diff options
Diffstat (limited to 'mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/text/tx3g/Tx3gDecoder.java')
| -rw-r--r-- | mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/text/tx3g/Tx3gDecoder.java | 241 |
1 files changed, 241 insertions, 0 deletions
diff --git a/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/text/tx3g/Tx3gDecoder.java b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/text/tx3g/Tx3gDecoder.java new file mode 100644 index 0000000000..a6b9ab5c63 --- /dev/null +++ b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/text/tx3g/Tx3gDecoder.java @@ -0,0 +1,241 @@ +/* + * 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 org.mozilla.thirdparty.com.google.android.exoplayer2.text.tx3g; + +import android.graphics.Color; +import android.graphics.Typeface; +import android.text.SpannableStringBuilder; +import android.text.Spanned; +import android.text.style.ForegroundColorSpan; +import android.text.style.StyleSpan; +import android.text.style.TypefaceSpan; +import android.text.style.UnderlineSpan; +import org.mozilla.thirdparty.com.google.android.exoplayer2.C; +import org.mozilla.thirdparty.com.google.android.exoplayer2.text.Cue; +import org.mozilla.thirdparty.com.google.android.exoplayer2.text.SimpleSubtitleDecoder; +import org.mozilla.thirdparty.com.google.android.exoplayer2.text.Subtitle; +import org.mozilla.thirdparty.com.google.android.exoplayer2.text.SubtitleDecoderException; +import org.mozilla.thirdparty.com.google.android.exoplayer2.util.ParsableByteArray; +import org.mozilla.thirdparty.com.google.android.exoplayer2.util.Util; +import java.nio.charset.Charset; +import java.util.List; + +/** + * A {@link SimpleSubtitleDecoder} for tx3g. + * <p> + * Currently supports parsing of a single text track with embedded styles. + */ +public final class Tx3gDecoder extends SimpleSubtitleDecoder { + + private static final char BOM_UTF16_BE = '\uFEFF'; + private static final char BOM_UTF16_LE = '\uFFFE'; + + private static final int TYPE_STYL = 0x7374796c; + private static final int TYPE_TBOX = 0x74626f78; + private static final String TX3G_SERIF = "Serif"; + + private static final int SIZE_ATOM_HEADER = 8; + private static final int SIZE_SHORT = 2; + private static final int SIZE_BOM_UTF16 = 2; + private static final int SIZE_STYLE_RECORD = 12; + + private static final int FONT_FACE_BOLD = 0x0001; + private static final int FONT_FACE_ITALIC = 0x0002; + private static final int FONT_FACE_UNDERLINE = 0x0004; + + private static final int SPAN_PRIORITY_LOW = 0xFF << Spanned.SPAN_PRIORITY_SHIFT; + private static final int SPAN_PRIORITY_HIGH = 0; + + private static final int DEFAULT_FONT_FACE = 0; + private static final int DEFAULT_COLOR = Color.WHITE; + private static final String DEFAULT_FONT_FAMILY = C.SANS_SERIF_NAME; + private static final float DEFAULT_VERTICAL_PLACEMENT = 0.85f; + + private final ParsableByteArray parsableByteArray; + + private boolean customVerticalPlacement; + private int defaultFontFace; + private int defaultColorRgba; + private String defaultFontFamily; + private float defaultVerticalPlacement; + private int calculatedVideoTrackHeight; + + /** + * Sets up a new {@link Tx3gDecoder} with default values. + * + * @param initializationData Sample description atom ('stsd') data with default subtitle styles. + */ + public Tx3gDecoder(List<byte[]> initializationData) { + super("Tx3gDecoder"); + parsableByteArray = new ParsableByteArray(); + + if (initializationData != null && initializationData.size() == 1 + && (initializationData.get(0).length == 48 || initializationData.get(0).length == 53)) { + byte[] initializationBytes = initializationData.get(0); + defaultFontFace = initializationBytes[24]; + defaultColorRgba = ((initializationBytes[26] & 0xFF) << 24) + | ((initializationBytes[27] & 0xFF) << 16) + | ((initializationBytes[28] & 0xFF) << 8) + | (initializationBytes[29] & 0xFF); + String fontFamily = + Util.fromUtf8Bytes(initializationBytes, 43, initializationBytes.length - 43); + defaultFontFamily = TX3G_SERIF.equals(fontFamily) ? C.SERIF_NAME : C.SANS_SERIF_NAME; + //font size (initializationBytes[25]) is 5% of video height + calculatedVideoTrackHeight = 20 * initializationBytes[25]; + customVerticalPlacement = (initializationBytes[0] & 0x20) != 0; + if (customVerticalPlacement) { + int requestedVerticalPlacement = ((initializationBytes[10] & 0xFF) << 8) + | (initializationBytes[11] & 0xFF); + defaultVerticalPlacement = (float) requestedVerticalPlacement / calculatedVideoTrackHeight; + defaultVerticalPlacement = Util.constrainValue(defaultVerticalPlacement, 0.0f, 0.95f); + } else { + defaultVerticalPlacement = DEFAULT_VERTICAL_PLACEMENT; + } + } else { + defaultFontFace = DEFAULT_FONT_FACE; + defaultColorRgba = DEFAULT_COLOR; + defaultFontFamily = DEFAULT_FONT_FAMILY; + customVerticalPlacement = false; + defaultVerticalPlacement = DEFAULT_VERTICAL_PLACEMENT; + } + } + + @Override + protected Subtitle decode(byte[] bytes, int length, boolean reset) + throws SubtitleDecoderException { + parsableByteArray.reset(bytes, length); + String cueTextString = readSubtitleText(parsableByteArray); + if (cueTextString.isEmpty()) { + return Tx3gSubtitle.EMPTY; + } + // Attach default styles. + SpannableStringBuilder cueText = new SpannableStringBuilder(cueTextString); + attachFontFace(cueText, defaultFontFace, DEFAULT_FONT_FACE, 0, cueText.length(), + SPAN_PRIORITY_LOW); + attachColor(cueText, defaultColorRgba, DEFAULT_COLOR, 0, cueText.length(), + SPAN_PRIORITY_LOW); + attachFontFamily(cueText, defaultFontFamily, DEFAULT_FONT_FAMILY, 0, cueText.length(), + SPAN_PRIORITY_LOW); + float verticalPlacement = defaultVerticalPlacement; + // Find and attach additional styles. + while (parsableByteArray.bytesLeft() >= SIZE_ATOM_HEADER) { + int position = parsableByteArray.getPosition(); + int atomSize = parsableByteArray.readInt(); + int atomType = parsableByteArray.readInt(); + if (atomType == TYPE_STYL) { + assertTrue(parsableByteArray.bytesLeft() >= SIZE_SHORT); + int styleRecordCount = parsableByteArray.readUnsignedShort(); + for (int i = 0; i < styleRecordCount; i++) { + applyStyleRecord(parsableByteArray, cueText); + } + } else if (atomType == TYPE_TBOX && customVerticalPlacement) { + assertTrue(parsableByteArray.bytesLeft() >= SIZE_SHORT); + int requestedVerticalPlacement = parsableByteArray.readUnsignedShort(); + verticalPlacement = (float) requestedVerticalPlacement / calculatedVideoTrackHeight; + verticalPlacement = Util.constrainValue(verticalPlacement, 0.0f, 0.95f); + } + parsableByteArray.setPosition(position + atomSize); + } + return new Tx3gSubtitle( + new Cue( + cueText, + /* textAlignment= */ null, + verticalPlacement, + Cue.LINE_TYPE_FRACTION, + Cue.ANCHOR_TYPE_START, + Cue.DIMEN_UNSET, + Cue.TYPE_UNSET, + Cue.DIMEN_UNSET)); + } + + private static String readSubtitleText(ParsableByteArray parsableByteArray) + throws SubtitleDecoderException { + assertTrue(parsableByteArray.bytesLeft() >= SIZE_SHORT); + int textLength = parsableByteArray.readUnsignedShort(); + if (textLength == 0) { + return ""; + } + if (parsableByteArray.bytesLeft() >= SIZE_BOM_UTF16) { + char firstChar = parsableByteArray.peekChar(); + if (firstChar == BOM_UTF16_BE || firstChar == BOM_UTF16_LE) { + return parsableByteArray.readString(textLength, Charset.forName(C.UTF16_NAME)); + } + } + return parsableByteArray.readString(textLength, Charset.forName(C.UTF8_NAME)); + } + + private void applyStyleRecord(ParsableByteArray parsableByteArray, + SpannableStringBuilder cueText) throws SubtitleDecoderException { + assertTrue(parsableByteArray.bytesLeft() >= SIZE_STYLE_RECORD); + int start = parsableByteArray.readUnsignedShort(); + int end = parsableByteArray.readUnsignedShort(); + parsableByteArray.skipBytes(2); // font identifier + int fontFace = parsableByteArray.readUnsignedByte(); + parsableByteArray.skipBytes(1); // font size + int colorRgba = parsableByteArray.readInt(); + attachFontFace(cueText, fontFace, defaultFontFace, start, end, SPAN_PRIORITY_HIGH); + attachColor(cueText, colorRgba, defaultColorRgba, start, end, SPAN_PRIORITY_HIGH); + } + + private static void attachFontFace(SpannableStringBuilder cueText, int fontFace, + int defaultFontFace, int start, int end, int spanPriority) { + if (fontFace != defaultFontFace) { + final int flags = Spanned.SPAN_EXCLUSIVE_EXCLUSIVE | spanPriority; + boolean isBold = (fontFace & FONT_FACE_BOLD) != 0; + boolean isItalic = (fontFace & FONT_FACE_ITALIC) != 0; + if (isBold) { + if (isItalic) { + cueText.setSpan(new StyleSpan(Typeface.BOLD_ITALIC), start, end, flags); + } else { + cueText.setSpan(new StyleSpan(Typeface.BOLD), start, end, flags); + } + } else if (isItalic) { + cueText.setSpan(new StyleSpan(Typeface.ITALIC), start, end, flags); + } + boolean isUnderlined = (fontFace & FONT_FACE_UNDERLINE) != 0; + if (isUnderlined) { + cueText.setSpan(new UnderlineSpan(), start, end, flags); + } + if (!isUnderlined && !isBold && !isItalic) { + cueText.setSpan(new StyleSpan(Typeface.NORMAL), start, end, flags); + } + } + } + + private static void attachColor(SpannableStringBuilder cueText, int colorRgba, + int defaultColorRgba, int start, int end, int spanPriority) { + if (colorRgba != defaultColorRgba) { + int colorArgb = ((colorRgba & 0xFF) << 24) | (colorRgba >>> 8); + cueText.setSpan(new ForegroundColorSpan(colorArgb), start, end, + Spanned.SPAN_EXCLUSIVE_EXCLUSIVE | spanPriority); + } + } + + @SuppressWarnings("ReferenceEquality") + private static void attachFontFamily(SpannableStringBuilder cueText, String fontFamily, + String defaultFontFamily, int start, int end, int spanPriority) { + if (fontFamily != defaultFontFamily) { + cueText.setSpan(new TypefaceSpan(fontFamily), start, end, + Spanned.SPAN_EXCLUSIVE_EXCLUSIVE | spanPriority); + } + } + + private static void assertTrue(boolean checkValue) throws SubtitleDecoderException { + if (!checkValue) { + throw new SubtitleDecoderException("Unexpected subtitle format."); + } + } +} |