// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
package org.chromium.components.browser_ui.photo_picker;
import android.content.ContentResolver;
import android.content.res.AssetFileDescriptor;
import android.graphics.Bitmap;
import android.media.MediaMetadataRetriever;
import android.net.Uri;
import android.util.Pair;
import androidx.annotation.IntDef;
import org.chromium.base.ThreadUtils;
import org.chromium.base.task.AsyncTask;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.util.List;
import java.util.Locale;
/** A worker task to decode video and extract information from it off of the UI thread. */
class DecodeVideoTask extends AsyncTask<List<Bitmap>> {
/** The possible error states while decoding. */
@Retention(RetentionPolicy.SOURCE)
@IntDef({
DecodingResult.SUCCESS,
DecodingResult.FILE_ERROR,
DecodingResult.RUNTIME_ERROR,
DecodingResult.IO_ERROR
})
public @interface DecodingResult {
int SUCCESS = 0;
int FILE_ERROR = 1;
int RUNTIME_ERROR = 2;
int IO_ERROR = 3;
}
/** An interface to use to communicate back the results to the client. */
public interface VideoDecodingCallback {
/**
* A callback to define to receive the list of all images on disk.
*
* @param uri The uri of the video decoded.
* @param bitmaps An array of thumbnails extracted from the video.
* @param duration The duration of the video.
* @param fullWidth Whether the image is using the full width of the screen.
* @param decodingStatus Whether the decoding was successful.
*/
void videoDecodedCallback(
Uri uri,
List<Bitmap> bitmaps,
String duration,
boolean fullWidth,
@DecodingResult int decodingStatus,
float ratio);
}
// The callback to use to communicate the results.
private VideoDecodingCallback mCallback;
// The URI of the video to decode.
private Uri mUri;
// The desired width and height (in pixels) of the returned thumbnail from the video.
int mSize;
// Whether the image is taking up the full width of the screen.
boolean mFullWidth;
// The number of frames to extract.
int mFrames;
// The interval between frames (in milliseconds).
long mIntervalMs;
// The ContentResolver to use to retrieve image metadata from disk.
private ContentResolver mContentResolver;
// Keeps track of errors during decoding.
private @DecodingResult int mDecodingResult;
// The duration of the video.
private String mDuration;
// The ratio of the first frame of the video.
private float mRatio;
/**
* A DecodeVideoTask constructor.
*
* @param callback The callback to use to communicate back the results.
* @param contentResolver The ContentResolver to use to retrieve image metadata from disk.
* @param uri The URI of the video to decode.
* @param size The desired width and height (in pixels) of the returned thumbnail from the
* video.
* @param fullWidth Whether this is a video thumbnail that takes up the full screen width.
* @param frames The number of frames to extract.
* @param intervalMs The interval between frames (in milliseconds).
*/
public DecodeVideoTask(
VideoDecodingCallback callback,
ContentResolver contentResolver,
Uri uri,
int size,
boolean fullWidth,
int frames,
long intervalMs) {
mCallback = callback;
mContentResolver = contentResolver;
mUri = uri;
mSize = size;
mFullWidth = fullWidth;
mFrames = frames;
mIntervalMs = intervalMs;
}
/**
* Converts a duration string in ms to a human-readable form.
*
* @param durationMs The duration in milliseconds.
* @return The duration in human-readable form.
*/
public static String formatDuration(Long durationMs) {
if (durationMs == null) return null;
long duration = durationMs / 1000;
long hours = duration / 3600;
duration -= hours * 3600;
long minutes = duration / 60;
duration -= minutes * 60;
long seconds = duration;
if (hours > 0) {
return String.format(Locale.US, "%d:%02d:%02d", hours, minutes, seconds);
} else {
return String.format(Locale.US, "%d:%02d", minutes, seconds);
}
}
/**
* Decodes a video and extracts metadata and a thumbnail. Called on a non-UI thread
*
* @return A list of bitmaps (video thumbnails).
*/
@Override
protected List<Bitmap> doInBackground() {
assert !ThreadUtils.runningOnUiThread();
if (isCancelled()) return null;
// TODO(finnur): Apply try-with-resources to MediaMetadataRetriever once Chrome no longer
// supports versions below Build.VERSION_CODES.Q. API 29 is when it started
// to implement AutoCloseable:
//
// https://developer.android.com/sdk/api_diff/29/changes/android.media.MediaMetadataRetriever
MediaMetadataRetriever retriever = null;
try (AssetFileDescriptor afd = mContentResolver.openAssetFileDescriptor(mUri, "r")) {
retriever = new MediaMetadataRetriever();
retriever.setDataSource(afd.getFileDescriptor());
String duration =
retriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_DURATION);
if (duration != null) {
// Adjust to a shorter video, if the frame requests exceed the length of the video.
long durationMs = Long.parseLong(duration);
if (mFrames > 1 && mFrames * mIntervalMs > durationMs) {
mIntervalMs = durationMs / mFrames;
}
duration = formatDuration(durationMs);
}
Pair<List<Bitmap>, Float> bitmaps =
BitmapUtils.decodeVideoFromFileDescriptor(
retriever,
afd.getFileDescriptor(),
mSize,
mFrames,
mFullWidth,
mIntervalMs);
mDuration = duration;
mRatio = bitmaps.second;
mDecodingResult = DecodingResult.SUCCESS;
return bitmaps.first;
} catch (FileNotFoundException exception) {
mDecodingResult = DecodingResult.FILE_ERROR;
return null;
} catch (RuntimeException exception) {
mDecodingResult = DecodingResult.RUNTIME_ERROR;
return null;
} catch (IOException exception) {
mDecodingResult = DecodingResult.IO_ERROR;
return null;
} finally {
try {
if (retriever != null) retriever.release();
} catch (IOException exception) {
}
}
}
/**
* Communicates the results back to the client. Called on the UI thread.
*
* @param results A pair of bitmap (video thumbnail) and the duration of the video.
*/
@Override
protected void onPostExecute(List<Bitmap> results) {
if (isCancelled()) {
return;
}
if (results == null) {
mCallback.videoDecodedCallback(mUri, null, "", mFullWidth, mDecodingResult, 1.0f);
return;
}
mCallback.videoDecodedCallback(
mUri, results, mDuration, mFullWidth, mDecodingResult, mRatio);
}
}
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