本文整理汇总了Java中com.google.android.exoplayer2.extractor.ExtractorInput.advancePeekPosition方法的典型用法代码示例。如果您正苦于以下问题:Java ExtractorInput.advancePeekPosition方法的具体用法?Java ExtractorInput.advancePeekPosition怎么用?Java ExtractorInput.advancePeekPosition使用的例子?那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类com.google.android.exoplayer2.extractor.ExtractorInput
的用法示例。
在下文中一共展示了ExtractorInput.advancePeekPosition方法的14个代码示例,这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞,您的评价将有助于系统推荐出更棒的Java代码示例。
示例1: sniff
import com.google.android.exoplayer2.extractor.ExtractorInput; //导入方法依赖的package包/类
@Override
public boolean sniff(ExtractorInput input) throws IOException, InterruptedException {
byte[] scratch = new byte[14];
input.peekFully(scratch, 0, 14);
// Verify the PACK_START_CODE for the first 4 bytes
if (PACK_START_CODE != (((scratch[0] & 0xFF) << 24) | ((scratch[1] & 0xFF) << 16)
| ((scratch[2] & 0xFF) << 8) | (scratch[3] & 0xFF))) {
return false;
}
// Verify the 01xxx1xx marker on the 5th byte
if ((scratch[4] & 0xC4) != 0x44) {
return false;
}
// Verify the xxxxx1xx marker on the 7th byte
if ((scratch[6] & 0x04) != 0x04) {
return false;
}
// Verify the xxxxx1xx marker on the 9th byte
if ((scratch[8] & 0x04) != 0x04) {
return false;
}
// Verify the xxxxxxx1 marker on the 10th byte
if ((scratch[9] & 0x01) != 0x01) {
return false;
}
// Verify the xxxxxx11 marker on the 13th byte
if ((scratch[12] & 0x03) != 0x03) {
return false;
}
// Read the stuffing length from the 14th byte (last 3 bits)
int packStuffingLength = scratch[13] & 0x07;
input.advancePeekPosition(packStuffingLength);
// Now check that the next 3 bytes are the beginning of an MPEG start code
input.peekFully(scratch, 0, 3);
return (PACKET_START_CODE_PREFIX == (((scratch[0] & 0xFF) << 16) | ((scratch[1] & 0xFF) << 8)
| (scratch[2] & 0xFF)));
}
示例2: sniff
import com.google.android.exoplayer2.extractor.ExtractorInput; //导入方法依赖的package包/类
@Override
public boolean sniff(ExtractorInput input) throws IOException, InterruptedException {
// Check if file starts with "FLV" tag
input.peekFully(scratch.data, 0, 3);
scratch.setPosition(0);
if (scratch.readUnsignedInt24() != FLV_TAG) {
return false;
}
// Checking reserved flags are set to 0
input.peekFully(scratch.data, 0, 2);
scratch.setPosition(0);
if ((scratch.readUnsignedShort() & 0xFA) != 0) {
return false;
}
// Read data offset
input.peekFully(scratch.data, 0, 4);
scratch.setPosition(0);
int dataOffset = scratch.readInt();
input.resetPeekPosition();
input.advancePeekPosition(dataOffset);
// Checking first "previous tag size" is set to 0
input.peekFully(scratch.data, 0, 4);
scratch.setPosition(0);
return scratch.readInt() == 0;
}
示例3: peekId3Data
import com.google.android.exoplayer2.extractor.ExtractorInput; //导入方法依赖的package包/类
/**
* Peeks ID3 data from the input, including gapless playback information.
*
* @param input The {@link ExtractorInput} from which data should be peeked.
* @throws IOException If an error occurred peeking from the input.
* @throws InterruptedException If the thread was interrupted.
*/
private void peekId3Data(ExtractorInput input) throws IOException, InterruptedException {
int peekedId3Bytes = 0;
while (true) {
input.peekFully(scratch.data, 0, Id3Decoder.ID3_HEADER_LENGTH);
scratch.setPosition(0);
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 = Id3Decoder.ID3_HEADER_LENGTH + 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);
// We need to parse enough ID3 metadata to retrieve any gapless playback information even
// if ID3 metadata parsing is disabled.
Id3Decoder.FramePredicate id3FramePredicate = (flags & FLAG_DISABLE_ID3_METADATA) != 0
? GaplessInfoHolder.GAPLESS_INFO_ID3_FRAME_PREDICATE : null;
metadata = new Id3Decoder(id3FramePredicate).decode(id3Data, tagLength);
if (metadata != null) {
gaplessInfoHolder.setFromMetadata(metadata);
}
} else {
input.advancePeekPosition(framesLength);
}
peekedId3Bytes += tagLength;
}
input.resetPeekPosition();
input.advancePeekPosition(peekedId3Bytes);
}
示例4: parseId3
import com.google.android.exoplayer2.extractor.ExtractorInput; //导入方法依赖的package包/类
/**
* Peeks data from the input and parses ID3 metadata.
*
* @param input The {@link ExtractorInput} from which data should be peeked.
* @param out The {@link GaplessInfoHolder} to populate.
* @throws IOException If an error occurred peeking from the input.
* @throws InterruptedException If the thread was interrupted.
*/
public static void parseId3(ExtractorInput input, GaplessInfoHolder out)
throws IOException, InterruptedException {
ParsableByteArray scratch = new ParsableByteArray(10);
int peekedId3Bytes = 0;
while (true) {
input.peekFully(scratch.data, 0, 10);
scratch.setPosition(0);
if (scratch.readUnsignedInt24() != ID3_TAG) {
break;
}
int majorVersion = scratch.readUnsignedByte();
int minorVersion = scratch.readUnsignedByte();
int flags = scratch.readUnsignedByte();
int length = scratch.readSynchSafeInt();
if (!out.hasGaplessInfo() && canParseMetadata(majorVersion, minorVersion, flags, length)) {
byte[] frame = new byte[length];
input.peekFully(frame, 0, length);
parseGaplessInfo(new ParsableByteArray(frame), majorVersion, flags, out);
} else {
input.advancePeekPosition(length);
}
peekedId3Bytes += 10 + length;
}
input.resetPeekPosition();
input.advancePeekPosition(peekedId3Bytes);
}
示例5: sniff
import com.google.android.exoplayer2.extractor.ExtractorInput; //导入方法依赖的package包/类
@Override
public boolean sniff(ExtractorInput input) throws IOException, InterruptedException {
// Skip any ID3 headers.
ParsableByteArray scratch = new ParsableByteArray(10);
ParsableBitArray scratchBits = new ParsableBitArray(scratch.data);
int startPosition = 0;
while (true) {
input.peekFully(scratch.data, 0, 10);
scratch.setPosition(0);
if (scratch.readUnsignedInt24() != ID3_TAG) {
break;
}
scratch.skipBytes(3);
int length = scratch.readSynchSafeInt();
startPosition += 10 + length;
input.advancePeekPosition(length);
}
input.resetPeekPosition();
input.advancePeekPosition(startPosition);
// Try to find four or more consecutive AAC audio frames, exceeding the MPEG TS packet size.
int headerPosition = startPosition;
int validFramesSize = 0;
int validFramesCount = 0;
while (true) {
input.peekFully(scratch.data, 0, 2);
scratch.setPosition(0);
int syncBytes = scratch.readUnsignedShort();
if ((syncBytes & 0xFFF6) != 0xFFF0) {
validFramesCount = 0;
validFramesSize = 0;
input.resetPeekPosition();
if (++headerPosition - startPosition >= MAX_SNIFF_BYTES) {
return false;
}
input.advancePeekPosition(headerPosition);
} else {
if (++validFramesCount >= 4 && validFramesSize > 188) {
return true;
}
// Skip the frame.
input.peekFully(scratch.data, 0, 4);
scratchBits.setPosition(14);
int frameSize = scratchBits.readBits(13);
// Either the stream is malformed OR we're not parsing an ADTS stream.
if (frameSize <= 6) {
return false;
}
input.advancePeekPosition(frameSize - 6);
validFramesSize += frameSize;
}
}
}
示例6: sniff
import com.google.android.exoplayer2.extractor.ExtractorInput; //导入方法依赖的package包/类
@Override
public boolean sniff(ExtractorInput input) throws IOException, InterruptedException {
// Skip any ID3 headers.
ParsableByteArray scratch = new ParsableByteArray(10);
int startPosition = 0;
while (true) {
input.peekFully(scratch.data, 0, 10);
scratch.setPosition(0);
if (scratch.readUnsignedInt24() != ID3_TAG) {
break;
}
scratch.skipBytes(3);
int length = scratch.readSynchSafeInt();
startPosition += 10 + length;
input.advancePeekPosition(length);
}
input.resetPeekPosition();
input.advancePeekPosition(startPosition);
int headerPosition = startPosition;
int validFramesCount = 0;
while (true) {
input.peekFully(scratch.data, 0, 5);
scratch.setPosition(0);
int syncBytes = scratch.readUnsignedShort();
if (syncBytes != AC3_SYNC_WORD) {
validFramesCount = 0;
input.resetPeekPosition();
if (++headerPosition - startPosition >= MAX_SNIFF_BYTES) {
return false;
}
input.advancePeekPosition(headerPosition);
} else {
if (++validFramesCount >= 4) {
return true;
}
int frameSize = Ac3Util.parseAc3SyncframeSize(scratch.data);
if (frameSize == C.LENGTH_UNSET) {
return false;
}
input.advancePeekPosition(frameSize - 5);
}
}
}
示例7: peek
import com.google.android.exoplayer2.extractor.ExtractorInput; //导入方法依赖的package包/类
/**
* Peeks and returns a {@code WavHeader}.
*
* @param input Input stream to peek the WAV header from.
* @throws ParserException If the input file is an incorrect RIFF WAV.
* @throws IOException If peeking from the input fails.
* @throws InterruptedException If interrupted while peeking from input.
* @return A new {@code WavHeader} peeked from {@code input}, or null if the input is not a
* supported WAV format.
*/
public static WavHeader peek(ExtractorInput input) throws IOException, InterruptedException {
Assertions.checkNotNull(input);
// Allocate a scratch buffer large enough to store the format chunk.
ParsableByteArray scratch = new ParsableByteArray(16);
// Attempt to read the RIFF chunk.
ChunkHeader chunkHeader = ChunkHeader.peek(input, scratch);
if (chunkHeader.id != Util.getIntegerCodeForString("RIFF")) {
return null;
}
input.peekFully(scratch.data, 0, 4);
scratch.setPosition(0);
int riffFormat = scratch.readInt();
if (riffFormat != Util.getIntegerCodeForString("WAVE")) {
Log.e(TAG, "Unsupported RIFF format: " + riffFormat);
return null;
}
// Skip chunks until we find the format chunk.
chunkHeader = ChunkHeader.peek(input, scratch);
while (chunkHeader.id != Util.getIntegerCodeForString("fmt ")) {
input.advancePeekPosition((int) chunkHeader.size);
chunkHeader = ChunkHeader.peek(input, scratch);
}
Assertions.checkState(chunkHeader.size >= 16);
input.peekFully(scratch.data, 0, 16);
scratch.setPosition(0);
int type = scratch.readLittleEndianUnsignedShort();
int numChannels = scratch.readLittleEndianUnsignedShort();
int sampleRateHz = scratch.readLittleEndianUnsignedIntToInt();
int averageBytesPerSecond = scratch.readLittleEndianUnsignedIntToInt();
int blockAlignment = scratch.readLittleEndianUnsignedShort();
int bitsPerSample = scratch.readLittleEndianUnsignedShort();
int expectedBlockAlignment = numChannels * bitsPerSample / 8;
if (blockAlignment != expectedBlockAlignment) {
throw new ParserException("Expected block alignment: " + expectedBlockAlignment + "; got: "
+ blockAlignment);
}
@C.PcmEncoding int encoding = Util.getPcmEncoding(bitsPerSample);
if (encoding == C.ENCODING_INVALID) {
Log.e(TAG, "Unsupported WAV bit depth: " + bitsPerSample);
return null;
}
if (type != TYPE_PCM && type != TYPE_WAVE_FORMAT_EXTENSIBLE) {
Log.e(TAG, "Unsupported WAV format type: " + type);
return null;
}
// If present, skip extensionSize, validBitsPerSample, channelMask, subFormatGuid, ...
input.advancePeekPosition((int) chunkHeader.size - 16);
return new WavHeader(numChannels, sampleRateHz, averageBytesPerSecond, blockAlignment,
bitsPerSample, encoding);
}
示例8: sniffInternal
import com.google.android.exoplayer2.extractor.ExtractorInput; //导入方法依赖的package包/类
private static boolean sniffInternal(ExtractorInput input, boolean fragmented)
throws IOException, InterruptedException {
long inputLength = input.getLength();
int bytesToSearch = (int) (inputLength == C.LENGTH_UNSET || inputLength > SEARCH_LENGTH
? SEARCH_LENGTH : inputLength);
ParsableByteArray buffer = new ParsableByteArray(64);
int bytesSearched = 0;
boolean foundGoodFileType = false;
boolean isFragmented = false;
while (bytesSearched < bytesToSearch) {
// Read an atom header.
int headerSize = Atom.HEADER_SIZE;
buffer.reset(headerSize);
input.peekFully(buffer.data, 0, headerSize);
long atomSize = buffer.readUnsignedInt();
int atomType = buffer.readInt();
if (atomSize == Atom.LONG_SIZE_PREFIX) {
headerSize = Atom.LONG_HEADER_SIZE;
input.peekFully(buffer.data, Atom.HEADER_SIZE, Atom.LONG_HEADER_SIZE - Atom.HEADER_SIZE);
buffer.setLimit(Atom.LONG_HEADER_SIZE);
atomSize = buffer.readUnsignedLongToLong();
}
if (atomSize < headerSize) {
// The file is invalid because the atom size is too small for its header.
return false;
}
bytesSearched += headerSize;
if (atomType == Atom.TYPE_moov) {
// Check for an mvex atom inside the moov atom to identify whether the file is fragmented.
continue;
}
if (atomType == Atom.TYPE_moof || atomType == Atom.TYPE_mvex) {
// The movie is fragmented. Stop searching as we must have read any ftyp atom already.
isFragmented = true;
break;
}
if (bytesSearched + atomSize - headerSize >= bytesToSearch) {
// Stop searching as peeking this atom would exceed the search limit.
break;
}
int atomDataSize = (int) (atomSize - headerSize);
bytesSearched += atomDataSize;
if (atomType == Atom.TYPE_ftyp) {
// Parse the atom and check the file type/brand is compatible with the extractors.
if (atomDataSize < 8) {
return false;
}
buffer.reset(atomDataSize);
input.peekFully(buffer.data, 0, atomDataSize);
int brandsCount = atomDataSize / 4;
for (int i = 0; i < brandsCount; i++) {
if (i == 1) {
// This index refers to the minorVersion, not a brand, so skip it.
buffer.skipBytes(4);
} else if (isCompatibleBrand(buffer.readInt())) {
foundGoodFileType = true;
break;
}
}
if (!foundGoodFileType) {
// The types were not compatible and there is only one ftyp atom, so reject the file.
return false;
}
} else if (atomDataSize != 0) {
// Skip the atom.
input.advancePeekPosition(atomDataSize);
}
}
return foundGoodFileType && fragmented == isFragmented;
}
示例9: sniff
import com.google.android.exoplayer2.extractor.ExtractorInput; //导入方法依赖的package包/类
/**
* @see com.google.android.exoplayer2.extractor.Extractor#sniff(ExtractorInput)
*/
public boolean sniff(ExtractorInput input) throws IOException, InterruptedException {
long inputLength = input.getLength();
int bytesToSearch = (int) (inputLength == C.LENGTH_UNSET || inputLength > SEARCH_LENGTH
? SEARCH_LENGTH : inputLength);
// Find four bytes equal to ID_EBML near the start of the input.
input.peekFully(scratch.data, 0, 4);
long tag = scratch.readUnsignedInt();
peekLength = 4;
while (tag != ID_EBML) {
if (++peekLength == bytesToSearch) {
return false;
}
input.peekFully(scratch.data, 0, 1);
tag = (tag << 8) & 0xFFFFFF00;
tag |= scratch.data[0] & 0xFF;
}
// Read the size of the EBML header and make sure it is within the stream.
long headerSize = readUint(input);
long headerStart = peekLength;
if (headerSize == Long.MIN_VALUE
|| (inputLength != C.LENGTH_UNSET && headerStart + headerSize >= inputLength)) {
return false;
}
// Read the payload elements in the EBML header.
while (peekLength < headerStart + headerSize) {
long id = readUint(input);
if (id == Long.MIN_VALUE) {
return false;
}
long size = readUint(input);
if (size < 0 || size > Integer.MAX_VALUE) {
return false;
}
if (size != 0) {
input.advancePeekPosition((int) size);
peekLength += size;
}
}
return peekLength == headerStart + headerSize;
}
示例10: synchronize
import com.google.android.exoplayer2.extractor.ExtractorInput; //导入方法依赖的package包/类
private boolean synchronize(ExtractorInput input, boolean sniffing)
throws IOException, InterruptedException {
int validFrameCount = 0;
int candidateSynchronizedHeaderData = 0;
int peekedId3Bytes = 0;
int searchedBytes = 0;
int searchLimitBytes = sniffing ? MAX_SNIFF_BYTES : MAX_SYNC_BYTES;
input.resetPeekPosition();
if (input.getPosition() == 0) {
peekId3Data(input);
peekedId3Bytes = (int) input.getPeekPosition();
if (!sniffing) {
input.skipFully(peekedId3Bytes);
}
}
while (true) {
if (!input.peekFully(scratch.data, 0, 4, validFrameCount > 0)) {
// We reached the end of the stream but found at least one valid frame.
break;
}
scratch.setPosition(0);
int headerData = scratch.readInt();
int frameSize;
if ((candidateSynchronizedHeaderData != 0
&& (headerData & HEADER_MASK) != (candidateSynchronizedHeaderData & HEADER_MASK))
|| (frameSize = MpegAudioHeader.getFrameSize(headerData)) == C.LENGTH_UNSET) {
// The header doesn't match the candidate header or is invalid. Try the next byte offset.
if (searchedBytes++ == searchLimitBytes) {
if (!sniffing) {
throw new ParserException("Searched too many bytes.");
}
return false;
}
validFrameCount = 0;
candidateSynchronizedHeaderData = 0;
if (sniffing) {
input.resetPeekPosition();
input.advancePeekPosition(peekedId3Bytes + searchedBytes);
} else {
input.skipFully(1);
}
} else {
// The header matches the candidate header and/or is valid.
validFrameCount++;
if (validFrameCount == 1) {
MpegAudioHeader.populateHeader(headerData, synchronizedHeader);
candidateSynchronizedHeaderData = headerData;
} else if (validFrameCount == 4) {
break;
}
input.advancePeekPosition(frameSize - 4);
}
}
// Prepare to read the synchronized frame.
if (sniffing) {
input.skipFully(peekedId3Bytes + searchedBytes);
} else {
input.resetPeekPosition();
}
synchronizedHeaderData = candidateSynchronizedHeaderData;
return true;
}
示例11: setupSeeker
import com.google.android.exoplayer2.extractor.ExtractorInput; //导入方法依赖的package包/类
/**
* Returns a {@link Seeker} to seek using metadata read from {@code input}, which should provide
* data from the start of the first frame in the stream. On returning, the input's position will
* be set to the start of the first frame of audio.
*
* @param input The {@link ExtractorInput} from which to read.
* @throws IOException Thrown if there was an error reading from the stream. Not expected if the
* next two frames were already peeked during synchronization.
* @throws InterruptedException Thrown if reading from the stream was interrupted. Not expected if
* the next two frames were already peeked during synchronization.
* @return a {@link Seeker}.
*/
private Seeker setupSeeker(ExtractorInput input) throws IOException, InterruptedException {
// Read the first frame which may contain a Xing or VBRI header with seeking metadata.
ParsableByteArray frame = new ParsableByteArray(synchronizedHeader.frameSize);
input.peekFully(frame.data, 0, synchronizedHeader.frameSize);
long position = input.getPosition();
long length = input.getLength();
int headerData = 0;
Seeker seeker = null;
// Check if there is a Xing header.
int xingBase = (synchronizedHeader.version & 1) != 0
? (synchronizedHeader.channels != 1 ? 36 : 21) // MPEG 1
: (synchronizedHeader.channels != 1 ? 21 : 13); // MPEG 2 or 2.5
if (frame.limit() >= xingBase + 4) {
frame.setPosition(xingBase);
headerData = frame.readInt();
}
if (headerData == XING_HEADER || headerData == INFO_HEADER) {
seeker = XingSeeker.create(synchronizedHeader, frame, position, length);
if (seeker != null && !gaplessInfoHolder.hasGaplessInfo()) {
// If there is a Xing header, read gapless playback metadata at a fixed offset.
input.resetPeekPosition();
input.advancePeekPosition(xingBase + 141);
input.peekFully(scratch.data, 0, 3);
scratch.setPosition(0);
gaplessInfoHolder.setFromXingHeaderValue(scratch.readUnsignedInt24());
}
input.skipFully(synchronizedHeader.frameSize);
} else if (frame.limit() >= 40) {
// Check if there is a VBRI header.
frame.setPosition(36); // MPEG audio header (4 bytes) + 32 bytes.
headerData = frame.readInt();
if (headerData == VBRI_HEADER) {
seeker = VbriSeeker.create(synchronizedHeader, frame, position, length);
input.skipFully(synchronizedHeader.frameSize);
}
}
if (seeker == null || (!seeker.isSeekable()
&& (flags & FLAG_ENABLE_CONSTANT_BITRATE_SEEKING) != 0)) {
// Repopulate the synchronized header in case we had to skip an invalid seeking header, which
// would give an invalid CBR bitrate.
input.resetPeekPosition();
input.peekFully(scratch.data, 0, 4);
scratch.setPosition(0);
MpegAudioHeader.populateHeader(scratch.readInt(), synchronizedHeader);
seeker = new ConstantBitrateSeeker(input.getPosition(), synchronizedHeader.bitrate, length);
}
return seeker;
}
示例12: sniff
import com.google.android.exoplayer2.extractor.ExtractorInput; //导入方法依赖的package包/类
/**
* @see Extractor#sniff
*/
public boolean sniff(ExtractorInput input) throws IOException, InterruptedException {
long inputLength = input.getLength();
int bytesToSearch = (int) (inputLength == C.LENGTH_UNSET || inputLength > SEARCH_LENGTH
? SEARCH_LENGTH : inputLength);
// Find four bytes equal to ID_EBML near the start of the input.
input.peekFully(scratch.data, 0, 4);
long tag = scratch.readUnsignedInt();
peekLength = 4;
while (tag != ID_EBML) {
if (++peekLength == bytesToSearch) {
return false;
}
input.peekFully(scratch.data, 0, 1);
tag = (tag << 8) & 0xFFFFFF00;
tag |= scratch.data[0] & 0xFF;
}
// Read the size of the EBML header and make sure it is within the stream.
long headerSize = readUint(input);
long headerStart = peekLength;
if (headerSize == Long.MIN_VALUE
|| (inputLength != C.LENGTH_UNSET && headerStart + headerSize >= inputLength)) {
return false;
}
// Read the payload elements in the EBML header.
while (peekLength < headerStart + headerSize) {
long id = readUint(input);
if (id == Long.MIN_VALUE) {
return false;
}
long size = readUint(input);
if (size < 0 || size > Integer.MAX_VALUE) {
return false;
}
if (size != 0) {
input.advancePeekPosition((int) size);
peekLength += size;
}
}
return peekLength == headerStart + headerSize;
}
示例13: synchronize
import com.google.android.exoplayer2.extractor.ExtractorInput; //导入方法依赖的package包/类
private boolean synchronize(ExtractorInput input, boolean sniffing)
throws IOException, InterruptedException {
int validFrameCount = 0;
int candidateSynchronizedHeaderData = 0;
int peekedId3Bytes = 0;
int searchedBytes = 0;
int searchLimitBytes = sniffing ? MAX_SNIFF_BYTES : MAX_SYNC_BYTES;
input.resetPeekPosition();
if (input.getPosition() == 0) {
Id3Util.parseId3(input, gaplessInfoHolder);
peekedId3Bytes = (int) input.getPeekPosition();
if (!sniffing) {
input.skipFully(peekedId3Bytes);
}
}
while (true) {
if (!input.peekFully(scratch.data, 0, 4, validFrameCount > 0)) {
// We reached the end of the stream but found at least one valid frame.
break;
}
scratch.setPosition(0);
int headerData = scratch.readInt();
int frameSize;
if ((candidateSynchronizedHeaderData != 0
&& (headerData & HEADER_MASK) != (candidateSynchronizedHeaderData & HEADER_MASK))
|| (frameSize = MpegAudioHeader.getFrameSize(headerData)) == C.LENGTH_UNSET) {
// The header doesn't match the candidate header or is invalid. Try the next byte offset.
if (searchedBytes++ == searchLimitBytes) {
if (!sniffing) {
throw new ParserException("Searched too many bytes.");
}
return false;
}
validFrameCount = 0;
candidateSynchronizedHeaderData = 0;
if (sniffing) {
input.resetPeekPosition();
input.advancePeekPosition(peekedId3Bytes + searchedBytes);
} else {
input.skipFully(1);
}
} else {
// The header matches the candidate header and/or is valid.
validFrameCount++;
if (validFrameCount == 1) {
MpegAudioHeader.populateHeader(headerData, synchronizedHeader);
candidateSynchronizedHeaderData = headerData;
} else if (validFrameCount == 4) {
break;
}
input.advancePeekPosition(frameSize - 4);
}
}
// Prepare to read the synchronized frame.
if (sniffing) {
input.skipFully(peekedId3Bytes + searchedBytes);
} else {
input.resetPeekPosition();
}
synchronizedHeaderData = candidateSynchronizedHeaderData;
return true;
}
示例14: setupSeeker
import com.google.android.exoplayer2.extractor.ExtractorInput; //导入方法依赖的package包/类
/**
* Returns a {@link Seeker} to seek using metadata read from {@code input}, which should provide
* data from the start of the first frame in the stream. On returning, the input's position will
* be set to the start of the first frame of audio.
*
* @param input The {@link ExtractorInput} from which to read.
* @throws IOException Thrown if there was an error reading from the stream. Not expected if the
* next two frames were already peeked during synchronization.
* @throws InterruptedException Thrown if reading from the stream was interrupted. Not expected if
* the next two frames were already peeked during synchronization.
* @return a {@link Seeker}.
*/
private Seeker setupSeeker(ExtractorInput input) throws IOException, InterruptedException {
// Read the first frame which may contain a Xing or VBRI header with seeking metadata.
ParsableByteArray frame = new ParsableByteArray(synchronizedHeader.frameSize);
input.peekFully(frame.data, 0, synchronizedHeader.frameSize);
long position = input.getPosition();
long length = input.getLength();
int headerData = 0;
Seeker seeker = null;
// Check if there is a Xing header.
int xingBase = (synchronizedHeader.version & 1) != 0
? (synchronizedHeader.channels != 1 ? 36 : 21) // MPEG 1
: (synchronizedHeader.channels != 1 ? 21 : 13); // MPEG 2 or 2.5
if (frame.limit() >= xingBase + 4) {
frame.setPosition(xingBase);
headerData = frame.readInt();
}
if (headerData == XING_HEADER || headerData == INFO_HEADER) {
seeker = XingSeeker.create(synchronizedHeader, frame, position, length);
if (seeker != null && !gaplessInfoHolder.hasGaplessInfo()) {
// If there is a Xing header, read gapless playback metadata at a fixed offset.
input.resetPeekPosition();
input.advancePeekPosition(xingBase + 141);
input.peekFully(scratch.data, 0, 3);
scratch.setPosition(0);
gaplessInfoHolder.setFromXingHeaderValue(scratch.readUnsignedInt24());
}
input.skipFully(synchronizedHeader.frameSize);
} else if (frame.limit() >= 40) {
// Check if there is a VBRI header.
frame.setPosition(36); // MPEG audio header (4 bytes) + 32 bytes.
headerData = frame.readInt();
if (headerData == VBRI_HEADER) {
seeker = VbriSeeker.create(synchronizedHeader, frame, position, length);
input.skipFully(synchronizedHeader.frameSize);
}
}
if (seeker == null) {
// Repopulate the synchronized header in case we had to skip an invalid seeking header, which
// would give an invalid CBR bitrate.
input.resetPeekPosition();
input.peekFully(scratch.data, 0, 4);
scratch.setPosition(0);
MpegAudioHeader.populateHeader(scratch.readInt(), synchronizedHeader);
seeker = new ConstantBitrateSeeker(input.getPosition(), synchronizedHeader.bitrate, length);
}
return seeker;
}