avcodec/msvideo1enc: Check all calls to avpriv_elbg_do()

Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavcodec/msvideo1enc.c

@@ -118,8 +118,10 @@ static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
             }
             // try to find optimal value to fill whole 4x4 block
             score = 0;
-            avpriv_elbg_do(&c->elbg, c->block, 3, 16, c->avg,
-                           1, 1, c->output, &c->rnd);
+            ret = avpriv_elbg_do(&c->elbg, c->block, 3, 16, c->avg,
+                                 1, 1, c->output, &c->rnd);
+            if (ret < 0)
+                return ret;
             if(c->avg[0] == 1) // red component = 1 will be written as skip code
                 c->avg[0] = 0;
             for(j = 0; j < 4; j++){
@@ -138,8 +140,10 @@ static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
             }
             // search for optimal filling of 2-color block
             score = 0;
-            avpriv_elbg_do(&c->elbg, c->block, 3, 16, c->codebook,
-                           2, 1, c->output, &c->rnd);
+            ret = avpriv_elbg_do(&c->elbg, c->block, 3, 16, c->codebook,
+                                 2, 1, c->output, &c->rnd);
+            if (ret < 0)
+                return ret;
             // last output value should be always 1, swap codebooks if needed
             if(!c->output[15]){
                 for(i = 0; i < 3; i++)
@@ -164,9 +168,11 @@ static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
             // search for optimal filling of 2-color 2x2 subblocks
             score = 0;
             for(i = 0; i < 4; i++){
-                avpriv_elbg_do(&c->elbg, c->block2 + i * 4 * 3, 3, 4,
-                               c->codebook2 + i * 2 * 3, 2, 1,
-                               c->output2 + i*4, &c->rnd);
+                ret = avpriv_elbg_do(&c->elbg, c->block2 + i * 4 * 3, 3, 4,
+                                     c->codebook2 + i * 2 * 3, 2, 1,
+                                     c->output2 + i * 4, &c->rnd);
+                if (ret < 0)
+                    return ret;
             }
             // last value should be always 1, swap codebooks if needed
             if(!c->output2[15]){