diff --git a/libavformat/rtpenc_jpeg.c b/libavformat/rtpenc_jpeg.c
index 91116832da..e4e95931f4 100644
--- a/libavformat/rtpenc_jpeg.c
+++ b/libavformat/rtpenc_jpeg.c
@@ -30,7 +30,7 @@ void ff_rtp_send_jpeg(AVFormatContext *s1, const uint8_t *buf, int size)
     RTPMuxContext *s = s1->priv_data;
     const uint8_t *qtables[4] = { NULL };
     int nb_qtables = 0;
-    uint8_t type;
+    uint8_t type = 2; /* initialized non-0/1 value for RTP/JPEG type check*/
     uint8_t w, h;
     uint8_t *p;
     int off = 0; /* fragment offset of the current JPEG frame */
@@ -45,20 +45,6 @@ void ff_rtp_send_jpeg(AVFormatContext *s1, const uint8_t *buf, int size)
     w = AV_CEIL_RSHIFT(s1->streams[0]->codecpar->width, 3);
     h = AV_CEIL_RSHIFT(s1->streams[0]->codecpar->height, 3);
 
-    /* get the pixel format type or fail */
-    if (s1->streams[0]->codecpar->format == AV_PIX_FMT_YUVJ422P ||
-        (s1->streams[0]->codecpar->color_range == AVCOL_RANGE_JPEG &&
-         s1->streams[0]->codecpar->format == AV_PIX_FMT_YUV422P)) {
-        type = 0;
-    } else if (s1->streams[0]->codecpar->format == AV_PIX_FMT_YUVJ420P ||
-               (s1->streams[0]->codecpar->color_range == AVCOL_RANGE_JPEG &&
-                s1->streams[0]->codecpar->format == AV_PIX_FMT_YUV420P)) {
-        type = 1;
-    } else {
-        av_log(s1, AV_LOG_ERROR, "Unsupported pixel format\n");
-        return;
-    }
-
     /* preparse the header for getting some info */
     for (i = 0; i < size; i++) {
         if (buf[i] != 0xff)
@@ -90,6 +76,23 @@ void ff_rtp_send_jpeg(AVFormatContext *s1, const uint8_t *buf, int size)
                        "Only 1x1 chroma blocks are supported. Aborted!\n");
                 return;
             }
+
+            /*
+             * Find out the sampling factor in SOF0.
+             * In SOF0, hsample/vsample is inserted in form of (2<<4) | (type ? 2 : 1).
+             * First 4-bit is hsample while Last 4-bit is vsample.
+             */
+
+            /* Luma channel sampling factor in 4:2:2 chroma subsampling are 2x1 */
+            if (buf[i + 11] == 33) {
+                type = 0;
+            /* Luma channel sampling factor in 4:2:0 chroma subsampling are 2x2 */
+            } else if (buf[i + 11] == 34) {
+                type = 1;
+            } else {
+                av_log(s1, AV_LOG_ERROR, "Unsupported pixel format\n");
+                return;
+            }
         } else if (buf[i + 1] == DHT) {
             int dht_size = AV_RB16(&buf[i + 2]);
             default_huffman_tables |= 1 << 4;
@@ -163,6 +166,14 @@ void ff_rtp_send_jpeg(AVFormatContext *s1, const uint8_t *buf, int size)
             break;
         }
     }
+
+    /* Check validity of RTP/JPEG type */
+    if (type != 0 && type != 1) {
+        av_log(s1, AV_LOG_ERROR,
+               "Invalid RTP/JPEG type\n");
+        return;
+    }
+
     if (default_huffman_tables && default_huffman_tables != 31) {
         av_log(s1, AV_LOG_ERROR,
                "RFC 2435 requires standard Huffman tables for jpeg\n");