From 70c0433525bc4f98c91c6a6d09025e90a847e62f Mon Sep 17 00:00:00 2001
From: Carl Eugen Hoyos <cehoyos@ag.or.at>
Date: Sun, 17 May 2015 10:22:03 +0200
Subject: [PATCH] lavc: Print a warning if gray decoding was requested but not
 enabled.

---
 libavcodec/utils.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/libavcodec/utils.c b/libavcodec/utils.c
index 48286cf07a..8695cb9689 100644
--- a/libavcodec/utils.c
+++ b/libavcodec/utils.c
@@ -1615,6 +1615,11 @@ int attribute_align_arg avcodec_open2(AVCodecContext *avctx, const AVCodec *code
     avctx->pts_correction_last_pts =
     avctx->pts_correction_last_dts = INT64_MIN;
 
+    if (   !CONFIG_GRAY && avctx->flags & CODEC_FLAG_GRAY
+        && avctx->codec_descriptor->type == AVMEDIA_TYPE_VIDEO)
+        av_log(avctx, AV_LOG_WARNING,
+               "gray decoding requested but not enabled at configuration time\n");
+
     if (   avctx->codec->init && (!(avctx->active_thread_type&FF_THREAD_FRAME)
         || avctx->internal->frame_thread_encoder)) {
         ret = avctx->codec->init(avctx);