vulkan_ffv1: add cached symbol reader for AMD

Speeds up everything on AMD by 3x.
This uses 32 local invocations to load state into cache, as well
as to do the RCT faster.

libavcodec/vulkan/ffv1_dec.comp

@@ -108,34 +108,37 @@ ivec2 get_pred(ivec2 sp, ivec2 off, int p, int sw, uint8_t quant_table_idx)
 #endif
 
 #ifndef GOLOMB
-int get_isymbol(inout RangeCoder c, uint64_t state)
+#ifdef CACHED_SYMBOL_READER
+shared uint8_t state[CONTEXT_SIZE];
+#define READ(c, off) get_rac_direct(c, state[off])
+#else
+#define READ(c, off) get_rac(c, uint64_t(slice_state) + (state_off + off))
+#endif
+
+int get_isymbol(inout RangeCoder c, uint state_off)
 {
-    if (get_rac(c, state))
+    if (READ(c, 0))
         return 0;
 
-    state += 1;
+    uint e = 1;
-
+    for (; e < 33; e++)
-    int e;
+        if (!READ(c, min(e, 10)))
-    for (e = 0; e < 32; e++)
-        if (!get_rac(c, state + min(e, 9)))
             break;
 
-    if (expectEXT(e == 0, false)) {
+    if (expectEXT(e == 1, false)) {
-        return get_rac(c, state + 10) ? -1 : 1;
+        return READ(c, 11) ? -1 : 1;
-    } else if (expectEXT(e > 31, false)) {
+    } else if (expectEXT(e == 33, false)) {
         corrupt = true;
         return 0;
     }
 
-    state += 21;
-
     int a = 1;
-    for (int i = e - 1; i >= 0; i--) {
+    for (uint i = e + 20; i >= 22; i--) {
         a <<= 1;
-        a |= int(get_rac(c, state + min(i, 9)));  // 22..31
+        a |= int(READ(c, min(i, 31)));
     }
 
-    return get_rac(c, state - 11 + min(e, 10)) ? -a : a;
+    return READ(c, min(e + 10, 21)) ? -a : a;
 }
 
 void decode_line_pcm(inout SliceContext sc, ivec2 sp, int w, int y, int p, int bits)
@@ -157,7 +160,7 @@ void decode_line_pcm(inout SliceContext sc, ivec2 sp, int w, int y, int p, int b
 }
 
 void decode_line(inout SliceContext sc, ivec2 sp, int w,
-                 int y, int p, int bits, uint64_t state,
+                 int y, int p, int bits, uint state_off,
                  uint8_t quant_table_idx, const int run_index)
 {
 #ifndef RGB
@@ -171,19 +174,33 @@ void decode_line(inout SliceContext sc, ivec2 sp, int w,
         ivec2 pr = get_pred(sp, ivec2(x, y), p, w,
                             quant_table_idx);
 
-        int diff = get_isymbol(sc.c, state + CONTEXT_SIZE*abs(pr[0]));
+        uint context_off = state_off + CONTEXT_SIZE*abs(pr[0]);
+#ifdef CACHED_SYMBOL_READER
+        u8buf sb = u8buf(uint64_t(slice_state) + context_off + gl_LocalInvocationID.x);
+        state[gl_LocalInvocationID.x] = sb.v;
+        barrier();
+        if (gl_LocalInvocationID.x == 0) {
+
+#endif
+
+            int diff = get_isymbol(sc.c, context_off);
             if (pr[0] < 0)
                 diff = -diff;
 
             uint v = zero_extend(pr[1] + diff, bits);
             imageStore(dec[p], sp + LADDR(ivec2(x, y)), uvec4(v));
+
+#ifdef CACHED_SYMBOL_READER
+        }
+        sb.v = state[gl_LocalInvocationID.x];
+#endif
     }
 }
 
 #else /* GOLOMB */
 
 void decode_line(inout SliceContext sc, ivec2 sp, int w,
-                 int y, int p, int bits, uint64_t state,
+                 int y, int p, int bits, uint state_off,
                  uint8_t quant_table_idx, inout int run_index)
 {
 #ifndef RGB
@@ -202,7 +219,7 @@ void decode_line(inout SliceContext sc, ivec2 sp, int w,
         ivec2 pr = get_pred(sp, ivec2(x, y), p, w,
                             quant_table_idx);
 
-        VlcState sb = VlcState(state + VLC_STATE_SIZE*abs(pr[0]));
+        VlcState sb = VlcState(uint64_t(slice_state) + state_off + VLC_STATE_SIZE*abs(pr[0]));
 
         if (pr[0] == 0 && run_mode == 0)
             run_mode = 1;
@@ -263,7 +280,7 @@ ivec4 transform_sample(ivec4 pix, ivec2 rct_coef)
 
 void writeout_rgb(in SliceContext sc, ivec2 sp, int w, int y, bool apply_rct)
 {
-    for (int x = 0; x < w; x++) {
+    for (uint x = gl_LocalInvocationID.x; x < w; x += gl_WorkGroupSize.x) {
         ivec2 lpos = sp + LADDR(ivec2(x, y));
         ivec2 pos = sc.slice_pos + ivec2(x, y);
 
@@ -305,6 +322,8 @@ void decode_slice(inout SliceContext sc, const uint slice_idx)
     /* PCM coding */
 #ifndef GOLOMB
     if (sc.slice_coding_mode == 1) {
+        if (gl_LocalInvocationID.x > 0)
+            return;
 #ifndef RGB
         for (int p = 0; p < planes; p++) {
             int h = sc.slice_dim.y;
@@ -328,9 +347,7 @@ void decode_slice(inout SliceContext sc, const uint slice_idx)
 #endif
     {
         u8vec4 quant_table_idx = sc.quant_table_idx.xyyz;
-        u64vec4 slice_state_off = (uint64_t(slice_state) +
+        u32vec4 slice_state_off = (slice_idx*codec_planes + uvec4(0, 1, 1, 2))*plane_state_size;
-                                   slice_idx*plane_state_size*codec_planes) +
-                                  plane_state_size*uvec4(0, 1, 1, 2);
 
 #ifndef RGB
         for (int p = 0; p < planes; p++) {

libavcodec/vulkan_ffv1.c

@@ -823,12 +823,14 @@ static int init_decode_shader(FFV1Context *f, FFVulkanContext *s,
     uint8_t *spv_data;
     size_t spv_len;
     void *spv_opaque = NULL;
+    int use_cached_reader = ac != AC_GOLOMB_RICE &&
+                            s->driver_props.driverID == VK_DRIVER_ID_MESA_RADV;
 
     RET(ff_vk_shader_init(s, shd, "ffv1_dec",
                           VK_SHADER_STAGE_COMPUTE_BIT,
                           (const char *[]) { "GL_EXT_buffer_reference",
                                              "GL_EXT_buffer_reference2" }, 2,
-                          1, 1, 1,
+                          use_cached_reader ? CONTEXT_SIZE : 1, 1, 1,
                           0));
 
     if (ac == AC_GOLOMB_RICE)
@@ -837,6 +839,9 @@ static int init_decode_shader(FFV1Context *f, FFVulkanContext *s,
     if (rgb)
         av_bprintf(&shd->src, "#define RGB\n");
 
+    if (use_cached_reader)
+        av_bprintf(&shd->src, "#define CACHED_SYMBOL_READER 1\n");
+
     /* Common codec header */
     GLSLD(ff_source_common_comp);