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Commit 77028b27 authored by Ray Essick's avatar Ray Essick Committed by JP Sugarbroad
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better mpeg2 TS elementary stream Access Unit parsing 

mpeg2 es stream access units have a 3 byte prefix and a 1 byte start
code. Searching for the next access unit started after the prefix
instead of after the start byte.

Bug: 74114680
Test: ran POC before/after
(cherry picked from commit 371066d0)
parent 67360f44

media/libstagefright/mpeg2ts/ESQueue.cpp

+7 −2
Original line number Diff line number Diff line
@@ -1486,7 +1486,9 @@ static ssize_t getNextChunkSize( 
        const uint8_t *data, size_t size) {

    static const char kStartCode[] = "\x00\x00\x01";



    if (size < 3) {

    // per ISO/IEC 14496-2 6.2.1, a chunk has a 3-byte prefix + 1-byte start code

    // we need at least <prefix><start><next prefix> to successfully scan

    if (size < 3 + 1 + 3) {

        return -EAGAIN;

    }
@@ -1494,7 +1496,7 @@ static ssize_t getNextChunkSize( 
        return -EAGAIN;

    }



    size_t offset = 3;

    size_t offset = 4;

    while (offset + 2 < size) {

        if (!memcmp(&data[offset], kStartCode, 3)) {

            return offset;
@@ -1545,6 +1547,9 @@ sp<ABuffer> ElementaryStreamQueue::dequeueAccessUnitMPEG4Video() { 
                    state = EXPECT_VISUAL_OBJECT_START;

                } else {

                    discard = true;

                    offset += chunkSize;

                    ALOGW("b/74114680, advance to next chunk");

                    android_errorWriteLog(0x534e4554, "74114680");

                }

                break;

            }