[FFmpeg-devel] [PATCH 2/6] cbs_h2645: Simplify representation of fixed values

Mark Thompson sw at jkqxz.net
Tue May 1 02:26:01 EEST 2018


---
Mainly to avoid messing with them in the following patch.


 libavcodec/cbs_h2645.c                |  5 +++++
 libavcodec/cbs_h264_syntax_template.c | 30 ++++++++++++---------------
 libavcodec/cbs_h265_syntax_template.c | 38 +++++++++++++++--------------------
 3 files changed, 34 insertions(+), 39 deletions(-)

diff --git a/libavcodec/cbs_h2645.c b/libavcodec/cbs_h2645.c
index 5585831cf6..c243dc7da4 100644
--- a/libavcodec/cbs_h2645.c
+++ b/libavcodec/cbs_h2645.c
@@ -239,6 +239,11 @@ static int cbs_write_se_golomb(CodedBitstreamContext *ctx, PutBitContext *pbc,
 #define FUNC_H264(rw, name) FUNC_NAME(rw, h264, name)
 #define FUNC_H265(rw, name) FUNC_NAME(rw, h265, name)
 
+#define fixed(width, name, value) do { \
+        av_unused uint32_t fixed_value = value; \
+        xu(width, name, fixed_value, value, value); \
+    } while (0)
+
 
 #define READ
 #define READWRITE read
diff --git a/libavcodec/cbs_h264_syntax_template.c b/libavcodec/cbs_h264_syntax_template.c
index b5cd0b2310..7c507b9a13 100644
--- a/libavcodec/cbs_h264_syntax_template.c
+++ b/libavcodec/cbs_h264_syntax_template.c
@@ -19,10 +19,10 @@
 static int FUNC(rbsp_trailing_bits)(CodedBitstreamContext *ctx, RWContext *rw)
 {
     int err;
-    av_unused int one = 1, zero = 0;
-    xu(1, rbsp_stop_one_bit, one, 1, 1);
+
+    fixed(1, rbsp_stop_one_bit, 1);
     while (byte_alignment(rw) != 0)
-        xu(1, rbsp_alignment_zero_bit, zero, 0, 0);
+        fixed(1, rbsp_alignment_zero_bit, 0);
 
     return 0;
 }
@@ -740,9 +740,8 @@ static int FUNC(sei_payload)(CodedBitstreamContext *ctx, RWContext *rw,
         break;
     case H264_SEI_TYPE_FILLER_PAYLOAD:
         {
-            av_unused int ff_byte = 0xff;
             for (i = 0; i  < current->payload_size; i++)
-                xu(8, ff_byte, ff_byte, 0xff, 0xff);
+                fixed(8, ff_byte, 0xff);
         }
         break;
     case H264_SEI_TYPE_USER_DATA_REGISTERED:
@@ -770,10 +769,9 @@ static int FUNC(sei_payload)(CodedBitstreamContext *ctx, RWContext *rw,
     }
 
     if (byte_alignment(rw)) {
-        av_unused int one = 1, zero = 0;
-        xu(1, bit_equal_to_one, one, 1, 1);
+        fixed(1, bit_equal_to_one, 1);
         while (byte_alignment(rw))
-            xu(1, bit_equal_to_zero, zero, 0, 0);
+            fixed(1, bit_equal_to_zero, 0);
     }
 
 #ifdef READ
@@ -810,14 +808,14 @@ static int FUNC(sei)(CodedBitstreamContext *ctx, RWContext *rw,
         uint32_t tmp;
 
         while (show_bits(rw, 8) == 0xff) {
-            xu(8, ff_byte, tmp, 0xff, 0xff);
+            fixed(8, ff_byte, 0xff);
             payload_type += 255;
         }
         xu(8, last_payload_type_byte, tmp, 0, 254);
         payload_type += tmp;
 
         while (show_bits(rw, 8) == 0xff) {
-            xu(8, ff_byte, tmp, 0xff, 0xff);
+            fixed(8, ff_byte, 0xff);
             payload_size += 255;
         }
         xu(8, last_payload_size_byte, tmp, 0, 254);
@@ -853,14 +851,14 @@ static int FUNC(sei)(CodedBitstreamContext *ctx, RWContext *rw,
 
             tmp = current->payload[k].payload_type;
             while (tmp >= 255) {
-                xu(8, ff_byte, 0xff, 0xff, 0xff);
+                fixed(8, ff_byte, 0xff);
                 tmp -= 255;
             }
             xu(8, last_payload_type_byte, tmp, 0, 254);
 
             tmp = current->payload[k].payload_size;
             while (tmp >= 255) {
-                xu(8, ff_byte, 0xff, 0xff, 0xff);
+                fixed(8, ff_byte, 0xff);
                 tmp -= 255;
             }
             xu(8, last_payload_size_byte, tmp, 0, 254);
@@ -1240,9 +1238,8 @@ static int FUNC(slice_header)(CodedBitstreamContext *ctx, RWContext *rw,
     }
 
     if (pps->entropy_coding_mode_flag) {
-        av_unused int one = 1;
         while (byte_alignment(rw))
-            xu(1, cabac_alignment_one_bit, one, 1, 1);
+            fixed(1, cabac_alignment_one_bit, 1);
     }
 
     return 0;
@@ -1251,7 +1248,6 @@ static int FUNC(slice_header)(CodedBitstreamContext *ctx, RWContext *rw,
 static int FUNC(filler)(CodedBitstreamContext *ctx, RWContext *rw,
                         H264RawFiller *current)
 {
-    av_unused int ff_byte = 0xff;
     int err;
 
     HEADER("Filler Data");
@@ -1261,14 +1257,14 @@ static int FUNC(filler)(CodedBitstreamContext *ctx, RWContext *rw,
 
 #ifdef READ
     while (show_bits(rw, 8) == 0xff) {
-        xu(8, ff_byte, ff_byte, 0xff, 0xff);
+        fixed(8, ff_byte, 0xff);
         ++current->filler_size;
     }
 #else
     {
         uint32_t i;
         for (i = 0; i < current->filler_size; i++)
-            xu(8, ff_byte, ff_byte, 0xff, 0xff);
+            fixed(8, ff_byte, 0xff);
     }
 #endif
 
diff --git a/libavcodec/cbs_h265_syntax_template.c b/libavcodec/cbs_h265_syntax_template.c
index 140c827c9d..58a79f3014 100644
--- a/libavcodec/cbs_h265_syntax_template.c
+++ b/libavcodec/cbs_h265_syntax_template.c
@@ -19,10 +19,10 @@
 static int FUNC(rbsp_trailing_bits)(CodedBitstreamContext *ctx, RWContext *rw)
 {
     int err;
-    av_unused int one = 1, zero = 0;
-    xu(1, rbsp_stop_one_bit, one, 1, 1);
+
+    fixed(1, rbsp_stop_one_bit, 1);
     while (byte_alignment(rw) != 0)
-        xu(1, rbsp_alignment_zero_bit, zero, 0, 0);
+        fixed(1, rbsp_alignment_zero_bit, 0);
 
     return 0;
 }
@@ -50,10 +50,10 @@ static int FUNC(nal_unit_header)(CodedBitstreamContext *ctx, RWContext *rw,
 static int FUNC(byte_alignment)(CodedBitstreamContext *ctx, RWContext *rw)
 {
     int err;
-    av_unused int one = 1, zero = 0;
-    xu(1, alignment_bit_equal_to_one, one, 1, 1);
+
+    fixed(1, alignment_bit_equal_to_one, 1);
     while (byte_alignment(rw) != 0)
-        xu(1, alignment_bit_equal_to_zero, zero, 0, 0);
+        fixed(1, alignment_bit_equal_to_zero, 0);
 
     return 0;
 }
@@ -90,7 +90,6 @@ static int FUNC(profile_tier_level)(CodedBitstreamContext *ctx, RWContext *rw,
                                     int profile_present_flag,
                                     int max_num_sub_layers_minus1)
 {
-    av_unused unsigned int zero = 0;
     int err, i, j;
 
     if (profile_present_flag) {
@@ -125,15 +124,15 @@ static int FUNC(profile_tier_level)(CodedBitstreamContext *ctx, RWContext *rw,
             if (profile_compatible(5) || profile_compatible(9) ||
                 profile_compatible(10)) {
                 flag(general_max_14bit_constraint_flag);
-                xu(24, general_reserved_zero_33bits, zero, 0, 0);
-                xu(9, general_reserved_zero_33bits, zero, 0, 0);
+                fixed(24, general_reserved_zero_33bits, 0);
+                fixed( 9, general_reserved_zero_33bits, 0);
             } else {
-                xu(24, general_reserved_zero_34bits, zero, 0, 0);
-                xu(10, general_reserved_zero_34bits, zero, 0, 0);
+                fixed(24, general_reserved_zero_34bits, 0);
+                fixed(10, general_reserved_zero_34bits, 0);
             }
         } else {
-            xu(24, general_reserved_zero_43bits, zero, 0, 0);
-            xu(19, general_reserved_zero_43bits, zero, 0, 0);
+            fixed(24, general_reserved_zero_43bits, 0);
+            fixed(19, general_reserved_zero_43bits, 0);
         }
 
         if (profile_compatible(1) || profile_compatible(2) ||
@@ -141,7 +140,7 @@ static int FUNC(profile_tier_level)(CodedBitstreamContext *ctx, RWContext *rw,
             profile_compatible(5) || profile_compatible(9)) {
             flag(general_inbld_flag);
         } else {
-            xu(1, general_reserved_zero_bit, zero, 0, 0);
+            fixed(1, general_reserved_zero_bit, 0);
         }
 #undef profile_compatible
     }
@@ -154,10 +153,8 @@ static int FUNC(profile_tier_level)(CodedBitstreamContext *ctx, RWContext *rw,
     }
 
     if (max_num_sub_layers_minus1 > 0) {
-        for (i = max_num_sub_layers_minus1; i < 8; i++) {
-            av_unused int zero = 0;
-            xu(2, reserved_zero_2bits, zero, 0, 0);
-        }
+        for (i = max_num_sub_layers_minus1; i < 8; i++)
+            fixed(2, reserved_zero_2bits, 0);
     }
 
     for (i = 0; i < max_num_sub_layers_minus1; i++) {
@@ -386,10 +383,7 @@ static int FUNC(vps)(CodedBitstreamContext *ctx, RWContext *rw,
         return AVERROR_INVALIDDATA;
     }
 
-    {
-        av_unused uint16_t ffff = 0xffff;
-        xu(16, vps_reserved_0xffff_16bits, ffff, 0xffff, 0xffff);
-    }
+    fixed(16, vps_reserved_0xffff_16bits, 0xffff);
 
     CHECK(FUNC(profile_tier_level)(ctx, rw, &current->profile_tier_level,
                                    1, current->vps_max_sub_layers_minus1));
-- 
2.16.3



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