client(2600000): Reserved pid(12747).
client(2600000): Reserved cmdname(/usr/bin/nautilus) and cmdargs(--gapplication-service).
AllocNewConnection: client index = 19, socket fd = 39
client(2600000): Released pid(12747).
client(2600000): Released cmdline(/usr/bin/nautilus) and cmdargs(--gapplication-service).
client(2600000): Reserved pid(12758).
client(2600000): Reserved cmdname(/usr/lib/gnome-terminal/gnome-terminal-server) and cmdargs(NULL).
AllocNewConnection: client index = 19, socket fd = 39
client(2600000): Released pid(12758).
client(2600000): Released cmdline(/usr/lib/gnome-terminal/gnome-terminal-server) and cmdargs(NULL).
client(2600000): Reserved pid(12821).
client(2600000): Reserved cmdname(mpv) and cmdargs(--vo=xv bisounours_le_film.avi).
AllocNewConnection: client index = 19, socket fd = 39
client(2800000): Reserved pid(12821).
client(2800000): Reserved cmdname(mpv) and cmdargs(--vo=xv bisounours_le_film.avi).
AllocNewConnection: client index = 20, socket fd = 43
client(2800000): Released pid(12821).
client(2800000): Released cmdline(mpv) and cmdargs(--vo=xv bisounours_le_film.avi).
client(2800000): Reserved pid(12853).
client(2800000): Reserved cmdname(xset) and cmdargs(-q).
AllocNewConnection: client index = 20, socket fd = 43
client(2800000): Released pid(12853).
client(2800000): Released cmdline(xset) and cmdargs(-q).
Failed to compile FS: 0:12(8): error: syntax error, unexpected SAMPLE, expecting ',' or ';'

Program source:
#ifdef GL_ES
precision mediump float;
#endif
uniform sampler2D y_sampler;
uniform sampler2D u_sampler;
uniform sampler2D v_sampler;
uniform vec4 offsetyco;
uniform vec4 ucogamma;
uniform vec4 vco;
varying vec2 tcs;
void main() {
        float sample;
        vec4 temp1;
        sample = texture2D(y_sampler, tcs).w;
        temp1.xyz = offsetyco.www * vec3(sample) + offsetyco.xyz;
        sample = texture2D(u_sampler, tcs).w;
        temp1.xyz = ucogamma.xyz * vec3(sample) + temp1.xyz;
        sample = texture2D(v_sampler, tcs).w;
        temp1.xyz = clamp(vco.xyz * vec3(sample) + temp1.xyz, 0.0, 1.0);
        temp1.w = 1.0;
        gl_FragColor = temp1;
}
(EE) 
Fatal server error:
(EE) GLSL compile failure
(EE)