diff options
Diffstat (limited to 'mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/GaplessInfoHolder.java')
-rw-r--r-- | mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/GaplessInfoHolder.java | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/GaplessInfoHolder.java b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/GaplessInfoHolder.java new file mode 100644 index 0000000000..11893d6136 --- /dev/null +++ b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/extractor/GaplessInfoHolder.java @@ -0,0 +1,131 @@ +/* + * 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.extractor; + +import org.mozilla.thirdparty.com.google.android.exoplayer2.Format; +import org.mozilla.thirdparty.com.google.android.exoplayer2.metadata.Metadata; +import org.mozilla.thirdparty.com.google.android.exoplayer2.metadata.id3.CommentFrame; +import org.mozilla.thirdparty.com.google.android.exoplayer2.metadata.id3.InternalFrame; +import java.util.regex.Matcher; +import java.util.regex.Pattern; + +/** + * Holder for gapless playback information. + */ +public final class GaplessInfoHolder { + + private static final String GAPLESS_DOMAIN = "com.apple.iTunes"; + private static final String GAPLESS_DESCRIPTION = "iTunSMPB"; + private static final Pattern GAPLESS_COMMENT_PATTERN = + Pattern.compile("^ [0-9a-fA-F]{8} ([0-9a-fA-F]{8}) ([0-9a-fA-F]{8})"); + + /** + * The number of samples to trim from the start of the decoded audio stream, or + * {@link Format#NO_VALUE} if not set. + */ + public int encoderDelay; + + /** + * The number of samples to trim from the end of the decoded audio stream, or + * {@link Format#NO_VALUE} if not set. + */ + public int encoderPadding; + + /** + * Creates a new holder for gapless playback information. + */ + public GaplessInfoHolder() { + encoderDelay = Format.NO_VALUE; + encoderPadding = Format.NO_VALUE; + } + + /** + * Populates the holder with data from an MP3 Xing header, if valid and non-zero. + * + * @param value The 24-bit value to decode. + * @return Whether the holder was populated. + */ + public boolean setFromXingHeaderValue(int value) { + int encoderDelay = value >> 12; + int encoderPadding = value & 0x0FFF; + if (encoderDelay > 0 || encoderPadding > 0) { + this.encoderDelay = encoderDelay; + this.encoderPadding = encoderPadding; + return true; + } + return false; + } + + /** + * Populates the holder with data parsed from ID3 {@link Metadata}. + * + * @param metadata The metadata from which to parse the gapless information. + * @return Whether the holder was populated. + */ + public boolean setFromMetadata(Metadata metadata) { + for (int i = 0; i < metadata.length(); i++) { + Metadata.Entry entry = metadata.get(i); + if (entry instanceof CommentFrame) { + CommentFrame commentFrame = (CommentFrame) entry; + if (GAPLESS_DESCRIPTION.equals(commentFrame.description) + && setFromComment(commentFrame.text)) { + return true; + } + } else if (entry instanceof InternalFrame) { + InternalFrame internalFrame = (InternalFrame) entry; + if (GAPLESS_DOMAIN.equals(internalFrame.domain) + && GAPLESS_DESCRIPTION.equals(internalFrame.description) + && setFromComment(internalFrame.text)) { + return true; + } + } + } + return false; + } + + /** + * Populates the holder with data parsed from a gapless playback comment (stored in an ID3 header + * or MPEG 4 user data), if valid and non-zero. + * + * @param data The comment's payload data. + * @return Whether the holder was populated. + */ + private boolean setFromComment(String data) { + Matcher matcher = GAPLESS_COMMENT_PATTERN.matcher(data); + if (matcher.find()) { + try { + int encoderDelay = Integer.parseInt(matcher.group(1), 16); + int encoderPadding = Integer.parseInt(matcher.group(2), 16); + if (encoderDelay > 0 || encoderPadding > 0) { + this.encoderDelay = encoderDelay; + this.encoderPadding = encoderPadding; + return true; + } + } catch (NumberFormatException e) { + // Ignore incorrectly formatted comments. + } + } + return false; + } + + /** + * Returns whether {@link #encoderDelay} and {@link #encoderPadding} have been set. + */ + public boolean hasGaplessInfo() { + return encoderDelay != Format.NO_VALUE && encoderPadding != Format.NO_VALUE; + } + +} |