Revert "avformat/rtp: Pass sources and block filter addresses via sdp file for rtp"

This reverts commit b7168586.

The commit lead to the use of an uninitialized variable.
Other issues were listed by Andreas Rheinhardt:
https://ffmpeg.org/pipermail/ffmpeg-devel/2020-March/259150.html

libavformat/rtsp.c

@@ -2447,8 +2447,8 @@ static int rtp_probe(const AVProbeData *p)
 static int rtp_read_header(AVFormatContext *s)
 {
     uint8_t recvbuf[RTP_MAX_PACKET_LENGTH];
-    char host[500], sdp[1000], filters_buf[1000];
-    int ret, port, sdp_length, nc;
+    char host[500], sdp[500];
+    int ret, port;
     URLContext* in = NULL;
     int payload_type;
     AVCodecParameters *par = NULL;
@@ -2456,7 +2456,6 @@ static int rtp_read_header(AVFormatContext *s)
     AVIOContext pb;
     socklen_t addrlen = sizeof(addr);
     RTSPState *rt = s->priv_data;
-    const char *p;
 
     if (!ff_network_init())
         return AVERROR(EIO);
@@ -2514,40 +2513,13 @@ static int rtp_read_header(AVFormatContext *s)
     av_url_split(NULL, 0, NULL, 0, host, sizeof(host), &port,
                  NULL, 0, s->url);
 
-    sdp_length = snprintf(sdp + sdp_length, sizeof(sdp) - sdp_length,
-                          "v=0\r\nc=IN IP%d %s\r\n",
-                          addr.ss_family == AF_INET ? 4 : 6, host);
-
-    p = strchr(s->url, '?');
-    if (p) {
-        static const char *filters[][2] = {{"sources", "incl"}, {"block", "excl"}, {NULL, NULL}};
-        int i;
-        char *q;
-        for (i = 0; filters[i][0]; i++) {
-            if (av_find_info_tag(filters_buf, sizeof(filters_buf), filters[i][0], p)) {
-                q = filters_buf;
-                while ((q = strchr(q, ',')) != NULL)
-                    *q = ' ';
-                nc = snprintf(sdp + sdp_length, sizeof(sdp) - sdp_length,
-                          "a=source-filter:%s IN IP%d %s %s\r\n",
-                          filters[i][1],
-                          addr.ss_family == AF_INET ? 4 : 6, host,
-                          filters_buf);
-                if (nc < 0 || nc + sdp_length >= sizeof(sdp))
-                    goto fail_nobuf;
-                sdp_length += nc;
-            }
-        }
-    }
-
-    nc = snprintf(sdp + sdp_length, sizeof(sdp) - sdp_length,
-                  "m=%s %d RTP/AVP %d\r\n",
-                  par->codec_type == AVMEDIA_TYPE_DATA  ? "application" :
-                  par->codec_type == AVMEDIA_TYPE_VIDEO ? "video" : "audio",
-                  port, payload_type);
-    if (nc < 0 || nc + sdp_length >= sizeof(sdp))
-        goto fail_nobuf;
-    sdp_length += nc;
+    snprintf(sdp, sizeof(sdp),
+             "v=0\r\nc=IN IP%d %s\r\nm=%s %d RTP/AVP %d\r\n",
+             addr.ss_family == AF_INET ? 4 : 6, host,
+             par->codec_type == AVMEDIA_TYPE_DATA  ? "application" :
+             par->codec_type == AVMEDIA_TYPE_VIDEO ? "video" : "audio",
+             port, payload_type);
+    av_log(s, AV_LOG_VERBOSE, "SDP:\n%s\n", sdp);
     avcodec_parameters_free(&par);
 
     ffio_init_context(&pb, sdp, strlen(sdp), 0, NULL, NULL, NULL, NULL);
@@ -2562,9 +2534,6 @@ static int rtp_read_header(AVFormatContext *s)
     s->pb = NULL;
     return ret;
 
-fail_nobuf:
-    ret = AVERROR(ENOBUFS);
-    av_log(s, AV_LOG_ERROR, "rtp_read_header(): not enough buffer space for sdp-headers\n");
 fail:
     avcodec_parameters_free(&par);
     if (in)