1/*
2 * RTP JPEG-compressed video Packetizer, RFC 2435
3 * Copyright (c) 2012 Samuel Pitoiset
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#include "libavcodec/bytestream.h"
23#include "libavcodec/mjpeg.h"
24#include "libavutil/intreadwrite.h"
25#include "rtpenc.h"
26
27void ff_rtp_send_jpeg(AVFormatContext *s1, const uint8_t *buf, int size)
28{
29    RTPMuxContext *s = s1->priv_data;
30    const uint8_t *qtables = NULL;
31    int nb_qtables = 0;
32    uint8_t type;
33    uint8_t w, h;
34    uint8_t *p;
35    int off = 0; /* fragment offset of the current JPEG frame */
36    int len;
37    int i;
38
39    s->buf_ptr   = s->buf;
40    s->timestamp = s->cur_timestamp;
41
42    /* convert video pixel dimensions from pixels to blocks */
43    w = s1->streams[0]->codec->width  >> 3;
44    h = s1->streams[0]->codec->height >> 3;
45
46    /* get the pixel format type or fail */
47    if (s1->streams[0]->codec->pix_fmt == AV_PIX_FMT_YUVJ422P ||
48        (s1->streams[0]->codec->color_range == AVCOL_RANGE_JPEG &&
49         s1->streams[0]->codec->pix_fmt == AV_PIX_FMT_YUV422P)) {
50        type = 0;
51    } else if (s1->streams[0]->codec->pix_fmt == AV_PIX_FMT_YUVJ420P ||
52               (s1->streams[0]->codec->color_range == AVCOL_RANGE_JPEG &&
53                s1->streams[0]->codec->pix_fmt == AV_PIX_FMT_YUV420P)) {
54        type = 1;
55    } else {
56        av_log(s1, AV_LOG_ERROR, "Unsupported pixel format\n");
57        return;
58    }
59
60    /* preparse the header for getting some infos */
61    for (i = 0; i < size; i++) {
62        if (buf[i] != 0xff)
63            continue;
64
65        if (buf[i + 1] == DQT) {
66            if (buf[i + 4])
67                av_log(s1, AV_LOG_WARNING,
68                       "Only 8-bit precision is supported.\n");
69
70            /* a quantization table is 64 bytes long */
71            nb_qtables = AV_RB16(&buf[i + 2]) / 65;
72            if (i + 4 + nb_qtables * 65 > size) {
73                av_log(s1, AV_LOG_ERROR, "Too short JPEG header. Aborted!\n");
74                return;
75            }
76
77            qtables = &buf[i + 4];
78        } else if (buf[i + 1] == SOF0) {
79            if (buf[i + 14] != 17 || buf[i + 17] != 17) {
80                av_log(s1, AV_LOG_ERROR,
81                       "Only 1x1 chroma blocks are supported. Aborted!\n");
82                return;
83            }
84        } else if (buf[i + 1] == SOS) {
85            /* SOS is last marker in the header */
86            i += AV_RB16(&buf[i + 2]) + 2;
87            break;
88        }
89    }
90
91    /* skip JPEG header */
92    buf  += i;
93    size -= i;
94
95    for (i = size - 2; i >= 0; i--) {
96        if (buf[i] == 0xff && buf[i + 1] == EOI) {
97            /* Remove the EOI marker */
98            size = i;
99            break;
100        }
101    }
102
103    p = s->buf_ptr;
104    while (size > 0) {
105        int hdr_size = 8;
106
107        if (off == 0 && nb_qtables)
108            hdr_size += 4 + 64 * nb_qtables;
109
110        /* payload max in one packet */
111        len = FFMIN(size, s->max_payload_size - hdr_size);
112
113        /* set main header */
114        bytestream_put_byte(&p, 0);
115        bytestream_put_be24(&p, off);
116        bytestream_put_byte(&p, type);
117        bytestream_put_byte(&p, 255);
118        bytestream_put_byte(&p, w);
119        bytestream_put_byte(&p, h);
120
121        if (off == 0 && nb_qtables) {
122            /* set quantization tables header */
123            bytestream_put_byte(&p, 0);
124            bytestream_put_byte(&p, 0);
125            bytestream_put_be16(&p, 64 * nb_qtables);
126
127            for (i = 0; i < nb_qtables; i++)
128                bytestream_put_buffer(&p, &qtables[65 * i + 1], 64);
129        }
130
131        /* copy payload data */
132        memcpy(p, buf, len);
133
134        /* marker bit is last packet in frame */
135        ff_rtp_send_data(s1, s->buf, len + hdr_size, size == len);
136
137        buf  += len;
138        size -= len;
139        off  += len;
140        p     = s->buf;
141    }
142}
143