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Parse the ASMRuleBook SDP line to dynamically create one new AVStream for

each "rule" described in the ASMRuleBook. Each rule represents a stream
of identical content compared to other streams in the same rulebook, but
with a possibly different codec/bitrate/etc. See "[PATCH] rdt.c: ASM
rulebook parsing and AVStream creation" thread on mailinglist.

Originally committed as revision 16466 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Ronald S. Bultje 2009-01-07 14:38:44 +00:00
parent b06688ffed
commit 3ca45429fe
3 changed files with 81 additions and 0 deletions

View File

@ -76,6 +76,11 @@ ff_rdt_parse_open(AVFormatContext *ic, int first_stream_of_set_idx,
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);
}
@ -423,6 +428,68 @@ rdt_parse_sdp_line (AVFormatContext *s, int st_index,
return 0;
}
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;
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_extradata (void)
{

View File

@ -101,4 +101,15 @@ int ff_rdt_parse_header(const uint8_t *buf, int len,
int ff_rdt_parse_packet(RDTDemuxContext *s, AVPacket *pkt,
const uint8_t *buf, int len);
/**
* Parse a server-related SDP line.
*
* @param s the RTSP AVFormatContext
* @param stream_index the index of the first stream in the set represented
* by the SDP m= line (in s->streams)
* @param buf the SDP line
*/
void ff_real_parse_sdp_a_line(AVFormatContext *s, int stream_index,
const char *buf);
#endif /* AVFORMAT_RDT_H */

View File

@ -549,6 +549,9 @@ static void sdp_parse_line(AVFormatContext *s, SDPParseState *s1,
if (atoi(p) == 1)
rt->transport = RTSP_TRANSPORT_RDT;
} else if (s->nb_streams > 0) {
if (rt->server_type == RTSP_SERVER_REAL)
ff_real_parse_sdp_a_line(s, s->nb_streams - 1, p);
rtsp_st = s->streams[s->nb_streams - 1]->priv_data;
if (rtsp_st->dynamic_handler &&
rtsp_st->dynamic_handler->parse_sdp_a_line)