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/*
* RTP VP8 Depacketizer
* Copyright (c) 2010 Josh Allmann
* Copyright (c) 2012 Martin Storsjo
*
* 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
*/
/**
* @file
* @brief RTP support for the VP8 payload
* @author Josh Allmann <joshua.allmann@gmail.com>
* @see http://tools.ietf.org/html/draft-ietf-payload-vp8-05
*/
#include "libavcodec/bytestream.h"
#include "rtpdec_formats.h"
struct PayloadContext {
AVIOContext *data;
uint32_t timestamp;
};
static void prepare_packet(AVPacket *pkt, PayloadContext *vp8, int stream)
{
av_init_packet(pkt);
pkt->stream_index = stream;
pkt->size = avio_close_dyn_buf(vp8->data, &pkt->data);
pkt->destruct = av_destruct_packet;
vp8->data = NULL;
}
static int vp8_handle_packet(AVFormatContext *ctx,
PayloadContext *vp8,
AVStream *st,
AVPacket *pkt,
uint32_t *timestamp,
const uint8_t *buf,
int len, int flags)
{
int start_partition, end_packet;
int extended_bits, non_ref, part_id;
int pictureid_present = 0, tl0picidx_present = 0, tid_present = 0,
keyidx_present = 0;
int pictureid = -1, keyidx = -1;
if (len < 1)
return AVERROR_INVALIDDATA;
extended_bits = buf[0] & 0x80;
non_ref = buf[0] & 0x20;
start_partition = buf[0] & 0x10;
part_id = buf[0] & 0x0f;
end_packet = flags & RTP_FLAG_MARKER;
buf++;
len--;
if (extended_bits) {
if (len < 1)
return AVERROR_INVALIDDATA;
pictureid_present = buf[0] & 0x80;
tl0picidx_present = buf[0] & 0x40;
tid_present = buf[0] & 0x20;
keyidx_present = buf[0] & 0x10;
buf++;
len--;
}
if (pictureid_present) {
if (len < 1)
return AVERROR_INVALIDDATA;
if (buf[0] & 0x80) {
if (len < 2)
return AVERROR_INVALIDDATA;
pictureid = AV_RB16(buf) & 0x7fff;
buf += 2;
len -= 2;
} else {
pictureid = buf[0] & 0x7f;
buf++;
len--;
}
}
if (tl0picidx_present) {
// Ignoring temporal level zero index
buf++;
len--;
}
if (tid_present || keyidx_present) {
// Ignoring temporal layer index and layer sync bit
if (len < 1)
return AVERROR_INVALIDDATA;
if (keyidx_present)
keyidx = buf[0] & 0x1f;
buf++;
len--;
}
if (len < 1)
return AVERROR_INVALIDDATA;
if (start_partition && part_id == 0) {
int res;
if (vp8->data) {
uint8_t *tmp;
avio_close_dyn_buf(vp8->data, &tmp);
av_free(tmp);
vp8->data = NULL;
}
if ((res = avio_open_dyn_buf(&vp8->data)) < 0)
return res;
vp8->timestamp = *timestamp;
}
if (!vp8->data || vp8->timestamp != *timestamp) {
av_log(ctx, AV_LOG_WARNING,
"Received no start marker; dropping frame\n");
return AVERROR(EAGAIN);
}
avio_write(vp8->data, buf, len);
if (end_packet) {
prepare_packet(pkt, vp8, st->index);
return 0;
}
return AVERROR(EAGAIN);
}
static PayloadContext *vp8_new_context(void)
{
return av_mallocz(sizeof(PayloadContext));
}
static void vp8_free_context(PayloadContext *vp8)
{
if (vp8->data) {
uint8_t *tmp;
avio_close_dyn_buf(vp8->data, &tmp);
av_free(tmp);
}
av_free(vp8);
}
RTPDynamicProtocolHandler ff_vp8_dynamic_handler = {
.enc_name = "VP8",
.codec_type = AVMEDIA_TYPE_VIDEO,
.codec_id = AV_CODEC_ID_VP8,
.alloc = vp8_new_context,
.free = vp8_free_context,
.parse_packet = vp8_handle_packet,
};
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