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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/attributes.h"
#include "libavutil/avassert.h"
#include "libavutil/avstring.h"
#include "libavutil/base64.h"
#include "libavcodec/bytestream.h"
#include "rtpdec.h"
#include "rtpdec_formats.h"
/**
* RTP/Xiph specific private data.
*/
struct PayloadContext {
unsigned ident; ///< 24-bit stream configuration identifier
uint32_t timestamp;
AVIOContext* fragment; ///< buffer for split payloads
uint8_t *split_buf;
int split_pos, split_buf_len, split_buf_size;
int split_pkts;
};
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;
avio_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->split_buf);
av_free(data);
}
static av_cold int xiph_vorbis_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 int xiph_handle_packet(AVFormatContext *ctx, PayloadContext *data,
AVStream *st, AVPacket *pkt, uint32_t *timestamp,
const uint8_t *buf, int len, uint16_t seq,
int flags)
{
int ident, fragmented, tdt, num_pkts, pkt_len;
if (!buf) {
if (!data->split_buf || data->split_pos + 2 > data->split_buf_len ||
data->split_pkts <= 0) {
av_log(ctx, AV_LOG_ERROR, "No more data to return\n");
return AVERROR_INVALIDDATA;
}
pkt_len = AV_RB16(data->split_buf + data->split_pos);
data->split_pos += 2;
if (data->split_pos + pkt_len > data->split_buf_len) {
av_log(ctx, AV_LOG_ERROR, "Not enough data to return\n");
return AVERROR_INVALIDDATA;
}
if (av_new_packet(pkt, pkt_len)) {
av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
return AVERROR(ENOMEM);
}
pkt->stream_index = st->index;
memcpy(pkt->data, data->split_buf + data->split_pos, pkt_len);
data->split_pos += pkt_len;
data->split_pkts--;
return data->split_pkts > 0;
}
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] & 0xf;
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) {
if (av_new_packet(pkt, pkt_len)) {
av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
return AVERROR(ENOMEM);
}
pkt->stream_index = st->index;
memcpy(pkt->data, buf, pkt_len);
buf += pkt_len;
len -= pkt_len;
num_pkts--;
if (num_pkts > 0) {
if (len > data->split_buf_size || !data->split_buf) {
av_freep(&data->split_buf);
data->split_buf_size = 2 * len;
data->split_buf = av_malloc(data->split_buf_size);
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, len);
data->split_buf_len = len;
data->split_pos = 0;
data->split_pkts = num_pkts;
return 1;
}
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 = avio_open_dyn_buf(&data->fragment)) < 0)
return res;
avio_write(data->fragment, buf, pkt_len);
data->timestamp = *timestamp;
} else {
av_assert1(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;
}
if (!data->fragment) {
av_log(ctx, AV_LOG_WARNING,
"Received packet without a start fragment; dropping.\n");
return AVERROR(EAGAIN);
}
// copy data to fragment buffer
avio_write(data->fragment, buf, pkt_len);
if (fragmented == 3) {
// end of xiph data packet
int ret = ff_rtp_finalize_packet(pkt, &data->fragment, st->index);
if (ret < 0) {
av_log(ctx, AV_LOG_ERROR,
"Error occurred when getting fragment buffer.");
return ret;
}
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 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")) {
if (!strcmp(value, "YCbCr-4:2:0")) {
codec->pix_fmt = AV_PIX_FMT_YUV420P;
} else if (!strcmp(value, "YCbCr-4:4:2")) {
codec->pix_fmt = AV_PIX_FMT_YUV422P;
} else if (!strcmp(value, "YCbCr-4:4:4")) {
codec->pix_fmt = AV_PIX_FMT_YUV444P;
} else {
av_log(codec, AV_LOG_ERROR,
"Unsupported pixel format %s\n", attr);
return AVERROR_INVALIDDATA;
}
} 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 (st_index < 0)
return 0;
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 = AV_CODEC_ID_THEORA,
.parse_sdp_a_line = xiph_parse_sdp_line,
.alloc = xiph_new_context,
.free = xiph_free_context,
.parse_packet = xiph_handle_packet
};
RTPDynamicProtocolHandler ff_vorbis_dynamic_handler = {
.enc_name = "vorbis",
.codec_type = AVMEDIA_TYPE_AUDIO,
.codec_id = AV_CODEC_ID_VORBIS,
.init = xiph_vorbis_init,
.parse_sdp_a_line = xiph_parse_sdp_line,
.alloc = xiph_new_context,
.free = xiph_free_context,
.parse_packet = xiph_handle_packet
};
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