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/*
* RTP parser for loss tolerant payload format for MP3 audio (RFC 5219)
* Copyright (c) 2015 Gilles Chanteperdrix <gch@xenomai.org>
*
* 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
*/
#include "libavutil/attributes.h"
#include "libavutil/intreadwrite.h"
#include "rtpdec_formats.h"
struct PayloadContext {
unsigned adu_size;
unsigned cur_size;
uint32_t timestamp;
uint8_t *split_buf;
int split_pos, split_buf_size, split_pkts;
AVIOContext *fragment;
};
static av_cold int mpa_robust_init(AVFormatContext *ctx, int st_index,
PayloadContext *data)
{
if (st_index < 0)
return 0;
ctx->streams[st_index]->need_parsing = AVSTREAM_PARSE_HEADERS;
return 0;
}
static PayloadContext *mpa_robust_new_context(void)
{
return av_mallocz(sizeof(PayloadContext));
}
static inline 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 mpa_robust_free_context(PayloadContext *data)
{
free_fragment(data);
av_free(data->split_buf);
av_free(data);
}
static int mpa_robust_parse_rtp_header(AVFormatContext *ctx,
const uint8_t *buf, int len,
unsigned *adu_size, unsigned *cont)
{
unsigned header_size;
if (len < 2) {
av_log(ctx, AV_LOG_ERROR, "Invalid %d bytes packet\n", len);
return AVERROR_INVALIDDATA;
}
*cont = !!(buf[0] & 0x80);
if (!(buf[0] & 0x40)) {
header_size = 1;
*adu_size = buf[0] & ~0xc0;
} else {
header_size = 2;
*adu_size = AV_RB16(buf) & ~0xc000;
}
return header_size;
}
static int mpa_robust_parse_packet(AVFormatContext *ctx, PayloadContext *data,
AVStream *st, AVPacket *pkt,
uint32_t *timestamp, const uint8_t *buf,
int len, uint16_t seq, int flags)
{
unsigned adu_size, continuation;
int err, header_size;
if (!buf) {
buf = &data->split_buf[data->split_pos];
len = data->split_buf_size - data->split_pos;
header_size = mpa_robust_parse_rtp_header(ctx, buf, len, &adu_size,
&continuation);
if (header_size < 0) {
av_freep(&data->split_buf);
return header_size;
}
buf += header_size;
len -= header_size;
if (continuation || adu_size > len) {
av_freep(&data->split_buf);
av_log(ctx, AV_LOG_ERROR, "Invalid frame\n");
return AVERROR_INVALIDDATA;
}
if (av_new_packet(pkt, adu_size)) {
av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
return AVERROR(ENOMEM);
}
pkt->stream_index = st->index;
memcpy(pkt->data, buf, adu_size);
data->split_pos += adu_size;
if (data->split_pos == data->split_buf_size) {
av_freep(&data->split_buf);
return 0;
}
return 1;
}
header_size = mpa_robust_parse_rtp_header(ctx, buf, len, &adu_size,
&continuation);
if (header_size < 0)
return header_size;
buf += header_size;
len -= header_size;
if (!continuation && adu_size <= len) {
/* One or more complete frames */
if (av_new_packet(pkt, adu_size)) {
av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
return AVERROR(ENOMEM);
}
pkt->stream_index = st->index;
memcpy(pkt->data, buf, adu_size);
buf += adu_size;
len -= adu_size;
if (len) {
data->split_buf_size = len;
data->split_buf = av_malloc(data->split_buf_size);
data->split_pos = 0;
if (!data->split_buf) {
av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
av_free_packet(pkt);
return AVERROR(ENOMEM);
}
memcpy(data->split_buf, buf, data->split_buf_size);
return 1;
}
return 0;
} else if (!continuation) { /* && adu_size > len */
/* First fragment */
free_fragment(data);
data->adu_size = adu_size;
data->cur_size = len;
data->timestamp = *timestamp;
err = avio_open_dyn_buf(&data->fragment);
if (err < 0)
return err;
avio_write(data->fragment, buf, len);
return AVERROR(EAGAIN);
}
/* else continuation == 1 */
/* 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 (adu_size = data->adu_size ||
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->cur_size += len;
if (data->cur_size < data->adu_size)
return AVERROR(EAGAIN);
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_mpeg_audio_robust_dynamic_handler = {
.codec_type = AVMEDIA_TYPE_AUDIO,
.codec_id = AV_CODEC_ID_MP3ADU,
.init = mpa_robust_init,
.alloc = mpa_robust_new_context,
.free = mpa_robust_free_context,
.parse_packet = mpa_robust_parse_packet,
.enc_name = "mpa-robust",
};
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