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FFmpeg/libavformat/rdt.c
Ronald S. Bultje 84f0aba18d handler can be NULL if we did not support this dynamic format (codec). 
Fixes issue 1658 (the crasher), although the format itself is obviously
still unsupported.

Originally committed as revision 21078 to svn://svn.ffmpeg.org/ffmpeg/trunk
2010-01-07 23:05:19 +00:00

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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 libavformat/rdt.c
* @brief Realmedia RTSP protocol (RDT) support
* @author Ronald S. Bultje <rbultje@ronald.bitfreak.net>
*/
#include "avformat.h"
#include "libavutil/avstring.h"
#include "rtpdec.h"
#include "rdt.h"
#include "libavutil/base64.h"
#include "libavutil/md5.h"
#include "rm.h"
#include "internal.h"
#include "libavcodec/get_bits.h"
struct RDTDemuxContext {
AVFormatContext *ic; /**< the containing (RTSP) demux context */
/** Each RDT stream-set (represented by one RTSPStream) can contain
* multiple streams (of the same content, but with possibly different
* codecs/bitrates). Each such stream is represented by one AVStream
* in the AVFormatContext, and this variable points to the offset in
* that array such that the first is the first stream of this set. */
AVStream **streams;
int n_streams; /**< streams with identifical content in this set */
void *dynamic_protocol_context;
DynamicPayloadPacketHandlerProc parse_packet;
uint32_t prev_timestamp;
int prev_set_id, prev_stream_id;
};
RDTDemuxContext *
ff_rdt_parse_open(AVFormatContext *ic, int first_stream_of_set_idx,
void *priv_data, RTPDynamicProtocolHandler *handler)
{
RDTDemuxContext *s = av_mallocz(sizeof(RDTDemuxContext));
if (!s)
return NULL;
s->ic = ic;
s->streams = &ic->streams[first_stream_of_set_idx];
do {
s->n_streams++;
} while (first_stream_of_set_idx + s->n_streams < ic->nb_streams &&
s->streams[s->n_streams]->priv_data == s->streams[0]->priv_data);
s->prev_set_id = -1;
s->prev_stream_id = -1;
s->prev_timestamp = -1;
s->parse_packet = handler ? handler->parse_packet : NULL;
s->dynamic_protocol_context = priv_data;
return s;
}
void
ff_rdt_parse_close(RDTDemuxContext *s)
{
int i;
for (i = 1; i < s->n_streams; i++)
s->streams[i]->priv_data = NULL;
av_free(s);
}
struct PayloadContext {
AVFormatContext *rmctx;
RMStream *rmst[MAX_STREAMS];
uint8_t *mlti_data;
unsigned int mlti_data_size;
char buffer[RTP_MAX_PACKET_LENGTH + FF_INPUT_BUFFER_PADDING_SIZE];
int audio_pkt_cnt; /**< remaining audio packets in rmdec */
};
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 (PayloadContext *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;
init_put_byte(&pb, rdt->mlti_data, rdt->mlti_data_size, 0,
NULL, NULL, NULL, NULL);
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);
}
if (ff_rm_read_mdpr_codecdata(rdt->rmctx, &pb, st, rdt->rmst[st->index], size) < 0)
return -1;
return 0;
}
/**
* Actual data handling.
*/
int
ff_rdt_parse_header(const uint8_t *buf, int len,
int *pset_id, int *pseq_no, int *pstream_id,
int *pis_keyframe, uint32_t *ptimestamp)
{
GetBitContext gb;
int consumed = 0, set_id, seq_no, stream_id, is_keyframe,
len_included, need_reliable;
uint32_t timestamp;
/* skip status packets */
while (len >= 5 && buf[1] == 0xFF /* status packet */) {
int pkt_len;
if (!(buf[0] & 0x80))
return -1; /* not followed by a data packet */
pkt_len = AV_RB16(buf+3);
buf += pkt_len;
len -= pkt_len;
consumed += pkt_len;
}
if (len < 16)
return -1;
/**
* Layout of the header (in bits):
* 1: len_included
* Flag indicating whether this header includes a length field;
* this can be used to concatenate multiple RDT packets in a
* single UDP/TCP data frame and is used to precede RDT data
* by stream status packets
* 1: need_reliable
* Flag indicating whether this header includes a "reliable
* sequence number"; these are apparently sequence numbers of
* data packets alone. For data packets, this flag is always
* set, according to the Real documentation [1]
* 5: set_id
* ID of a set of streams of identical content, possibly with
* different codecs or bitrates
* 1: is_reliable
* Flag set for certain streams deemed less tolerable for packet
* loss
* 16: seq_no
* Packet sequence number; if >=0xFF00, this is a non-data packet
* containing stream status info, the second byte indicates the
* type of status packet (see wireshark docs / source code [2])
* if (len_included) {
* 16: packet_len
* } else {
* packet_len = remainder of UDP/TCP frame
* }
* 1: is_back_to_back
* Back-to-Back flag; used for timing, set for one in every 10
* packets, according to the Real documentation [1]
* 1: is_slow_data
* Slow-data flag; currently unused, according to Real docs [1]
* 5: stream_id
* ID of the stream within this particular set of streams
* 1: is_no_keyframe
* Non-keyframe flag (unset if packet belongs to a keyframe)
* 32: timestamp (PTS)
* if (set_id == 0x1F) {
* 16: set_id (extended set-of-streams ID; see set_id)
* }
* if (need_reliable) {
* 16: reliable_seq_no
* Reliable sequence number (see need_reliable)
* }
* if (stream_id == 0x3F) {
* 16: stream_id (extended stream ID; see stream_id)
* }
* [1] https://protocol.helixcommunity.org/files/2005/devdocs/RDT_Feature_Level_20.txt
* [2] http://www.wireshark.org/docs/dfref/r/rdt.html and
* http://anonsvn.wireshark.org/viewvc/trunk/epan/dissectors/packet-rdt.c
*/
init_get_bits(&gb, buf, len << 3);
len_included = get_bits1(&gb);
need_reliable = get_bits1(&gb);
set_id = get_bits(&gb, 5);
skip_bits(&gb, 1);
seq_no = get_bits(&gb, 16);
if (len_included)
skip_bits(&gb, 16);
skip_bits(&gb, 2);
stream_id = get_bits(&gb, 5);
is_keyframe = !get_bits1(&gb);
timestamp = get_bits_long(&gb, 32);
if (set_id == 0x1f)
set_id = get_bits(&gb, 16);
if (need_reliable)
skip_bits(&gb, 16);
if (stream_id == 0x1f)
stream_id = get_bits(&gb, 16);
if (pset_id) *pset_id = set_id;
if (pseq_no) *pseq_no = seq_no;
if (pstream_id) *pstream_id = stream_id;
if (pis_keyframe) *pis_keyframe = is_keyframe;
if (ptimestamp) *ptimestamp = timestamp;
return consumed + (get_bits_count(&gb) >> 3);
}
/**< return 0 on packet, no more left, 1 on packet, 1 on partial packet... */
static int
rdt_parse_packet (AVFormatContext *ctx, PayloadContext *rdt, AVStream *st,
AVPacket *pkt, uint32_t *timestamp,
const uint8_t *buf, int len, int flags)
{
int seq = 1, res;
ByteIOContext pb;
if (rdt->audio_pkt_cnt == 0) {
int pos;
init_put_byte(&pb, buf, len, 0, NULL, NULL, NULL, NULL);
flags = (flags & RTP_FLAG_KEY) ? 2 : 0;
res = ff_rm_parse_packet (rdt->rmctx, &pb, st, rdt->rmst[st->index], len, pkt,
&seq, flags, *timestamp);
pos = url_ftell(&pb);
if (res < 0)
return res;
if (res > 0) {
if (st->codec->codec_id == CODEC_ID_AAC) {
memcpy (rdt->buffer, buf + pos, len - pos);
rdt->rmctx->pb = av_alloc_put_byte (rdt->buffer, len - pos, 0,
NULL, NULL, NULL, NULL);
}
goto get_cache;
}
} else {
get_cache:
rdt->audio_pkt_cnt =
ff_rm_retrieve_cache (rdt->rmctx, rdt->rmctx->pb,
st, rdt->rmst[st->index], pkt);
if (rdt->audio_pkt_cnt == 0 &&
st->codec->codec_id == CODEC_ID_AAC)
av_freep(&rdt->rmctx->pb);
}
pkt->stream_index = st->index;
pkt->pts = *timestamp;
return rdt->audio_pkt_cnt > 0;
}
int
ff_rdt_parse_packet(RDTDemuxContext *s, AVPacket *pkt,
const uint8_t *buf, int len)
{
int seq_no, flags = 0, stream_id, set_id, is_keyframe;
uint32_t timestamp;
int rv= 0;
if (!s->parse_packet)
return -1;
if (!buf && s->prev_stream_id != -1) {
/* 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= s->parse_packet(s->ic, s->dynamic_protocol_context,
s->streams[s->prev_stream_id],
pkt, &timestamp, NULL, 0, flags);
return rv;
}
if (len < 12)
return -1;
rv = ff_rdt_parse_header(buf, len, &set_id, &seq_no, &stream_id, &is_keyframe, &timestamp);
if (rv < 0)
return rv;
if (is_keyframe &&
(set_id != s->prev_set_id || timestamp != s->prev_timestamp ||
stream_id != s->prev_stream_id)) {
flags |= RTP_FLAG_KEY;
s->prev_set_id = set_id;
s->prev_timestamp = timestamp;
}
s->prev_stream_id = stream_id;
buf += rv;
len -= rv;
if (s->prev_stream_id >= s->n_streams) {
s->prev_stream_id = -1;
return -1;
}
rv = s->parse_packet(s->ic, s->dynamic_protocol_context,
s->streams[s->prev_stream_id],
pkt, &timestamp, buf, len, flags);
return rv;
}
void
ff_rdt_subscribe_rule (char *cmd, int size,
int stream_nr, int rule_nr)
{
av_strlcatf(cmd, size, "stream=%d;rule=%d,stream=%d;rule=%d",
stream_nr, rule_nr * 2, stream_nr, rule_nr * 2 + 1);
}
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 (AVFormatContext *s, int st_index,
PayloadContext *rdt, const char *line)
{
AVStream *stream = s->streams[st_index];
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);
else if (av_strstart(p, "ASMRuleBook:string;", &p)) {
int n = st_index, first = -1;
for (n = 0; n < s->nb_streams; n++)
if (s->streams[n]->priv_data == stream->priv_data) {
if (first == -1) first = n;
rdt->rmst[s->streams[n]->index] = ff_rm_alloc_rmstream();
rdt_load_mdpr(rdt, s->streams[n], (n - first) * 2);
if (s->streams[n]->codec->codec_id == CODEC_ID_AAC)
s->streams[n]->codec->frame_size = 1; // FIXME
}
}
return 0;
}
static void
real_parse_asm_rule(AVStream *st, const char *p, const char *end)
{
do {
/* can be either averagebandwidth= or AverageBandwidth= */
if (sscanf(p, " %*1[Aa]verage%*1[Bb]andwidth=%d", &st->codec->bit_rate) == 1)
break;
if (!(p = strchr(p, ',')) || p > end)
p = end;
p++;
} while (p < end);
}
static AVStream *
add_dstream(AVFormatContext *s, AVStream *orig_st)
{
AVStream *st;
if (!(st = av_new_stream(s, 0)))
return NULL;
st->codec->codec_type = orig_st->codec->codec_type;
st->priv_data = orig_st->priv_data;
st->first_dts = orig_st->first_dts;
return st;
}
static void
real_parse_asm_rulebook(AVFormatContext *s, AVStream *orig_st,
const char *p)
{
const char *end;
int n_rules, odd = 0;
AVStream *st;
/**
* The ASMRuleBook contains a list of comma-separated strings per rule,
* and each rule is separated by a ;. The last one also has a ; at the
* end so we can use it as delimiter.
* Every rule occurs twice, once for when the RTSP packet header marker
* is set and once for if it isn't. We only read the first because we
* don't care much (that's what the "odd" variable is for).
* Each rule contains a set of one or more statements, optionally
* preceeded by a single condition. If there's a condition, the rule
* starts with a '#'. Multiple conditions are merged between brackets,
* so there are never multiple conditions spread out over separate
* statements. Generally, these conditions are bitrate limits (min/max)
* for multi-bitrate streams.
*/
if (*p == '\"') p++;
for (n_rules = 0; s->nb_streams < MAX_STREAMS;) {
if (!(end = strchr(p, ';')))
break;
if (!odd && end != p) {
if (n_rules > 0)
st = add_dstream(s, orig_st);
else
st = orig_st;
real_parse_asm_rule(st, p, end);
n_rules++;
}
p = end + 1;
odd ^= 1;
}
}
void
ff_real_parse_sdp_a_line (AVFormatContext *s, int stream_index,
const char *line)
{
const char *p = line;
if (av_strstart(p, "ASMRuleBook:string;", &p))
real_parse_asm_rulebook(s, s->streams[stream_index], p);
}
static PayloadContext *
rdt_new_context (void)
{
PayloadContext *rdt = av_mallocz(sizeof(PayloadContext));
av_open_input_stream(&rdt->rmctx, NULL, "", &rdt_demuxer, NULL);
return rdt;
}
static void
rdt_free_context (PayloadContext *rdt)
{
int i;
for (i = 0; i < MAX_STREAMS; i++)
if (rdt->rmst[i]) {
ff_rm_free_rmstream(rdt->rmst[i]);
av_freep(&rdt->rmst[i]);
}
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 = { \
.enc_name = s, \
.codec_type = t, \
.codec_id = CODEC_ID_NONE, \
.parse_sdp_a_line = rdt_parse_sdp_line, \
.open = rdt_new_context, \
.close = rdt_free_context, \
.parse_packet = rdt_parse_packet \
};
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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