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Commit 7b26a5d8 authored by Kim Sungyeon's avatar Kim Sungyeon Committed by Lajos Molnar
Browse files

VT: Change to KMP algorithm for searching H.264 start prefix code 



Bug: 153702641

Merged-in: Iccc95de1f01738f1f7a48672312c82332e173da2
Change-Id: Iccc95de1f01738f1f7a48672312c82332e173da2
Signed-off-by: default avatarKim Sungyeon <sy85.kim@samsung.com>
parent b9ee5f4b

media/libstagefright/rtsp/ARTPWriter.cpp

+20 −12
Original line number Diff line number Diff line
@@ -277,7 +277,6 @@ status_t ARTPWriter::pause() { 
    return OK;

}



// return size of SPS if there is more NAL unit found following to SPS.

static void StripStartcode(MediaBufferBase *buffer) {

    if (buffer->range_length() < 4) {

        return;
@@ -294,6 +293,7 @@ static void StripStartcode(MediaBufferBase *buffer) { 


static const uint8_t SPCSize = 4;      // Start Prefix Code Size

static const uint8_t startPrefixCode[SPCSize] = {0,0,0,1};

static const uint8_t spcKMPidx[SPCSize] = {0,0,2,0};

static void SpsPpsParser(MediaBufferBase *buffer,

    MediaBufferBase **spsBuffer, MediaBufferBase **ppsBuffer) {
@@ -310,32 +310,40 @@ static void SpsPpsParser(MediaBufferBase *buffer, 
        }

        ALOGV("SPS(7) or PPS(8) found. Type %d", *NALPtr & H264_NALU_MASK);



        uint32_t targetSize = buffer->range_length();

        uint32_t bufferSize = buffer->range_length();

        MediaBufferBase*& target = *targetPtr;

        uint32_t j;

        uint32_t i = 0, j = 0;

        bool isBoundFound = false;

        for (j = 0; j < targetSize - SPCSize ; j++) {

            if (!memcmp(NALPtr + j, startPrefixCode, SPCSize)) {

        for (i = 0; i < bufferSize ; i++) {

            while (j > 0 && NALPtr[i] != startPrefixCode[j])

                j = spcKMPidx[j-1];

            if (NALPtr[i] == startPrefixCode[j]) {

                j++;

                if (j == SPCSize) {

                    isBoundFound = true;

                    break;

                }

            }

        }



        uint32_t targetSize;

        if (target != NULL)

            target->release();

        if (isBoundFound) {

            target = MediaBufferBase::Create(j);

            targetSize = i - SPCSize + 1;

            target = MediaBufferBase::Create(targetSize);

            memcpy(target->data(),

                   (const uint8_t *)buffer->data() + buffer->range_offset(),

                   j);

            buffer->set_range(buffer->range_offset() + j + SPCSize,

                              buffer->range_length() - j - SPCSize);

                   targetSize);

            buffer->set_range(buffer->range_offset() + targetSize + SPCSize,

                              buffer->range_length() - targetSize - SPCSize);

        } else {

            targetSize = bufferSize;

            target = MediaBufferBase::Create(targetSize);

            memcpy(target->data(),

                   (const uint8_t *)buffer->data() + buffer->range_offset(),

                   targetSize);

            buffer->set_range(buffer->range_offset() + targetSize, 0);

            buffer->set_range(buffer->range_offset() + bufferSize, 0);

            return;

        }

    }