nl.vpro.domain.subtitles.WEBVTTandSRT Maven / Gradle / Ivy
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Subtitles are related to media, but are implemented completely parallel. Classes to contain, parse, and assemble subtitle objects are here.
package nl.vpro.domain.subtitles;
import lombok.extern.slf4j.Slf4j;
import java.io.*;
import java.nio.charset.Charset;
import java.time.Duration;
import java.util.*;
import java.util.regex.Pattern;
import java.util.stream.*;
import org.apache.commons.lang3.StringUtils;
import nl.vpro.util.SkipAtStartInputStream;
import static java.nio.charset.StandardCharsets.UTF_8;
/**
* https://developer.mozilla.org/en-US/docs/Web/API/WebVTT_A
* TODO: we support only a subset of WEBVTT.
*
* @author Michiel Meeuwissen
* @since 4.8
*/
@Slf4j
public class WEBVTTandSRT {
private WEBVTTandSRT() {
}
static final String WEBVTT_INTRO = "WEBVTT";
public static final Charset SRT_CHARSET = SubtitlesFormat.SRT.getCharset();
public static final Charset VTT_CHARSET = UTF_8;
public static ParseResult parseWEBVTT(String parent, InputStream inputStream) {
return parseWEBVTT(parent, Duration.ZERO, inputStream, null);
}
public static Stream parseSRT(String parent, InputStream inputStream) {
return parseSRT(parent, Duration.ZERO, inputStream, null);
}
public static ParseResult parseWEBVTT(String parent, Duration offset, InputStream inputStream, Charset charset) {
return parse(parent,
offset,
new InputStreamReader(inputStream, charset == null ? VTT_CHARSET : charset), ".");
}
public static Stream parseSRT(String parent, Duration offset, InputStream inputStream, Charset charset) {
if (! UTF_8.equals(charset)) {
inputStream = SkipAtStartInputStream.skipUnicodeByteOrderMarks(inputStream);
}
return parse(parent, offset, new InputStreamReader(inputStream, charset == null ? SRT_CHARSET : charset), ",").getCues();
}
/**
* A WebVTT timestamp consists of the following components, in the given order:
*
* Optionally (required if hours is non-zero):
* Two or more ASCII digits, representing the hours as a base ten integer.
* // REMARK: We accept 1 too.
* A U+003A COLON character (:)
* Two ASCII digits, representing the minutes as a base ten integer in the range 0 ≤ minutes ≤ 59.
* A U+003A COLON character (:)
* Two ASCII digits, representing the seconds as a base ten integer in the range 0 ≤ seconds ≤ 59.
* A U+002E FULL STOP character (.).
* Three ASCII digits, representing the thousandths of a second seconds-frac as a base ten integer.
*/
static final String TIMESTAMP = "((?:\\d{1,}:\\d{1,2}:\\d{2}[.,]\\d{3})|(?:\\d{1,2}:\\d{2}[.,]\\d{3}))";
static final Pattern CUETIMING =
Pattern.compile(TIMESTAMP + "[ \\t]+-->[ \\t]+" + TIMESTAMP + ".*");
static ParseResult parse(
String parent,
Duration offset,
Reader reader,
String decimalSeparator) {
final List headers = new ArrayList<>();
final Iterator stream = new BufferedReader(reader)
.lines()
.iterator();
Iterator cues = new Iterator() {
boolean needsFindNext = true;
String cueIdentifier;
String timeLine = null;
final StringBuilder content = new StringBuilder();
boolean readIntro = false;
@Override
public boolean hasNext() {
findNext();
return timeLine != null;
}
@Override
public Cue next() {
findNext();
if (timeLine == null) {
throw new NoSuchElementException();
}
needsFindNext = true;
try {
return parseCue(parent, cueIdentifier, offset, timeLine, content.toString(), decimalSeparator);
} catch (IllegalArgumentException e) {
log.warn("Error: {} while parsing\nheadline:{}\ntimeline:{}", e.getMessage(), cueIdentifier, StringUtils.abbreviate(timeLine, 100));
return null;
}
}
protected void findNext() {
if (needsFindNext) {
cueIdentifier= null;
timeLine = null;
content.setLength(0);
String headLine = null;
while (stream.hasNext()) {
String l = stream.next();
if (StringUtils.isNotBlank(l)) {
if (! readIntro) {
if (WEBVTT_INTRO.equals(l.trim())) {
StringBuilder content = new StringBuilder();
while (stream.hasNext()) {
l = stream.next();
if (StringUtils.isBlank(l)) {
readIntro = true;
} else {
log.debug("Read {}", l);
if (readIntro) {
break;
} else {
content.append(l);
}
}
}
if (content.length() > 0) {
headers.add(
Meta.builder().content(content.toString()).type(MetaType.INTRO).build()
);
}
while (StringUtils.isBlank(l) && stream.hasNext()) {
l = stream.next();
}
}
}
readIntro = true;
while (l.startsWith("NOTE") || l.startsWith("STYLE") || l.startsWith("REGION")) {
while (stream.hasNext()) {
l = stream.next();
if (StringUtils.isBlank(l)) {
break;
}
}
while (StringUtils.isBlank(l) && stream.hasNext()) {
l = stream.next();
}
}
headLine = l.trim();
break;
}
}
if (headLine != null) {
if (! CUETIMING.matcher(headLine).matches()) {
cueIdentifier = headLine;
if (stream.hasNext()) {
timeLine = stream.next();
}
} else {
timeLine = headLine;
}
}
// now read conent
while (stream.hasNext()) {
String l = stream.next();
if (StringUtils.isBlank(l)) {
break;
}
if (content.length() > 0) {
content.append('\n');
}
content.append(l.trim());
}
needsFindNext = false;
}
}
};
return ParseResult.of(
StreamSupport.stream(Spliterators.spliteratorUnknownSize(cues, Spliterator.ORDERED), false),
headers);
}
static Cue parseCue(String parent, String cueNumber, Duration offset, String timeLine, String content, String decimalSeparator) {
String[] split = timeLine.split("\\s+", 4);
try {
if (offset == null) {
offset = Duration.ZERO;
}
if (split.length < 3) {
throw new IllegalArgumentException("Timeline could not be parsed " + timeLine);
}
String start = split[0];
String arrow = split[1];
String end = split[2];
String settings = split.length > 3 ? split[3] :null;
Integer sequence;
try {
sequence = Integer.parseInt(cueNumber);
} catch (NumberFormatException nfe) {
sequence = null;
}
return Cue.builder()
.mid(parent)
.identifier(cueNumber)
.sequence(sequence)
.start(parseDuration(start, decimalSeparator).minus(offset))
.end(parseDuration(end, decimalSeparator).minus(offset))
.settings(CueSettings.webvtt(settings))
.content(content)
.build();
} catch(NumberFormatException nfe) {
throw new IllegalArgumentException("For " + parent + " could not parse timeline " + StringUtils.abbreviate(timeLine, 100) +
" (" + Arrays.stream(split).limit(20).map(s -> StringUtils.abbreviate(s, 100)).collect(Collectors.joining(","))
+ "). Headline: " + cueNumber + ". Expected content: " + StringUtils.abbreviate(content, 100) + ". Reason: " + nfe.getClass() + " " + nfe.getMessage(), nfe);
}
}
static void formatSRT(Iterator cueIterator, OutputStream out) throws IOException {
Writer writer = new OutputStreamWriter(out, SRT_CHARSET);
StringBuilder builder = new StringBuilder();
while (cueIterator.hasNext()) {
Cue cue = cueIterator.next();
if (cue != null) {
formatCue(cue, builder, ",", false);
writer.write(builder.toString());
builder.setLength(0);
}
}
writer.flush();
}
static void formatWEBVTT(Iterator cueIterator, OutputStream out) throws IOException {
Writer writer = new OutputStreamWriter(out, VTT_CHARSET);
formatWEBVTT(cueIterator, writer);
writer.flush();
}
static void formatWEBVTT(Iterator cueIterator, Writer writer) throws IOException {
writer.write(WEBVTT_INTRO);
writer.write("\n\n");
StringBuilder builder = new StringBuilder();
while (cueIterator.hasNext()) {
Cue cue = cueIterator.next();
if (cue != null) {
formatCue(cue, builder, ".", true);
writer.write(builder.toString());
builder.setLength(0);
}
}
}
static String formatDuration(Duration duration, String separator) {
long millis = duration.toMillis();
boolean negative = millis < 0L;
if (negative) {
millis *= -1;
}
long hours = millis / 3600000;
millis -= hours * 3600000;
long minutes = millis / 60000;
millis -= minutes * 60000;
long seconds = millis / 1000;
millis -= seconds * 1000;
return String.format("%s%02d:%02d:%02d%s%03d", negative ? "-" : "", hours, minutes, seconds, separator, millis);
}
static Duration parseDuration(String duration, String decimalSeparator) {
boolean negative = false;
if (duration.startsWith("-")) {
negative = true;
duration = duration.substring(1);
}
String[] split = duration.split(":", 3);
int index = 0;
long hours;
if (split.length == 3) {
hours = Long.parseLong(split[0]);
index++;
} else {
hours = 0L;
}
long minutes;
if (split.length >= 2) {
minutes = Long.parseLong(split[index]);
index++;
} else {
minutes = 0L;
}
String [] split2 = split[index].split(Pattern.quote(decimalSeparator), 2);
long seconds = Long.parseLong(split2[0]);
long millis = Long.parseLong(split2[1]);
Duration result = Duration.ofHours(hours).plusMinutes(minutes).plusSeconds(seconds).plusMillis(millis);
if (negative) {
result = result.negated();
}
return result;
}
static StringBuilder formatCue(Cue cue, StringBuilder builder, String decimalSeparator, boolean settings) {
if (cue.getSequence() != null) {
builder.append(cue.getSequence());
}
Duration offset = Duration.ZERO;
builder.append("\n");
if (cue.getStart() != null) {
builder.append(formatDuration(cue.getStart().minus(offset), decimalSeparator));
}
builder.append(" --> ");
if (cue.getEnd() != null) {
builder.append(formatDuration(cue.getEnd().minus(offset), decimalSeparator));
}
if (settings && cue.getSettings() != null && StringUtils.isNotBlank(cue.getSettings().getValue())) {
builder.append(" ").append(cue.getSettings().getValue());
}
builder.append("\n");
if (cue.getContent() != null) {
builder.append(cue.getContent());//replaceAll("\\s+", " "));
}
builder.append("\n\n");
return builder;
}
}
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