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/*
* RTP VP8 Depacketizer
* Copyright (c) 2010 Josh Allmann
*
* 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 RTP support for the VP8 payload
* @author Josh Allmann <joshua.allmann@gmail.com>
* @see http://www.webmproject.org/code/specs/rtp/
*/
#include "libavcodec/bytestream.h"
#include "rtpdec_formats.h"
struct PayloadContext {
AVIOContext *data;
uint32_t timestamp;
int is_keyframe;
};
static void prepare_packet(AVPacket *pkt, PayloadContext *vp8, int stream)
{
av_init_packet(pkt);
pkt->stream_index = stream;
pkt->flags = vp8->is_keyframe ? AV_PKT_FLAG_KEY : 0;
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_packet, end_packet, has_au, ret = AVERROR(EAGAIN);
if (!buf) {
// only called when vp8_handle_packet returns 1
if (!vp8->data) {
av_log(ctx, AV_LOG_ERROR, "Invalid VP8 data passed\n");
return AVERROR_INVALIDDATA;
}
prepare_packet(pkt, vp8, st->index);
*timestamp = vp8->timestamp;
return 0;
}
start_packet = *buf & 1;
end_packet = flags & RTP_FLAG_MARKER;
has_au = *buf & 2;
buf++;
len--;
if (start_packet) {
int res;
uint32_t ts = *timestamp;
if (vp8->data) {
// missing end marker; return old frame anyway. untested
prepare_packet(pkt, vp8, st->index);
*timestamp = vp8->timestamp; // reset timestamp from old frame
// if current frame fits into one rtp packet, need to hold
// that for the next av_get_packet call
ret = end_packet ? 1 : 0;
}
if ((res = avio_open_dyn_buf(&vp8->data)) < 0)
return res;
vp8->is_keyframe = *buf & 1;
vp8->timestamp = ts;
}
if (!vp8->data || vp8->timestamp != *timestamp && ret == AVERROR(EAGAIN)) {
av_log(ctx, AV_LOG_WARNING,
"Received no start marker; dropping frame\n");
return AVERROR(EAGAIN);
}
// cycle through VP8AU headers if needed
// not tested with actual VP8AUs
while (len) {
int au_len = len;
if (has_au && len > 2) {
au_len = AV_RB16(buf);
buf += 2;
len -= 2;
if (buf + au_len > buf + len) {
av_log(ctx, AV_LOG_ERROR, "Invalid VP8AU length\n");
return AVERROR_INVALIDDATA;
}
}
avio_write(vp8->data, buf, au_len);
buf += au_len;
len -= au_len;
}
if (ret != AVERROR(EAGAIN)) // did we miss a end marker?
return ret;
if (end_packet) {
prepare_packet(pkt, vp8, st->index);
return 0;
}
return AVERROR(EAGAIN);
}
static PayloadContext *vp8_new_context(void)
{
av_log(NULL, AV_LOG_ERROR, "RTP VP8 payload implementation is incompatible "
"with the latest spec drafts.\n");
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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