MPEG2TSWriter: Write a proper CRC in PAT and PMT (98399574) · Commits · e / os / android_frameworks_av

include/media/stagefright/MPEG2TSWriter.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -71,6 +71,7 @@ private:
		int64_t mNumTSPacketsBeforeMeta;
		int mPATContinuityCounter;
		int mPMTContinuityCounter;
		uint32_t mCrcTable[256];

		void init();

		@@ -78,6 +79,8 @@ private:
		void writeProgramAssociationTable();
		void writeProgramMap();
		void writeAccessUnit(int32_t sourceIndex, const sp<ABuffer> &buffer);
		void initCrcTable();
		uint32_t crc32(const uint8_t *start, size_t length);

		ssize_t internalWrite(const void *data, size_t size);
		status_t reset();

media/libstagefright/MPEG2TSWriter.cpp

+37 −6

Original line number	Diff line number	Diff line
		@@ -28,6 +28,7 @@
		#include <media/stagefright/MediaSource.h>
		#include <media/stagefright/MetaData.h>
		#include <media/stagefright/Utils.h>
		#include <arpa/inet.h>

		#include "include/ESDS.h"

		@@ -508,6 +509,8 @@ MPEG2TSWriter::MPEG2TSWriter(
		void MPEG2TSWriter::init() {
		CHECK(mFile != NULL \|\| mWriteFunc != NULL);

		initCrcTable();

		mLooper = new ALooper;
		mLooper->setName("MPEG2TSWriter");

		@@ -735,7 +738,7 @@ void MPEG2TSWriter::writeProgramAssociationTable() {
		};

		sp<ABuffer> buffer = new ABuffer(188);
		memset(buffer->data(), 0, buffer->size());
		memset(buffer->data(), 0xff, buffer->size());
		memcpy(buffer->data(), kData, sizeof(kData));

		if (++mPATContinuityCounter == 16) {
		@@ -743,6 +746,9 @@ void MPEG2TSWriter::writeProgramAssociationTable() {
		}
		buffer->data()[3] \|= mPATContinuityCounter;

		uint32_t crc = htonl(crc32(&buffer->data()[5], 12));
		memcpy(&buffer->data()[17], &crc, sizeof(crc));

		CHECK_EQ(internalWrite(buffer->data(), buffer->size()), buffer->size());
		}

		@@ -789,7 +795,7 @@ void MPEG2TSWriter::writeProgramMap() {
		};

		sp<ABuffer> buffer = new ABuffer(188);
		memset(buffer->data(), 0, buffer->size());
		memset(buffer->data(), 0xff, buffer->size());
		memcpy(buffer->data(), kData, sizeof(kData));

		if (++mPMTContinuityCounter == 16) {
		@@ -816,10 +822,8 @@ void MPEG2TSWriter::writeProgramMap() {
		*ptr++ = 0x00;
		}

		*ptr++ = 0x00;
		*ptr++ = 0x00;
		*ptr++ = 0x00;
		*ptr++ = 0x00;
		uint32_t crc = htonl(crc32(&buffer->data()[5], 12+mSources.size()*5));
		memcpy(&buffer->data()[17+mSources.size()*5], &crc, sizeof(crc));

		CHECK_EQ(internalWrite(buffer->data(), buffer->size()), buffer->size());
		}
		@@ -966,6 +970,33 @@ void MPEG2TSWriter::writeTS() {
		}
		}

		void MPEG2TSWriter::initCrcTable() {
		uint32_t poly = 0x04C11DB7;

		for (int i = 0; i < 256; i++) {
		uint32_t crc = i << 24;
		for (int j = 0; j < 8; j++) {
		crc = (crc << 1) ^ ((crc & 0x80000000) ? (poly) : 0);
		}
		mCrcTable[i] = crc;
		}
		}

		/**
		* Compute CRC32 checksum for buffer starting at offset start and for length
		* bytes.
		*/
		uint32_t MPEG2TSWriter::crc32(const uint8_t *p_start, size_t length) {
		uint32_t crc = 0xFFFFFFFF;
		const uint8_t *p;

		for (p = p_start; p < p_start + length; p++) {
		crc = (crc << 8) ^ mCrcTable[((crc >> 24) ^ *p) & 0xFF];
		}

		return crc;
		}

		ssize_t MPEG2TSWriter::internalWrite(const void *data, size_t size) {
		if (mFile != NULL) {
		return fwrite(data, 1, size, mFile);