avcodec: check malloc return value.

modules/codec/avcodec/video.c

@@ -814,6 +814,8 @@ picture_t *DecodeVideo( decoder_t *p_dec, block_t **pp_block )
             p_pic->i_qstride = p_sys->p_ff_pic->qstride;
             int i_mb_h = ( p_pic->format.i_height + 15 ) / 16;
             p_pic->p_q = malloc( p_pic->i_qstride * i_mb_h );
+            if( p_pic->p_q )
+            {
                 memcpy( p_pic->p_q, p_sys->p_ff_pic->qscale_table,
                         p_pic->i_qstride * i_mb_h );
                 switch( p_sys->p_ff_pic->qscale_type )
@@ -828,6 +830,7 @@ picture_t *DecodeVideo( decoder_t *p_dec, block_t **pp_block )
                     p_pic->i_qtype = QTYPE_H264;
                     break;
                 }
+            }
 
             return p_pic;
         }