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在项目开发过程中遇到一个问题，play之后，不能推送rtp数据包，跟踪代码调试发现，在获取H264视频数据，封包，发送，这条循环的链断开了，导致该问题的原因是：
在H264VideoStreamFramer.cpp中
unsigned H264VideoStreamParser::parse()
{
#if DEBUG_SHOWCHN
printf("Parser() chn:%d\n", fchn);
#endif
try{
// The stream must start with a 0x00000001:
if (!fHaveSeenFirstStartCode)
{
// Skip over any input bytes that precede the first 0x00000001:
u_int32_t first4Bytes;
while ((first4Bytes = test4Bytes()) != 0x00000001)
{
get1Byte(); setParseState(); // ensures that we progress over bad data
}
skipBytes(4); // skip this initial code
setParseState();
fHaveSeenFirstStartCode = True; // from now on
}
if (fOutputStartCodeSize > 0 && curFrameSize() == 0 && !haveSeenEOF())
{
// Include a start code in the output:
save4Bytes(0x00000001);
}
// Then save everything up until the next 0x00000001 (4 bytes) or 0x000001 (3 bytes), or we hit EOF.
// Also make note of the first byte, because it contains the "nal_unit_type":
if (haveSeenEOF())
{
// We hit EOF the last time that we tried to parse this data, so we know that any remaining unparsed data
// forms a complete NAL unit, and that there's no 'start code' at the end:
unsigned remainingDataSize = totNumValidBytes() - curOffset();
#ifdef DEBUG
unsigned const trailingNALUnitSize = remainingDataSize;
#endif
while (remainingDataSize > 0)
{
u_int8_t nextByte = get1Byte();
if (!fHaveSeenFirstByteOfNALUnit)
{
fFirstByteOfNALUnit = nextByte;
fHaveSeenFirstByteOfNALUnit = True;
}
saveByte(nextByte);
--remainingDataSize;
}
#ifdef DEBUG
u_int8_t nal_ref_idc = (fFirstByteOfNALUnit&0x60)>>5;
u_int8_t nal_unit_type = fFirstByteOfNALUnit&0x1F;
fprintf(stderr, "Parsed trailing %d-byte NAL-unit (nal_ref_idc: %d, nal_unit_type: %d (\"%s\"))\n",
trailingNALUnitSize, nal_ref_idc, nal_unit_type, nal_unit_type_description[nal_unit_type]);
#endif
(void)get1Byte(); // forces another read, which will cause EOF to get handled for real this time
return 0;
}
else
{
u_int32_t next4Bytes = test4Bytes();
if (!fHaveSeenFirstByteOfNALUnit)
{
fFirstByteOfNALUnit = next4Bytes>>24;
fHaveSeenFirstByteOfNALUnit = True;
}
///////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////
//如果获取的H264数据不完整或错误 只有帧头 没有帧体curFrameSize()会等于0
while (next4Bytes != 0x00000001 && (next4Bytes&0xFFFFFF00) != 0x00000100)
{
// We save at least some of "next4Bytes".
if ((unsigned)(next4Bytes&0xFF) > 1)
{
// Common case: 0x00000001 or 0x000001 definitely doesn't begin anywhere in "next4Bytes", so we save all of it:
save4Bytes(next4Bytes);
skipBytes(4);
}
else
{
// Save the first byte, and continue testing the rest:
saveByte(next4Bytes>>24);
skipBytes(1);
}
setParseState(); // ensures forward progress
next4Bytes = test4Bytes();
}
// Assert: next4Bytes starts with 0x00000001 or 0x000001, and we've saved all previous bytes (forming a complete NAL unit).
// Skip over these remaining bytes, up until the start of the next NAL unit:
if (next4Bytes == 0x00000001)
{
skipBytes(4);
}
else
{
skipBytes(3);
}
}
u_int8_t nal_ref_idc = (fFirstByteOfNALUnit&0x60)>>5;
u_int8_t nal_unit_type = fFirstByteOfNALUnit&0x1F;
fHaveSeenFirstByteOfNALUnit = False; // for the next NAL unit that we parse
#ifdef DEBUG
fprintf(stderr, "Parsed %d-byte NAL-unit (nal_ref_idc: %d, nal_unit_type: %d (\"%s\"))\n",
curFrameSize()-fOutputStartCodeSize, nal_ref_idc, nal_unit_type, nal_unit_type_description[nal_unit_type]);
#endif
switch (nal_unit_type)
{
case 6:
{
// Supplemental enhancement information (SEI)
analyze_sei_data();
// Later, perhaps adjust "fPresentationTime" if we saw a "pic_timing" SEI payload??? #####
break;
}
case 7:
{
// Sequence parameter set
// First, save a copy of this NAL unit, in case the downstream object wants to see it:
usingSource()->saveCopyOfSPS(fStartOfFrame + fOutputStartCodeSize, fTo - fStartOfFrame - fOutputStartCodeSize);
// Parse this NAL unit to check whether frame rate information is present:
unsigned num_units_in_tick, time_scale, fixed_frame_rate_flag;
analyze_seq_parameter_set_data(num_units_in_tick, time_scale, fixed_frame_rate_flag);
if (time_scale > 0 && num_units_in_tick > 0)
{
usingSource()->fFrameRate = time_scale/(2.0*num_units_in_tick);
#ifdef DEBUG
fprintf(stderr, "Set frame rate to %f fps\n", usingSource()->fFrameRate);
if (fixed_frame_rate_flag == 0)
{
fprintf(stderr, "\tWARNING: \"fixed_frame_rate_flag\" was not set\n");
}
#endif
}
else
{
#ifdef DEBUG
fprintf(stderr, "\tThis \"Sequence Parameter Set\" NAL unit contained no frame rate information, so we use a default frame rate of %f fps\n", usingSource()->fFrameRate);
#endif
}
break;
}
case 8:
{
// Picture parameter set
// Save a copy of this NAL unit, in case the downstream object wants to see it:
usingSource()->saveCopyOfPPS(fStartOfFrame + fOutputStartCodeSize, fTo - fStartOfFrame - fOutputStartCodeSize);
}
}
usingSource()->setPresentationTime();
#ifdef DEBUG
unsigned long secs = (unsigned long)usingSource()->fPresentationTime.tv_sec;
unsigned uSecs = (unsigned)usingSource()->fPresentationTime.tv_usec;
//fprintf(stderr, "\tPresentation time: %lu.%06u\n", secs, uSecs);
#endif
// We check whether this NAL unit ends an 'access unit'.
// (RTP streamers need to know this in order to figure out whether or not to set the "M" bit.)
Boolean thisNALUnitEndsAccessUnit;
if (haveSeenEOF() || nal_unit_type == 11/*End of stream*/)
{
// There is no next NAL unit, so we assume that this one ends the current 'access unit':
thisNALUnitEndsAccessUnit = True;
}
else if ((nal_unit_type >= 6 && nal_unit_type <= 9) || (nal_unit_type >= 14 && nal_unit_type <= 18))
{
// These NAL units usually *begin* an access unit, so we assume that they don't end one here:
thisNALUnitEndsAccessUnit = False;
}
else
{
// We need to check the *next* NAL unit to figure out whether the current NAL unit ends an 'access unit':
u_int8_t firstBytesOfNextNALUnit[2];
testBytes(firstBytesOfNextNALUnit, 2);
u_int8_t const& next_nal_unit_type = firstBytesOfNextNALUnit[0]&0x1F;
Boolean const nextNALUnitIsVCL = next_nal_unit_type <= 5 && nal_unit_type > 0;
if (nextNALUnitIsVCL)
{
// The high-order bit of the 2nd byte tells us whether this is the start of a new 'access unit':
thisNALUnitEndsAccessUnit = (firstBytesOfNextNALUnit[1]&0x80) != 0;
}
else if ((next_nal_unit_type >= 6 && next_nal_unit_type <= 9) || (next_nal_unit_type >= 14 && next_nal_unit_type <= 18))
{
// The next NAL unit's type is one that usually appears at the start of an 'access unit',
// so we assume that the current NAL unit ends an 'access unit':
thisNALUnitEndsAccessUnit = True;
}
else
{
// The next NAL unit definitely doesn't start a new 'access unit', which means that the current NAL unit doesn't end one:
thisNALUnitEndsAccessUnit = False;
}
}
if (thisNALUnitEndsAccessUnit)
{
#ifdef DEBUG
fprintf(stderr, "*****This NAL unit ends the current access unit*****\n");
#endif
usingSource()->fPictureEndMarker = True;
++usingSource()->fPictureCount;
// Note that the presentation time for the next NAL unit will be different:
struct timeval& nextPT = usingSource()->fNextPresentationTime; // alias
nextPT = usingSource()->fPresentationTime;
double nextFraction = nextPT.tv_usec/1000000.0 + 1/usingSource()->fFrameRate;
unsigned nextSecsIncrement = (long)nextFraction;
nextPT.tv_sec += (long)nextSecsIncrement;
nextPT.tv_usec = (long)((nextFraction - nextSecsIncrement)*1000000);
}
setParseState();
#if DEBUG_SHOWCHN
printf("parse() return curFrameSize()=%d chn:%d\n", curFrameSize(), fchn);
#endif
///////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////
//如果返回的curFrameSize()等于0, 获取视频 封包 发送 这个循环的过程就终止了
//返回后使程序能循环转起来的回调函数调用不到了 所以增加如下代码
if (0 == curFrameSize())
{
#if DEBUG_SHOWCHN
printf("curFrameSize = 0 parse again chn:%d\n", fchn);
#endif
fHaveSeenFirstStartCode = false;
parse();
}
return curFrameSize();
}
catch (int /*e*/)
{
#ifdef DEBUG
//fprintf(stderr, "H264VideoStreamParser::parse() EXCEPTION (This is normal behavior - *not* an error)\n");
#endif
return 0; // the parsing got interrupted
}
}
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原文地址：http://blog.csdn.net/daminglanyu/article/details/43196159
