1 files changed, 6 insertions, 3 deletions
diff --git a/video/out/gpu/video.c b/video/out/gpu/video.c
index add7985f78..035619891b 100644
--- a/video/out/gpu/video.c
+++ b/video/out/gpu/video.c
@@ -2698,9 +2698,12 @@ static void pass_dither(struct gl_video *p)
 
             struct image img = image_wrap(p->error_diffusion_tex[0], PLANE_RGB, p->components);
 
-            // 1024 is minimal required number of invocation allowed in single
-            // work group in OpenGL. Use it for maximal performance.
-            int block_size = MPMIN(1024, o_h);
+            // Ensure the block size doesn't exceed the minimum defined by the
+            // specification (1024 in desktop GL, 128 in GLES).
+            // TODO: Look up the actual maximum block size for the
+            // implementation using:
+            //     glGetIntegerv(MAX_COMPUTE_WORK_GROUP_INVOCATIONS, &value);
+            int block_size = MPMIN(p->ra->glsl_es ? 128 : 1024, o_h);
 
             pass_describe(p, "dither=error-diffusion (kernel=%s, depth=%d)",
                              kernel->name, dst_depth);