avcodec/mationpixels: free memory after malloc failures

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

libavcodec/motionpixels.c

@@ -68,8 +68,12 @@ static av_cold int mp_decode_init(AVCodecContext *avctx)
     mp->offset_bits_len = av_log2(avctx->width * avctx->height) + 1;
     mp->vpt = av_mallocz(avctx->height * sizeof(YuvPixel));
     mp->hpt = av_mallocz(h4 * w4 / 16 * sizeof(YuvPixel));
-    if (!mp->changes_map || !mp->vpt || !mp->hpt)
+    if (!mp->changes_map || !mp->vpt || !mp->hpt) {
+        av_freep(&mp->changes_map);
+        av_freep(&mp->vpt);
+        av_freep(&mp->hpt);
         return AVERROR(ENOMEM);
+    }
     avctx->pix_fmt = AV_PIX_FMT_RGB555;
     avcodec_get_frame_defaults(&mp->frame);
     return 0;