CURLOPT_INTERLEAVEFUNCTION(curl_easy_setopt optioCURLOPT_INTERLEAVEFUNCTION(3)
NAME
CURLOPT_INTERLEAVEFUNCTION - callback for RTSP interleaved data
SYNOPSIS
#include <curl/curl.h>
size_t interleave_callback(void *ptr, size_t size, size_t nmemb,
void *userdata);
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_INTERLEAVEFUNCTION,
interleave_callback);
DESCRIPTION
Pass a pointer to your callback function, which should match the proto-
type shown above.
This callback function gets called by libcurl as soon as it has re-
ceived interleaved RTP data. This function gets called for each $ block
and therefore contains exactly one upper-layer protocol unit (e.g. one
RTP packet). Curl writes the interleaved header as well as the included
data for each call. The first byte is always an ASCII dollar sign. The
dollar sign is followed by a one byte channel identifier and then a 2
byte integer length in network byte order. See RFC2326 Section 10.12
for more information on how RTP interleaving behaves. If unset or set
to NULL, curl will use the default write function.
Interleaved RTP poses some challenges for the client application. Since
the stream data is sharing the RTSP control connection, it is critical
to service the RTP in a timely fashion. If the RTP data is not handled
quickly, subsequent response processing may become unreasonably delayed
and the connection may close. The application may use CURL_RTSPREQ_RE-
CEIVE to service RTP data when no requests are desired. If the applica-
tion makes a request, (e.g. CURL_RTSPREQ_PAUSE) then the response han-
dler will process any pending RTP data before marking the request as
finished.
The CURLOPT_INTERLEAVEDATA(3) is passed in the userdata argument in the
callback.
DEFAULT
NULL, the interleave data is then passed to the regular write function:
CURLOPT_WRITEFUNCTION(3).
PROTOCOLS
RTSP
EXAMPLE
static size_t rtp_write(void *ptr, size_t size, size_t nmemb, void *user)
{
struct local *l = (struct local *)user;
/* take care of the packet in 'ptr', then return... */
return size * nmemb;
}
{
struct local rtp_data;
curl_easy_setopt(curl, CURLOPT_INTERLEAVEFUNCTION, rtp_write);
curl_easy_setopt(curl, CURLOPT_INTERLEAVEDATA, &rtp_data);
}
AVAILABILITY
Added in 7.20.0
RETURN VALUE
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION
if not.
SEE ALSO
CURLOPT_INTERLEAVEDATA(3), CURLOPT_RTSP_REQUEST(3),
libcurl 7.81.0 September 08, 2021 CURLOPT_INTERLEAVEFUNCTION(3)
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