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/*
* RTP packetizer for HEVC/H.265 payload format (draft version 6)
* Copyright (c) 2014 Thomas Volkert <thomas@homer-conferencing.com>
*
* 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 "libavutil/intreadwrite.h"
#include "avc.h"
#include "avformat.h"
#include "rtpenc.h"
#define RTP_HEVC_HEADERS_SIZE 3
static void flush_buffered(AVFormatContext *s1, int last)
{
RTPMuxContext *s = s1->priv_data;
if (s->buf_ptr != s->buf) {
// If only sending one single NAL unit, skip the aggregation framing
if (s->buffered_nals == 1)
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 *ctx, const uint8_t *buf, int len, int last_packet_of_frame)
{
RTPMuxContext *rtp_ctx = ctx->priv_data;
int rtp_payload_size = rtp_ctx->max_payload_size - RTP_HEVC_HEADERS_SIZE;
int nal_type = (buf[0] >> 1) & 0x3F;
/* send it as one single NAL unit? */
if (len <= rtp_ctx->max_payload_size) {
int buffered_size = rtp_ctx->buf_ptr - rtp_ctx->buf;
/* Flush buffered NAL units if the current unit doesn't fit */
if (buffered_size + 2 + len > rtp_ctx->max_payload_size) {
flush_buffered(ctx, 0);
buffered_size = 0;
}
/* If the NAL unit fits including the framing, write the unit
* to the buffer as an aggregate packet, otherwise flush and
* send as single NAL. */
if (buffered_size + 4 + len <= rtp_ctx->max_payload_size) {
if (buffered_size == 0) {
*rtp_ctx->buf_ptr++ = 48 << 1;
*rtp_ctx->buf_ptr++ = 1;
}
AV_WB16(rtp_ctx->buf_ptr, len);
rtp_ctx->buf_ptr += 2;
memcpy(rtp_ctx->buf_ptr, buf, len);
rtp_ctx->buf_ptr += len;
rtp_ctx->buffered_nals++;
} else {
flush_buffered(ctx, 0);
ff_rtp_send_data(ctx, buf, len, last_packet_of_frame);
}
} else {
flush_buffered(ctx, 0);
/*
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
*/
rtp_ctx->buf[0] = 49 << 1;
rtp_ctx->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
*/
rtp_ctx->buf[2] = nal_type;
/* set the S bit: mark as start fragment */
rtp_ctx->buf[2] |= 1 << 7;
/* pass the original NAL header */
buf += 2;
len -= 2;
while (len > rtp_payload_size) {
/* complete and send current RTP packet */
memcpy(&rtp_ctx->buf[RTP_HEVC_HEADERS_SIZE], buf, rtp_payload_size);
ff_rtp_send_data(ctx, rtp_ctx->buf, rtp_ctx->max_payload_size, 0);
buf += rtp_payload_size;
len -= rtp_payload_size;
/* reset the S bit */
rtp_ctx->buf[2] &= ~(1 << 7);
}
/* set the E bit: mark as last fragment */
rtp_ctx->buf[2] |= 1 << 6;
/* complete and send last RTP packet */
memcpy(&rtp_ctx->buf[RTP_HEVC_HEADERS_SIZE], buf, len);
ff_rtp_send_data(ctx, rtp_ctx->buf, len + 2, last_packet_of_frame);
}
}
void ff_rtp_send_hevc(AVFormatContext *ctx, const uint8_t *frame_buf, int frame_size)
{
const uint8_t *next_NAL_unit;
const uint8_t *buf_ptr, *buf_end = frame_buf + frame_size;
RTPMuxContext *rtp_ctx = ctx->priv_data;
/* use the default 90 KHz time stamp */
rtp_ctx->timestamp = rtp_ctx->cur_timestamp;
rtp_ctx->buf_ptr = rtp_ctx->buf;
if (rtp_ctx->nal_length_size)
buf_ptr = ff_avc_mp4_find_startcode(frame_buf, buf_end, rtp_ctx->nal_length_size) ? frame_buf : buf_end;
else
buf_ptr = ff_avc_find_startcode(frame_buf, buf_end);
/* find all NAL units and send them as separate packets */
while (buf_ptr < buf_end) {
if (rtp_ctx->nal_length_size) {
next_NAL_unit = ff_avc_mp4_find_startcode(buf_ptr, buf_end, rtp_ctx->nal_length_size);
if (!next_NAL_unit)
next_NAL_unit = buf_end;
buf_ptr += rtp_ctx->nal_length_size;
} else {
while (!*(buf_ptr++))
;
next_NAL_unit = ff_avc_find_startcode(buf_ptr, buf_end);
}
/* send the next NAL unit */
nal_send(ctx, buf_ptr, next_NAL_unit - buf_ptr, next_NAL_unit == buf_end);
/* jump to the next NAL unit */
buf_ptr = next_NAL_unit;
}
flush_buffered(ctx, 1);
}
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