Properly respect NALLengthSize in the AVC Configuration header to determine how many bits encode the nal unit size.
related-to-bug: 2363596
diff --git a/media/libstagefright/MPEG4Extractor.cpp b/media/libstagefright/MPEG4Extractor.cpp
index 143e8ee..b340b29 100644
--- a/media/libstagefright/MPEG4Extractor.cpp
+++ b/media/libstagefright/MPEG4Extractor.cpp
@@ -66,6 +66,8 @@
uint32_t mCurrentSampleIndex;
bool mIsAVC;
+ size_t mNALLengthSize;
+
bool mStarted;
MediaBufferGroup *mGroup;
@@ -76,6 +78,8 @@
uint8_t *mSrcBuffer;
+ size_t parseNALSize(const uint8_t *data) const;
+
MPEG4Source(const MPEG4Source &);
MPEG4Source &operator=(const MPEG4Source &);
};
@@ -770,6 +774,7 @@
mSampleTable(sampleTable),
mCurrentSampleIndex(0),
mIsAVC(false),
+ mNALLengthSize(0),
mStarted(false),
mGroup(NULL),
mBuffer(NULL),
@@ -780,6 +785,21 @@
CHECK(success);
mIsAVC = !strcasecmp(mime, MEDIA_MIMETYPE_VIDEO_AVC);
+
+ if (mIsAVC) {
+ uint32_t type;
+ const void *data;
+ size_t size;
+ CHECK(format->findData(kKeyAVCC, &type, &data, &size));
+
+ const uint8_t *ptr = (const uint8_t *)data;
+
+ CHECK(size >= 7);
+ CHECK_EQ(ptr[0], 1); // configurationVersion == 1
+
+ // The number of bytes used to encode the length of a NAL unit.
+ mNALLengthSize = 1 + (ptr[4] & 3);
+ }
}
MPEG4Source::~MPEG4Source() {
@@ -837,6 +857,25 @@
return mFormat;
}
+size_t MPEG4Source::parseNALSize(const uint8_t *data) const {
+ switch (mNALLengthSize) {
+ case 1:
+ return *data;
+ case 2:
+ return U16_AT(data);
+ case 3:
+ return ((size_t)data[0] << 16) | U16_AT(&data[1]);
+ case 4:
+ return U32_AT(data);
+ }
+
+ // This cannot happen, mNALLengthSize springs to life by adding 1 to
+ // a 2-bit integer.
+ CHECK(!"Should not be here.");
+
+ return 0;
+}
+
status_t MPEG4Source::read(
MediaBuffer **out, const ReadOptions *options) {
CHECK(mStarted);
@@ -919,21 +958,20 @@
// Each NAL unit is split up into its constituent fragments and
// each one of them returned in its own buffer.
- CHECK(mBuffer->range_length() >= 2);
+ CHECK(mBuffer->range_length() >= mNALLengthSize);
const uint8_t *src =
(const uint8_t *)mBuffer->data() + mBuffer->range_offset();
- size_t nal_size = U16_AT(src);
-
- CHECK(mBuffer->range_length() >= 2 + nal_size);
+ size_t nal_size = parseNALSize(src);
+ CHECK(mBuffer->range_length() >= mNALLengthSize + nal_size);
MediaBuffer *clone = mBuffer->clone();
- clone->set_range(mBuffer->range_offset() + 2, nal_size);
+ clone->set_range(mBuffer->range_offset() + mNALLengthSize, nal_size);
mBuffer->set_range(
- mBuffer->range_offset() + 2 + nal_size,
- mBuffer->range_length() - 2 - nal_size);
+ mBuffer->range_offset() + mNALLengthSize + nal_size,
+ mBuffer->range_length() - mNALLengthSize - nal_size);
if (mBuffer->range_length() == 0) {
mBuffer->release();
@@ -960,12 +998,12 @@
uint8_t *dstData = (uint8_t *)mBuffer->data();
size_t srcOffset = 0;
size_t dstOffset = 0;
+
while (srcOffset < size) {
- CHECK(srcOffset + 1 < size);
- size_t nalLength =
- (mSrcBuffer[srcOffset] << 8) | mSrcBuffer[srcOffset + 1];
- CHECK(srcOffset + 1 + nalLength < size);
- srcOffset += 2;
+ CHECK(srcOffset + mNALLengthSize <= size);
+ size_t nalLength = parseNALSize(&mSrcBuffer[srcOffset]);
+ srcOffset += mNALLengthSize;
+ CHECK(srcOffset + nalLength <= size);
if (nalLength == 0) {
continue;
@@ -981,6 +1019,7 @@
srcOffset += nalLength;
dstOffset += nalLength;
}
+ CHECK_EQ(srcOffset, size);
mBuffer->set_range(0, dstOffset);
mBuffer->meta_data()->clear();
