rtpdec: Clean up FMTP parsing code in AMR RTP depacketizer

Patch by Josh Allmann, joshua dot allmann at gmail

Originally committed as revision 23861 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/rtpdec_amr.c

@@ -30,6 +30,26 @@ static const uint8_t frame_sizes_wb[16] = {
     17, 23, 32, 36, 40, 46, 50, 58, 60, 5, 5, 0, 0, 0, 0, 0
 };
 
+struct PayloadContext {
+    int octet_align;
+    int crc;
+    int interleaving;
+    int channels;
+};
+
+static PayloadContext *amr_new_context(void)
+{
+    PayloadContext *data = av_mallocz(sizeof(PayloadContext));
+    if(!data) return data;
+    data->channels = 1;
+    return data;
+}
+
+static void amr_free_context(PayloadContext *data)
+{
+    av_free(data);
+}
+
 static int amr_handle_packet(AVFormatContext *ctx,
                              PayloadContext *data,
                              AVStream *st,
@@ -120,50 +140,48 @@ static int amr_handle_packet(AVFormatContext *ctx,
     return 0;
 }
 
-static int amr_parse_sdp_line(AVFormatContext *s, int st_index,
-                              PayloadContext *data, const char *line)
+static int amr_parse_fmtp(AVStream *stream, PayloadContext *data,
+                          char *attr, char *value)
 {
-    const char *p;
-    char attr[25], value[25];
-
-    /* Parse an fmtp line this one:
-     * a=fmtp:97 octet-align=1; interleaving=0
-     * That is, a normal fmtp: line followed by semicolon & space
-     * separated key/value pairs.
-     */
-    if (av_strstart(line, "fmtp:", &p)) {
-        int octet_align = 0;
-        int crc = 0;
-        int interleaving = 0;
-        int channels = 1;
-
-        while (*p && *p == ' ') p++; /* strip spaces */
-        while (*p && *p != ' ') p++; /* eat protocol identifier */
-        while (*p && *p == ' ') p++; /* strip trailing spaces */
-
-        while (ff_rtsp_next_attr_and_value(&p, attr, sizeof(attr), value, sizeof(value))) {
             /* Some AMR SDP configurations contain "octet-align", without
              * the trailing =1. Therefore, if the value is empty,
              * interpret it as "1".
              */
             if (!strcmp(value, "")) {
-                av_log(s, AV_LOG_WARNING, "AMR fmtp attribute %s had "
-                                          "nonstandard empty value\n", attr);
+                av_log(NULL, AV_LOG_WARNING, "AMR fmtp attribute %s had "
+                                             "nonstandard empty value\n", attr);
                 strcpy(value, "1");
             }
             if (!strcmp(attr, "octet-align"))
-                octet_align = atoi(value);
+                data->octet_align = atoi(value);
             else if (!strcmp(attr, "crc"))
-                crc = atoi(value);
+                data->crc = atoi(value);
             else if (!strcmp(attr, "interleaving"))
-                interleaving = atoi(value);
+                data->interleaving = atoi(value);
             else if (!strcmp(attr, "channels"))
-                channels = atoi(value);
-        }
-        if (!octet_align || crc || interleaving || channels != 1) {
+                data->channels = atoi(value);
+    return 0;
+}
+
+static int amr_parse_sdp_line(AVFormatContext *s, int st_index,
+                              PayloadContext *data, const char *line)
+{
+    const char *p;
+    int ret;
+
+    /* Parse an fmtp line this one:
+     * a=fmtp:97 octet-align=1; interleaving=0
+     * That is, a normal fmtp: line followed by semicolon & space
+     * separated key/value pairs.
+     */
+    if (av_strstart(line, "fmtp:", &p)) {
+        ret = ff_parse_fmtp(s->streams[st_index], data, p, amr_parse_fmtp);
+        if (!data->octet_align || data->crc ||
+            data->interleaving || data->channels != 1) {
             av_log(s, AV_LOG_ERROR, "Unsupported RTP/AMR configuration!\n");
             return -1;
         }
+        return ret;
     }
     return 0;
 }
@@ -173,6 +191,8 @@ RTPDynamicProtocolHandler ff_amr_nb_dynamic_handler = {
     .codec_type       = AVMEDIA_TYPE_AUDIO,
     .codec_id         = CODEC_ID_AMR_NB,
     .parse_sdp_a_line = amr_parse_sdp_line,
+    .open             = amr_new_context,
+    .close            = amr_free_context,
     .parse_packet     = amr_handle_packet,
 };
 
@@ -181,6 +201,8 @@ RTPDynamicProtocolHandler ff_amr_wb_dynamic_handler = {
     .codec_type       = AVMEDIA_TYPE_AUDIO,
     .codec_id         = CODEC_ID_AMR_WB,
     .parse_sdp_a_line = amr_parse_sdp_line,
+    .open             = amr_new_context,
+    .close            = amr_free_context,
     .parse_packet     = amr_handle_packet,
 };