http: add -content_type user option.

libavformat/http.c

@@ -46,6 +46,7 @@ typedef struct {
     int line_count;
     int http_code;
     int64_t chunksize;      /**< Used if "Transfer-Encoding: chunked" otherwise -1. */
+    char *content_type;
     char *user_agent;
     int64_t off, filesize;
     char location[MAX_URL_SIZE];
@@ -72,6 +73,7 @@ static const AVOption options[] = {
 {"seekable", "Control seekability of connection", OFFSET(seekable), AV_OPT_TYPE_INT, {.i64 = -1}, -1, 1, D },
 {"chunked_post", "use chunked transfer-encoding for posts", OFFSET(chunked_post), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, E },
 {"headers", "custom HTTP headers, can override built in default headers", OFFSET(headers), AV_OPT_TYPE_STRING, { 0 }, 0, 0, D|E },
+{"content_type", "force a content type", OFFSET(content_type), AV_OPT_TYPE_STRING, { 0 }, 0, 0, D|E },
 {"user-agent", "override User-Agent header", OFFSET(user_agent), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC},
 {"multiple_requests", "use persistent connections", OFFSET(multiple_requests), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, D|E },
 {"post_data", "custom HTTP post data", OFFSET(post_data), AV_OPT_TYPE_BINARY, .flags = D|E },
@@ -451,6 +453,9 @@ static int http_connect(URLContext *h, const char *path, const char *local_path,
     if (!has_header(s->headers, "\r\nContent-Length: ") && s->post_data)
         len += av_strlcatf(headers + len, sizeof(headers) - len,
                            "Content-Length: %d\r\n", s->post_datalen);
+    if (!has_header(s->headers, "\r\nContent-Type: ") && s->content_type)
+        len += av_strlcatf(headers + len, sizeof(headers) - len,
+                           "Content-Type: %s\r\n", s->content_type);
 
     /* now add in custom headers */
     if (s->headers)