diff options
Diffstat (limited to 'modules/gst_video1/h264.c')
-rw-r--r-- | modules/gst_video1/h264.c | 160 |
1 files changed, 160 insertions, 0 deletions
diff --git a/modules/gst_video1/h264.c b/modules/gst_video1/h264.c new file mode 100644 index 0000000..85e3442 --- /dev/null +++ b/modules/gst_video1/h264.c @@ -0,0 +1,160 @@ +/** + * @file gst_video/h264.c H.264 Packetization + * + * Copyright (C) 2010 Creytiv.com + */ +#include <string.h> +#include <re.h> +#include <rem.h> +#include <baresip.h> +#include "gst_video.h" + + +/** NAL unit types (RFC 3984, Table 1) */ +enum { + H264_NAL_UNKNOWN = 0, + /* 1-23 NAL unit Single NAL unit packet per H.264 */ + H264_NAL_SLICE = 1, + H264_NAL_DPA = 2, + H264_NAL_DPB = 3, + H264_NAL_DPC = 4, + H264_NAL_IDR_SLICE = 5, + H264_NAL_SEI = 6, + H264_NAL_SPS = 7, + H264_NAL_PPS = 8, + H264_NAL_AUD = 9, + H264_NAL_END_SEQUENCE = 10, + H264_NAL_END_STREAM = 11, + H264_NAL_FILLER_DATA = 12, + H264_NAL_SPS_EXT = 13, + H264_NAL_AUX_SLICE = 19, + + H264_NAL_STAP_A = 24, /**< Single-time aggregation packet */ + H264_NAL_STAP_B = 25, /**< Single-time aggregation packet */ + H264_NAL_MTAP16 = 26, /**< Multi-time aggregation packet */ + H264_NAL_MTAP24 = 27, /**< Multi-time aggregation packet */ + H264_NAL_FU_A = 28, /**< Fragmentation unit */ + H264_NAL_FU_B = 29, /**< Fragmentation unit */ +}; + + +const uint8_t gst_video_h264_level_idc = 0x0c; + + +/* + * Find the NAL start sequence in a H.264 byte stream + * + * @note: copied from ffmpeg source + */ +static 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, + videnc_packet_h *pkth, void *arg) +{ + return pkth(eof, hdr, hdr_sz, buf, sz, arg); +} + + +static int h264_nal_send(bool first, bool last, + bool marker, uint32_t ihdr, 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, + 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, + 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, + pkth, arg); + } + + return err; +} + + +int gst_video_h264_packetize(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 = start + len; + const uint8_t *r; + int err = 0; + + r = h264_find_startcode(buf, 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], + r+1, r1-r-1, pktsize, + pkth, arg); + r = r1; + } + + return err; +} |