sws: handle jpeg pixel formats in sws_init_context()

Fixes Ticket576
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libswscale/utils.c

@@ -771,6 +771,15 @@ int sws_init_context(SwsContext *c, SwsFilter *srcFilter, SwsFilter *dstFilter)
 
     unscaled = (srcW == dstW && srcH == dstH);
 
+    handle_jpeg(&srcFormat);
+    handle_jpeg(&dstFormat);
+
+    if(srcFormat!=c->srcFormat || dstFormat!=c->dstFormat){
+        av_log(c, AV_LOG_WARNING, "deprecated pixel format used, make sure you did set range correctly\n");
+        c->srcFormat= srcFormat;
+        c->dstFormat= dstFormat;
+    }
+
     if (!sws_isSupportedInput(srcFormat)) {
         av_log(c, AV_LOG_ERROR, "%s is not supported as input pixel format\n", av_get_pix_fmt_name(srcFormat));
         return AVERROR(EINVAL);