status_t MyVorbisExtractor::init() {
mMeta = new MetaData;
mMeta->setCString(kKeyMIMEType, MEDIA_MIMETYPE_AUDIO_VORBIS);
MediaBuffer *packet;
status_t err;
if ((err = readNextPacket(&packet)) != OK) {
return err;
}
ALOGV("read packet of size %d\n", packet->range_length());
err = verifyHeader(packet, 1);
packet->release();
packet = NULL;
if (err != OK) {
return err;
}
if ((err = readNextPacket(&packet)) != OK) {
return err;
}
ALOGV("read packet of size %d\n", packet->range_length());
err = verifyHeader(packet, 3);
packet->release();
packet = NULL;
if (err != OK) {
return err;
}
if ((err = readNextPacket(&packet)) != OK) {
return err;
}
ALOGV("read packet of size %d\n", packet->range_length());
err = verifyHeader(packet, 5);
packet->release();
packet = NULL;
if (err != OK) {
return err;
}
mFirstDataOffset = mOffset + mCurrentPageSize;
off64_t size;
uint64_t lastGranulePosition;
if (mSource->getSize(&size) == OK
&& findPrevGranulePosition(size, &lastGranulePosition) == OK) {
// Let's assume it's cheap to seek to the end.
// The granule position of the final page in the stream will
// give us the exact duration of the content, something that
// we can only approximate using avg. bitrate if seeking to
// the end is too expensive or impossible (live streaming).
int64_t durationUs = lastGranulePosition * 1000000ll / mVi.rate;
mMeta->setInt64(kKeyDuration, durationUs);
buildTableOfContents();
}
return OK;
}
status_t MyVorbisExtractor::seekToOffset(off64_t offset) {
if (mFirstDataOffset >= 0 && offset < mFirstDataOffset) {
// Once we know where the actual audio data starts (past the headers)
// don't ever seek to anywhere before that.
offset = mFirstDataOffset;
}
off64_t pageOffset;
status_t err = findNextPage(offset, &pageOffset);
if (err != OK) {
return err;
}
// We found the page we wanted to seek to, but we'll also need
// the page preceding it to determine how many valid samples are on
// this page.
findPrevGranulePosition(pageOffset, &mPrevGranulePosition);
mOffset = pageOffset;
mCurrentPageSize = 0;
mFirstPacketInPage = true;
mCurrentPageSamples = 0;
mCurrentPage.mNumSegments = 0;
mNextLaceIndex = 0;
// XXX what if new page continues packet from last???
return OK;
}
status_t MyVorbisExtractor::findGranulePositionofPage(off64_t offset,uint64_t *granulePositionofPage)
{
if (mFirstDataOffset >= 0 && offset < mFirstDataOffset) {
// Once we know where the actual audio data starts (past the headers)
// don't ever seek to anywhere before that.
offset = mFirstDataOffset;
}
if(((uint64_t)offset) == mFileSize)
{
findPrevGranulePosition(mFileSize, granulePositionofPage);
if((*granulePositionofPage) < 0xFFFFFFFFFFFF)
return OK;
else
return UNKNOWN_ERROR;
}
off64_t pageOffset;
status_t err = findNextPage_l(offset, &pageOffset);
if (err != OK) {
err = findNextPage(offset, &pageOffset);
if((err == OK) && (offset == pageOffset))
{
Page page;
readPage(offset, &page);
*granulePositionofPage = page.mGranulePosition;
}
else
findPrevGranulePosition(mFileSize, granulePositionofPage);
if((*granulePositionofPage) < 0xFFFFFFFFFFFF)
return OK;
else
return UNKNOWN_ERROR;
}
// We found the page we wanted to seek to, but we'll also need
// the page preceding it to determine how many valid samples are on
// this page.
findPrevGranulePosition(pageOffset, granulePositionofPage);
if((*granulePositionofPage) < 0xFFFFFFFFFFFF)
return OK;
else
return UNKNOWN_ERROR;
}
