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ffmpeg/libavformat/rtpenc_jpeg.c

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/*
* RTP JPEG-compressed video Packetizer, RFC 2435
* Copyright (c) 2012 Samuel Pitoiset
*
* 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 "libavcodec/bytestream.h"
#include "libavcodec/mjpeg.h"
#include "libavcodec/jpegtables.h"
#include "libavutil/intreadwrite.h"
#include "rtpenc.h"
void ff_rtp_send_jpeg(AVFormatContext *s1, const uint8_t *buf, int size)
{
RTPMuxContext *s = s1->priv_data;
const uint8_t *qtables[4] = { NULL };
int nb_qtables = 0;
uint8_t type = 2; /* initialized non-0/1 value for RTP/JPEG type check*/
uint8_t w, h;
uint8_t *p;
int off = 0; /* fragment offset of the current JPEG frame */
int len;
int i;
int default_huffman_tables = 0;
s->buf_ptr = s->buf;
s->timestamp = s->cur_timestamp;
/* convert video pixel dimensions from pixels to blocks */
w = AV_CEIL_RSHIFT(s1->streams[0]->codecpar->width, 3);
h = AV_CEIL_RSHIFT(s1->streams[0]->codecpar->height, 3);
/* preparse the header for getting some info */
for (i = 0; i < size; i++) {
if (buf[i] != 0xff)
continue;
if (buf[i + 1] == DQT) {
int tables, j;
if (buf[i + 4] & 0xF0)
av_log(s1, AV_LOG_WARNING,
"Only 8-bit precision is supported.\n");
/* a quantization table is 64 bytes long */
tables = AV_RB16(&buf[i + 2]) / 65;
if (i + 5 + tables * 65 > size) {
av_log(s1, AV_LOG_ERROR, "Too short JPEG header. Aborted!\n");
return;
}
if (nb_qtables + tables > 4) {
av_log(s1, AV_LOG_ERROR, "Invalid number of quantisation tables\n");
return;
}
for (j = 0; j < tables; j++)
qtables[nb_qtables + j] = buf + i + 5 + j * 65;
nb_qtables += tables;
} else if (buf[i + 1] == SOF0) {
if (buf[i + 14] != 17 || buf[i + 17] != 17) {
av_log(s1, AV_LOG_ERROR,
"Only 1x1 chroma blocks are supported. Aborted!\n");
return;
}
/*
* Find out the sampling factor in SOF0.
* In SOF0, hsample/vsample is inserted in form of (2<<4) | (type ? 2 : 1).
* First 4-bit is hsample while Last 4-bit is vsample.
*/
/* Luma channel sampling factor in 4:2:2 chroma subsampling are 2x1 */
if (buf[i + 11] == 33) {
type = 0;
/* Luma channel sampling factor in 4:2:0 chroma subsampling are 2x2 */
} else if (buf[i + 11] == 34) {
type = 1;
} else {
av_log(s1, AV_LOG_ERROR, "Unsupported pixel format\n");
return;
}
} else if (buf[i + 1] == DHT) {
int dht_size = AV_RB16(&buf[i + 2]);
default_huffman_tables |= 1 << 4;
i += 3;
dht_size -= 2;
if (i + dht_size >= size)
continue;
while (dht_size > 0)
switch (buf[i + 1]) {
case 0x00:
if ( dht_size >= 29
&& !memcmp(buf + i + 2, ff_mjpeg_bits_dc_luminance + 1, 16)
&& !memcmp(buf + i + 18, ff_mjpeg_val_dc, 12)) {
default_huffman_tables |= 1;
i += 29;
dht_size -= 29;
} else {
i += dht_size;
dht_size = 0;
}
break;
case 0x01:
if ( dht_size >= 29
&& !memcmp(buf + i + 2, ff_mjpeg_bits_dc_chrominance + 1, 16)
&& !memcmp(buf + i + 18, ff_mjpeg_val_dc, 12)) {
default_huffman_tables |= 1 << 1;
i += 29;
dht_size -= 29;
} else {
i += dht_size;
dht_size = 0;
}
break;
case 0x10:
if ( dht_size >= 179
&& !memcmp(buf + i + 2, ff_mjpeg_bits_ac_luminance + 1, 16)
&& !memcmp(buf + i + 18, ff_mjpeg_val_ac_luminance, 162)) {
default_huffman_tables |= 1 << 2;
i += 179;
dht_size -= 179;
} else {
i += dht_size;
dht_size = 0;
}
break;
case 0x11:
if ( dht_size >= 179
&& !memcmp(buf + i + 2, ff_mjpeg_bits_ac_chrominance + 1, 16)
&& !memcmp(buf + i + 18, ff_mjpeg_val_ac_chrominance, 162)) {
default_huffman_tables |= 1 << 3;
i += 179;
dht_size -= 179;
} else {
i += dht_size;
dht_size = 0;
}
break;
default:
i += dht_size;
dht_size = 0;
continue;
}
} else if (buf[i + 1] == SOS) {
/* SOS is last marker in the header */
i += AV_RB16(&buf[i + 2]) + 2;
if (i > size) {
av_log(s1, AV_LOG_ERROR,
"Insufficient data. Aborted!\n");
return;
}
break;
}
}
/* Check validity of RTP/JPEG type */
if (type != 0 && type != 1) {
av_log(s1, AV_LOG_ERROR,
"Invalid RTP/JPEG type\n");
return;
}
if (default_huffman_tables && default_huffman_tables != 31) {
av_log(s1, AV_LOG_ERROR,
"RFC 2435 requires standard Huffman tables for jpeg\n");
return;
}
if (nb_qtables && nb_qtables != 2)
av_log(s1, AV_LOG_WARNING,
"RFC 2435 suggests two quantization tables, %d provided\n",
nb_qtables);
/* skip JPEG header */
buf += i;
size -= i;
for (i = size - 2; i >= 0; i--) {
if (buf[i] == 0xff && buf[i + 1] == EOI) {
/* Remove the EOI marker */
size = i;
break;
}
}
p = s->buf_ptr;
while (size > 0) {
int hdr_size = 8;
if (off == 0 && nb_qtables)
hdr_size += 4 + 64 * nb_qtables;
/* payload max in one packet */
len = FFMIN(size, s->max_payload_size - hdr_size);
/* set main header */
bytestream_put_byte(&p, 0);
bytestream_put_be24(&p, off);
bytestream_put_byte(&p, type);
bytestream_put_byte(&p, 255);
bytestream_put_byte(&p, w);
bytestream_put_byte(&p, h);
if (off == 0 && nb_qtables) {
/* set quantization tables header */
bytestream_put_byte(&p, 0);
bytestream_put_byte(&p, 0);
bytestream_put_be16(&p, 64 * nb_qtables);
for (i = 0; i < nb_qtables; i++)
bytestream_put_buffer(&p, qtables[i], 64);
}
/* copy payload data */
memcpy(p, buf, len);
/* marker bit is last packet in frame */
ff_rtp_send_data(s1, s->buf, len + hdr_size, size == len);
buf += len;
size -= len;
off += len;
p = s->buf;
}
}
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