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ffmpeg/libavformat/rtpdec_xiph.c

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/*
* Xiph RTP Protocols
* Copyright (c) 2009 Colin McQuillian
* 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 Xiph / RTP Code
* @author Colin McQuillan <m.niloc@gmail.com>
* @author Josh Allmann <joshua.allmann@gmail.com>
*/
#include "libavutil/avstring.h"
#include "libavutil/base64.h"
#include "libavcodec/bytestream.h"
#include <assert.h>
#include "rtpdec.h"
#include "rtpdec_xiph.h"
/**
* RTP/Xiph specific private data.
*/
struct PayloadContext {
unsigned ident; ///< 24-bit stream configuration identifier
uint32_t timestamp;
ByteIOContext* fragment; ///< buffer for split payloads
};
static PayloadContext *xiph_new_context(void)
{
return av_mallocz(sizeof(PayloadContext));
}
static inline void free_fragment_if_needed(PayloadContext * data)
{
if (data->fragment) {
uint8_t* p;
url_close_dyn_buf(data->fragment, &p);
av_free(p);
data->fragment = NULL;
}
}
static void xiph_free_context(PayloadContext * data)
{
free_fragment_if_needed(data);
av_free(data);
}
static int xiph_handle_packet(AVFormatContext * ctx,
PayloadContext * data,
AVStream * st,
AVPacket * pkt,
uint32_t * timestamp,
const uint8_t * buf, int len, int flags)
{
int ident, fragmented, tdt, num_pkts, pkt_len;
if (len < 6) {
av_log(ctx, AV_LOG_ERROR, "Invalid %d byte packet\n", len);
return AVERROR_INVALIDDATA;
}
// read xiph rtp headers
ident = AV_RB24(buf);
fragmented = buf[3] >> 6;
tdt = (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 Xiph SDP configuration change detected\n");
return AVERROR_PATCHWELCOME;
}
if (tdt) {
av_log(ctx, AV_LOG_ERROR,
"Unimplemented RTP Xiph packet settings (%d,%d,%d)\n",
fragmented, tdt, num_pkts);
return AVERROR_PATCHWELCOME;
}
buf += 6; // move past header bits
len -= 6;
if (fragmented == 0) {
// whole frame(s)
int i, data_len, write_len;
buf -= 2;
len += 2;
// fast first pass to calculate total length
for (i = 0, data_len = 0; (i < num_pkts) && (len >= 2); i++) {
int off = data_len + (i << 1);
pkt_len = AV_RB16(buf + off);
data_len += pkt_len;
len -= pkt_len + 2;
}
if (len < 0 || i < num_pkts) {
av_log(ctx, AV_LOG_ERROR,
"Bad packet: %d bytes left at frame %d of %d\n",
len, i, num_pkts);
return AVERROR_INVALIDDATA;
}
if (av_new_packet(pkt, data_len)) {
av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
return AVERROR(ENOMEM);
}
pkt->stream_index = st->index;
// concatenate frames
for (i = 0, write_len = 0; write_len < data_len; i++) {
pkt_len = AV_RB16(buf);
buf += 2;
memcpy(pkt->data + write_len, buf, pkt_len);
write_len += pkt_len;
buf += pkt_len;
}
assert(write_len == data_len);
return 0;
} else if (fragmented == 1) {
// start of xiph data fragment
int res;
// end packet has been lost somewhere, so drop buffered data
free_fragment_if_needed(data);
if((res = url_open_dyn_buf(&data->fragment)) < 0)
return res;
put_buffer(data->fragment, buf, pkt_len);
data->timestamp = *timestamp;
} else {
assert(fragmented < 4);
if (data->timestamp != *timestamp) {
// skip if fragmented timestamp is incorrect;
// a start packet has been lost somewhere
free_fragment_if_needed(data);
av_log(ctx, AV_LOG_ERROR, "RTP timestamps don't match!\n");
return AVERROR_INVALIDDATA;
}
// copy data to fragment buffer
put_buffer(data->fragment, buf, pkt_len);
if (fragmented == 3) {
// end of xiph data packet
av_init_packet(pkt);
pkt->size = url_close_dyn_buf(data->fragment, &pkt->data);
if (pkt->size < 0) {
av_log(ctx, AV_LOG_ERROR,
"Error occurred when getting fragment buffer.");
return pkt->size;
}
pkt->stream_index = st->index;
pkt->destruct = av_destruct_packet;
data->fragment = NULL;
return 0;
}
}
return AVERROR(EAGAIN);
}
/**
* 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;
}
/**
* Based off parse_packed_headers in Vorbis RTP
*/
static unsigned int
parse_packed_headers(const uint8_t * packed_headers,
const uint8_t * packed_headers_end,
AVCodecContext * codec, PayloadContext * xiph_data)
{
unsigned num_packed, num_headers, length, length1, length2, extradata_alloc;
uint8_t *ptr;
if (packed_headers_end - packed_headers < 9) {
av_log(codec, AV_LOG_ERROR,
"Invalid %td byte packed header.",
packed_headers_end - packed_headers);
return AVERROR_INVALIDDATA;
}
num_packed = bytestream_get_be32(&packed_headers);
xiph_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,%td,%d)\n", length1,
length2, packed_headers_end - packed_headers, length);
return AVERROR_INVALIDDATA;
}
/* allocate extra space:
* -- length/255 +2 for xiphlacing
* -- one for the '2' marker
* -- FF_INPUT_BUFFER_PADDING_SIZE required */
extradata_alloc = length + length/255 + 3 + FF_INPUT_BUFFER_PADDING_SIZE;
ptr = codec->extradata = av_malloc(extradata_alloc);
if (!ptr) {
av_log(codec, AV_LOG_ERROR, "Out of memory\n");
return AVERROR(ENOMEM);
}
*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;
// clear out remaining parts of the buffer
memset(ptr, 0, extradata_alloc - codec->extradata_size);
return 0;
}
static int xiph_parse_fmtp_pair(AVStream* stream,
PayloadContext *xiph_data,
char *attr, char *value)
{
AVCodecContext *codec = stream->codec;
int result = 0;
if (!strcmp(attr, "sampling")) {
return AVERROR_PATCHWELCOME;
} else if (!strcmp(attr, "width")) {
/* This is an integer between 1 and 1048561
* and MUST be in multiples of 16. */
codec->width = atoi(value);
return 0;
} else if (!strcmp(attr, "height")) {
/* This is an integer between 1 and 1048561
* and MUST be in multiples of 16. */
codec->height = atoi(value);
return 0;
} else if (!strcmp(attr, "delivery-method")) {
/* Possible values are: inline, in_band, out_band/specific_name. */
return AVERROR_PATCHWELCOME;
} else if (!strcmp(attr, "configuration-uri")) {
/* NOTE: configuration-uri is supported only under 2 conditions:
*--after the delivery-method tag
* --with a delivery-method value of out_band */
return AVERROR_PATCHWELCOME;
} else if (!strcmp(attr, "configuration")) {
/* NOTE: configuration is supported only AFTER the delivery-method tag
* The configuration value is a base64 encoded packed header */
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,
xiph_data);
} else {
av_log(codec, AV_LOG_ERROR,
"Out of memory while decoding SDP configuration.\n");
result = AVERROR(ENOMEM);
}
} else {
av_log(codec, AV_LOG_ERROR, "Packet too large\n");
result = AVERROR_INVALIDDATA;
}
av_free(decoded_packet);
}
return result;
}
static int xiph_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,
xiph_parse_fmtp_pair);
}
return 0;
}
RTPDynamicProtocolHandler ff_theora_dynamic_handler = {
.enc_name = "theora",
.codec_type = AVMEDIA_TYPE_VIDEO,
.codec_id = CODEC_ID_THEORA,
.parse_sdp_a_line = xiph_parse_sdp_line,
.open = xiph_new_context,
.close = xiph_free_context,
.parse_packet = xiph_handle_packet
};
RTPDynamicProtocolHandler ff_vorbis_dynamic_handler = {
.enc_name = "vorbis",
.codec_type = AVMEDIA_TYPE_AUDIO,
.codec_id = CODEC_ID_VORBIS,
.parse_sdp_a_line = xiph_parse_sdp_line,
.open = xiph_new_context,
.close = xiph_free_context,
.parse_packet = xiph_handle_packet
};
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