Remove AVIF_HEADER_DEFAULT

AOMediaCodec · Aug 20, 2024 · 9859239 · 9859239
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commit 9859239
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Showing 5 changed files with 26 additions and 32 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -17,8 +17,7 @@ The changes are relative to the previous release, unless the baseline is specifi
   draft.
 * Ignore gain maps with unsupported metadata. Handle gain maps with
   writer_version > 0 correctly.
-* Add AVIF_HEADER_DEFAULT which writes an empty HandlerBox name field instead of
-  "libavif". Select AVIF_HEADER_DEFAULT by default in avifEncoderCreate().
+* Write an empty HandlerBox name field instead of "libavif" (saves 7 bytes).
 
 ## [1.1.1] - 2024-07-30
 

diff --git a/apps/avifenc.c b/apps/avifenc.c
@@ -1398,7 +1398,7 @@ int main(int argc, char * argv[])
     settings.layered = AVIF_FALSE;
     settings.layers = 0;
     settings.speed = 6;
-    settings.headerFormat = AVIF_HEADER_DEFAULT;
+    settings.headerFormat = AVIF_HEADER_FULL;
     settings.repetitionCount = AVIF_REPETITION_COUNT_INFINITE;
     settings.keyframeInterval = 0;
     settings.ignoreExif = AVIF_FALSE;

diff --git a/include/avif/avif.h b/include/avif/avif.h
@@ -216,8 +216,6 @@ typedef enum avifHeaderFormat
 {
     // AVIF file with an "avif" brand, a MetaBox and all its required boxes for maximum compatibility.
     AVIF_HEADER_FULL,
-    // Same as AVIF_HEADER_FULL but the name field of the HandlerBox is empty instead of "libavif".
-    AVIF_HEADER_DEFAULT,
 #if defined(AVIF_ENABLE_EXPERIMENTAL_MINI)
     // AVIF file with a "mif3" brand and a MinimizedImageBox to reduce the encoded file size.
     // This is based on the w24144 "Low-overhead image file format" MPEG proposal for HEIF.

diff --git a/src/write.c b/src/write.c
@@ -484,7 +484,7 @@ avifEncoder * avifEncoderCreate(void)
         avifEncoderDestroy(encoder);
         return NULL;
     }
-    encoder->headerFormat = AVIF_HEADER_DEFAULT;
+    encoder->headerFormat = AVIF_HEADER_FULL;
 #if defined(AVIF_ENABLE_EXPERIMENTAL_SAMPLE_TRANSFORM)
     encoder->sampleTransformRecipe = AVIF_SAMPLE_TRANSFORM_NONE;
 #endif
@@ -773,16 +773,12 @@ static avifResult avifEncoderWriteExtendedColorProperties(avifRWStream * dedupSt
 
 static avifResult avifEncoderWriteHandlerBox(avifEncoder * encoder, avifRWStream * s, const char handler_type[4])
 {
-    // ISO/IEC 14496-12, Section 8.4.3.3:
-    //   name gives a human-readable name for the track type (for debugging and inspection purposes).
-    const char * handlerName = encoder->headerFormat == AVIF_HEADER_FULL ? "libavif" : "";
-
     avifBoxMarker hdlr;
     AVIF_CHECKRES(avifRWStreamWriteFullBox(s, "hdlr", AVIF_BOX_SIZE_TBD, 0, 0, &hdlr));
-    AVIF_CHECKRES(avifRWStreamWriteU32(s, 0));                                      // unsigned int(32) pre_defined = 0;
-    AVIF_CHECKRES(avifRWStreamWriteChars(s, handler_type, 4));                      // unsigned int(32) handler_type;
-    AVIF_CHECKRES(avifRWStreamWriteZeros(s, 12));                                   // const unsigned int(32)[3] reserved = 0;
-    AVIF_CHECKRES(avifRWStreamWriteChars(s, handlerName, strlen(handlerName) + 1)); // string name; (writing null terminator)
+    AVIF_CHECKRES(avifRWStreamWriteU32(s, 0));                 // unsigned int(32) pre_defined = 0;
+    AVIF_CHECKRES(avifRWStreamWriteChars(s, handler_type, 4)); // unsigned int(32) handler_type;
+    AVIF_CHECKRES(avifRWStreamWriteZeros(s, 12));              // const unsigned int(32)[3] reserved = 0;
+    AVIF_CHECKRES(avifRWStreamWriteChars(s, "", 1));           // string name; (writing null terminator)
     avifRWStreamFinishBox(s, hdlr);
     return AVIF_RESULT_OK;
 }

diff --git a/tests/gtest/avifheadertest.cc b/tests/gtest/avifheadertest.cc
@@ -1,6 +1,8 @@
 // Copyright 2024 Google LLC
 // SPDX-License-Identifier: BSD-2-Clause
 
+#include <algorithm>
+
 #include "avif/avif.h"
 #include "aviftest_helpers.h"
 #include "gtest/gtest.h"
@@ -13,25 +15,24 @@ TEST(BasicTest, EncodeDecode) {
                                          AVIF_PLANES_ALL);
   ASSERT_NE(image, nullptr);
   testutil::FillImageGradient(image.get());
+  const testutil::AvifRwData avif = testutil::Encode(image.get());
+  ASSERT_NE(avif.data, nullptr);
 
-  EncoderPtr encoder_header_full(avifEncoderCreate());
-  ASSERT_NE(encoder_header_full, nullptr);
-  encoder_header_full->headerFormat = AVIF_HEADER_FULL;
-  testutil::AvifRwData encoded_header_full;
-  ASSERT_EQ(avifEncoderWrite(encoder_header_full.get(), image.get(),
-                             &encoded_header_full),
-            AVIF_RESULT_OK);
-
-  EncoderPtr encoder_header_default(avifEncoderCreate());
-  ASSERT_NE(encoder_header_default, nullptr);
-  encoder_header_default->headerFormat = AVIF_HEADER_DEFAULT;
-  testutil::AvifRwData encoded_header_default;
-  ASSERT_EQ(avifEncoderWrite(encoder_header_default.get(), image.get(),
-                             &encoded_header_default),
-            AVIF_RESULT_OK);
-
-  // AVIF_HEADER_DEFAULT saves 7 bytes by omitting "libavif" as 'hdlr' name.
-  EXPECT_EQ(encoded_header_full.size, encoded_header_default.size + 7);
+  // Make sure the HandlerBox is as small as possible, meaning its name field is
+  // empty.
+  const uint8_t* kHdlr = reinterpret_cast<const uint8_t*>("hdlr");
+  uint8_t* hdlr_position =
+      std::search(avif.data, avif.data + avif.size, kHdlr, kHdlr + 4);
+  ASSERT_NE(hdlr_position, avif.data + avif.size);
+  // The previous four bytes represent the size of the box as a big endian
+  // unsigned integer.
+  constexpr uint8_t kExpectedHdlrSize =
+      /*size field*/ 4 + /*"hdlr"*/ 4 + /*version*/ 3 + /*flags*/ 1 +
+      /*pre_defined*/ 4 + /*handler_type*/ 4 + /*reserved*/ 4 * 3 + /*name*/ 1;
+  ASSERT_EQ(hdlr_position[-4], 0);
+  ASSERT_EQ(hdlr_position[-3], 0);
+  ASSERT_EQ(hdlr_position[-2], 0);
+  ASSERT_EQ(hdlr_position[-1], kExpectedHdlrSize);
 }
 
 }  // namespace