.
     * 
     * @return A Bitmap containing a representative video frame, which can be
     *         null, if such a frame cannot be retrieved.
     */
    public native Bitmap captureFrame();

    /**
     * Call this method after setDataSource(). This method finds the optional
     * graphic or album art associated (embedded or external url linked) the
     * related data source.
     * 
     * @return null if no such graphic is found.
     */
    public native byte[] extractAlbumArt();

    /**
     * Call it when one is done with the object. This method releases the memory
     * allocated internally.
     */
    public native void release();

    private native void native_setup();

    private static native void native_init();

    private native final void native_finalize();

    @Override
    protected void finalize() throws Throwable {
        try {
            native_finalize();
        } finally {
            super.finalize();
        }
    }

    public static final int MODE_GET_METADATA_ONLY = 0x01;
    public static final int MODE_CAPTURE_FRAME_ONLY = 0x02;

    /*
     * Do not change these values without updating their counterparts in
     * include/media/mediametadataretriever.h!
     */
    public static final int METADATA_KEY_CD_TRACK_NUMBER = 0;
    public static final int METADATA_KEY_ALBUM = 1;
    public static final int METADATA_KEY_ARTIST = 2;
    public static final int METADATA_KEY_AUTHOR = 3;
    public static final int METADATA_KEY_COMPOSER = 4;
    public static final int METADATA_KEY_DATE = 5;
    public static final int METADATA_KEY_GENRE = 6;
    public static final int METADATA_KEY_TITLE = 7;
    public static final int METADATA_KEY_YEAR = 8;
    public static final int METADATA_KEY_DURATION = 9;
    public static final int METADATA_KEY_NUM_TRACKS = 10;
    public static final int METADATA_KEY_IS_DRM_CRIPPLED = 11;
    public static final int METADATA_KEY_CODEC = 12;
    public static final int METADATA_KEY_RATING = 13;
    public static final int METADATA_KEY_COMMENT = 14;
    public static final int METADATA_KEY_COPYRIGHT = 15;
    public static final int METADATA_KEY_BIT_RATE = 16;
    public static final int METADATA_KEY_FRAME_RATE = 17;
    public static final int METADATA_KEY_VIDEO_FORMAT = 18;
    public static final int METADATA_KEY_VIDEO_HEIGHT = 19;
    public static final int METADATA_KEY_VIDEO_WIDTH = 20;
    public static final int METADATA_KEY_WRITER = 21;
    public static final int METADATA_KEY_MIMETYPE = 22;
    public static final int METADATA_KEY_DISCNUMBER = 23;
    public static final int METADATA_KEY_ALBUMARTIST = 24;
    // Add more here...
}

Answer 8

Android 1.5和1.6不提供此缩略图,但2.0确实如此,正如官方发行说明所示:

媒体

• MediaScanner现在可以在将所有图像插入MediaStore时为其生成缩略图.
• 新的缩略图API,用于按需检索图像和视频缩略图.