Java SeekableByteChannel.position方法代码示例

import org.jcodec.common.SeekableByteChannel; //导入方法依赖的package包/类
public static List<Atom> getRootAtoms(SeekableByteChannel input) throws IOException {
    input.position(0);
    List<Atom> result = new ArrayList<Atom>();
    long off = 0;
    Header atom;
    while (off < input.size()) {
        input.position(off);
        atom = Header.read(NIOUtils.fetchFrom(input, 16));
        if (atom == null)
            break;
        result.add(new Atom(atom, off));
        off += atom.getSize();
    }

    return result;
}
 

import org.jcodec.common.SeekableByteChannel; //导入方法依赖的package包/类
public Y4MDecoder(SeekableByteChannel is) throws IOException {
    ByteBuffer buf = NIOUtils.fetchFrom(is, 2048);
    String[] header = split(readLine(buf), ' ');

    if (!"YUV4MPEG2".equals(header[0])) {
        invalidFormat = "Not yuv4mpeg stream";
        return;
    }
    String chroma = find(header, 'C');
    if (chroma != null && !chroma.startsWith("420")) {
        invalidFormat = "Only yuv420p is supported";
        return;
    }

    width = Integer.parseInt(find(header, 'W'));
    height = Integer.parseInt(find(header, 'H'));

    String fpsStr = find(header, 'F');
    if (fpsStr != null) {
        String[] numden = split(fpsStr, ':');
        fps = new Rational(Integer.parseInt(numden[0]), Integer.parseInt(numden[1]));
    }

    is.position(buf.position());
    bufSize = width * height * 2;
}
 

import org.jcodec.common.SeekableByteChannel; //导入方法依赖的package包/类
private void cacheAudioFrameSizes(SeekableByteChannel ch) throws IOException {
    for (MXFPartition mxfPartition : partitions) {
        if (mxfPartition.getEssenceLength() > 0) {
            ch.position(mxfPartition.getEssenceFilePos());
            KLV kl;
            do {
                kl = KLV.readKL(ch);
                if (kl == null)
                    break;
                ch.position(ch.position() + kl.len);
            } while (!essenceUL.equals(kl.key));

            if (essenceUL.equals(kl.key)) {
                dataLen = (int) kl.len;
                break;
            }
        }
    }
}
 

import org.jcodec.common.SeekableByteChannel; //导入方法依赖的package包/类
@Override
public ByteBuffer getData() throws IOException {
    ByteBuffer bb = ByteBuffer.allocate(packet.getSize());
    SeekableByteChannel ch = null;
    try {
        ch = pool.getChannel();
        if(packet.getFileOff() >= ch.size())
            return null;
        ch.position(packet.getFileOff());
        ch.read(bb);
        bb.flip();
        return bb;
    } finally {
        if (ch != null)
            ch.close();
    }
}
 

import org.jcodec.common.SeekableByteChannel; //导入方法依赖的package包/类
@Override
public ByteBuffer getData() throws IOException {
    SeekableByteChannel ch = null;
    try {
        ch = fp.getChannel();
        ch.position(pkt.getOffset());

        KLV kl = KLV.readKL(ch);
        while (kl != null && !essenceUL.equals(kl.key)) {
            ch.position(ch.position() + kl.len);
            kl = KLV.readKL(ch);
        }

        return kl != null && essenceUL.equals(kl.key) ? NIOUtils.fetchFrom(ch, (int) kl.len) : null;
    } finally {
        NIOUtils.closeQuietly(ch);
    }
}
 

import org.jcodec.common.SeekableByteChannel; //导入方法依赖的package包/类
public void parseHeader(SeekableByteChannel ff) throws IOException {
    KLV kl;
    header = readHeaderPartition(ff);

    metadata = new ArrayList<MXFMetadata>();

    partitions = new ArrayList<MXFPartition>();
    long nextPartition = ff.size();
    ff.position(header.getPack().getFooterPartition());
    do {
        long thisPartition = ff.position();
        kl = KLV.readKL(ff);
        ByteBuffer fetchFrom = NIOUtils.fetchFrom(ff, (int) kl.len);
        header = MXFPartition.read(kl.key, fetchFrom, ff.position() - kl.offset, nextPartition);

        if (header.getPack().getNbEssenceContainers() > 0)
            partitions.add(0, header);

        metadata.addAll(0, readPartitionMeta(ff, header));

        ff.position(header.getPack().getPrevPartition());
        nextPartition = thisPartition;
    } while (header.getPack().getThisPartition() != 0);
}
 

import org.jcodec.common.SeekableByteChannel; //导入方法依赖的package包/类
protected ByteBuffer readPacketData(SeekableByteChannel input, ByteBuffer buffer, long offset, int size)
        throws IOException {
    ByteBuffer result = buffer.duplicate();
    synchronized (input) {
        input.position(offset);
        NIOUtils.read(input, result, size);
    }
    result.flip();
    return result;
}
 

import org.jcodec.common.SeekableByteChannel; //导入方法依赖的package包/类
public void write(Chunk chunk) throws IOException {
    SeekableByteChannel input = getInput(chunk);
    input.position(chunk.getOffset());
    long pos = out.position();

    out.write(NIOUtils.fetchFrom(input, (int) chunk.getSize()));
    offsets[curChunk++] = pos;
}
 

import org.jcodec.common.SeekableByteChannel; //导入方法依赖的package包/类
public WebOptimizedMP4Muxer(SeekableByteChannel output, Brand brand, int headerSize) throws IOException {
    super(output, brand);
    headerPos = output.position() - 24;
    output.position(headerPos);

    header = ByteBuffer.allocate(headerSize);
    output.write(header);
    header.clear();

    new Header("wide", 8).write(output);
    new Header("mdat", 1).write(output);
    mdatOffset = output.position();
    NIOUtils.writeLong(output, 0);
}
 

import org.jcodec.common.SeekableByteChannel; //导入方法依赖的package包/类
@Override
public ByteBuffer getData() throws IOException {
    SeekableByteChannel ch = null;
    try {
        ch = pool.getChannel();
        ch.position(offset);
        ByteBuffer buffer = ByteBuffer.allocate(dataLen);
        NIOUtils.read(ch, buffer);
        buffer.flip();
        return buffer;
    } finally {
        ch.close();
    }
}
 

import org.jcodec.common.SeekableByteChannel; //导入方法依赖的package包/类
protected ByteBuffer readPes(SeekableByteChannel ch, long pesPosition, int pesSize, int payloadSize, int pesIdx)
        throws IOException {
    ch.position(pesPosition);
    ByteBuffer pes = NIOUtils.fetchFrom(ch, pesSize);
    readPESHeader(pes, 0);
    return pes;
}
 

import org.jcodec.common.SeekableByteChannel; //导入方法依赖的package包/类
@Override
protected ByteBuffer readPes(SeekableByteChannel ch, long pesPosition, int pesSize, int payloadSize,
        int pesAbsIdx) throws IOException {
    ch.position(pesPosition * 188);
    ByteBuffer buf = NIOUtils.fetchFrom(ch, pesSize * 188);

    // NOW REMOVE THE TS CRAP
    ByteBuffer dst = buf.duplicate();
    while (buf.hasRemaining()) {
        ByteBuffer tsBuf = NIOUtils.read(buf, 188);
        Assert.assertEquals(0x47, tsBuf.get() & 0xff);
        int guidFlags = ((tsBuf.get() & 0xff) << 8) | (tsBuf.get() & 0xff);
        int guid = (int) guidFlags & 0x1fff;
        if (guid == targetGuid) {
            int b0 = tsBuf.get() & 0xff;
            int counter = b0 & 0xf;
            if ((b0 & 0x20) != 0) {
                NIOUtils.skip(tsBuf, tsBuf.get() & 0xff);
            }
            dst.put(tsBuf);
        }
    }
    dst.flip();
    readPESHeader(dst, 0);
    dst.limit(dst.position() + payloadSize);
    return dst;
}
 

import org.jcodec.common.SeekableByteChannel; //导入方法依赖的package包/类
public void readTsFile(SeekableByteChannel ch) throws IOException {
    ch.position(0);
    ByteBuffer buf = ByteBuffer.allocate(BUFFER_SIZE);

    for (long pos = ch.position(); ch.read(buf) != -1; pos = ch.position()) {
        buf.flip();
        while (buf.hasRemaining()) {
            ByteBuffer tsBuf = NIOUtils.read(buf, 188);
            pos += 188;
            Assert.assertEquals(0x47, tsBuf.get() & 0xff);
            int guidFlags = ((tsBuf.get() & 0xff) << 8) | (tsBuf.get() & 0xff);
            int guid = (int) guidFlags & 0x1fff;

            int payloadStart = (guidFlags >> 14) & 0x1;
            int b0 = tsBuf.get() & 0xff;
            int counter = b0 & 0xf;
            if ((b0 & 0x20) != 0) {
                NIOUtils.skip(tsBuf, tsBuf.get() & 0xff);
            }
            boolean sectionSyntax = payloadStart == 1 && (getRel(tsBuf, getRel(tsBuf, 0) + 2) & 0x80) == 0x80;
            if (sectionSyntax) {
                NIOUtils.skip(tsBuf, tsBuf.get() & 0xff);
            }
            if (!onPkt(guid, payloadStart == 1, tsBuf, pos - tsBuf.remaining()))
                return;
        }
        buf.flip();
    }
}
 

import org.jcodec.common.SeekableByteChannel; //导入方法依赖的package包/类
public MXFDemuxer(SeekableByteChannel ch) throws IOException {
    this.ch = ch;
    ch.position(0);
    parseHeader(ch);
    findIndex();
    tracks = findTracks();
    timecode = MXFUtil.findMeta(metadata, TimecodeComponent.class);
}
 

import org.jcodec.common.SeekableByteChannel; //导入方法依赖的package包/类
public static List<MXFMetadata> readPartitionMeta(SeekableByteChannel ff, MXFPartition header) throws IOException {
    KLV kl;
    long basePos = ff.position();
    List<MXFMetadata> local = new ArrayList<MXFMetadata>();
    ByteBuffer metaBuffer = NIOUtils.fetchFrom(ff, (int) Math.max(0, header.getEssenceFilePos() - basePos));
    while (metaBuffer.hasRemaining() && (kl = KLV.readKL(metaBuffer, basePos)) != null) {
        MXFMetadata meta = parseMeta(kl.key, NIOUtils.read(metaBuffer, (int) kl.len));
        if (meta != null)
            local.add(meta);
    }
    return local;
}