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enhanced avc decode, parse the sps get width+height. 2.0.156.

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This commit is contained in:
winlin 2015-04-03 23:17:50 +08:00
parent 7e1749e029
commit 70c59da1bf
9 changed files with 351 additions and 8 deletions
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47
trunk/src/kernel/srs_kernel_utility.cpp
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@ -46,6 +46,53 @@ using namespace std;
// @see SRS_SYS_TIME_RESOLUTION_MS_TIMES
#define SYS_TIME_RESOLUTION_US 300*1000
int srs_avc_nalu_read_uev(SrsBitStream* stream, int64_t& v)
{
int ret = ERROR_SUCCESS;
if (stream->empty()) {
return ERROR_AVC_NALU_UEV;
}
// ue(v) in 9.1 Parsing process for Exp-Golomb codes
// H.264-AVC-ISO_IEC_14496-10-2012.pdf, page 227.
// Syntax elements coded as ue(v), me(v), or se(v) are Exp-Golomb-coded.
// leadingZeroBits = -1;
// for( b = 0; !b; leadingZeroBits++ )
// b = read_bits( 1 )
// The variable codeNum is then assigned as follows:
// codeNum = (2<<leadingZeroBits) – 1 + read_bits( leadingZeroBits )
int leadingZeroBits = -1;
for (int8_t b = 0; !b && !stream->empty(); leadingZeroBits++) {
b = stream->read_bit();
}
if (leadingZeroBits >= 64) {
return ERROR_AVC_NALU_UEV;
}
v = (1 << leadingZeroBits) - 1;
for (int i = 0; i < leadingZeroBits; i++) {
int64_t b = stream->read_bit();
v += b << (leadingZeroBits - 1);
}
return ret;
}
int srs_avc_nalu_read_bit(SrsBitStream* stream, int8_t& v)
{
int ret = ERROR_SUCCESS;
if (stream->empty()) {
return ERROR_AVC_NALU_UEV;
}
v = stream->read_bit();
return ret;
}
static int64_t _srs_system_time_us_cache = 0;
static int64_t _srs_system_time_startup_time = 0;