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/*
* RTP parser for AC3 payload format (RFC 4184)
* Copyright (c) 2015 Gilles Chanteperdrix <gch@xenomai.org>
*
* 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 "avformat.h"
#include "rtpdec_formats.h"
#define RTP_AC3_PAYLOAD_HEADER_SIZE 2
struct PayloadContext {
unsigned nr_frames;
unsigned last_frame;
uint32_t timestamp;
AVIOContext *fragment;
};
static av_cold int ac3_init(AVFormatContext *s, int st_index,
PayloadContext *data)
{
if (st_index < 0)
return 0;
s->streams[st_index]->need_parsing = AVSTREAM_PARSE_FULL;
return 0;
}
static PayloadContext *ac3_new_context(void)
{
return av_mallocz(sizeof(PayloadContext));
}
static void free_fragment(PayloadContext *data)
{
if (data->fragment) {
uint8_t *p;
avio_close_dyn_buf(data->fragment, &p);
av_free(p);
data->fragment = NULL;
}
}
static void ac3_free_context(PayloadContext *data)
{
free_fragment(data);
av_free(data);
}
static int ac3_handle_packet(AVFormatContext *ctx, PayloadContext *data,
AVStream *st, AVPacket *pkt, uint32_t *timestamp,
const uint8_t *buf, int len, uint16_t seq,
int flags)
{
unsigned frame_type;
unsigned nr_frames;
int err;
if (len < RTP_AC3_PAYLOAD_HEADER_SIZE + 1) {
av_log(ctx, AV_LOG_ERROR, "Invalid %d bytes packet\n", len);
return AVERROR_INVALIDDATA;
}
frame_type = buf[0] & 0x3;
nr_frames = buf[1];
buf += RTP_AC3_PAYLOAD_HEADER_SIZE;
len -= RTP_AC3_PAYLOAD_HEADER_SIZE;
switch (frame_type) {
case 0: /* One or more complete frames */
if (!nr_frames) {
av_log(ctx, AV_LOG_ERROR, "Invalid AC3 packet data\n");
return AVERROR_INVALIDDATA;
}
if (av_new_packet(pkt, len)) {
av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
return AVERROR(ENOMEM);
}
pkt->stream_index = st->index;
memcpy(pkt->data, buf, len);
return 0;
case 1:
case 2: /* First fragment */
free_fragment(data);
data->last_frame = 1;
data->nr_frames = nr_frames;
err = avio_open_dyn_buf(&data->fragment);
if (err < 0)
return err;
avio_write(data->fragment, buf, len);
data->timestamp = *timestamp;
return AVERROR(EAGAIN);
case 3: /* Fragment other than first */
if (!data->fragment) {
av_log(ctx, AV_LOG_WARNING,
"Received packet without a start fragment; dropping.\n");
return AVERROR(EAGAIN);
}
if (nr_frames != data->nr_frames ||
data->timestamp != *timestamp) {
free_fragment(data);
av_log(ctx, AV_LOG_ERROR, "Invalid packet received\n");
return AVERROR_INVALIDDATA;
}
avio_write(data->fragment, buf, len);
data->last_frame++;
}
if (!(flags & RTP_FLAG_MARKER))
return AVERROR(EAGAIN);
if (data->last_frame != data->nr_frames) {
free_fragment(data);
av_log(ctx, AV_LOG_ERROR, "Missed %d packets\n",
data->nr_frames - data->last_frame);
return AVERROR_INVALIDDATA;
}
err = ff_rtp_finalize_packet(pkt, &data->fragment, st->index);
if (err < 0) {
av_log(ctx, AV_LOG_ERROR,
"Error occurred when getting fragment buffer.\n");
return err;
}
return 0;
}
RTPDynamicProtocolHandler ff_ac3_dynamic_handler = {
.enc_name = "ac3",
.codec_type = AVMEDIA_TYPE_AUDIO,
.codec_id = AV_CODEC_ID_AC3,
.init = ac3_init,
.alloc = ac3_new_context,
.free = ac3_free_context,
.parse_packet = ac3_handle_packet,
};
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