CURLOPT_INTERLEAVEFUNCTION(3)                         curl_easy_setopt options

NAME
       CURLOPT_INTERLEAVEFUNCTION - callback function 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
       prototype shown above.

       This callback function gets called by libcurl as soon as it has
       received 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_RECEIVE to service RTP data when no requests are desired.
       If the application makes a request, (e.g.  CURL_RTSPREQ_PAUSE) then the
       response handler will process any pending RTP data before marking the
       request as finished.

       The _INTERLEAVEDATA&section=3">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:
       _WRITEFUNCTION&section=3">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 7.77.0                 November 4, 2020  CURLOPT_INTERLEAVEFUNCTION(3)