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ffmpeg/libavformat/rdt.c

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/*
* Realmedia RTSP protocol (RDT) support.
* Copyright (c) 2007 Ronald S. Bultje
*
* 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 rdt.c
* @brief Realmedia RTSP protocol (RDT) support
* @author Ronald S. Bultje <rbultje@ronald.bitfreak.net>
*/
#include "avformat.h"
#include "libavutil/avstring.h"
#include "rtp_internal.h"
#include "rdt.h"
#include "libavutil/base64.h"
#include "libavutil/md5.h"
#include "rm.h"
#include "internal.h"
typedef struct rdt_data {
AVFormatContext *rmctx;
uint8_t *mlti_data;
unsigned int mlti_data_size;
uint32_t prev_sn, prev_ts;
char buffer[RTP_MAX_PACKET_LENGTH + FF_INPUT_BUFFER_PADDING_SIZE];
} rdt_data;
void
ff_rdt_calc_response_and_checksum(char response[41], char chksum[9],
const char *challenge)
{
int ch_len = strlen (challenge), i;
unsigned char zres[16],
buf[64] = { 0xa1, 0xe9, 0x14, 0x9d, 0x0e, 0x6b, 0x3b, 0x59 };
#define XOR_TABLE_SIZE 37
const unsigned char xor_table[XOR_TABLE_SIZE] = {
0x05, 0x18, 0x74, 0xd0, 0x0d, 0x09, 0x02, 0x53,
0xc0, 0x01, 0x05, 0x05, 0x67, 0x03, 0x19, 0x70,
0x08, 0x27, 0x66, 0x10, 0x10, 0x72, 0x08, 0x09,
0x63, 0x11, 0x03, 0x71, 0x08, 0x08, 0x70, 0x02,
0x10, 0x57, 0x05, 0x18, 0x54 };
/* some (length) checks */
if (ch_len == 40) /* what a hack... */
ch_len = 32;
else if (ch_len > 56)
ch_len = 56;
memcpy(buf + 8, challenge, ch_len);
/* xor challenge bytewise with xor_table */
for (i = 0; i < XOR_TABLE_SIZE; i++)
buf[8 + i] ^= xor_table[i];
av_md5_sum(zres, buf, 64);
ff_data_to_hex(response, zres, 16);
for (i=0;i<32;i++) response[i] = tolower(response[i]);
/* add tail */
strcpy (response + 32, "01d0a8e3");
/* calculate checksum */
for (i = 0; i < 8; i++)
chksum[i] = response[i * 4];
chksum[8] = 0;
}
static int
rdt_load_mdpr (rdt_data *rdt, AVStream *st, int rule_nr)
{
ByteIOContext *pb;
int size;
uint32_t tag;
/**
* Layout of the MLTI chunk:
* 4:MLTI
* 2:<number of streams>
* Then for each stream ([number_of_streams] times):
* 2:<mdpr index>
* 2:<number of mdpr chunks>
* Then for each mdpr chunk ([number_of_mdpr_chunks] times):
* 4:<size>
* [size]:<data>
* we skip MDPR chunks until we reach the one of the stream
* we're interested in, and forward that ([size]+[data]) to
* the RM demuxer to parse the stream-specific header data.
*/
if (!rdt->mlti_data)
return -1;
url_open_buf(&pb, rdt->mlti_data, rdt->mlti_data_size, URL_RDONLY);
tag = get_le32(pb);
if (tag == MKTAG('M', 'L', 'T', 'I')) {
int num, chunk_nr;
/* read index of MDPR chunk numbers */
num = get_be16(pb);
if (rule_nr < 0 || rule_nr >= num)
return -1;
url_fskip(pb, rule_nr * 2);
chunk_nr = get_be16(pb);
url_fskip(pb, (num - 1 - rule_nr) * 2);
/* read MDPR chunks */
num = get_be16(pb);
if (chunk_nr >= num)
return -1;
while (chunk_nr--)
url_fskip(pb, get_be32(pb));
size = get_be32(pb);
} else {
size = rdt->mlti_data_size;
url_fseek(pb, 0, SEEK_SET);
}
rdt->rmctx->pb = pb;
if (ff_rm_read_mdpr_codecdata(rdt->rmctx, st, size) < 0)
return -1;
url_close_buf(pb);
return 0;
}
/**
* Actual data handling.
*/
static int rdt_parse_header(struct RTPDemuxContext *s, const uint8_t *buf,
int len, int *seq, uint32_t *timestamp, int *flags)
{
rdt_data *rdt = s->dynamic_protocol_context;
int consumed = 0, sn;
if (buf[0] < 0x40 || buf[0] > 0x42) {
buf += 9;
len -= 9;
consumed += 9;
}
sn = (buf[0]>>1) & 0x1f;
*seq = AV_RB16(buf+1);
*timestamp = AV_RB32(buf+4);
if (!(buf[3] & 1) && (sn != rdt->prev_sn || *timestamp != rdt->prev_ts)) {
*flags |= PKT_FLAG_KEY;
rdt->prev_sn = sn;
rdt->prev_ts = *timestamp;
}
return consumed + 10;
}
/**< return 0 on packet, no more left, 1 on packet, 1 on partial packet... */
static int
rdt_parse_packet (RTPDemuxContext *s, AVPacket *pkt, uint32_t *timestamp,
const uint8_t *buf, int len, int flags)
{
rdt_data *rdt = s->dynamic_protocol_context;
int seq = 1, res;
ByteIOContext *pb = rdt->rmctx->pb;
RMContext *rm = rdt->rmctx->priv_data;
AVStream *st = s->st;
if (rm->audio_pkt_cnt == 0) {
int pos;
url_open_buf (&pb, buf, len, URL_RDONLY);
flags = (flags & PKT_FLAG_KEY) ? 2 : 0;
rdt->rmctx->pb = pb;
res = ff_rm_parse_packet (rdt->rmctx, st, len, pkt,
&seq, &flags, timestamp);
pos = url_ftell(pb);
url_close_buf (pb);
if (res < 0)
return res;
if (rm->audio_pkt_cnt > 0 &&
st->codec->codec_id == CODEC_ID_AAC) {
memcpy (rdt->buffer, buf + pos, len - pos);
url_open_buf (&pb, rdt->buffer, len - pos, URL_RDONLY);
rdt->rmctx->pb = pb;
}
} else {
ff_rm_retrieve_cache (rdt->rmctx, st, pkt);
if (rm->audio_pkt_cnt == 0 &&
st->codec->codec_id == CODEC_ID_AAC)
url_close_buf (pb);
}
pkt->stream_index = st->index;
pkt->pts = *timestamp;
return rm->audio_pkt_cnt > 0;
}
int
ff_rdt_parse_packet(RTPDemuxContext *s, AVPacket *pkt,
const uint8_t *buf, int len)
{
int seq, flags = 0;
uint32_t timestamp;
int rv= 0;
if (!buf) {
/* return the next packets, if any */
timestamp= 0; ///< Should not be used if buf is NULL, but should be set to the timestamp of the packet returned....
rv= rdt_parse_packet(s, pkt, &timestamp, NULL, 0, flags);
return rv;
}
if (len < 12)
return -1;
rv = rdt_parse_header(s, buf, len, &seq, &timestamp, &flags);
if (rv < 0)
return rv;
buf += rv;
len -= rv;
s->seq = seq;
rv = rdt_parse_packet(s, pkt, &timestamp, buf, len, flags);
return rv;
}
void
ff_rdt_subscribe_rule (RTPDemuxContext *s, char *cmd, int size,
int stream_nr, int rule_nr)
{
rdt_data *rdt = s->dynamic_protocol_context;
av_strlcatf(cmd, size, "stream=%d;rule=%d,stream=%d;rule=%d",
stream_nr, rule_nr, stream_nr, rule_nr + 1);
rdt_load_mdpr(rdt, s->st, 0);
}
static unsigned char *
rdt_parse_b64buf (unsigned int *target_len, const char *p)
{
unsigned char *target;
int len = strlen(p);
if (*p == '\"') {
p++;
len -= 2; /* skip embracing " at start/end */
}
*target_len = len * 3 / 4;
target = av_mallocz(*target_len + FF_INPUT_BUFFER_PADDING_SIZE);
av_base64_decode(target, p, *target_len);
return target;
}
static int
rdt_parse_sdp_line (AVStream *stream, void *d, const char *line)
{
rdt_data *rdt = d;
const char *p = line;
if (av_strstart(p, "OpaqueData:buffer;", &p)) {
rdt->mlti_data = rdt_parse_b64buf(&rdt->mlti_data_size, p);
} else if (av_strstart(p, "StartTime:integer;", &p))
stream->first_dts = atoi(p);
return 0;
}
static void *
rdt_new_extradata (void)
{
rdt_data *rdt = av_mallocz(sizeof(rdt_data));
av_open_input_stream(&rdt->rmctx, NULL, "", &rdt_demuxer, NULL);
rdt->prev_ts = -1;
rdt->prev_sn = -1;
return rdt;
}
static void
rdt_free_extradata (void *d)
{
rdt_data *rdt = d;
if (rdt->rmctx)
av_close_input_stream(rdt->rmctx);
av_freep(&rdt->mlti_data);
av_free(rdt);
}
#define RDT_HANDLER(n, s, t) \
static RTPDynamicProtocolHandler ff_rdt_ ## n ## _handler = { \
s, \
t, \
CODEC_ID_NONE, \
rdt_parse_sdp_line, \
rdt_new_extradata, \
rdt_free_extradata \
};
RDT_HANDLER(live_video, "x-pn-multirate-realvideo-live", CODEC_TYPE_VIDEO);
RDT_HANDLER(live_audio, "x-pn-multirate-realaudio-live", CODEC_TYPE_AUDIO);
RDT_HANDLER(video, "x-pn-realvideo", CODEC_TYPE_VIDEO);
RDT_HANDLER(audio, "x-pn-realaudio", CODEC_TYPE_AUDIO);
void av_register_rdt_dynamic_payload_handlers(void)
{
ff_register_dynamic_payload_handler(&ff_rdt_video_handler);
ff_register_dynamic_payload_handler(&ff_rdt_audio_handler);
ff_register_dynamic_payload_handler(&ff_rdt_live_video_handler);
ff_register_dynamic_payload_handler(&ff_rdt_live_audio_handler);
}
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