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/*
* RTP packetization for H.264 (RFC3984)
* RTP packetizer for HEVC/H.265 payload format (draft version 6)
* Copyright (c) 2008 Luca Abeni
* Copyright (c) 2014 Thomas Volkert <thomas@homer-conferencing.com>
*
* 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
*/
/**
* @file
* @brief H.264/HEVC packetization
* @author Luca Abeni <lucabe72@email.it>
*/
#include "libavutil/intreadwrite.h"
#include "avformat.h"
#include "avc.h"
#include "rtpenc.h"
static void flush_buffered(AVFormatContext *s1, int last)
{
RTPMuxContext *s = s1->priv_data;
if (s->buf_ptr != s->buf) {
// If we're only sending one single NAL unit, send it as such, skip
// the STAP-A/AP framing
if (s->buffered_nals == 1) {
enum AVCodecID codec = s1->streams[0]->codecpar->codec_id;
if (codec == AV_CODEC_ID_H264)
ff_rtp_send_data(s1, s->buf + 3, s->buf_ptr - s->buf - 3, last);
else
ff_rtp_send_data(s1, s->buf + 4, s->buf_ptr - s->buf - 4, last);
} else
ff_rtp_send_data(s1, s->buf, s->buf_ptr - s->buf, last);
}
s->buf_ptr = s->buf;
s->buffered_nals = 0;
}
static void nal_send(AVFormatContext *s1, const uint8_t *buf, int size, int last)
{
RTPMuxContext *s = s1->priv_data;
enum AVCodecID codec = s1->streams[0]->codecpar->codec_id;
av_log(s1, AV_LOG_DEBUG, "Sending NAL %x of len %d M=%d\n", buf[0] & 0x1F, size, last);
if (size <= s->max_payload_size) {
int buffered_size = s->buf_ptr - s->buf;
int header_size;
int skip_aggregate = 0;
if (codec == AV_CODEC_ID_H264) {
header_size = 1;
skip_aggregate = s->flags & FF_RTP_FLAG_H264_MODE0;
} else {
header_size = 2;
}
// Flush buffered NAL units if the current unit doesn't fit
if (buffered_size + 2 + size > s->max_payload_size) {
flush_buffered(s1, 0);
buffered_size = 0;
}
// If we aren't using mode 0, and the NAL unit fits including the
// framing (2 bytes length, plus 1/2 bytes for the STAP-A/AP marker),
// write the unit to the buffer as a STAP-A/AP packet, otherwise flush
// and send as single NAL.
if (buffered_size + 2 + header_size + size <= s->max_payload_size &&
!skip_aggregate) {
if (buffered_size == 0) {
if (codec == AV_CODEC_ID_H264) {
*s->buf_ptr++ = 24;
} else {
*s->buf_ptr++ = 48 << 1;
*s->buf_ptr++ = 1;
}
}
AV_WB16(s->buf_ptr, size);
s->buf_ptr += 2;
memcpy(s->buf_ptr, buf, size);
s->buf_ptr += size;
s->buffered_nals++;
} else {
flush_buffered(s1, 0);
ff_rtp_send_data(s1, buf, size, last);
}
} else {
int flag_byte, header_size;
flush_buffered(s1, 0);
if (codec == AV_CODEC_ID_H264 && (s->flags & FF_RTP_FLAG_H264_MODE0)) {
av_log(s1, AV_LOG_ERROR,
"NAL size %d > %d, try -slice-max-size %d\n", size,
s->max_payload_size, s->max_payload_size);
return;
}
av_log(s1, AV_LOG_DEBUG, "NAL size %d > %d\n", size, s->max_payload_size);
if (codec == AV_CODEC_ID_H264) {
uint8_t type = buf[0] & 0x1F;
uint8_t nri = buf[0] & 0x60;
s->buf[0] = 28; /* FU Indicator; Type = 28 ---> FU-A */
s->buf[0] |= nri;
s->buf[1] = type;
s->buf[1] |= 1 << 7;
buf += 1;
size -= 1;
flag_byte = 1;
header_size = 2;
} else {
uint8_t nal_type = (buf[0] >> 1) & 0x3F;
/*
* create the HEVC payload header and transmit the buffer as fragmentation units (FU)
*
* 0 1
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* |F| Type | LayerId | TID |
* +-------------+-----------------+
*
* F = 0
* Type = 49 (fragmentation unit (FU))
* LayerId = 0
* TID = 1
*/
s->buf[0] = 49 << 1;
s->buf[1] = 1;
/*
* create the FU header
*
* 0 1 2 3 4 5 6 7
* +-+-+-+-+-+-+-+-+
* |S|E| FuType |
* +---------------+
*
* S = variable
* E = variable
* FuType = NAL unit type
*/
s->buf[2] = nal_type;
/* set the S bit: mark as start fragment */
s->buf[2] |= 1 << 7;
/* pass the original NAL header */
buf += 2;
size -= 2;
flag_byte = 2;
header_size = 3;
}
while (size + header_size > s->max_payload_size) {
memcpy(&s->buf[header_size], buf, s->max_payload_size - header_size);
ff_rtp_send_data(s1, s->buf, s->max_payload_size, 0);
buf += s->max_payload_size - header_size;
size -= s->max_payload_size - header_size;
s->buf[flag_byte] &= ~(1 << 7);
}
s->buf[flag_byte] |= 1 << 6;
memcpy(&s->buf[header_size], buf, size);
ff_rtp_send_data(s1, s->buf, size + header_size, last);
}
}
void ff_rtp_send_h264_hevc(AVFormatContext *s1, const uint8_t *buf1, int size)
{
const uint8_t *r, *end = buf1 + size;
RTPMuxContext *s = s1->priv_data;
s->timestamp = s->cur_timestamp;
s->buf_ptr = s->buf;
if (s->nal_length_size)
r = ff_avc_mp4_find_startcode(buf1, end, s->nal_length_size) ? buf1 : end;
else
r = ff_avc_find_startcode(buf1, end);
while (r < end) {
const uint8_t *r1;
if (s->nal_length_size) {
r1 = ff_avc_mp4_find_startcode(r, end, s->nal_length_size);
if (!r1)
r1 = end;
r += s->nal_length_size;
} else {
while (!*(r++));
r1 = ff_avc_find_startcode(r, end);
}
nal_send(s1, r, r1 - r, r1 == end);
r = r1;
}
flush_buffered(s1, 1);
}
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