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Add support to CSS in WebVTT files

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This CL adds the support of CSS styling in Cues through id and "universal" cue selector.
The more sophisticated selectors will be left for later, because they requier a bit more
complex logic. Also narrowed a little bit the responsibilities of the WebvttCueParser to
move some to the WebvttParser.
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=119547731
This commit is contained in:
aquilescanta 2016-04-11 10:54:31 -07:00 committed by Oliver Woodman
parent 087cf9546f
commit efe76def89
8 changed files with 258 additions and 62 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
library/src/androidTest/assets/webvtt/with_css_styles Normal file
View File

@ -0,0 +1,23 @@
WEBVTT
STYLE
::cue {
background-color: green;
color: papayawhip;
}
/* Style blocks cannot use blank lines nor "dash dash greater than" */
NOTE comment blocks can be used between style blocks.
STYLE
::cue(2) {
color: peachpuff;
}
1
00:00.000 --> 00:01.234
This is the first subtitle.
2
00:02.345 --> 00:03.456
This is the second subtitle.

47
library/src/androidTest/java/com/google/android/exoplayer/text/webvtt/WebvttParserTest.java
View File

@ -21,6 +21,9 @@ import com.google.android.exoplayer.text.Cue;
import android.test.InstrumentationTestCase;
import android.text.Layout.Alignment;
import android.text.Spanned;
import android.text.style.BackgroundColorSpan;
import android.text.style.ForegroundColorSpan;
import java.io.IOException;
import java.util.List;
@ -36,6 +39,7 @@ public class WebvttParserTest extends InstrumentationTestCase {
private static final String WITH_POSITIONING_FILE = "webvtt/with_positioning";
private static final String WITH_BAD_CUE_HEADER_FILE = "webvtt/with_bad_cue_header";
private static final String WITH_TAGS_FILE = "webvtt/with_tags";
private static final String WITH_CSS_STYLES = "webvtt/with_css_styles";
private static final String EMPTY_FILE = "webvtt/empty";
public void testParseEmpty() throws IOException {
@ -54,10 +58,10 @@ public class WebvttParserTest extends InstrumentationTestCase {
byte[] bytes = TestUtil.getByteArray(getInstrumentation(), TYPICAL_FILE);
WebvttSubtitle subtitle = parser.decode(bytes, bytes.length);
// test event count
// Test event count.
assertEquals(4, subtitle.getEventTimeCount());
// test cues
// Test cues.
assertCue(subtitle, 0, 0, 1234000, "This is the first subtitle.");
assertCue(subtitle, 2, 2345000, 3456000, "This is the second subtitle.");
}
@ -67,10 +71,10 @@ public class WebvttParserTest extends InstrumentationTestCase {
byte[] bytes = TestUtil.getByteArray(getInstrumentation(), TYPICAL_WITH_IDS_FILE);
WebvttSubtitle subtitle = parser.decode(bytes, bytes.length);
// test event count
// Test event count.
assertEquals(4, subtitle.getEventTimeCount());
// test cues
// Test cues.
assertCue(subtitle, 0, 0, 1234000, "This is the first subtitle.");
assertCue(subtitle, 2, 2345000, 3456000, "This is the second subtitle.");
}
@ -93,10 +97,10 @@ public class WebvttParserTest extends InstrumentationTestCase {
byte[] bytes = TestUtil.getByteArray(getInstrumentation(), WITH_TAGS_FILE);
WebvttSubtitle subtitle = parser.decode(bytes, bytes.length);
// test event count
// Test event count.
assertEquals(8, subtitle.getEventTimeCount());
// test cues
// Test cues.
assertCue(subtitle, 0, 0, 1234000, "This is the first subtitle.");
assertCue(subtitle, 2, 2345000, 3456000, "This is the second subtitle.");
assertCue(subtitle, 4, 4000000, 5000000, "This is the third subtitle.");
@ -108,10 +112,10 @@ public class WebvttParserTest extends InstrumentationTestCase {
byte[] bytes = TestUtil.getByteArray(getInstrumentation(), WITH_POSITIONING_FILE);
WebvttSubtitle subtitle = parser.decode(bytes, bytes.length);
// test event count
// Test event count.
assertEquals(12, subtitle.getEventTimeCount());
// test cues
// Test cues.
assertCue(subtitle, 0, 0, 1234000, "This is the first subtitle.", Alignment.ALIGN_NORMAL,
Cue.DIMEN_UNSET, Cue.TYPE_UNSET, Cue.TYPE_UNSET, 0.1f, Cue.ANCHOR_TYPE_START, 0.35f);
assertCue(subtitle, 2, 2345000, 3456000, "This is the second subtitle.",
@ -136,13 +140,34 @@ public class WebvttParserTest extends InstrumentationTestCase {
byte[] bytes = TestUtil.getByteArray(getInstrumentation(), WITH_BAD_CUE_HEADER_FILE);
WebvttSubtitle subtitle = parser.decode(bytes, bytes.length);
// test event count
// Test event count.
assertEquals(4, subtitle.getEventTimeCount());
// test cues
// Test cues.
assertCue(subtitle, 0, 0, 1234000, "This is the first subtitle.");
assertCue(subtitle, 2, 4000000, 5000000, "This is the third subtitle.");
}
public void testWebvttWithCssStyle() throws IOException {
WebvttParser parser = new WebvttParser();
byte[] bytes = TestUtil.getByteArray(getInstrumentation(), WITH_CSS_STYLES);
WebvttSubtitle subtitle = parser.decode(bytes, bytes.length);
// Test event count.
assertEquals(4, subtitle.getEventTimeCount());
// Test cues.
assertCue(subtitle, 0, 0, 1234000, "This is the first subtitle.");
assertCue(subtitle, 2, 2345000, 3456000, "This is the second subtitle.");
Cue cue1 = subtitle.getCues(0).get(0);
Cue cue2 = subtitle.getCues(2345000).get(0);
Spanned s1 = (Spanned) cue1.text;
Spanned s2 = (Spanned) cue2.text;
assertEquals(1, s1.getSpans(0, s1.length(), ForegroundColorSpan.class).length);
assertEquals(1, s1.getSpans(0, s1.length(), BackgroundColorSpan.class).length);
assertEquals(2, s2.getSpans(0, s2.length(), ForegroundColorSpan.class).length);
}
private static void assertCue(WebvttSubtitle subtitle, int eventTimeIndex, long startTimeUs,
int endTimeUs, String text) {
@ -157,7 +182,7 @@ public class WebvttParserTest extends InstrumentationTestCase {
assertEquals(endTimeUs, subtitle.getEventTime(eventTimeIndex + 1));
List<Cue> cues = subtitle.getCues(subtitle.getEventTime(eventTimeIndex));
assertEquals(1, cues.size());
// Assert cue properties
// Assert cue properties.
Cue cue = cues.get(0);
assertEquals(text, cue.text.toString());
assertEquals(textAlignment, cue.textAlignment);

3
library/src/main/java/com/google/android/exoplayer/hls/WebvttExtractor.java
View File

@ -25,7 +25,6 @@ import com.google.android.exoplayer.extractor.PositionHolder;
import com.google.android.exoplayer.extractor.SeekMap;
import com.google.android.exoplayer.extractor.TrackOutput;
import com.google.android.exoplayer.extractor.ts.PtsTimestampAdjuster;
import com.google.android.exoplayer.text.webvtt.WebvttCueParser;
import com.google.android.exoplayer.text.webvtt.WebvttParserUtil;
import com.google.android.exoplayer.util.MimeTypes;
import com.google.android.exoplayer.util.ParsableByteArray;
@ -145,7 +144,7 @@ import java.util.regex.Pattern;
}
// Find the first cue header and parse the start time.
Matcher cueHeaderMatcher = WebvttCueParser.findNextCueHeader(webvttData);
Matcher cueHeaderMatcher = WebvttParserUtil.findNextCueHeader(webvttData);
if (cueHeaderMatcher == null) {
// No cues found. Don't output a sample, but still output a corresponding track.
buildTrackOutput(0);

7
library/src/main/java/com/google/android/exoplayer/text/webvtt/CssParser.java
View File

@ -54,6 +54,7 @@ import java.util.Map;
* @param styleMap The map that contains styles accessible by selector.
*/
public void parseBlock(ParsableByteArray input, Map<String, WebvttCssStyle> styleMap) {
stringBuilder.setLength(0);
int initialInputPosition = input.getPosition();
skipStyleBlock(input);
styleInput.reset(input.data, input.getPosition());
@ -97,8 +98,8 @@ import java.util.Map;
* ::cue(v[voice="Someone"])
*
* @param input From which the selector is obtained.
* @return A string containing the target, empty string if targets all cues and null if an error
* was encountered.
* @return A string containing the target, {@link WebvttCue#UNIVERSAL_CUE_ID} if targets all cues
* and null if an error was encountered.
*/
private static String parseSelector(ParsableByteArray input, StringBuilder stringBuilder) {
skipWhitespaceAndComments(input);
@ -116,7 +117,7 @@ import java.util.Map;
}
if ("{".equals(token)) {
input.setPosition(position);
return "";
return WebvttCue.UNIVERSAL_CUE_ID;
}
String target = null;
if ("(".equals(token)) {

95
library/src/main/java/com/google/android/exoplayer/text/webvtt/WebvttCue.java
View File

@ -18,13 +18,31 @@ package com.google.android.exoplayer.text.webvtt;
import com.google.android.exoplayer.text.Cue;
import android.text.Layout.Alignment;
import android.text.Spannable;
import android.text.SpannableStringBuilder;
import android.text.Spanned;
import android.text.style.AbsoluteSizeSpan;
import android.text.style.AlignmentSpan;
import android.text.style.BackgroundColorSpan;
import android.text.style.ForegroundColorSpan;
import android.text.style.RelativeSizeSpan;
import android.text.style.StrikethroughSpan;
import android.text.style.StyleSpan;
import android.text.style.TypefaceSpan;
import android.text.style.UnderlineSpan;
import android.util.Log;
import java.util.Collections;
import java.util.Map;
/**
* A representation of a WebVTT cue.
*/
/* package */ final class WebvttCue extends Cue {
public static final String UNIVERSAL_CUE_ID = "";
public final String id;
public final long startTime;
public final long endTime;
@ -33,13 +51,15 @@ import android.util.Log;
}
public WebvttCue(long startTime, long endTime, CharSequence text) {
this(startTime, endTime, text, null, Cue.DIMEN_UNSET, Cue.TYPE_UNSET, Cue.TYPE_UNSET,
this(null, startTime, endTime, text, null, Cue.DIMEN_UNSET, Cue.TYPE_UNSET, Cue.TYPE_UNSET,
Cue.DIMEN_UNSET, Cue.TYPE_UNSET, Cue.DIMEN_UNSET);
}
public WebvttCue(long startTime, long endTime, CharSequence text, Alignment textAlignment,
float line, int lineType, int lineAnchor, float position, int positionAnchor, float width) {
public WebvttCue(String id, long startTime, long endTime, CharSequence text,
Alignment textAlignment, float line, int lineType, int lineAnchor, float position,
int positionAnchor, float width) {
super(text, textAlignment, line, lineType, lineAnchor, position, positionAnchor, width);
this.id = id;
this.startTime = startTime;
this.endTime = endTime;
}
@ -62,9 +82,10 @@ import android.util.Log;
private static final String TAG = "WebvttCueBuilder";
private String id;
private long startTime;
private long endTime;
private CharSequence text;
private SpannableStringBuilder text;
private Alignment textAlignment;
private float line;
private int lineType;
@ -92,16 +113,28 @@ import android.util.Log;
width = Cue.DIMEN_UNSET;
}
// Construction methods
// Construction methods.
public WebvttCue build() {
return build(Collections.<String, WebvttCssStyle>emptyMap());
}
public WebvttCue build(Map<String, WebvttCssStyle> styleMap) {
// TODO: Add support for inner spans.
maybeApplyStyleToText(styleMap.get(UNIVERSAL_CUE_ID), 0, text.length());
maybeApplyStyleToText(styleMap.get(id), 0, text.length());
if (position != Cue.DIMEN_UNSET && positionAnchor == Cue.TYPE_UNSET) {
derivePositionAnchorFromAlignment();
}
return new WebvttCue(startTime, endTime, text, textAlignment, line, lineType, lineAnchor,
return new WebvttCue(id, startTime, endTime, text, textAlignment, line, lineType, lineAnchor,
position, positionAnchor, width);
}
public Builder setId(String id) {
this.id = id;
return this;
}
public Builder setStartTime(long time) {
startTime = time;
return this;
@ -112,7 +145,7 @@ import android.util.Log;
return this;
}
public Builder setText(CharSequence aText) {
public Builder setText(SpannableStringBuilder aText) {
text = aText;
return this;
}
@ -175,6 +208,54 @@ import android.util.Log;
return this;
}
private void maybeApplyStyleToText(WebvttCssStyle style, int start, int end) {
if (style == null) {
return;
}
if (style.getStyle() != WebvttCssStyle.UNSPECIFIED) {
text.setSpan(new StyleSpan(style.getStyle()), start, end,
Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
}
if (style.isLinethrough()) {
text.setSpan(new StrikethroughSpan(), start, end, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
}
if (style.isUnderline()) {
text.setSpan(new UnderlineSpan(), start, end, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
}
if (style.hasFontColor()) {
text.setSpan(new ForegroundColorSpan(style.getFontColor()), start, end,
Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
}
if (style.hasBackgroundColor()) {
text.setSpan(new BackgroundColorSpan(style.getBackgroundColor()), start, end,
Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
}
if (style.getFontFamily() != null) {
text.setSpan(new TypefaceSpan(style.getFontFamily()), start, end,
Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
}
if (style.getTextAlign() != null) {
text.setSpan(new AlignmentSpan.Standard(style.getTextAlign()), start, end,
Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
}
if (style.getFontSizeUnit() != WebvttCssStyle.UNSPECIFIED) {
switch (style.getFontSizeUnit()) {
case WebvttCssStyle.FONT_SIZE_UNIT_PIXEL:
text.setSpan(new AbsoluteSizeSpan((int) style.getFontSize(), true), start, end,
Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
break;
case WebvttCssStyle.FONT_SIZE_UNIT_EM:
text.setSpan(new RelativeSizeSpan(style.getFontSize()), start, end,
Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
break;
case WebvttCssStyle.FONT_SIZE_UNIT_PERCENT:
text.setSpan(new RelativeSizeSpan(style.getFontSize() / 100), start, end,
Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
break;
}
}
}
}
}

48
library/src/main/java/com/google/android/exoplayer/text/webvtt/WebvttCueParser.java
View File

@ -33,12 +33,11 @@ import java.util.regex.Pattern;
/**
* Parser for WebVTT cues. (https://w3c.github.io/webvtt/#cues)
*/
public final class WebvttCueParser {
/* package */ final class WebvttCueParser {
public static final Pattern CUE_HEADER_PATTERN = Pattern
.compile("^(\\S+)\\s+-->\\s+(\\S+)(.*)?$");
private static final Pattern COMMENT = Pattern.compile("^NOTE((\u0020|\u0009).*)?$");
private static final Pattern CUE_SETTING_PATTERN = Pattern.compile("(\\S+?):(\\S+)");
private static final char CHAR_LESS_THAN = '<';
@ -71,7 +70,7 @@ public final class WebvttCueParser {
public WebvttCueParser() {
textBuilder = new StringBuilder();
}
/**
* Parses the next valid WebVTT cue in a parsable array, including timestamps, settings and text.
*
@ -79,11 +78,20 @@ public final class WebvttCueParser {
* @param builder Builder for WebVTT Cues.
* @return True if a valid Cue was found, false otherwise.
*/
/* package */ boolean parseNextValidCue(ParsableByteArray webvttData, WebvttCue.Builder builder) {
Matcher cueHeaderMatcher;
while ((cueHeaderMatcher = findNextCueHeader(webvttData)) != null) {
if (parseCue(cueHeaderMatcher, webvttData, builder, textBuilder)) {
return true;
/* package */ boolean parseCue(ParsableByteArray webvttData, WebvttCue.Builder builder) {
String firstLine = webvttData.readLine();
Matcher cueHeaderMatcher = WebvttCueParser.CUE_HEADER_PATTERN.matcher(firstLine);
if (cueHeaderMatcher.matches()) {
// We have found the timestamps in the first line. No id present.
return parseCue(cueHeaderMatcher, webvttData, builder, textBuilder);
} else {
// The first line is not the timestamps, but could be the cue id.
String secondLine = webvttData.readLine();
cueHeaderMatcher = WebvttCueParser.CUE_HEADER_PATTERN.matcher(secondLine);
if (cueHeaderMatcher.matches()) {
// We can do the rest of the parsing, including the id.
builder.setId(firstLine.trim());
return parseCue(cueHeaderMatcher, webvttData, builder, textBuilder);
}
}
return false;
@ -120,30 +128,6 @@ public final class WebvttCueParser {
}
}
/**
* Reads lines up to and including the next WebVTT cue header.
*
* @param input The input from which lines should be read.
* @return A {@link Matcher} for the WebVTT cue header, or null if the end of the input was
* reached without a cue header being found. In the case that a cue header is found, groups 1,
* 2 and 3 of the returned matcher contain the start time, end time and settings list.
*/
public static Matcher findNextCueHeader(ParsableByteArray input) {
String line;
while ((line = input.readLine()) != null) {
if (COMMENT.matcher(line).matches()) {
// Skip until the end of the comment block.
while ((line = input.readLine()) != null && !line.isEmpty()) {}
} else {
Matcher cueHeaderMatcher = WebvttCueParser.CUE_HEADER_PATTERN.matcher(line);
if (cueHeaderMatcher.matches()) {
return cueHeaderMatcher;
}
}
}
return null;
}
/**
* Parses the text payload of a WebVTT Cue and applies modifications on {@link WebvttCue.Builder}.
*

71
library/src/main/java/com/google/android/exoplayer/text/webvtt/WebvttParser.java
View File

@ -22,6 +22,7 @@ import com.google.android.exoplayer.util.ParsableByteArray;
import android.text.TextUtils;
import java.util.ArrayList;
import java.util.HashMap;
/**
* A simple WebVTT parser.
@ -30,32 +31,88 @@ import java.util.ArrayList;
*/
public final class WebvttParser extends SubtitleParser {
private static final int NO_EVENT_FOUND = -1;
private static final int END_OF_FILE_FOUND = 0;
private static final int COMMENT_FOUND = 1;
private static final int STYLE_BLOCK_FOUND = 2;
private static final int CUE_FOUND = 3;
private static final String COMMENT_START = "NOTE";
private static final String STYLE_START = "STYLE";
private final WebvttCueParser cueParser;
private final ParsableByteArray parsableWebvttData;
private final WebvttCue.Builder webvttCueBuilder;
private final CssParser cssParser;
private final HashMap<String, WebvttCssStyle> styleMap;
public WebvttParser() {
cueParser = new WebvttCueParser();
parsableWebvttData = new ParsableByteArray();
webvttCueBuilder = new WebvttCue.Builder();
cssParser = new CssParser();
styleMap = new HashMap<>();
}
@Override
protected final WebvttSubtitle decode(byte[] bytes, int length) throws ParserException {
protected WebvttSubtitle decode(byte[] bytes, int length) throws ParserException {
parsableWebvttData.reset(bytes, length);
webvttCueBuilder.reset(); // In case a previous parse run failed with a ParserException.
// Initialization for consistent starting state.
webvttCueBuilder.reset();
styleMap.clear();
// Validate the first line of the header, and skip the remainder.
WebvttParserUtil.validateWebvttHeaderLine(parsableWebvttData);
while (!TextUtils.isEmpty(parsableWebvttData.readLine())) {}
// Extract Cues
int eventFound;
ArrayList<WebvttCue> subtitles = new ArrayList<>();
while (cueParser.parseNextValidCue(parsableWebvttData, webvttCueBuilder)) {
subtitles.add(webvttCueBuilder.build());
webvttCueBuilder.reset();
while ((eventFound = getNextEvent(parsableWebvttData)) != END_OF_FILE_FOUND) {
if (eventFound == COMMENT_FOUND) {
skipComment(parsableWebvttData);
} else if (eventFound == STYLE_BLOCK_FOUND) {
if (!subtitles.isEmpty()) {
throw new ParserException("A style block was found after the first cue.");
}
parsableWebvttData.readLine(); // Consume the "STYLE" header.
cssParser.parseBlock(parsableWebvttData, styleMap);
} else if (eventFound == CUE_FOUND) {
if (cueParser.parseCue(parsableWebvttData, webvttCueBuilder)) {
subtitles.add(webvttCueBuilder.build(styleMap));
webvttCueBuilder.reset();
}
}
}
return new WebvttSubtitle(subtitles);
}
/**
* Positions the input right before the next event, and returns the kind of event found. Does not
* consume any data from such event, if any.
*
* @return The kind of event found.
*/
private static int getNextEvent(ParsableByteArray parsableWebvttData) {
int foundEvent = NO_EVENT_FOUND;
int currentInputPosition = 0;
while (foundEvent == NO_EVENT_FOUND) {
currentInputPosition = parsableWebvttData.getPosition();
String line = parsableWebvttData.readLine();
if (line == null) {
foundEvent = END_OF_FILE_FOUND;
} else if (STYLE_START.equals(line)) {
foundEvent = STYLE_BLOCK_FOUND;
} else if (COMMENT_START.startsWith(line)) {
foundEvent = COMMENT_FOUND;
} else {
foundEvent = CUE_FOUND;
}
}
parsableWebvttData.setPosition(currentInputPosition);
return foundEvent;
}
private static void skipComment(ParsableByteArray parsableWebvttData) {
while (!TextUtils.isEmpty(parsableWebvttData.readLine())) {}
}
}

26
library/src/main/java/com/google/android/exoplayer/text/webvtt/WebvttParserUtil.java
View File

@ -18,6 +18,7 @@ package com.google.android.exoplayer.text.webvtt;
import com.google.android.exoplayer.ParserException;
import com.google.android.exoplayer.util.ParsableByteArray;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
@ -25,6 +26,7 @@ import java.util.regex.Pattern;
*/
public final class WebvttParserUtil {
private static final Pattern COMMENT = Pattern.compile("^NOTE((\u0020|\u0009).*)?$");
private static final Pattern HEADER = Pattern.compile("^\uFEFF?WEBVTT((\u0020|\u0009).*)?$");
private WebvttParserUtil() {}
@ -71,5 +73,29 @@ public final class WebvttParserUtil {
}
return Float.parseFloat(s.substring(0, s.length() - 1)) / 100;
}
/**
* Reads lines up to and including the next WebVTT cue header.
*
* @param input The input from which lines should be read.
* @return A {@link Matcher} for the WebVTT cue header, or null if the end of the input was
* reached without a cue header being found. In the case that a cue header is found, groups 1,
* 2 and 3 of the returned matcher contain the start time, end time and settings list.
*/
public static Matcher findNextCueHeader(ParsableByteArray input) {
String line;
while ((line = input.readLine()) != null) {
if (COMMENT.matcher(line).matches()) {
// Skip until the end of the comment block.
while ((line = input.readLine()) != null && !line.isEmpty()) {}
} else {
Matcher cueHeaderMatcher = WebvttCueParser.CUE_HEADER_PATTERN.matcher(line);
if (cueHeaderMatcher.matches()) {
return cueHeaderMatcher;
}
}
}
return null;
}
}