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/*
* RTP Vorbis Protocol (RFC5215)
* Copyright (c) 2009 Colin McQuillan
*
* 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 libavformat/rtp_vorbis.c
* @brief Vorbis / RTP Code (RFC 5215)
* @author Colin McQuillan <m.niloc@gmail.com>
*/
#include "libavutil/base64.h"
#include "libavutil/avstring.h"
#include "libavcodec/bytestream.h"
#include <assert.h>
#include "rtpdec.h"
#include "rtp_vorbis.h"
/**
* RTP/Vorbis specific private data.
*/
struct PayloadContext {
unsigned ident; ///< 24-bit stream configuration identifier
};
/**
* Length encoding described in RFC5215 section 3.1.1.
*/
static int get_base128(const uint8_t ** buf, const uint8_t * buf_end)
{
int n = 0;
for (; *buf < buf_end; ++*buf) {
n <<= 7;
n += **buf & 0x7f;
if (!(**buf & 0x80)) {
++*buf;
return n;
}
}
return 0;
}
/**
* Out-of-band headers, described in RFC 5251 section 3.2.1
*/
static unsigned int
parse_packed_headers(const uint8_t * packed_headers,
const uint8_t * packed_headers_end,
AVCodecContext * codec, PayloadContext * vorbis_data)
{
unsigned num_packed, num_headers, length, length1, length2;
uint8_t *ptr;
num_packed = bytestream_get_be32(&packed_headers);
vorbis_data->ident = bytestream_get_be24(&packed_headers);
length = bytestream_get_be16(&packed_headers);
num_headers = get_base128(&packed_headers, packed_headers_end);
length1 = get_base128(&packed_headers, packed_headers_end);
length2 = get_base128(&packed_headers, packed_headers_end);
if (num_packed != 1 || num_headers > 3) {
av_log(codec, AV_LOG_ERROR,
"Unimplemented number of headers: %d packed headers, %d headers\n",
num_packed, num_headers);
return AVERROR_PATCHWELCOME;
}
if (packed_headers_end - packed_headers != length ||
length1 > length || length2 > length - length1) {
av_log(codec, AV_LOG_ERROR,
"Bad packed header lengths (%d,%d,%d,%d)\n", length1,
length2, packed_headers_end - packed_headers, length);
return AVERROR_INVALIDDATA;
}
ptr = codec->extradata = av_mallocz(length + length / 255 + 64);
if (!ptr) {
av_log(codec, AV_LOG_ERROR, "Out of memory");
return AVERROR_NOMEM;
}
*ptr++ = 2;
ptr += av_xiphlacing(ptr, length1);
ptr += av_xiphlacing(ptr, length2);
memcpy(ptr, packed_headers, length);
ptr += length;
codec->extradata_size = ptr - codec->extradata;
return 0;
}
int
ff_vorbis_parse_fmtp_config(AVCodecContext * codec,
void *vorbis_data, char *attr, char *value)
{
int result = 0;
assert(codec->codec_id == CODEC_ID_VORBIS);
assert(vorbis_data);
// The configuration value is a base64 encoded packed header
if (!strcmp(attr, "configuration")) {
uint8_t *decoded_packet = NULL;
int packet_size;
size_t decoded_alloc = strlen(value) / 4 * 3 + 4;
if (decoded_alloc <= INT_MAX) {
decoded_packet = av_malloc(decoded_alloc);
if (decoded_packet) {
packet_size =
av_base64_decode(decoded_packet, value, decoded_alloc);
result = parse_packed_headers
(decoded_packet, decoded_packet + packet_size, codec,
vorbis_data);
} else {
av_log(codec, AV_LOG_ERROR,
"Out of memory while decoding SDP configuration.\n");
result = AVERROR_NOMEM;
}
} else {
av_log(codec, AV_LOG_ERROR, "Packet too large\n");
result = AVERROR_INVALIDDATA;
}
av_free(decoded_packet);
}
return result;
}
static PayloadContext *vorbis_new_context(void)
{
return av_mallocz(sizeof(PayloadContext));
}
static void vorbis_free_context(PayloadContext * data)
{
av_free(data);
}
/**
* Handle payload as described in RFC 5215 section 2.2
*/
static int
vorbis_handle_packet(AVFormatContext * ctx,
PayloadContext * data,
AVStream * st,
AVPacket * pkt,
uint32_t * timestamp,
const uint8_t * buf, int len, int flags)
{
int ident, fragmented, vdt, num_pkts, pkt_len;
if (len < 6) {
av_log(ctx, AV_LOG_ERROR, "Invalid %d byte packet\n", len);
return AVERROR_INVALIDDATA;
}
ident = AV_RB24(buf);
fragmented = buf[3] >> 6;
vdt = (buf[3] >> 4) & 3;
num_pkts = buf[3] & 7;
pkt_len = AV_RB16(buf + 4);
if (pkt_len > len - 6) {
av_log(ctx, AV_LOG_ERROR,
"Invalid packet length %d in %d byte packet\n", pkt_len,
len);
return AVERROR_INVALIDDATA;
}
if (ident != data->ident) {
av_log(ctx, AV_LOG_ERROR,
"Unimplemented Vorbis SDP configuration change detected\n");
return AVERROR_PATCHWELCOME;
}
if (fragmented != 0 || vdt != 0 || num_pkts != 1) {
av_log(ctx, AV_LOG_ERROR,
"Unimplemented RTP Vorbis packet settings (%d,%d,%d)\n",
fragmented, vdt, num_pkts);
return AVERROR_PATCHWELCOME;
}
if (av_new_packet(pkt, pkt_len)) {
av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
return AVERROR_NOMEM;
}
memcpy(pkt->data, buf + 6, pkt_len);
pkt->stream_index = st->index;
return 0;
}
RTPDynamicProtocolHandler ff_vorbis_dynamic_handler = {
.enc_name = "vorbis",
.codec_type = CODEC_TYPE_AUDIO,
.codec_id = CODEC_ID_VORBIS,
.parse_sdp_a_line = NULL,
.open = vorbis_new_context,
.close = vorbis_free_context,
.parse_packet = vorbis_handle_packet
};
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