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Properly parse Matroska lacing flags and extract all frames contained in a block.

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Change-Id: I1aca46b2e28b9cad88bf4a296f675e81e66ee095
related-to-bug: 3331623
This commit is contained in:
Andreas Huber
2011-01-11 11:56:06 -08:00
parent e0b1912480
commit 6fe6b4c6f3
3 changed files with 290 additions and 61 deletions
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346
media/libstagefright/matroska/MatroskaExtractor.cpp
View File

@@ -118,6 +118,9 @@ struct MatroskaSource : public MediaSource {
virtual status_t read(
MediaBuffer **buffer, const ReadOptions *options);
protected:
virtual ~MatroskaSource();
private:
enum Type {
AVC,
@@ -131,8 +134,13 @@ private:
BlockIterator mBlockIter;
size_t mNALSizeLen; // for type AVC
List<MediaBuffer *> mPendingFrames;
status_t advance();
status_t readBlock();
void clearPendingFrames();
MatroskaSource(const MatroskaSource &);
MatroskaSource &operator=(const MatroskaSource &);
};
@@ -168,6 +176,10 @@ MatroskaSource::MatroskaSource(
}
}
MatroskaSource::~MatroskaSource() {
clearPendingFrames();
}
status_t MatroskaSource::start(MetaData *params) {
mBlockIter.reset();
@@ -175,6 +187,8 @@ status_t MatroskaSource::start(MetaData *params) {
}
status_t MatroskaSource::stop() {
clearPendingFrames();
return OK;
}
@@ -256,6 +270,214 @@ static unsigned U24_AT(const uint8_t *ptr) {
return ptr[0] << 16 | ptr[1] << 8 | ptr[2];
}
static size_t clz(uint8_t x) {
size_t numLeadingZeroes = 0;
while (!(x & 0x80)) {
++numLeadingZeroes;
x = x << 1;
}
return numLeadingZeroes;
}
void MatroskaSource::clearPendingFrames() {
while (!mPendingFrames.empty()) {
MediaBuffer *frame = *mPendingFrames.begin();
mPendingFrames.erase(mPendingFrames.begin());
frame->release();
frame = NULL;
}
}
#define BAIL(err) \
do { \
if (bigbuf) { \
bigbuf->release(); \
bigbuf = NULL; \
} \
\
return err; \
} while (0)
status_t MatroskaSource::readBlock() {
CHECK(mPendingFrames.empty());
if (mBlockIter.eos()) {
return ERROR_END_OF_STREAM;
}
const mkvparser::Block *block = mBlockIter.block();
size_t size = block->GetSize();
int64_t timeUs = mBlockIter.blockTimeUs();
int32_t isSync = block->IsKey();
MediaBuffer *bigbuf = new MediaBuffer(size);
long res = block->Read(
mExtractor->mReader, (unsigned char *)bigbuf->data());
if (res != 0) {
bigbuf->release();
bigbuf = NULL;
return ERROR_END_OF_STREAM;
}
mBlockIter.advance();
bigbuf->meta_data()->setInt64(kKeyTime, timeUs);
bigbuf->meta_data()->setInt32(kKeyIsSyncFrame, isSync);
unsigned lacing = (block->Flags() >> 1) & 3;
if (lacing == 0) {
mPendingFrames.push_back(bigbuf);
return OK;
}
LOGV("lacing = %u, size = %d", lacing, size);
const uint8_t *data = (const uint8_t *)bigbuf->data();
// hexdump(data, size);
if (size == 0) {
BAIL(ERROR_MALFORMED);
}
unsigned numFrames = (unsigned)data[0] + 1;
++data;
--size;
Vector<uint64_t> frameSizes;
switch (lacing) {
case 1: // Xiph
{
for (size_t i = 0; i < numFrames - 1; ++i) {
size_t frameSize = 0;
uint8_t byte;
do {
if (size == 0) {
BAIL(ERROR_MALFORMED);
}
byte = data[0];
++data;
--size;
frameSize += byte;
} while (byte == 0xff);
frameSizes.push(frameSize);
}
break;
}
case 2: // fixed-size
{
if ((size % numFrames) != 0) {
BAIL(ERROR_MALFORMED);
}
size_t frameSize = size / numFrames;
for (size_t i = 0; i < numFrames - 1; ++i) {
frameSizes.push(frameSize);
}
break;
}
case 3: // EBML
{
uint64_t lastFrameSize = 0;
for (size_t i = 0; i < numFrames - 1; ++i) {
uint8_t byte;
if (size == 0) {
BAIL(ERROR_MALFORMED);
}
byte = data[0];
++data;
--size;
size_t numLeadingZeroes = clz(byte);
uint64_t frameSize = byte & ~(0x80 >> numLeadingZeroes);
for (size_t j = 0; j < numLeadingZeroes; ++j) {
if (size == 0) {
BAIL(ERROR_MALFORMED);
}
frameSize = frameSize << 8;
frameSize |= data[0];
++data;
--size;
}
if (i == 0) {
frameSizes.push(frameSize);
} else {
size_t shift =
7 - numLeadingZeroes + 8 * numLeadingZeroes;
int64_t delta =
(int64_t)frameSize - (1ll << (shift - 1)) + 1;
frameSize = lastFrameSize + delta;
frameSizes.push(frameSize);
}
lastFrameSize = frameSize;
}
break;
}
default:
TRESPASS();
}
#if 0
AString out;
for (size_t i = 0; i < frameSizes.size(); ++i) {
if (i > 0) {
out.append(", ");
}
out.append(StringPrintf("%llu", frameSizes.itemAt(i)));
}
LOGV("sizes = [%s]", out.c_str());
#endif
for (size_t i = 0; i < frameSizes.size(); ++i) {
uint64_t frameSize = frameSizes.itemAt(i);
if (size < frameSize) {
BAIL(ERROR_MALFORMED);
}
MediaBuffer *mbuf = new MediaBuffer(frameSize);
mbuf->meta_data()->setInt64(kKeyTime, timeUs);
mbuf->meta_data()->setInt32(kKeyIsSyncFrame, isSync);
memcpy(mbuf->data(), data, frameSize);
mPendingFrames.push_back(mbuf);
data += frameSize;
size -= frameSize;
}
size_t offset = bigbuf->range_length() - size;
bigbuf->set_range(offset, size);
mPendingFrames.push_back(bigbuf);
return OK;
}
#undef BAIL
status_t MatroskaSource::read(
MediaBuffer **out, const ReadOptions *options) {
*out = NULL;
@@ -263,17 +485,38 @@ status_t MatroskaSource::read(
int64_t seekTimeUs;
ReadOptions::SeekMode mode;
if (options && options->getSeekTo(&seekTimeUs, &mode)) {
clearPendingFrames();
mBlockIter.seek(seekTimeUs);
}
again:
if (mBlockIter.eos()) {
return ERROR_END_OF_STREAM;
while (mPendingFrames.empty()) {
status_t err = readBlock();
if (err != OK) {
clearPendingFrames();
return err;
}
}
const mkvparser::Block *block = mBlockIter.block();
size_t size = block->GetSize();
int64_t timeUs = mBlockIter.blockTimeUs();
MediaBuffer *frame = *mPendingFrames.begin();
mPendingFrames.erase(mPendingFrames.begin());
size_t size = frame->range_length();
if (mType != AVC) {
*out = frame;
return OK;
}
if (size < mNALSizeLen) {
frame->release();
frame = NULL;
return ERROR_MALFORMED;
}
// In the case of AVC content, each NAL unit is prefixed by
// mNALSizeLen bytes of length. We want to prefix the data with
@@ -283,73 +526,54 @@ again:
static const size_t kPadding = 3;
MediaBuffer *buffer = new MediaBuffer(size + kPadding);
int64_t timeUs;
CHECK(frame->meta_data()->findInt64(kKeyTime, &timeUs));
int32_t isSync;
CHECK(frame->meta_data()->findInt32(kKeyIsSyncFrame, &isSync));
buffer->meta_data()->setInt64(kKeyTime, timeUs);
buffer->meta_data()->setInt32(kKeyIsSyncFrame, block->IsKey());
buffer->meta_data()->setInt32(kKeyIsSyncFrame, isSync);
long res = block->Read(
mExtractor->mReader, (unsigned char *)buffer->data() + kPadding);
if (res != 0) {
return ERROR_END_OF_STREAM;
}
memcpy((uint8_t *)buffer->data() + kPadding,
(const uint8_t *)frame->data() + frame->range_offset(),
size);
buffer->set_range(kPadding, size);
if (mType == AVC) {
CHECK_GE(size, mNALSizeLen);
frame->release();
frame = NULL;
uint8_t *data = (uint8_t *)buffer->data();
uint8_t *data = (uint8_t *)buffer->data();
size_t NALsize;
switch (mNALSizeLen) {
case 1: NALsize = data[kPadding]; break;
case 2: NALsize = U16_AT(&data[kPadding]); break;
case 3: NALsize = U24_AT(&data[kPadding]); break;
case 4: NALsize = U32_AT(&data[kPadding]); break;
default:
TRESPASS();
}
CHECK_GE(size, NALsize + mNALSizeLen);
if (size > NALsize + mNALSizeLen) {
LOGW("discarding %d bytes of data.", size - NALsize - mNALSizeLen);
}
// actual data starts at &data[kPadding + mNALSizeLen]
memcpy(&data[mNALSizeLen - 1], "\x00\x00\x00\x01", 4);
buffer->set_range(mNALSizeLen - 1, NALsize + 4);
} else if (mType == AAC) {
// There's strange junk at the beginning...
const uint8_t *data = (const uint8_t *)buffer->data() + kPadding;
// hexdump(data, size);
size_t offset = 0;
while (offset < size && data[offset] != 0x21) {
++offset;
}
if (size == offset) {
buffer->release();
mBlockIter.advance();
goto again;
}
buffer->set_range(kPadding + offset, size - offset);
size_t NALsize;
switch (mNALSizeLen) {
case 1: NALsize = data[kPadding]; break;
case 2: NALsize = U16_AT(&data[kPadding]); break;
case 3: NALsize = U24_AT(&data[kPadding]); break;
case 4: NALsize = U32_AT(&data[kPadding]); break;
default:
TRESPASS();
}
if (size < NALsize + mNALSizeLen) {
buffer->release();
buffer = NULL;
return ERROR_MALFORMED;
}
if (size > NALsize + mNALSizeLen) {
LOGW("discarding %d bytes of data.", size - NALsize - mNALSizeLen);
}
// actual data starts at &data[kPadding + mNALSizeLen]
memcpy(&data[mNALSizeLen - 1], "\x00\x00\x00\x01", 4);
buffer->set_range(mNALSizeLen - 1, NALsize + 4);
*out = buffer;
#if 0
hexdump((const uint8_t *)buffer->data() + buffer->range_offset(),
buffer->range_length());
#endif
mBlockIter.advance();
return OK;
}

3
media/libstagefright/matroska/mkvparser.cpp
View File

@@ -4474,6 +4474,9 @@ bool Block::IsKey() const
return ((m_flags & static_cast<unsigned char>(1 << 7)) != 0);
}
unsigned char Block::Flags() const {
return m_flags;
}
void Block::SetKey(bool bKey)
{

2
media/libstagefright/matroska/mkvparser.hpp
View File

@@ -80,6 +80,8 @@ public:
bool IsKey() const;
void SetKey(bool);
unsigned char Flags() const;
long long GetOffset() const;
long GetSize() const;
long Read(IMkvReader*, unsigned char*) const;