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/**
* RTP Depacketization of MP4A-LATM, RFC 3016
* Copyright (c) 2010 Martin Storsjo
*
* 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 "rtpdec_formats.h"
#include "internal.h"
#include "libavutil/avstring.h"
#include "libavcodec/get_bits.h"
#include <strings.h>
struct PayloadContext {
AVIOContext *dyn_buf;
uint8_t *buf;
int pos, len;
uint32_t timestamp;
};
static PayloadContext *latm_new_context(void)
{
return av_mallocz(sizeof(PayloadContext));
}
static void latm_free_context(PayloadContext *data)
{
if (!data)
return;
if (data->dyn_buf) {
uint8_t *p;
avio_close_dyn_buf(data->dyn_buf, &p);
av_free(p);
}
av_free(data->buf);
av_free(data);
}
static int latm_parse_packet(AVFormatContext *ctx, PayloadContext *data,
AVStream *st, AVPacket *pkt, uint32_t *timestamp,
const uint8_t *buf, int len, int flags)
{
int ret, cur_len;
if (buf) {
if (!data->dyn_buf || data->timestamp != *timestamp) {
av_freep(&data->buf);
if (data->dyn_buf)
avio_close_dyn_buf(data->dyn_buf, &data->buf);
data->dyn_buf = NULL;
av_freep(&data->buf);
data->timestamp = *timestamp;
if ((ret = avio_open_dyn_buf(&data->dyn_buf)) < 0)
return ret;
}
avio_write(data->dyn_buf, buf, len);
if (!(flags & RTP_FLAG_MARKER))
return AVERROR(EAGAIN);
av_free(data->buf);
data->len = avio_close_dyn_buf(data->dyn_buf, &data->buf);
data->dyn_buf = NULL;
data->pos = 0;
}
if (!data->buf) {
av_log(ctx, AV_LOG_ERROR, "No data available yet\n");
return AVERROR(EIO);
}
cur_len = 0;
while (data->pos < data->len) {
uint8_t val = data->buf[data->pos++];
cur_len += val;
if (val != 0xff)
break;
}
if (data->pos + cur_len > data->len) {
av_log(ctx, AV_LOG_ERROR, "Malformed LATM packet\n");
return AVERROR(EIO);
}
if ((ret = av_new_packet(pkt, cur_len)) < 0)
return ret;
memcpy(pkt->data, data->buf + data->pos, cur_len);
data->pos += cur_len;
pkt->stream_index = st->index;
return data->pos < data->len;
}
static int parse_fmtp_config(AVStream *st, char *value)
{
int len = ff_hex_to_data(NULL, value), i, ret = 0;
GetBitContext gb;
uint8_t *config;
int audio_mux_version, same_time_framing, num_programs, num_layers;
/* Pad this buffer, too, to avoid out of bounds reads with get_bits below */
config = av_mallocz(len + FF_INPUT_BUFFER_PADDING_SIZE);
if (!config)
return AVERROR(ENOMEM);
ff_hex_to_data(config, value);
init_get_bits(&gb, config, len*8);
audio_mux_version = get_bits(&gb, 1);
same_time_framing = get_bits(&gb, 1);
skip_bits(&gb, 6); /* num_sub_frames */
num_programs = get_bits(&gb, 4);
num_layers = get_bits(&gb, 3);
if (audio_mux_version != 0 || same_time_framing != 1 || num_programs != 0 ||
num_layers != 0) {
av_log(NULL, AV_LOG_WARNING, "Unsupported LATM config (%d,%d,%d,%d)\n",
audio_mux_version, same_time_framing,
num_programs, num_layers);
ret = AVERROR_PATCHWELCOME;
goto end;
}
av_freep(&st->codec->extradata);
st->codec->extradata_size = (get_bits_left(&gb) + 7)/8;
st->codec->extradata = av_mallocz(st->codec->extradata_size +
FF_INPUT_BUFFER_PADDING_SIZE);
if (!st->codec->extradata) {
ret = AVERROR(ENOMEM);
goto end;
}
for (i = 0; i < st->codec->extradata_size; i++)
st->codec->extradata[i] = get_bits(&gb, 8);
end:
av_free(config);
return ret;
}
static int parse_fmtp(AVStream *stream, PayloadContext *data,
char *attr, char *value)
{
int res;
if (!strcmp(attr, "config")) {
res = parse_fmtp_config(stream, value);
if (res < 0)
return res;
} else if (!strcmp(attr, "cpresent")) {
int cpresent = atoi(value);
if (cpresent != 0)
av_log_missing_feature(NULL, "RTP MP4A-LATM with in-band "
"configuration", 1);
}
return 0;
}
static int latm_parse_sdp_line(AVFormatContext *s, int st_index,
PayloadContext *data, const char *line)
{
const char *p;
if (av_strstart(line, "fmtp:", &p))
return ff_parse_fmtp(s->streams[st_index], data, p, parse_fmtp);
return 0;
}
RTPDynamicProtocolHandler ff_mp4a_latm_dynamic_handler = {
.enc_name = "MP4A-LATM",
.codec_type = AVMEDIA_TYPE_AUDIO,
.codec_id = CODEC_ID_AAC,
.parse_sdp_a_line = latm_parse_sdp_line,
.alloc = latm_new_context,
.free = latm_free_context,
.parse_packet = latm_parse_packet
};
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