examples/qsvdec: convert to the new decoding API

doc/examples/qsvdec.c

@@ -92,24 +92,27 @@ static int decode_packet(DecodeContext *decode, AVCodecContext *decoder_ctx,
                          AVPacket *pkt, AVIOContext *output_ctx)
 {
     int ret = 0;
-    int got_frame = 1;
 
-    while (pkt->size > 0 || (!pkt->data && got_frame)) {
-        ret = avcodec_decode_video2(decoder_ctx, frame, &got_frame, pkt);
+    ret = avcodec_send_packet(decoder_ctx, pkt);
     if (ret < 0) {
         fprintf(stderr, "Error during decoding\n");
         return ret;
     }
 
-        pkt->data += ret;
-        pkt->size -= ret;
+    while (ret >= 0) {
+        int i, j;
+
+        ret = avcodec_receive_frame(decoder_ctx, frame);
+        if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
+            break;
+        else if (ret < 0) {
+            fprintf(stderr, "Error during decoding\n");
+            return ret;
+        }
 
         /* A real program would do something useful with the decoded frame here.
          * We just retrieve the raw data and write it to a file, which is rather
          * useless but pedagogic. */
-        if (got_frame) {
-            int i, j;
-
         ret = av_hwframe_transfer_data(sw_frame, frame, 0);
         if (ret < 0) {
             fprintf(stderr, "Error transferring the data to system memory\n");
@@ -127,7 +130,6 @@ fail:
         if (ret < 0)
             return ret;
     }
-    }
 
     return 0;
 }