qpeg: return a meaningful error code.

libavcodec/qpeg.c

@@ -247,7 +247,7 @@ static int decode_frame(AVCodecContext *avctx,
     QpegContext * const a = avctx->priv_data;
     AVFrame * const p = &a->pic;
     uint8_t* outdata;
-    int delta;
+    int delta, ret;
     const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
 
     if (avpkt->size < 0x86) {
@@ -257,9 +257,9 @@ static int decode_frame(AVCodecContext *avctx,
 
     bytestream2_init(&a->buffer, avpkt->data, avpkt->size);
     p->reference = 3;
-    if (avctx->reget_buffer(avctx, p) < 0) {
+    if ((ret = avctx->reget_buffer(avctx, p)) < 0) {
         av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
-        return -1;
+        return ret;
     }
     outdata = a->pic.data[0];
     bytestream2_skip(&a->buffer, 4);