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Yet more misc ID3 improvements

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This commit is contained in:
Oliver Woodman 2016-10-19 17:18:17 +01:00
parent 7e352295d7
commit 3e3248d712
2 changed files with 97 additions and 51 deletions
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40
library/src/main/java/com/google/android/exoplayer2/extractor/mp3/Mp3Extractor.java
View file

@ -15,7 +15,6 @@
*/
package com.google.android.exoplayer2.extractor.mp3;
import android.util.Log;
import com.google.android.exoplayer2.C;
import com.google.android.exoplayer2.Format;
import com.google.android.exoplayer2.ParserException;
@ -29,7 +28,6 @@ import com.google.android.exoplayer2.extractor.PositionHolder;
import com.google.android.exoplayer2.extractor.SeekMap;
import com.google.android.exoplayer2.extractor.TrackOutput;
import com.google.android.exoplayer2.metadata.Metadata;
import com.google.android.exoplayer2.metadata.MetadataDecoderException;
import com.google.android.exoplayer2.metadata.id3.Id3Decoder;
import com.google.android.exoplayer2.util.ParsableByteArray;
import com.google.android.exoplayer2.util.Util;
@ -53,8 +51,6 @@ public final class Mp3Extractor implements Extractor {
};
private static final String TAG = "Mp3Extractor";
/**
* The maximum number of bytes to search when synchronizing, before giving up.
*/
@ -63,14 +59,6 @@ public final class Mp3Extractor implements Extractor {
* The maximum number of bytes to peek when sniffing, excluding the ID3 header, before giving up.
*/
private static final int MAX_SNIFF_BYTES = MpegAudioHeader.MAX_FRAME_SIZE_BYTES;
/**
* First three bytes of a well formed ID3 tag header.
*/
private static final int ID3_TAG = Util.getIntegerCodeForString("ID3");
/**
* Length of an ID3 tag header.
*/
private static final int ID3_HEADER_LENGTH = 10;
/**
* Maximum length of data read into {@link #scratch}.
*/
@ -282,30 +270,26 @@ public final class Mp3Extractor implements Extractor {
private void peekId3Data(ExtractorInput input) throws IOException, InterruptedException {
int peekedId3Bytes = 0;
while (true) {
input.peekFully(scratch.data, 0, ID3_HEADER_LENGTH);
input.peekFully(scratch.data, 0, Id3Decoder.ID3_HEADER_LENGTH);
scratch.setPosition(0);
if (scratch.readUnsignedInt24() != ID3_TAG) {
if (scratch.readUnsignedInt24() != Id3Decoder.ID3_TAG) {
// Not an ID3 tag.
break;
}
scratch.skipBytes(3); // Skip major version, minor version and flags.
int framesLength = scratch.readSynchSafeInt();
int tagLength = ID3_HEADER_LENGTH + framesLength;
int tagLength = Id3Decoder.ID3_HEADER_LENGTH + framesLength;
try {
if (metadata == null) {
byte[] id3Data = new byte[tagLength];
System.arraycopy(scratch.data, 0, id3Data, 0, ID3_HEADER_LENGTH);
input.peekFully(id3Data, ID3_HEADER_LENGTH, framesLength);
metadata = new Id3Decoder().decode(id3Data, tagLength);
if (metadata != null) {
gaplessInfoHolder.setFromMetadata(metadata);
}
} else {
input.advancePeekPosition(framesLength);
if (metadata == null) {
byte[] id3Data = new byte[tagLength];
System.arraycopy(scratch.data, 0, id3Data, 0, Id3Decoder.ID3_HEADER_LENGTH);
input.peekFully(id3Data, Id3Decoder.ID3_HEADER_LENGTH, framesLength);
metadata = new Id3Decoder().decode(id3Data, tagLength);
if (metadata != null) {
gaplessInfoHolder.setFromMetadata(metadata);
}
} catch (MetadataDecoderException e) {
Log.e(TAG, "Failed to decode ID3 tag", e);
} else {
input.advancePeekPosition(framesLength);
}
peekedId3Bytes += tagLength;

108
library/src/main/java/com/google/android/exoplayer2/metadata/id3/Id3Decoder.java
View file

@ -18,9 +18,9 @@ package com.google.android.exoplayer2.metadata.id3;
import android.util.Log;
import com.google.android.exoplayer2.metadata.Metadata;
import com.google.android.exoplayer2.metadata.MetadataDecoder;
import com.google.android.exoplayer2.metadata.MetadataDecoderException;
import com.google.android.exoplayer2.util.MimeTypes;
import com.google.android.exoplayer2.util.ParsableByteArray;
import com.google.android.exoplayer2.util.Util;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.Arrays;
@ -28,12 +28,21 @@ import java.util.List;
import java.util.Locale;
/**
* Decodes individual TXXX text frames from raw ID3 data.
* Decodes ID3 tags.
*/
public final class Id3Decoder implements MetadataDecoder {
private static final String TAG = "Id3Decoder";
/**
* The first three bytes of a well formed ID3 tag header.
*/
public static final int ID3_TAG = Util.getIntegerCodeForString("ID3");
/**
* Length of an ID3 tag header.
*/
public static final int ID3_HEADER_LENGTH = 10;
private static final int ID3_TEXT_ENCODING_ISO_8859_1 = 0;
private static final int ID3_TEXT_ENCODING_UTF_16 = 1;
private static final int ID3_TEXT_ENCODING_UTF_16BE = 2;
@ -45,7 +54,7 @@ public final class Id3Decoder implements MetadataDecoder {
}
@Override
public Metadata decode(byte[] data, int size) throws MetadataDecoderException {
public Metadata decode(byte[] data, int size) {
List<Id3Frame> id3Frames = new ArrayList<>();
ParsableByteArray id3Data = new ParsableByteArray(data, size);
@ -61,9 +70,21 @@ public final class Id3Decoder implements MetadataDecoder {
}
id3Data.setLimit(startPosition + framesSize);
boolean unsignedIntFrameSizeHack = false;
if (id3Header.majorVersion == 4) {
if (!validateV4Frames(id3Data, false)) {
if (validateV4Frames(id3Data, true)) {
unsignedIntFrameSizeHack = true;
} else {
Log.w(TAG, "Failed to validate V4 ID3 tag");
return null;
}
}
}
int frameHeaderSize = id3Header.majorVersion == 2 ? 6 : 10;
while (id3Data.bytesLeft() >= frameHeaderSize) {
Id3Frame frame = decodeFrame(id3Header.majorVersion, id3Data);
Id3Frame frame = decodeFrame(id3Header.majorVersion, id3Data, unsignedIntFrameSizeHack);
if (frame != null) {
id3Frames.add(frame);
}
@ -109,16 +130,17 @@ public final class Id3Decoder implements MetadataDecoder {
/**
* @param data A {@link ParsableByteArray} from which the header should be read.
* @return The parsed header, or null if the ID3 tag is unsupported.
* @throws MetadataDecoderException If the first three bytes differ from "ID3".
*/
private static Id3Header decodeHeader(ParsableByteArray data)
throws MetadataDecoderException {
int id1 = data.readUnsignedByte();
int id2 = data.readUnsignedByte();
int id3 = data.readUnsignedByte();
if (id1 != 'I' || id2 != 'D' || id3 != '3') {
throw new MetadataDecoderException(String.format(Locale.US,
"Unexpected ID3 tag identifier, expected \"ID3\", actual \"%c%c%c\".", id1, id2, id3));
private static Id3Header decodeHeader(ParsableByteArray data) {
if (data.bytesLeft() < ID3_HEADER_LENGTH) {
Log.w(TAG, "Data too short to be an ID3 tag");
return null;
}
int id = data.readUnsignedInt24();
if (id != ID3_TAG) {
Log.w(TAG, "Unexpected first three bytes of ID3 tag header: " + id);
return null;
}
int majorVersion = data.readUnsignedByte();
@ -129,7 +151,7 @@ public final class Id3Decoder implements MetadataDecoder {
if (majorVersion == 2) {
boolean isCompressed = (flags & 0x40) != 0;
if (isCompressed) {
Log.w(TAG, "Skipped ID3 tag with majorVersion=1 and undefined compression scheme");
Log.w(TAG, "Skipped ID3 tag with majorVersion=2 and undefined compression scheme");
return null;
}
} else if (majorVersion == 3) {
@ -160,8 +182,49 @@ public final class Id3Decoder implements MetadataDecoder {
return new Id3Header(majorVersion, isUnsynchronized, framesSize);
}
private Id3Frame decodeFrame(int majorVersion, ParsableByteArray id3Data)
throws MetadataDecoderException {
private static boolean validateV4Frames(ParsableByteArray id3Data,
boolean unsignedIntFrameSizeHack) {
int startPosition = id3Data.getPosition();
try {
while (id3Data.bytesLeft() >= 10) {
int id = id3Data.readInt();
int frameSize = id3Data.readUnsignedIntToInt();
int flags = id3Data.readUnsignedShort();
if (id == 0 && frameSize == 0 && flags == 0) {
return true;
} else {
if (!unsignedIntFrameSizeHack) {
// Parse the data size as a synchsafe integer, as per the spec.
if ((frameSize & 0x808080L) != 0) {
return false;
}
frameSize = (frameSize & 0xFF) | (((frameSize >> 8) & 0xFF) << 7)
| (((frameSize >> 16) & 0xFF) << 14) | (((frameSize >> 24) & 0xFF) << 21);
}
int minimumFrameSize = 0;
if ((flags & 0x0040) != 0 /* hasGroupIdentifier */) {
minimumFrameSize++;
}
if ((flags & 0x0001) != 0 /* hasDataLength */) {
minimumFrameSize += 4;
}
if (frameSize < minimumFrameSize) {
return false;
}
if (id3Data.bytesLeft() < frameSize) {
return false;
}
id3Data.skipBytes(frameSize); // flags
}
}
return true;
} finally {
id3Data.setPosition(startPosition);
}
}
private static Id3Frame decodeFrame(int majorVersion, ParsableByteArray id3Data,
boolean unsignedIntFrameSizeHack) {
int frameId0 = id3Data.readUnsignedByte();
int frameId1 = id3Data.readUnsignedByte();
int frameId2 = id3Data.readUnsignedByte();
@ -170,13 +233,9 @@ public final class Id3Decoder implements MetadataDecoder {
int frameSize;
if (majorVersion == 4) {
frameSize = id3Data.readUnsignedIntToInt();
if ((frameSize & 0x808080L) == 0) {
// Parse the frame size as a syncsafe integer, as per the spec.
if (!unsignedIntFrameSizeHack) {
frameSize = (frameSize & 0xFF) | (((frameSize >> 8) & 0xFF) << 7)
| (((frameSize >> 16) & 0xFF) << 14) | (((frameSize >> 24) & 0xFF) << 21);
} else {
// Proceed using the frame size read as an unsigned integer.
Log.w(TAG, "Frame size not specified as syncsafe integer");
}
} else if (majorVersion == 3) {
frameSize = id3Data.readUnsignedIntToInt();
@ -184,7 +243,7 @@ public final class Id3Decoder implements MetadataDecoder {
frameSize = id3Data.readUnsignedInt24();
}
int flags = majorVersion >= 3 ? id3Data.readShort() : 0;
int flags = majorVersion >= 3 ? id3Data.readUnsignedShort() : 0;
if (frameId0 == 0 && frameId1 == 0 && frameId2 == 0 && frameId3 == 0 && frameSize == 0
&& flags == 0) {
// We must be reading zero padding at the end of the tag.
@ -194,6 +253,8 @@ public final class Id3Decoder implements MetadataDecoder {
int nextFramePosition = id3Data.getPosition() + frameSize;
if (nextFramePosition > id3Data.limit()) {
Log.w(TAG, "Frame size exceeds remaining tag data");
id3Data.setPosition(id3Data.limit());
return null;
}
@ -263,7 +324,8 @@ public final class Id3Decoder implements MetadataDecoder {
}
return frame;
} catch (UnsupportedEncodingException e) {
throw new MetadataDecoderException("Unsupported character encoding");
Log.w(TAG, "Unsupported character encoding");
return null;
} finally {
id3Data.setPosition(nextFramePosition);
}