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/**
* @file src/h264.c H.264 video codec packetization (RFC 3984)
*
* Copyright (C) 2010 - 2015 Creytiv.com
*/
#include <string.h>
#include <re.h>
#include <rem.h>
#include <baresip.h>
int h264_hdr_encode(const struct h264_hdr *hdr, struct mbuf *mb)
{
uint8_t v;
v = hdr->f<<7 | hdr->nri<<5 | hdr->type<<0;
return mbuf_write_u8(mb, v);
}
int h264_hdr_decode(struct h264_hdr *hdr, struct mbuf *mb)
{
uint8_t v;
if (mbuf_get_left(mb) < 1)
return ENOENT;
v = mbuf_read_u8(mb);
hdr->f = v>>7 & 0x1;
hdr->nri = v>>5 & 0x3;
hdr->type = v>>0 & 0x1f;
return 0;
}
int h264_fu_hdr_encode(const struct h264_fu *fu, struct mbuf *mb)
{
uint8_t v = fu->s<<7 | fu->s<<6 | fu->r<<5 | fu->type;
return mbuf_write_u8(mb, v);
}
int h264_fu_hdr_decode(struct h264_fu *fu, struct mbuf *mb)
{
uint8_t v;
if (mbuf_get_left(mb) < 1)
return ENOENT;
v = mbuf_read_u8(mb);
fu->s = v>>7 & 0x1;
fu->e = v>>6 & 0x1;
fu->r = v>>5 & 0x1;
fu->type = v>>0 & 0x1f;
return 0;
}
/*
* Find the NAL start sequence in a H.264 byte stream
*
* @note: copied from ffmpeg source
*/
const uint8_t *h264_find_startcode(const uint8_t *p, const uint8_t *end)
{
const uint8_t *a = p + 4 - ((long)p & 3);
for (end -= 3; p < a && p < end; p++ ) {
if (p[0] == 0 && p[1] == 0 && p[2] == 1)
return p;
}
for (end -= 3; p < end; p += 4) {
uint32_t x = *(const uint32_t*)(void *)p;
if ( (x - 0x01010101) & (~x) & 0x80808080 ) {
if (p[1] == 0 ) {
if ( p[0] == 0 && p[2] == 1 )
return p;
if ( p[2] == 0 && p[3] == 1 )
return p+1;
}
if ( p[3] == 0 ) {
if ( p[2] == 0 && p[4] == 1 )
return p+2;
if ( p[4] == 0 && p[5] == 1 )
return p+3;
}
}
}
for (end += 3; p < end; p++) {
if (p[0] == 0 && p[1] == 0 && p[2] == 1)
return p;
}
return end + 3;
}
static int rtp_send_data(const uint8_t *hdr, size_t hdr_sz,
const uint8_t *buf, size_t sz,
bool eof, uint64_t rtp_ts,
videnc_packet_h *pkth, void *arg)
{
return pkth(eof, rtp_ts, hdr, hdr_sz, buf, sz, arg);
}
int h264_nal_send(bool first, bool last,
bool marker, uint32_t ihdr, uint64_t rtp_ts,
const uint8_t *buf, size_t size, size_t maxsz,
videnc_packet_h *pkth, void *arg)
{
uint8_t hdr = (uint8_t)ihdr;
int err = 0;
if (first && last && size <= maxsz) {
err = rtp_send_data(&hdr, 1, buf, size, marker, rtp_ts,
pkth, arg);
}
else {
uint8_t fu_hdr[2];
const uint8_t type = hdr & 0x1f;
const uint8_t nri = hdr & 0x60;
const size_t sz = maxsz - 2;
fu_hdr[0] = nri | H264_NAL_FU_A;
fu_hdr[1] = first ? (1<<7 | type) : type;
while (size > sz) {
err |= rtp_send_data(fu_hdr, 2, buf, sz, false,
rtp_ts,
pkth, arg);
buf += sz;
size -= sz;
fu_hdr[1] &= ~(1 << 7);
}
if (last)
fu_hdr[1] |= 1<<6; /* end bit */
err |= rtp_send_data(fu_hdr, 2, buf, size, marker && last,
rtp_ts,
pkth, arg);
}
return err;
}
int h264_packetize(uint64_t rtp_ts, const uint8_t *buf, size_t len,
size_t pktsize, videnc_packet_h *pkth, void *arg)
{
const uint8_t *start = buf;
const uint8_t *end = buf + len;
const uint8_t *r;
int err = 0;
r = h264_find_startcode(start, end);
while (r < end) {
const uint8_t *r1;
/* skip zeros */
while (!*(r++))
;
r1 = h264_find_startcode(r, end);
err |= h264_nal_send(true, true, (r1 >= end), r[0],
rtp_ts, r+1, r1-r-1, pktsize,
pkth, arg);
r = r1;
}
return err;
}
/**
* Get the name of an H.264 nal unit
*
* @param type NAL unit type
*
* @return A string containing the NAL unit name
*/
const char *h264_nalunit_name(int type)
{
switch (type) {
case H264_NAL_SLICE: return "SLICE";
case H264_NAL_DPA: return "DPA";
case H264_NAL_DPB: return "DPB";
case H264_NAL_DPC: return "DPC";
case H264_NAL_IDR_SLICE: return "IDR_SLICE";
case H264_NAL_SEI: return "SEI";
case H264_NAL_SPS: return "SPS";
case H264_NAL_PPS: return "PPS";
case H264_NAL_AUD: return "AUD";
case H264_NAL_FILLER_DATA: return "FILLER";
case H264_NAL_FU_A: return "FU-A";
case H264_NAL_FU_B: return "FU-B";
}
return "???";
}
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