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 Libav.
*
* Libav 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.
*
* Libav 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 Libav; 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 "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 = NULL;
int nb_qtables = 0;
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uint8_t type;
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uint8_t w, h;
uint8_t *p;
int off = 0; /* fragment offset of the current JPEG frame */
int len;
int i;
s->buf_ptr = s->buf;
s->timestamp = s->cur_timestamp;
/* convert video pixel dimensions from pixels to blocks */
lavf: replace AVStream.codec with AVStream.codecpar Currently, AVStream contains an embedded AVCodecContext instance, which is used by demuxers to export stream parameters to the caller and by muxers to receive stream parameters from the caller. It is also used internally as the codec context that is passed to parsers. In addition, it is also widely used by the callers as the decoding (when demuxer) or encoding (when muxing) context, though this has been officially discouraged since Libav 11. There are multiple important problems with this approach: - the fields in AVCodecContext are in general one of * stream parameters * codec options * codec state However, it's not clear which ones are which. It is consequently unclear which fields are a demuxer allowed to set or a muxer allowed to read. This leads to erratic behaviour depending on whether decoding or encoding is being performed or not (and whether it uses the AVStream embedded codec context). - various synchronization issues arising from the fact that the same context is used by several different APIs (muxers/demuxers, parsers, bitstream filters and encoders/decoders) simultaneously, with there being no clear rules for who can modify what and the different processes being typically delayed with respect to each other. - avformat_find_stream_info() making it necessary to support opening and closing a single codec context multiple times, thus complicating the semantics of freeing various allocated objects in the codec context. Those problems are resolved by replacing the AVStream embedded codec context with a newly added AVCodecParameters instance, which stores only the stream parameters exported by the demuxers or read by the muxers.
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w = (s1->streams[0]->codecpar->width + 7) >> 3;
h = (s1->streams[0]->codecpar->height + 7) >> 3;
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/* get the pixel format type or fail */
lavf: replace AVStream.codec with AVStream.codecpar Currently, AVStream contains an embedded AVCodecContext instance, which is used by demuxers to export stream parameters to the caller and by muxers to receive stream parameters from the caller. It is also used internally as the codec context that is passed to parsers. In addition, it is also widely used by the callers as the decoding (when demuxer) or encoding (when muxing) context, though this has been officially discouraged since Libav 11. There are multiple important problems with this approach: - the fields in AVCodecContext are in general one of * stream parameters * codec options * codec state However, it's not clear which ones are which. It is consequently unclear which fields are a demuxer allowed to set or a muxer allowed to read. This leads to erratic behaviour depending on whether decoding or encoding is being performed or not (and whether it uses the AVStream embedded codec context). - various synchronization issues arising from the fact that the same context is used by several different APIs (muxers/demuxers, parsers, bitstream filters and encoders/decoders) simultaneously, with there being no clear rules for who can modify what and the different processes being typically delayed with respect to each other. - avformat_find_stream_info() making it necessary to support opening and closing a single codec context multiple times, thus complicating the semantics of freeing various allocated objects in the codec context. Those problems are resolved by replacing the AVStream embedded codec context with a newly added AVCodecParameters instance, which stores only the stream parameters exported by the demuxers or read by the muxers.
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if (s1->streams[0]->codecpar->format == AV_PIX_FMT_YUVJ422P ||
(s1->streams[0]->codecpar->color_range == AVCOL_RANGE_JPEG &&
s1->streams[0]->codecpar->format == AV_PIX_FMT_YUV422P)) {
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type = 0;
lavf: replace AVStream.codec with AVStream.codecpar Currently, AVStream contains an embedded AVCodecContext instance, which is used by demuxers to export stream parameters to the caller and by muxers to receive stream parameters from the caller. It is also used internally as the codec context that is passed to parsers. In addition, it is also widely used by the callers as the decoding (when demuxer) or encoding (when muxing) context, though this has been officially discouraged since Libav 11. There are multiple important problems with this approach: - the fields in AVCodecContext are in general one of * stream parameters * codec options * codec state However, it's not clear which ones are which. It is consequently unclear which fields are a demuxer allowed to set or a muxer allowed to read. This leads to erratic behaviour depending on whether decoding or encoding is being performed or not (and whether it uses the AVStream embedded codec context). - various synchronization issues arising from the fact that the same context is used by several different APIs (muxers/demuxers, parsers, bitstream filters and encoders/decoders) simultaneously, with there being no clear rules for who can modify what and the different processes being typically delayed with respect to each other. - avformat_find_stream_info() making it necessary to support opening and closing a single codec context multiple times, thus complicating the semantics of freeing various allocated objects in the codec context. Those problems are resolved by replacing the AVStream embedded codec context with a newly added AVCodecParameters instance, which stores only the stream parameters exported by the demuxers or read by the muxers.
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} else if (s1->streams[0]->codecpar->format == AV_PIX_FMT_YUVJ420P ||
(s1->streams[0]->codecpar->color_range == AVCOL_RANGE_JPEG &&
s1->streams[0]->codecpar->format == AV_PIX_FMT_YUV420P)) {
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type = 1;
} else {
av_log(s1, AV_LOG_ERROR, "Unsupported pixel format\n");
return;
}
/* preparse the header for getting some info */
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for (i = 0; i < size; i++) {
if (buf[i] != 0xff)
continue;
if (buf[i + 1] == DQT) {
if (buf[i + 4])
av_log(s1, AV_LOG_WARNING,
"Only 8-bit precision is supported.\n");
/* a quantization table is 64 bytes long */
nb_qtables = AV_RB16(&buf[i + 2]) / 65;
if (i + 4 + nb_qtables * 65 > size) {
av_log(s1, AV_LOG_ERROR, "Too short JPEG header. Aborted!\n");
return;
}
qtables = &buf[i + 4];
} 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;
}
} else if (buf[i + 1] == SOS) {
/* SOS is last marker in the header */
i += AV_RB16(&buf[i + 2]) + 2;
break;
}
}
/* 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[65 * i + 1], 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;
}
}