Add WebVTT parser.
This commit is contained in:
Oliver Woodman
parent
525b309764
commit
4344675098
@ -0,0 +1,202 @@
|
|||||||
|
/*
|
||||||
|
* Copyright (C) 2014 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 com.google.android.exoplayer.text.webvtt;
|
||||||
|
|
||||||
|
import com.google.android.exoplayer.C;
|
||||||
|
import com.google.android.exoplayer.ParserException;
|
||||||
|
import com.google.android.exoplayer.text.SubtitleParser;
|
||||||
|
import com.google.android.exoplayer.util.MimeTypes;
|
||||||
|
|
||||||
|
import java.io.BufferedReader;
|
||||||
|
import java.io.IOException;
|
||||||
|
import java.io.InputStream;
|
||||||
|
import java.io.InputStreamReader;
|
||||||
|
import java.util.ArrayList;
|
||||||
|
import java.util.regex.Matcher;
|
||||||
|
import java.util.regex.Pattern;
|
||||||
|
|
||||||
|
/**
|
||||||
|
* A simple WebVTT parser.
|
||||||
|
* <p>
|
||||||
|
* @see <a href="http://dev.w3.org/html5/webvtt">WebVTT specification</a>
|
||||||
|
* <p>
|
||||||
|
*/
|
||||||
|
public class WebvttParser implements SubtitleParser {
|
||||||
|
|
||||||
|
/**
|
||||||
|
* This parser allows a custom header to be prepended to the WebVTT data, in the form of a text
|
||||||
|
* line starting with this string.
|
||||||
|
*
|
||||||
|
* @hide
|
||||||
|
*/
|
||||||
|
public static final String EXO_HEADER = "EXO-HEADER";
|
||||||
|
/**
|
||||||
|
* A {@code OFFSET + value} element can be added to the custom header to specify an offset time
|
||||||
|
* (in microseconds) that should be subtracted from the embedded MPEGTS value.
|
||||||
|
*
|
||||||
|
* @hide
|
||||||
|
*/
|
||||||
|
public static final String OFFSET = "OFFSET:";
|
||||||
|
|
||||||
|
private static final long SAMPLING_RATE = 90;
|
||||||
|
|
||||||
|
private static final String WEBVTT_TIMESTAMP_STRING = "(\\d+:)?[0-5]\\d:[0-5]\\d\\.\\d{3}";
|
||||||
|
private static final Pattern WEBVTT_TIMESTAMP = Pattern.compile(WEBVTT_TIMESTAMP_STRING);
|
||||||
|
private static final Pattern MEDIA_TIMESTAMP_OFFSET = Pattern.compile(OFFSET + "\\d+");
|
||||||
|
private static final Pattern MEDIA_TIMESTAMP = Pattern.compile("MPEGTS:\\d+");
|
||||||
|
|
||||||
|
@Override
|
||||||
|
public WebvttSubtitle parse(InputStream inputStream, String inputEncoding, long startTimeUs)
|
||||||
|
throws IOException {
|
||||||
|
ArrayList<WebvttCue> subtitles = new ArrayList<WebvttCue>();
|
||||||
|
long mediaTimestampUs = startTimeUs;
|
||||||
|
long mediaTimestampOffsetUs = 0;
|
||||||
|
|
||||||
|
BufferedReader webvttData = new BufferedReader(new InputStreamReader(inputStream, C.UTF8_NAME));
|
||||||
|
String line;
|
||||||
|
|
||||||
|
// file should start with "WEBVTT" on the first line or "EXO-HEADER"
|
||||||
|
line = webvttData.readLine();
|
||||||
|
if (line == null) {
|
||||||
|
throw new ParserException("Expected WEBVTT or EXO-HEADER. Got null");
|
||||||
|
}
|
||||||
|
if (line.startsWith(EXO_HEADER)) {
|
||||||
|
// parse the timestamp offset, if present
|
||||||
|
Matcher matcher = MEDIA_TIMESTAMP_OFFSET.matcher(line);
|
||||||
|
if (matcher.find()) {
|
||||||
|
mediaTimestampOffsetUs = Long.parseLong(matcher.group().substring(7));
|
||||||
|
}
|
||||||
|
|
||||||
|
// read the next line, which should now be WEBVTT
|
||||||
|
line = webvttData.readLine();
|
||||||
|
if (line == null) {
|
||||||
|
throw new ParserException("Expected WEBVTT. Got null");
|
||||||
|
}
|
||||||
|
}
|
||||||
|
if (!line.equals("WEBVTT")) {
|
||||||
|
throw new ParserException("Expected WEBVTT. Got " + line);
|
||||||
|
}
|
||||||
|
|
||||||
|
// after "WEBVTT" there should be either an empty line or an "X-TIMESTAMP-MAP" line and then
|
||||||
|
// and empty line
|
||||||
|
line = webvttData.readLine();
|
||||||
|
if (!line.isEmpty()) {
|
||||||
|
if (!line.startsWith("X-TIMESTAMP-MAP")) {
|
||||||
|
throw new ParserException("Expected an empty line or X-TIMESTAMP-MAP. Got " + line);
|
||||||
|
}
|
||||||
|
|
||||||
|
// parse the media timestamp
|
||||||
|
Matcher matcher = MEDIA_TIMESTAMP.matcher(line);
|
||||||
|
if (!matcher.find()) {
|
||||||
|
throw new ParserException("X-TIMESTAMP-MAP doesn't contain media timestmap: " + line);
|
||||||
|
} else {
|
||||||
|
mediaTimestampUs = (Long.parseLong(matcher.group().substring(7)) * 1000) / SAMPLING_RATE
|
||||||
|
- mediaTimestampOffsetUs;
|
||||||
|
}
|
||||||
|
mediaTimestampUs = getAdjustedStartTime(mediaTimestampUs);
|
||||||
|
|
||||||
|
// read in the next line (which should be an empty line)
|
||||||
|
line = webvttData.readLine();
|
||||||
|
}
|
||||||
|
if (!line.isEmpty()) {
|
||||||
|
throw new ParserException("Expected an empty line after WEBVTT or X-TIMESTAMP-MAP. Got "
|
||||||
|
+ line);
|
||||||
|
}
|
||||||
|
|
||||||
|
// process the cues and text
|
||||||
|
while ((line = webvttData.readLine()) != null) {
|
||||||
|
// parse the cue timestamps
|
||||||
|
Matcher matcher = WEBVTT_TIMESTAMP.matcher(line);
|
||||||
|
long startTime;
|
||||||
|
long endTime;
|
||||||
|
String text = "";
|
||||||
|
|
||||||
|
// parse start timestamp
|
||||||
|
if (!matcher.find()) {
|
||||||
|
throw new ParserException("Expected cue start time: " + line);
|
||||||
|
} else {
|
||||||
|
startTime = parseTimestampUs(matcher.group()) + mediaTimestampUs;
|
||||||
|
}
|
||||||
|
|
||||||
|
// parse end timestamp
|
||||||
|
if (!matcher.find()) {
|
||||||
|
throw new ParserException("Expected cue end time: " + line);
|
||||||
|
} else {
|
||||||
|
endTime = parseTimestampUs(matcher.group()) + mediaTimestampUs;
|
||||||
|
}
|
||||||
|
|
||||||
|
// parse text
|
||||||
|
while (((line = webvttData.readLine()) != null) && (!line.isEmpty())) {
|
||||||
|
text += line.trim() + "\n";
|
||||||
|
}
|
||||||
|
|
||||||
|
WebvttCue cue = new WebvttCue(startTime, endTime, text);
|
||||||
|
subtitles.add(cue);
|
||||||
|
}
|
||||||
|
|
||||||
|
webvttData.close();
|
||||||
|
inputStream.close();
|
||||||
|
|
||||||
|
// copy WebvttCue data into arrays for WebvttSubtitle constructor
|
||||||
|
String[] cueText = new String[subtitles.size()];
|
||||||
|
long[] cueTimesUs = new long[2 * subtitles.size()];
|
||||||
|
for (int subtitleIndex = 0; subtitleIndex < subtitles.size(); subtitleIndex++) {
|
||||||
|
int arrayIndex = subtitleIndex * 2;
|
||||||
|
WebvttCue cue = subtitles.get(subtitleIndex);
|
||||||
|
cueTimesUs[arrayIndex] = cue.startTime;
|
||||||
|
cueTimesUs[arrayIndex + 1] = cue.endTime;
|
||||||
|
cueText[subtitleIndex] = cue.text;
|
||||||
|
}
|
||||||
|
|
||||||
|
WebvttSubtitle subtitle = new WebvttSubtitle(cueText, mediaTimestampUs, cueTimesUs);
|
||||||
|
return subtitle;
|
||||||
|
}
|
||||||
|
|
||||||
|
@Override
|
||||||
|
public boolean canParse(String mimeType) {
|
||||||
|
return MimeTypes.TEXT_VTT.equals(mimeType);
|
||||||
|
}
|
||||||
|
|
||||||
|
protected long getAdjustedStartTime(long startTimeUs) {
|
||||||
|
return startTimeUs;
|
||||||
|
}
|
||||||
|
|
||||||
|
private static long parseTimestampUs(String s) throws NumberFormatException {
|
||||||
|
if (!s.matches(WEBVTT_TIMESTAMP_STRING)) {
|
||||||
|
throw new NumberFormatException("has invalid format");
|
||||||
|
}
|
||||||
|
|
||||||
|
String[] parts = s.split("\\.", 2);
|
||||||
|
long value = 0;
|
||||||
|
for (String group : parts[0].split(":")) {
|
||||||
|
value = value * 60 + Long.parseLong(group);
|
||||||
|
}
|
||||||
|
return (value * 1000 + Long.parseLong(parts[1])) * 1000;
|
||||||
|
}
|
||||||
|
|
||||||
|
private static class WebvttCue {
|
||||||
|
public final long startTime;
|
||||||
|
public final long endTime;
|
||||||
|
public final String text;
|
||||||
|
|
||||||
|
public WebvttCue(long startTime, long endTime, String text) {
|
||||||
|
this.startTime = startTime;
|
||||||
|
this.endTime = endTime;
|
||||||
|
this.text = text;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
}
|
||||||
@ -0,0 +1,93 @@
|
|||||||
|
/*
|
||||||
|
* Copyright (C) 2014 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 com.google.android.exoplayer.text.webvtt;
|
||||||
|
|
||||||
|
import com.google.android.exoplayer.text.Subtitle;
|
||||||
|
import com.google.android.exoplayer.util.Assertions;
|
||||||
|
import com.google.android.exoplayer.util.Util;
|
||||||
|
|
||||||
|
import java.util.Arrays;
|
||||||
|
|
||||||
|
/**
|
||||||
|
* A representation of a WebVTT subtitle.
|
||||||
|
*/
|
||||||
|
public class WebvttSubtitle implements Subtitle {
|
||||||
|
|
||||||
|
private final String[] cueText;
|
||||||
|
private final long startTimeUs;
|
||||||
|
private final long[] cueTimesUs;
|
||||||
|
private final long[] sortedCueTimesUs;
|
||||||
|
|
||||||
|
/**
|
||||||
|
* @param cueText Text to be displayed during each cue.
|
||||||
|
* @param startTimeUs The start time of the subtitle.
|
||||||
|
* @param cueTimesUs Cue event times, where cueTimesUs[2 * i] and cueTimesUs[(2 * i) + 1] are
|
||||||
|
* the start and end times, respectively, corresponding to cueText[i].
|
||||||
|
*/
|
||||||
|
public WebvttSubtitle(String[] cueText, long startTimeUs, long[] cueTimesUs) {
|
||||||
|
this.cueText = cueText;
|
||||||
|
this.startTimeUs = startTimeUs;
|
||||||
|
this.cueTimesUs = cueTimesUs;
|
||||||
|
this.sortedCueTimesUs = Arrays.copyOf(cueTimesUs, cueTimesUs.length);
|
||||||
|
Arrays.sort(sortedCueTimesUs);
|
||||||
|
}
|
||||||
|
|
||||||
|
@Override
|
||||||
|
public long getStartTime() {
|
||||||
|
return startTimeUs;
|
||||||
|
}
|
||||||
|
|
||||||
|
@Override
|
||||||
|
public int getNextEventTimeIndex(long timeUs) {
|
||||||
|
Assertions.checkArgument(timeUs >= 0);
|
||||||
|
int index = Util.binarySearchCeil(sortedCueTimesUs, timeUs, false, false);
|
||||||
|
return index < sortedCueTimesUs.length ? index : -1;
|
||||||
|
}
|
||||||
|
|
||||||
|
@Override
|
||||||
|
public int getEventTimeCount() {
|
||||||
|
return sortedCueTimesUs.length;
|
||||||
|
}
|
||||||
|
|
||||||
|
@Override
|
||||||
|
public long getEventTime(int index) {
|
||||||
|
Assertions.checkArgument(index >= 0);
|
||||||
|
Assertions.checkArgument(index < sortedCueTimesUs.length);
|
||||||
|
return sortedCueTimesUs[index];
|
||||||
|
}
|
||||||
|
|
||||||
|
@Override
|
||||||
|
public long getLastEventTime() {
|
||||||
|
if (getEventTimeCount() == 0) {
|
||||||
|
return -1;
|
||||||
|
}
|
||||||
|
return sortedCueTimesUs[sortedCueTimesUs.length - 1];
|
||||||
|
}
|
||||||
|
|
||||||
|
@Override
|
||||||
|
public String getText(long timeUs) {
|
||||||
|
StringBuilder subtitleStringBuilder = new StringBuilder();
|
||||||
|
|
||||||
|
for (int i = 0; i < cueTimesUs.length; i += 2) {
|
||||||
|
if ((cueTimesUs[i] <= timeUs) && (timeUs < cueTimesUs[i + 1])) {
|
||||||
|
subtitleStringBuilder.append(cueText[i / 2]);
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
return (subtitleStringBuilder.length() > 0) ? subtitleStringBuilder.toString() : null;
|
||||||
|
}
|
||||||
|
|
||||||
|
}
|
||||||
Loading…
x
Reference in New Issue
Block a user