1/*
2 * RTP packetization for H.264 (RFC3984)
3 * Copyright (c) 2008 Luca Abeni
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22/**
23 * @file
24 * @brief H.264 packetization
25 * @author Luca Abeni <lucabe72@email.it>
26 */
27
28#include "avformat.h"
29#include "avc.h"
30#include "rtpenc.h"
31
32static const uint8_t *avc_mp4_find_startcode(const uint8_t *start, const uint8_t *end, int nal_length_size)
33{
34    unsigned int res = 0;
35
36    if (end - start < nal_length_size)
37        return NULL;
38    while (nal_length_size--)
39        res = (res << 8) | *start++;
40
41    if (res > end - start)
42        return NULL;
43
44    return start + res;
45}
46
47static void nal_send(AVFormatContext *s1, const uint8_t *buf, int size, int last)
48{
49    RTPMuxContext *s = s1->priv_data;
50
51    av_log(s1, AV_LOG_DEBUG, "Sending NAL %x of len %d M=%d\n", buf[0] & 0x1F, size, last);
52    if (size <= s->max_payload_size) {
53        ff_rtp_send_data(s1, buf, size, last);
54    } else {
55        uint8_t type = buf[0] & 0x1F;
56        uint8_t nri = buf[0] & 0x60;
57
58        if (s->flags & FF_RTP_FLAG_H264_MODE0) {
59            av_log(s1, AV_LOG_ERROR,
60                   "NAL size %d > %d, try -slice-max-size %d\n", size,
61                   s->max_payload_size, s->max_payload_size);
62            return;
63        }
64        av_log(s1, AV_LOG_DEBUG, "NAL size %d > %d\n", size, s->max_payload_size);
65        s->buf[0] = 28;        /* FU Indicator; Type = 28 ---> FU-A */
66        s->buf[0] |= nri;
67        s->buf[1] = type;
68        s->buf[1] |= 1 << 7;
69        buf += 1;
70        size -= 1;
71        while (size + 2 > s->max_payload_size) {
72            memcpy(&s->buf[2], buf, s->max_payload_size - 2);
73            ff_rtp_send_data(s1, s->buf, s->max_payload_size, 0);
74            buf += s->max_payload_size - 2;
75            size -= s->max_payload_size - 2;
76            s->buf[1] &= ~(1 << 7);
77        }
78        s->buf[1] |= 1 << 6;
79        memcpy(&s->buf[2], buf, size);
80        ff_rtp_send_data(s1, s->buf, size + 2, last);
81    }
82}
83
84void ff_rtp_send_h264(AVFormatContext *s1, const uint8_t *buf1, int size)
85{
86    const uint8_t *r, *end = buf1 + size;
87    RTPMuxContext *s = s1->priv_data;
88
89    s->timestamp = s->cur_timestamp;
90    if (s->nal_length_size)
91        r = avc_mp4_find_startcode(buf1, end, s->nal_length_size) ? buf1 : end;
92    else
93        r = ff_avc_find_startcode(buf1, end);
94    while (r < end) {
95        const uint8_t *r1;
96
97        if (s->nal_length_size) {
98            r1 = avc_mp4_find_startcode(r, end, s->nal_length_size);
99            if (!r1)
100                r1 = end;
101            r += s->nal_length_size;
102        } else {
103            while (!*(r++));
104            r1 = ff_avc_find_startcode(r, end);
105        }
106        nal_send(s1, r, r1 - r, r1 == end);
107        r = r1;
108    }
109}
110