rtpdec_jpeg: Merge two if statements

This makes the code more readable and robust.
Signed-off-by: Martin Storsjö <martin@martin.st>

libavformat/rtpdec_jpeg.c

@@ -252,9 +252,13 @@ static int jpeg_parse_packet(AVFormatContext *ctx, PayloadContext *jpeg,
     }
 
     /* Parse the quantization table header. */
-    if (q > 127 && off == 0) {
-        uint8_t precision;
+    if (off == 0) {
+        /* Start of JPEG data packet. */
+        uint8_t new_qtables[128];
+        uint8_t hdr[1024];
 
+        if (q > 127) {
+            uint8_t precision;
             if (len < 4) {
                 av_log(ctx, AV_LOG_ERROR, "Too short RTP/JPEG packet.\n");
                 return AVERROR_INVALIDDATA;
@@ -286,11 +290,6 @@ static int jpeg_parse_packet(AVFormatContext *ctx, PayloadContext *jpeg,
             }
         }
 
-    if (off == 0) {
-        /* Start of JPEG data packet. */
-        uint8_t new_qtables[128];
-        uint8_t hdr[1024];
-
         /* Skip the current frame in case of the end packet
          * has been lost somewhere. */
         free_frame_if_needed(jpeg);