aboutsummaryrefslogtreecommitdiffstats
path: root/libavformat/rtpenc_hevc.c
blob: ce661fa1a8fb45df8345dc07aafef43d88680ed0 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
/*
 * RTP packetizer for HEVC/H.265 payload format (draft version 6)
 * Copyright (c) 2014 Thomas Volkert <thomas@homer-conferencing.com>
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "avc.h"
#include "avformat.h"
#include "rtpenc.h"

#define RTP_HEVC_HEADERS_SIZE 3

static void nal_send(AVFormatContext *ctx, const uint8_t *buf, int len, int last_packet_of_frame)
{
    RTPMuxContext *rtp_ctx = ctx->priv_data;
    int rtp_payload_size   = rtp_ctx->max_payload_size - RTP_HEVC_HEADERS_SIZE;
    int nal_type           = (buf[0] >> 1) & 0x3F;

    /* send it as one single NAL unit? */
    if (len <= rtp_ctx->max_payload_size) {
        /* use the original NAL unit buffer and transmit it as RTP payload */
        ff_rtp_send_data(ctx, buf, len, last_packet_of_frame);
    } else {
        /*
          create the HEVC payload header and transmit the buffer as fragmentation units (FU)

             0                   1
             0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
            |F|   Type    |  LayerId  | TID |
            +-------------+-----------------+

               F       = 0
               Type    = 49 (fragmentation unit (FU))
               LayerId = 0
               TID     = 1
         */
        rtp_ctx->buf[0] = 49 << 1;
        rtp_ctx->buf[1] = 1;

        /*
              create the FU header

              0 1 2 3 4 5 6 7
             +-+-+-+-+-+-+-+-+
             |S|E|  FuType   |
             +---------------+

                S       = variable
                E       = variable
                FuType  = NAL unit type
         */
        rtp_ctx->buf[2]  = nal_type;
        /* set the S bit: mark as start fragment */
        rtp_ctx->buf[2] |= 1 << 7;

        /* pass the original NAL header */
        buf += 2;
        len -= 2;

        while (len > rtp_payload_size) {
            /* complete and send current RTP packet */
            memcpy(&rtp_ctx->buf[RTP_HEVC_HEADERS_SIZE], buf, rtp_payload_size);
            ff_rtp_send_data(ctx, rtp_ctx->buf, rtp_ctx->max_payload_size, 0);

            buf += rtp_payload_size;
            len -= rtp_payload_size;

            /* reset the S bit */
            rtp_ctx->buf[2] &= ~(1 << 7);
        }

        /* set the E bit: mark as last fragment */
        rtp_ctx->buf[2] |= 1 << 6;

        /* complete and send last RTP packet */
        memcpy(&rtp_ctx->buf[RTP_HEVC_HEADERS_SIZE], buf, len);
        ff_rtp_send_data(ctx, rtp_ctx->buf, len + 2, last_packet_of_frame);
    }
}

void ff_rtp_send_hevc(AVFormatContext *ctx, const uint8_t *frame_buf, int frame_size)
{
    const uint8_t *next_NAL_unit;
    const uint8_t *buf_ptr, *buf_end = frame_buf + frame_size;
    RTPMuxContext *rtp_ctx = ctx->priv_data;

    /* use the default 90 KHz time stamp */
    rtp_ctx->timestamp = rtp_ctx->cur_timestamp;

    if (rtp_ctx->nal_length_size)
        buf_ptr = ff_avc_mp4_find_startcode(frame_buf, buf_end, rtp_ctx->nal_length_size) ? frame_buf : buf_end;
    else
        buf_ptr = ff_avc_find_startcode(frame_buf, buf_end);

    /* find all NAL units and send them as separate packets */
    while (buf_ptr < buf_end) {
        if (rtp_ctx->nal_length_size) {
            next_NAL_unit = ff_avc_mp4_find_startcode(buf_ptr, buf_end, rtp_ctx->nal_length_size);
            if (!next_NAL_unit)
                next_NAL_unit = buf_end;

            buf_ptr += rtp_ctx->nal_length_size;
        } else {
            while (!*(buf_ptr++))
                ;
            next_NAL_unit = ff_avc_find_startcode(buf_ptr, buf_end);
        }
        /* send the next NAL unit */
        nal_send(ctx, buf_ptr, next_NAL_unit - buf_ptr, next_NAL_unit == buf_end);

        /* jump to the next NAL unit */
        buf_ptr = next_NAL_unit;
    }
}