Need help combining shaders

Hello I am trying to combine two shaders and I am having problems getting both to render. Both shaders contain dependencies required for two pieces of functionality, but I can't get it to render. I think I need a grab pass in there. Any help would be appreciated.

Shader "Custom/VideoShaderKey" {
Properties{
_MainTex1("MainTex", 2D) = "white" {}
_BgColor("BgColor", Color) = (1,1,1,1)
_KeyColor("KeyColor", Color) = (1,1,1,1)
_DChroma("D Chroma", range(0.0, 1.0)) = 0.5
_DChromaT("D Chroma Tolerance", range(0.0, 1.0)) = 0.05

_Chroma("Chroma (Main -> Bg)", range(0.0, 1.0)) = 0.5
_Luma("Luma (Main -> Bg)", range(0.0, 1.0)) = 0.5
_Saturation("Saturation (0 -> Chroma)", range(0.0, 1.0)) = 1.0
_Alpha("Alpha (Chroma -> Bg)", range(0.0, 1.0)) = 1.0
}
CGINCLUDE
#include "UnityCG.cginc"
struct VS_OUT {
fixed4 positionOSITION;
fixed2 texcoord0:TEXCOORD0;
};

sampler2D _MainTex1;
fixed4 _MainTex_ST;

fixed4 _BgColor;

fixed4 _KeyColor;
fixed _DChroma;
fixed _DChromaT;

fixed _Chroma;
fixed _Luma;
fixed _Saturation;
fixed _Alpha;

VS_OUT vert(appdata_base input) {
VS_OUT o;
o.position = UnityObjectToClipPos(input.vertex);
o.texcoord0 = TRANSFORM_TEX(input.texcoord, _MainTex);
return o;
}

fixed3 RGB_To_YCbCr(fixed3 RGB) {
fixed Y = 0.299 * RGB.r + 0.587 * RGB.g + 0.114 * RGB.b;
fixed Cb = 0.564 * (RGB.b - Y);
fixed Cr = 0.713 * (RGB.r - Y);
return fixed3(Cb, Cr, Y);
}

fixed3 YCbCr_To_RGB(fixed3 YCbCr) {
fixed R = YCbCr.z + 1.402 * YCbCr.y;
fixed G = YCbCr.z - 0.334 * YCbCr.x - 0.714 * YCbCr.y;
fixed B = YCbCr.z + 1.772 * YCbCr.x;
return fixed3(R, G, B);
}
fixed2 lerp3_2(fixed2 A, fixed2 B, fixed2 C, fixed v) {
if (v < 0.5) {
return lerp(A, B, 2*v);
}
else {
return lerp(B, C, 2*(v-0.5));
}
}
fixed lerp3_1(fixed A, fixed B, fixed C, fixed v) {
if (v < 0.5) {
return lerp(A, B, 2 * v);
}
else {
return lerp(B, C, 2 * (v - 0.5));
}
}
fixed4 frag(VS_OUT input) : SV_Target {
fixed4 c = tex2D(_MainTex1, input.texcoord0);
if(c.a > 0) {
fixed4 c_bg = _BgColor;

fixed3 src_YCbCr = RGB_To_YCbCr(c.rgb);
fixed3 target_YCbCr = RGB_To_YCbCr(c_bg.rgb);
fixed3 key_YCbCr = RGB_To_YCbCr(_KeyColor);

fixed dChroma = distance(src_YCbCr.xy, key_YCbCr.xy);
if (dChroma < _DChroma) {
fixed ta = 0;
c.rgb = c_bg.rgb;
if (dChroma > _DChroma - _DChromaT) {
ta = (dChroma - _DChroma + _DChromaT) / _DChromaT;
fixed2 cta = lerp(src_YCbCr.xy, target_YCbCr.xy, 1 - ta);
fixed2 ct = lerp3_2(src_YCbCr.xy, cta, target_YCbCr.xy, _Chroma);

fixed sa = length(cta);
fixed s = lerp(0, sa, _Saturation);
ct *= s / sa;

fixed la = lerp(src_YCbCr.z, target_YCbCr.z, 1 - ta);
fixed l = lerp3_1(src_YCbCr.z, la, target_YCbCr.z, _Luma);

c.rgb = YCbCr_To_RGB(float3(ct.x, ct.y, l));
}
ta = lerp(ta, c.a, _Alpha);
if(c.a > ta){
c.a = ta;
}
}
}
return c;
}
ENDCG
//////////////////////


SubShader {
Tags{ "Queue" = "Background" }
Pass {

Lighting Off
ZWrite Off
ZTest Off
Cull Off

CGPROGRAM
// use "vert" function as the vertex shader
#pragma vertex vert
// use "frag" function as the pixel (fragment) shader
#pragma fragment frag

// vertex shader inputs
struct appdata
{
float4 vertex : POSITION; // vertex position
float2 uv : TEXCOORD0; // texture coordinate
};

// vertex shader outputs ("vertex to fragment")
struct v2f
{
float2 uv : TEXCOORD0; // texture coordinate
float4 vertex : SV_POSITION; // clip space position
};
int _Rotation = 0;
float _ScaleX = 1.0;
float _ScaleY = 1.0;
int _Mirror = 0;
int _VerticalMirror = 0;
int _InvertTextureChannels = 0;

// vertex shader
v2f vert(appdata v)
{
v2f o;

// transform position to clip space
o.vertex = float4(v.vertex.x*_ScaleX, v.vertex.y*_ScaleY, 0.0, 1.0);

if (_Rotation == 1)
{
float tmp = o.vertex.x;
o.vertex.x = o.vertex.y;
o.vertex.y = -tmp;
}
else if (_Rotation == 2)
{
o.vertex.x = -o.vertex.x;
o.vertex.y = -o.vertex.y;
}
else if (_Rotation == 3)
{
float tmp = o.vertex.x;
o.vertex.x = -o.vertex.y;
o.vertex.y = tmp;
}

// pass the texture coordinate
o.uv = v.uv;
if (_Mirror == 1)
o.uv.x = 1.0 - o.uv.x;
if (_VerticalMirror == 1)
o.uv.y = 1.0 - o.uv.y; // image is flipped upside down (depending on pixel formats and devices)

return o;
}



fixed4 frag(v2f i) : SV_Target
{
// sample texture and return it
fixed4 col = tex2D(_MainTex1, i.uv);
if (_InvertTextureChannels == 1)
col = fixed4(col.b, col.g, col.r, col.a);
return col;
}
ENDCG
}
}

///////////////////////
SubShader {
Tags{ "Queue" = "Transparent" "RenderType" = "Transparent" "IgnoreProjector" = "True" }
Lighting Off
ZWrite Off
AlphaTest Off
Blend SrcAlpha OneMinusSrcAlpha, One One

Pass {
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
ENDCG
}
}
Fallback Off
}