Shader - Video Quality

Hi all!

I have a question I haven't been able to solve or found an online forum/answer for it.

I am building a 360video AR portal and have some 360º videos with pretty good quality. I have my video on a sphere that has a material applied to it with a custom shader. All works great but the video seems to loose a lot of quality and becomes a bit blurry. I understand this is caused by the shader but I am not sure how to fix or find a solution for it.

Any help will be appreciated!

Here's the shader I am using:

Shader "Custom/Equirectangular" { Properties { _Color ("Main Color", Color) = (1,1,1,1) _MainTex ("Diffuse (RGB) Alpha (A)", 2D) = "gray" {} [Enum(Equal,3,NotEqual,6)] stest ("STENCILTEST", int) = 3

} SubShader{ Pass { Tags {"LightMode" = "Always"} LOD 100

        Stencil
  {
  Ref 1
  Comp [stest]
  }
  Cull off
       
      CGPROGRAM
          #pragma vertex vert
          #pragma fragment frag
          #pragma fragmentoption ARB_precision_hint_fastest
          #pragma glsl
          #pragma target 3.0
          #include "UnityCG.cginc"
          struct appdata {
             float4 vertex : POSITION;
             float3 normal : NORMAL;
          };
          struct v2f
          {
              float4    pos : SV_POSITION;
              float3    normal : TEXCOORD0;
          };
          v2f vert (appdata v)
          {
              v2f o;
              o.pos = UnityObjectToClipPos(v.vertex);
              o.normal = v.normal;
              return o;
          }
          sampler2D _MainTex;
          #define PI 3.141592653589793
          inline float2 RadialCoords(float3 a_coords)
          {
              float3 a_coords_n = normalize(a_coords);
              float lon = atan2(a_coords_n.z, a_coords_n.x);
              float lat = acos(a_coords_n.y);
              float2 sphereCoords = float2(lon, lat) * (1.0 / PI);
              return float2(sphereCoords.x * 0.5 + 0.5, 1 - sphereCoords.y);
          }
          float4 frag(v2f IN) : COLOR
          {
              float2 equiUV = RadialCoords(IN.normal);
              return tex2D(_MainTex, equiUV);
          }
      ENDCG
  }

} FallBack "VertexLit" }