| /* |
| * Copyright (C) 2016 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.exoplayer2.text.subrip; |
| |
| import android.text.Html; |
| import android.text.Spanned; |
| import android.text.TextUtils; |
| import androidx.annotation.Nullable; |
| import com.google.android.exoplayer2.text.Cue; |
| import com.google.android.exoplayer2.text.SimpleSubtitleDecoder; |
| import com.google.android.exoplayer2.text.Subtitle; |
| import com.google.android.exoplayer2.util.Assertions; |
| import com.google.android.exoplayer2.util.Log; |
| import com.google.android.exoplayer2.util.LongArray; |
| import com.google.android.exoplayer2.util.ParsableByteArray; |
| import java.util.ArrayList; |
| import java.util.regex.Matcher; |
| import java.util.regex.Pattern; |
| |
| /** A {@link SimpleSubtitleDecoder} for SubRip. */ |
| public final class SubripDecoder extends SimpleSubtitleDecoder { |
| |
| // Fractional positions for use when alignment tags are present. |
| private static final float START_FRACTION = 0.08f; |
| private static final float END_FRACTION = 1 - START_FRACTION; |
| private static final float MID_FRACTION = 0.5f; |
| |
| private static final String TAG = "SubripDecoder"; |
| |
| // Some SRT files don't include hours or milliseconds in the timecode, so we use optional groups. |
| private static final String SUBRIP_TIMECODE = "(?:(\\d+):)?(\\d+):(\\d+)(?:,(\\d+))?"; |
| private static final Pattern SUBRIP_TIMING_LINE = |
| Pattern.compile("\\s*(" + SUBRIP_TIMECODE + ")\\s*-->\\s*(" + SUBRIP_TIMECODE + ")\\s*"); |
| |
| // NOTE: Android Studio's suggestion to simplify '\\}' is incorrect [internal: b/144480183]. |
| private static final Pattern SUBRIP_TAG_PATTERN = Pattern.compile("\\{\\\\.*?\\}"); |
| private static final String SUBRIP_ALIGNMENT_TAG = "\\{\\\\an[1-9]\\}"; |
| |
| // Alignment tags for SSA V4+. |
| private static final String ALIGN_BOTTOM_LEFT = "{\\an1}"; |
| private static final String ALIGN_BOTTOM_MID = "{\\an2}"; |
| private static final String ALIGN_BOTTOM_RIGHT = "{\\an3}"; |
| private static final String ALIGN_MID_LEFT = "{\\an4}"; |
| private static final String ALIGN_MID_MID = "{\\an5}"; |
| private static final String ALIGN_MID_RIGHT = "{\\an6}"; |
| private static final String ALIGN_TOP_LEFT = "{\\an7}"; |
| private static final String ALIGN_TOP_MID = "{\\an8}"; |
| private static final String ALIGN_TOP_RIGHT = "{\\an9}"; |
| |
| private final StringBuilder textBuilder; |
| private final ArrayList<String> tags; |
| |
| public SubripDecoder() { |
| super("SubripDecoder"); |
| textBuilder = new StringBuilder(); |
| tags = new ArrayList<>(); |
| } |
| |
| @Override |
| protected Subtitle decode(byte[] bytes, int length, boolean reset) { |
| ArrayList<Cue> cues = new ArrayList<>(); |
| LongArray cueTimesUs = new LongArray(); |
| ParsableByteArray subripData = new ParsableByteArray(bytes, length); |
| |
| @Nullable String currentLine; |
| while ((currentLine = subripData.readLine()) != null) { |
| if (currentLine.length() == 0) { |
| // Skip blank lines. |
| continue; |
| } |
| |
| // Parse and check the index line. |
| try { |
| Integer.parseInt(currentLine); |
| } catch (NumberFormatException e) { |
| Log.w(TAG, "Skipping invalid index: " + currentLine); |
| continue; |
| } |
| |
| // Read and parse the timing line. |
| currentLine = subripData.readLine(); |
| if (currentLine == null) { |
| Log.w(TAG, "Unexpected end"); |
| break; |
| } |
| |
| Matcher matcher = SUBRIP_TIMING_LINE.matcher(currentLine); |
| if (matcher.matches()) { |
| cueTimesUs.add(parseTimecode(matcher, /* groupOffset= */ 1)); |
| cueTimesUs.add(parseTimecode(matcher, /* groupOffset= */ 6)); |
| } else { |
| Log.w(TAG, "Skipping invalid timing: " + currentLine); |
| continue; |
| } |
| |
| // Read and parse the text and tags. |
| textBuilder.setLength(0); |
| tags.clear(); |
| currentLine = subripData.readLine(); |
| while (!TextUtils.isEmpty(currentLine)) { |
| if (textBuilder.length() > 0) { |
| textBuilder.append("<br>"); |
| } |
| textBuilder.append(processLine(currentLine, tags)); |
| currentLine = subripData.readLine(); |
| } |
| |
| Spanned text = Html.fromHtml(textBuilder.toString()); |
| |
| @Nullable String alignmentTag = null; |
| for (int i = 0; i < tags.size(); i++) { |
| String tag = tags.get(i); |
| if (tag.matches(SUBRIP_ALIGNMENT_TAG)) { |
| alignmentTag = tag; |
| // Subsequent alignment tags should be ignored. |
| break; |
| } |
| } |
| cues.add(buildCue(text, alignmentTag)); |
| cues.add(Cue.EMPTY); |
| } |
| |
| Cue[] cuesArray = cues.toArray(new Cue[0]); |
| long[] cueTimesUsArray = cueTimesUs.toArray(); |
| return new SubripSubtitle(cuesArray, cueTimesUsArray); |
| } |
| |
| /** |
| * Trims and removes tags from the given line. The removed tags are added to {@code tags}. |
| * |
| * @param line The line to process. |
| * @param tags A list to which removed tags will be added. |
| * @return The processed line. |
| */ |
| private String processLine(String line, ArrayList<String> tags) { |
| line = line.trim(); |
| |
| int removedCharacterCount = 0; |
| StringBuilder processedLine = new StringBuilder(line); |
| Matcher matcher = SUBRIP_TAG_PATTERN.matcher(line); |
| while (matcher.find()) { |
| String tag = matcher.group(); |
| tags.add(tag); |
| int start = matcher.start() - removedCharacterCount; |
| int tagLength = tag.length(); |
| processedLine.replace(start, /* end= */ start + tagLength, /* str= */ ""); |
| removedCharacterCount += tagLength; |
| } |
| |
| return processedLine.toString(); |
| } |
| |
| /** |
| * Build a {@link Cue} based on the given text and alignment tag. |
| * |
| * @param text The text. |
| * @param alignmentTag The alignment tag, or {@code null} if no alignment tag is available. |
| * @return Built cue |
| */ |
| private Cue buildCue(Spanned text, @Nullable String alignmentTag) { |
| Cue.Builder cue = new Cue.Builder().setText(text); |
| if (alignmentTag == null) { |
| return cue.build(); |
| } |
| |
| // Horizontal alignment. |
| switch (alignmentTag) { |
| case ALIGN_BOTTOM_LEFT: |
| case ALIGN_MID_LEFT: |
| case ALIGN_TOP_LEFT: |
| cue.setPositionAnchor(Cue.ANCHOR_TYPE_START); |
| break; |
| case ALIGN_BOTTOM_RIGHT: |
| case ALIGN_MID_RIGHT: |
| case ALIGN_TOP_RIGHT: |
| cue.setPositionAnchor(Cue.ANCHOR_TYPE_END); |
| break; |
| case ALIGN_BOTTOM_MID: |
| case ALIGN_MID_MID: |
| case ALIGN_TOP_MID: |
| default: |
| cue.setPositionAnchor(Cue.ANCHOR_TYPE_MIDDLE); |
| break; |
| } |
| |
| // Vertical alignment. |
| switch (alignmentTag) { |
| case ALIGN_BOTTOM_LEFT: |
| case ALIGN_BOTTOM_MID: |
| case ALIGN_BOTTOM_RIGHT: |
| cue.setLineAnchor(Cue.ANCHOR_TYPE_END); |
| break; |
| case ALIGN_TOP_LEFT: |
| case ALIGN_TOP_MID: |
| case ALIGN_TOP_RIGHT: |
| cue.setLineAnchor(Cue.ANCHOR_TYPE_START); |
| break; |
| case ALIGN_MID_LEFT: |
| case ALIGN_MID_MID: |
| case ALIGN_MID_RIGHT: |
| default: |
| cue.setLineAnchor(Cue.ANCHOR_TYPE_MIDDLE); |
| break; |
| } |
| |
| return cue.setPosition(getFractionalPositionForAnchorType(cue.getPositionAnchor())) |
| .setLine(getFractionalPositionForAnchorType(cue.getLineAnchor()), Cue.LINE_TYPE_FRACTION) |
| .build(); |
| } |
| |
| private static long parseTimecode(Matcher matcher, int groupOffset) { |
| @Nullable String hours = matcher.group(groupOffset + 1); |
| long timestampMs = hours != null ? Long.parseLong(hours) * 60 * 60 * 1000 : 0; |
| timestampMs += |
| Long.parseLong(Assertions.checkNotNull(matcher.group(groupOffset + 2))) * 60 * 1000; |
| timestampMs += Long.parseLong(Assertions.checkNotNull(matcher.group(groupOffset + 3))) * 1000; |
| @Nullable String millis = matcher.group(groupOffset + 4); |
| if (millis != null) { |
| timestampMs += Long.parseLong(millis); |
| } |
| return timestampMs * 1000; |
| } |
| |
| /* package */ static float getFractionalPositionForAnchorType(@Cue.AnchorType int anchorType) { |
| switch (anchorType) { |
| case Cue.ANCHOR_TYPE_START: |
| return SubripDecoder.START_FRACTION; |
| case Cue.ANCHOR_TYPE_MIDDLE: |
| return SubripDecoder.MID_FRACTION; |
| case Cue.ANCHOR_TYPE_END: |
| return SubripDecoder.END_FRACTION; |
| case Cue.TYPE_UNSET: |
| default: |
| // Should never happen. |
| throw new IllegalArgumentException(); |
| } |
| } |
| } |