Provide better duration and seek accuracy if playing vorbis audio from a non-streaming source.
Change-Id: Ib823c2dd28e84f4c49e3676f4e4962a6e006b166
related-to-bug: 3107013
diff --git a/media/libstagefright/OggExtractor.cpp b/media/libstagefright/OggExtractor.cpp
index 0e51caf..6538a05 100644
--- a/media/libstagefright/OggExtractor.cpp
+++ b/media/libstagefright/OggExtractor.cpp
@@ -73,6 +73,7 @@
// Returns an approximate bitrate in bits per second.
uint64_t approxBitrate();
+ status_t seekToTime(int64_t timeUs);
status_t seekToOffset(off64_t offset);
status_t readNextPacket(MediaBuffer **buffer);
@@ -90,6 +91,11 @@
uint8_t mLace[255];
};
+ struct TOCEntry {
+ off64_t mPageOffset;
+ int64_t mTimeUs;
+ };
+
sp<DataSource> mSource;
off64_t mOffset;
Page mCurrentPage;
@@ -107,6 +113,8 @@
sp<MetaData> mMeta;
sp<MetaData> mFileMeta;
+ Vector<TOCEntry> mTableOfContents;
+
ssize_t readPage(off64_t offset, Page *page);
status_t findNextPage(off64_t startOffset, off64_t *pageOffset);
@@ -115,7 +123,9 @@
void parseFileMetaData();
- uint64_t findPrevGranulePosition(off64_t pageOffset);
+ status_t findPrevGranulePosition(off64_t pageOffset, uint64_t *granulePos);
+
+ void buildTableOfContents();
MyVorbisExtractor(const MyVorbisExtractor &);
MyVorbisExtractor &operator=(const MyVorbisExtractor &);
@@ -164,10 +174,7 @@
int64_t seekTimeUs;
ReadOptions::SeekMode mode;
if (options && options->getSeekTo(&seekTimeUs, &mode)) {
- off64_t pos = seekTimeUs * mExtractor->mImpl->approxBitrate() / 8000000ll;
- LOGV("seeking to offset %ld", pos);
-
- if (mExtractor->mImpl->seekToOffset(pos) != OK) {
+ if (mExtractor->mImpl->seekToTime(seekTimeUs) != OK) {
return ERROR_END_OF_STREAM;
}
}
@@ -237,7 +244,7 @@
if (!memcmp(signature, "OggS", 4)) {
if (*pageOffset > startOffset) {
- LOGV("skipped %ld bytes of junk to reach next frame",
+ LOGV("skipped %lld bytes of junk to reach next frame",
*pageOffset - startOffset);
}
@@ -252,7 +259,10 @@
// it (if any) and return its granule position.
// To do this we back up from the "current" page's offset until we find any
// page preceding it and then scan forward to just before the current page.
-uint64_t MyVorbisExtractor::findPrevGranulePosition(off64_t pageOffset) {
+status_t MyVorbisExtractor::findPrevGranulePosition(
+ off64_t pageOffset, uint64_t *granulePos) {
+ *granulePos = 0;
+
off64_t prevPageOffset = 0;
off64_t prevGuess = pageOffset;
for (;;) {
@@ -262,9 +272,12 @@
prevGuess = 0;
}
- LOGV("backing up %ld bytes", pageOffset - prevGuess);
+ LOGV("backing up %lld bytes", pageOffset - prevGuess);
- CHECK_EQ(findNextPage(prevGuess, &prevPageOffset), (status_t)OK);
+ status_t err = findNextPage(prevGuess, &prevPageOffset);
+ if (err != OK) {
+ return err;
+ }
if (prevPageOffset < pageOffset || prevGuess == 0) {
break;
@@ -273,27 +286,64 @@
if (prevPageOffset == pageOffset) {
// We did not find a page preceding this one.
- return 0;
+ return UNKNOWN_ERROR;
}
- LOGV("prevPageOffset at %ld, pageOffset at %ld", prevPageOffset, pageOffset);
+ LOGV("prevPageOffset at %lld, pageOffset at %lld",
+ prevPageOffset, pageOffset);
for (;;) {
Page prevPage;
ssize_t n = readPage(prevPageOffset, &prevPage);
if (n <= 0) {
- return 0;
+ return (status_t)n;
}
prevPageOffset += n;
if (prevPageOffset == pageOffset) {
- return prevPage.mGranulePosition;
+ *granulePos = prevPage.mGranulePosition;
+ return OK;
}
}
}
+status_t MyVorbisExtractor::seekToTime(int64_t timeUs) {
+ if (mTableOfContents.isEmpty()) {
+ // Perform approximate seeking based on avg. bitrate.
+
+ off64_t pos = timeUs * approxBitrate() / 8000000ll;
+
+ LOGV("seeking to offset %lld", pos);
+ return seekToOffset(pos);
+ }
+
+ size_t left = 0;
+ size_t right = mTableOfContents.size();
+ while (left < right) {
+ size_t center = left / 2 + right / 2 + (left & right & 1);
+
+ const TOCEntry &entry = mTableOfContents.itemAt(center);
+
+ if (timeUs < entry.mTimeUs) {
+ right = center;
+ } else if (timeUs > entry.mTimeUs) {
+ left = center + 1;
+ } else {
+ left = right = center;
+ break;
+ }
+ }
+
+ const TOCEntry &entry = mTableOfContents.itemAt(left);
+
+ LOGV("seeking to entry %d / %d at offset %lld",
+ left, mTableOfContents.size(), entry.mPageOffset);
+
+ return seekToOffset(entry.mPageOffset);
+}
+
status_t MyVorbisExtractor::seekToOffset(off64_t offset) {
if (mFirstDataOffset >= 0 && offset < mFirstDataOffset) {
// Once we know where the actual audio data starts (past the headers)
@@ -311,7 +361,7 @@
// 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.
- mPrevGranulePosition = findPrevGranulePosition(pageOffset);
+ findPrevGranulePosition(pageOffset, &mPrevGranulePosition);
mOffset = pageOffset;
@@ -330,7 +380,8 @@
uint8_t header[27];
if (mSource->readAt(offset, header, sizeof(header))
< (ssize_t)sizeof(header)) {
- LOGV("failed to read %d bytes at offset 0x%08lx", sizeof(header), offset);
+ LOGV("failed to read %d bytes at offset 0x%016llx",
+ sizeof(header), offset);
return ERROR_IO;
}
@@ -447,7 +498,8 @@
packetSize);
if (n < (ssize_t)packetSize) {
- LOGV("failed to read %d bytes at 0x%08lx", packetSize, dataOffset);
+ LOGV("failed to read %d bytes at 0x%016llx",
+ packetSize, dataOffset);
return ERROR_IO;
}
@@ -563,9 +615,66 @@
mFirstDataOffset = mOffset + mCurrentPageSize;
+ off64_t size;
+ uint64_t lastGranulePosition;
+ if (!(mSource->flags() & DataSource::kIsCachingDataSource)
+ && 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;
}
+void MyVorbisExtractor::buildTableOfContents() {
+ off64_t offset = mFirstDataOffset;
+ Page page;
+ ssize_t pageSize;
+ while ((pageSize = readPage(offset, &page)) > 0) {
+ mTableOfContents.push();
+
+ TOCEntry &entry =
+ mTableOfContents.editItemAt(mTableOfContents.size() - 1);
+
+ entry.mPageOffset = offset;
+ entry.mTimeUs = page.mGranulePosition * 1000000ll / mVi.rate;
+
+ offset += (size_t)pageSize;
+ }
+
+ // Limit the maximum amount of RAM we spend on the table of contents,
+ // if necessary thin out the table evenly to trim it down to maximum
+ // size.
+
+ static const size_t kMaxTOCSize = 8192;
+ static const size_t kMaxNumTOCEntries = kMaxTOCSize / sizeof(TOCEntry);
+
+ size_t numerator = mTableOfContents.size();
+
+ if (numerator > kMaxNumTOCEntries) {
+ size_t denom = numerator - kMaxNumTOCEntries;
+
+ size_t accum = 0;
+ for (ssize_t i = mTableOfContents.size() - 1; i >= 0; --i) {
+ accum += denom;
+ if (accum >= numerator) {
+ mTableOfContents.removeAt(i);
+ accum -= numerator;
+ }
+ }
+ }
+}
+
status_t MyVorbisExtractor::verifyHeader(
MediaBuffer *buffer, uint8_t type) {
const uint8_t *data =