1 /*
2 * RTP packetization for H.264 (RFC3984)
3 * RTP packetizer for HEVC/H.265 payload format (draft version 6)
4 * Copyright (c) 2008 Luca Abeni
5 * Copyright (c) 2014 Thomas Volkert <thomas@homer-conferencing.com>
6 *
7 * This file is part of FFmpeg.
8 *
9 * FFmpeg is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public
11 * License as published by the Free Software Foundation; either
12 * version 2.1 of the License, or (at your option) any later version.
13 *
14 * FFmpeg is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Lesser General Public License for more details.
18 *
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with FFmpeg; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 */
23
24 /**
25 * @file
26 * @brief H.264/HEVC packetization
27 * @author Luca Abeni <lucabe72@email.it>
28 */
29
30 #include "libavutil/intreadwrite.h"
31
32 #include "avformat.h"
33 #include "avc.h"
34 #include "rtpenc.h"
35
flush_buffered(AVFormatContext * s1,int last)36 static void flush_buffered(AVFormatContext *s1, int last)
37 {
38 RTPMuxContext *s = s1->priv_data;
39 if (s->buf_ptr != s->buf) {
40 // If we're only sending one single NAL unit, send it as such, skip
41 // the STAP-A/AP framing
42 if (s->buffered_nals == 1) {
43 enum AVCodecID codec = s1->streams[0]->codecpar->codec_id;
44 if (codec == AV_CODEC_ID_H264)
45 ff_rtp_send_data(s1, s->buf + 3, s->buf_ptr - s->buf - 3, last);
46 else
47 ff_rtp_send_data(s1, s->buf + 4, s->buf_ptr - s->buf - 4, last);
48 } else
49 ff_rtp_send_data(s1, s->buf, s->buf_ptr - s->buf, last);
50 }
51 s->buf_ptr = s->buf;
52 s->buffered_nals = 0;
53 }
54
nal_send(AVFormatContext * s1,const uint8_t * buf,int size,int last)55 static void nal_send(AVFormatContext *s1, const uint8_t *buf, int size, int last)
56 {
57 RTPMuxContext *s = s1->priv_data;
58 enum AVCodecID codec = s1->streams[0]->codecpar->codec_id;
59
60 av_log(s1, AV_LOG_DEBUG, "Sending NAL %x of len %d M=%d\n", buf[0] & 0x1F, size, last);
61 if (size <= s->max_payload_size) {
62 int buffered_size = s->buf_ptr - s->buf;
63 int header_size;
64 int skip_aggregate = 0;
65
66 if (codec == AV_CODEC_ID_H264) {
67 header_size = 1;
68 skip_aggregate = s->flags & FF_RTP_FLAG_H264_MODE0;
69 } else {
70 header_size = 2;
71 }
72
73 // Flush buffered NAL units if the current unit doesn't fit
74 if (buffered_size + 2 + size > s->max_payload_size) {
75 flush_buffered(s1, 0);
76 buffered_size = 0;
77 }
78 // If we aren't using mode 0, and the NAL unit fits including the
79 // framing (2 bytes length, plus 1/2 bytes for the STAP-A/AP marker),
80 // write the unit to the buffer as a STAP-A/AP packet, otherwise flush
81 // and send as single NAL.
82 if (buffered_size + 2 + header_size + size <= s->max_payload_size &&
83 !skip_aggregate) {
84 if (buffered_size == 0) {
85 if (codec == AV_CODEC_ID_H264) {
86 *s->buf_ptr++ = 24;
87 } else {
88 *s->buf_ptr++ = 48 << 1;
89 *s->buf_ptr++ = 1;
90 }
91 }
92 AV_WB16(s->buf_ptr, size);
93 s->buf_ptr += 2;
94 memcpy(s->buf_ptr, buf, size);
95 s->buf_ptr += size;
96 s->buffered_nals++;
97 } else {
98 flush_buffered(s1, 0);
99 ff_rtp_send_data(s1, buf, size, last);
100 }
101 } else {
102 int flag_byte, header_size;
103 flush_buffered(s1, 0);
104 if (codec == AV_CODEC_ID_H264 && (s->flags & FF_RTP_FLAG_H264_MODE0)) {
105 av_log(s1, AV_LOG_ERROR,
106 "NAL size %d > %d, try -slice-max-size %d\n", size,
107 s->max_payload_size, s->max_payload_size);
108 return;
109 }
110 av_log(s1, AV_LOG_DEBUG, "NAL size %d > %d\n", size, s->max_payload_size);
111 if (codec == AV_CODEC_ID_H264) {
112 uint8_t type = buf[0] & 0x1F;
113 uint8_t nri = buf[0] & 0x60;
114
115 s->buf[0] = 28; /* FU Indicator; Type = 28 ---> FU-A */
116 s->buf[0] |= nri;
117 s->buf[1] = type;
118 s->buf[1] |= 1 << 7;
119 buf += 1;
120 size -= 1;
121
122 flag_byte = 1;
123 header_size = 2;
124 } else {
125 uint8_t nal_type = (buf[0] >> 1) & 0x3F;
126 /*
127 * create the HEVC payload header and transmit the buffer as fragmentation units (FU)
128 *
129 * 0 1
130 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
131 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
132 * |F| Type | LayerId | TID |
133 * +-------------+-----------------+
134 *
135 * F = 0
136 * Type = 49 (fragmentation unit (FU))
137 * LayerId = 0
138 * TID = 1
139 */
140 s->buf[0] = 49 << 1;
141 s->buf[1] = 1;
142
143 /*
144 * create the FU header
145 *
146 * 0 1 2 3 4 5 6 7
147 * +-+-+-+-+-+-+-+-+
148 * |S|E| FuType |
149 * +---------------+
150 *
151 * S = variable
152 * E = variable
153 * FuType = NAL unit type
154 */
155 s->buf[2] = nal_type;
156 /* set the S bit: mark as start fragment */
157 s->buf[2] |= 1 << 7;
158
159 /* pass the original NAL header */
160 buf += 2;
161 size -= 2;
162
163 flag_byte = 2;
164 header_size = 3;
165 }
166
167 while (size + header_size > s->max_payload_size) {
168 memcpy(&s->buf[header_size], buf, s->max_payload_size - header_size);
169 ff_rtp_send_data(s1, s->buf, s->max_payload_size, 0);
170 buf += s->max_payload_size - header_size;
171 size -= s->max_payload_size - header_size;
172 s->buf[flag_byte] &= ~(1 << 7);
173 }
174 s->buf[flag_byte] |= 1 << 6;
175 memcpy(&s->buf[header_size], buf, size);
176 ff_rtp_send_data(s1, s->buf, size + header_size, last);
177 }
178 }
179
ff_rtp_send_h264_hevc(AVFormatContext * s1,const uint8_t * buf1,int size)180 void ff_rtp_send_h264_hevc(AVFormatContext *s1, const uint8_t *buf1, int size)
181 {
182 const uint8_t *r, *end = buf1 + size;
183 RTPMuxContext *s = s1->priv_data;
184
185 s->timestamp = s->cur_timestamp;
186 s->buf_ptr = s->buf;
187 if (s->nal_length_size)
188 r = ff_avc_mp4_find_startcode(buf1, end, s->nal_length_size) ? buf1 : end;
189 else
190 r = ff_avc_find_startcode(buf1, end);
191 while (r < end) {
192 const uint8_t *r1;
193
194 if (s->nal_length_size) {
195 r1 = ff_avc_mp4_find_startcode(r, end, s->nal_length_size);
196 if (!r1)
197 r1 = end;
198 r += s->nal_length_size;
199 } else {
200 while (!*(r++));
201 r1 = ff_avc_find_startcode(r, end);
202 }
203 nal_send(s1, r, r1 - r, r1 == end);
204 r = r1;
205 }
206 flush_buffered(s1, 1);
207 }
208