Make sure the gain map metadata is towards the start of the file. (#2479

)

The 'tmap' item data containing the gain map metadata was mistakenly being put at the end of the file.

src/write.c

@@ -2195,8 +2195,8 @@ static avifResult avifEncoderWriteMediaDataBox(avifEncoder * encoder,
     const size_t mdatStartOffset = avifRWStreamOffset(s);
     for (uint32_t itemPasses = 0; itemPasses < 3; ++itemPasses) {
         // Use multiple passes to pack in the following order:
-        //   * Pass 0: metadata (Exif/XMP)
-        //   * Pass 1: alpha, gain map (AV1)
+        //   * Pass 0: metadata (Exif/XMP/gain map metadata)
+        //   * Pass 1: alpha, gain map image (AV1)
         //   * Pass 2: all other item data (AV1 color)
         //
         // See here for the discussion on alpha coming before color:
@@ -2215,7 +2215,8 @@ static avifResult avifEncoderWriteMediaDataBox(avifEncoder * encoder,
                 // this item has nothing for the mdat box
                 continue;
             }
-            const avifBool isMetadata = !memcmp(item->type, "mime", 4) || !memcmp(item->type, "Exif", 4);
+            const avifBool isMetadata = !memcmp(item->type, "mime", 4) || !memcmp(item->type, "Exif", 4) ||
+                                        !memcmp(item->type, "tmap", 4);
             if (metadataPass != isMetadata) {
                 // only process metadata (XMP/Exif) payloads when metadataPass is true
                 continue;

tests/gtest/avif_fuzztest_dec_incr.cc

@@ -99,7 +99,10 @@ void DecodeIncr(const std::string& arbitrary_bytes, bool is_persistent,
     const uint32_t max_cell_height = reference->height;
     const avifResult result = DecodeIncrementally(
         encoded_data, decoder.get(), is_persistent, give_size_hint,
-        use_nth_image_api, *reference, max_cell_height);
+        use_nth_image_api, *reference, max_cell_height,
+        /*enable_fine_incremental_check=*/false,
+        /*expect_whole_file_read=*/true,
+        /*expect_parse_success_from_partial_file=*/false);
     // The result does not matter, as long as we do not crash.
     (void)result;
   }

tests/gtest/avif_fuzztest_enc_dec_incr.cc

@@ -59,7 +59,9 @@ void EncodeDecodeGridValid(ImagePtr image, EncoderPtr encoder,
 
   const avifResult decode_result = DecodeNonIncrementallyAndIncrementally(
       encoded_data, decoder.get(), is_encoded_data_persistent,
-      give_size_hint_to_decoder, /*use_nth_image_api=*/true, cell_height);
+      give_size_hint_to_decoder, /*use_nth_image_api=*/true, cell_height,
+      /*enable_fine_incremental_check=*/false, /*expect_whole_file_read=*/true,
+      /*expect_parse_success_from_partial_file=*/false);
   ASSERT_EQ(decode_result, AVIF_RESULT_OK) << avifResultToString(decode_result);
 }
 

tests/gtest/avif_fuzztest_enc_dec_incr_experimental.cc

@@ -91,7 +91,8 @@ void EncodeDecodeGridValid(ImagePtr image, EncoderPtr encoder,
   const avifResult decode_result = DecodeNonIncrementallyAndIncrementally(
       encoded_data, decoder.get(), is_encoded_data_persistent,
       give_size_hint_to_decoder, /*use_nth_image_api=*/true, cell_height,
-      /*enable_fine_incremental_check=*/false, expect_whole_file_read);
+      /*enable_fine_incremental_check=*/false, expect_whole_file_read,
+      /*expect_parse_success_from_partial_file=*/false);
   ASSERT_EQ(decode_result, AVIF_RESULT_OK) << avifResultToString(decode_result);
 }
 

tests/gtest/avifgainmaptest.cc

@@ -344,17 +344,18 @@ TEST(GainMapTest, EncodeDecodeGrid) {
   constexpr int kCellHeight = 200;
 
   for (int i = 0; i < kGridCols * kGridRows; ++i) {
+    const int gradient_offset = i * 10;
     ImagePtr image =
         testutil::CreateImage(kCellWidth, kCellHeight, /*depth=*/10,
                               AVIF_PIXEL_FORMAT_YUV444, AVIF_PLANES_ALL);
     ASSERT_NE(image, nullptr);
     image->transferCharacteristics = AVIF_TRANSFER_CHARACTERISTICS_PQ;
-    testutil::FillImageGradient(image.get());
+    testutil::FillImageGradient(image.get(), gradient_offset);
     ImagePtr gain_map =
         testutil::CreateImage(kCellWidth / 2, kCellHeight / 2, /*depth=*/8,
                               AVIF_PIXEL_FORMAT_YUV420, AVIF_PLANES_YUV);
     ASSERT_NE(gain_map, nullptr);
-    testutil::FillImageGradient(gain_map.get());
+    testutil::FillImageGradient(gain_map.get(), gradient_offset);
     // 'image' now owns the gain map.
     image->gainMap = avifGainMapCreate();
     ASSERT_NE(image->gainMap, nullptr);
@@ -422,7 +423,8 @@ TEST(GainMapTest, EncodeDecodeGrid) {
                 /*is_persistent=*/true, /*give_size_hint=*/true,
                 /*use_nth_image_api=*/false, kCellHeight,
                 /*enable_fine_incremental_check=*/true),
-            AVIF_RESULT_OK);
+            AVIF_RESULT_OK)
+      << decoder->diag.error;
 
   // Uncomment the following to save the encoded image as an AVIF file.
   //  std::ofstream("/tmp/avifgainmaptest_grid.avif", std::ios::binary)

tests/gtest/avifincrtest_helpers.cc

@@ -80,8 +80,8 @@ void ComparePartialYuva(const avifImage& image1, const avifImage& image2,
 // byte_count were given to the decoder, for an image of height rows, split into
 // cells of cell_height rows.
 uint32_t GetMinDecodedRowCount(uint32_t height, uint32_t cell_height,
-                               bool has_alpha, size_t available_byte_count,
-                               size_t byte_count,
+                               bool has_alpha, bool has_gain_map,
+                               size_t available_byte_count, size_t byte_count,
                                bool enable_fine_incremental_check) {
   // The whole image should be available when the full input is.
   if (available_byte_count >= byte_count) {
@@ -104,15 +104,17 @@ uint32_t GetMinDecodedRowCount(uint32_t height, uint32_t cell_height,
   }
   available_byte_count -= 500;
   byte_count -= 500;
-  // Alpha, if any, is assumed to be located before the other planes and to
-  // represent at most 50% of the payload.
-  if (has_alpha) {
-    if (available_byte_count <= (byte_count / 2)) {
-      return 0;
-    }
-    available_byte_count -= byte_count / 2;
-    byte_count -= byte_count / 2;
+  // Extra planes (alpha, gain map), if any, are assumed to be located before
+  // the color planes. It's assumed that each extra planes is at most
+  // total_size / (1 + num_extra_planes).
+  const int num_extra_planes = (has_alpha ? 1 : 0) + (has_gain_map ? 1 : 0);
+  const size_t max_size_of_extra_planes = static_cast<size_t>(
+      (byte_count / (num_extra_planes + 1)) * num_extra_planes);
+  if (available_byte_count <= max_size_of_extra_planes) {
+    return 0;
   }
+  available_byte_count -= max_size_of_extra_planes;
+  byte_count -= max_size_of_extra_planes;
   // Linearly map the input availability ratio to the decoded row ratio.
   const uint32_t min_decoded_cell_row_count = static_cast<uint32_t>(
       (height / cell_height) * available_byte_count / byte_count);
@@ -295,7 +297,8 @@ avifResult DecodeIncrementally(const avifRWData& encoded_avif,
                                bool give_size_hint, bool use_nth_image_api,
                                const avifImage& reference, uint32_t cell_height,
                                bool enable_fine_incremental_check,
-                               bool expect_whole_file_read) {
+                               bool expect_whole_file_read,
+                               bool expect_parse_success_from_partial_file) {
   // AVIF cells are at least 64 pixels tall.
   if (cell_height != reference.height) {
     AVIF_CHECKERR(cell_height >= 64u, AVIF_RESULT_INVALID_ARGUMENT);
@@ -332,6 +335,15 @@ avifResult DecodeIncrementally(const avifRWData& encoded_avif,
     data.available.size = std::min(data.available.size + step, data.full_size);
     parse_result = avifDecoderParse(decoder);
   }
+  if (data.available.size == data.full_size &&
+      expect_parse_success_from_partial_file) {
+    // Can happen if the data is in 'idat', or if some metadata is at the end of
+    // the file. But ideally this should be avoided.
+    printf(
+        "ERROR: had to provide the whole file for avifDecoderParse() to "
+        "succeed\n");
+    AVIF_CHECKERR(false, AVIF_RESULT_INVALID_ARGUMENT);
+  }
   AVIF_CHECKRES(parse_result);
 
   // Decoding is incremental.
@@ -344,16 +356,29 @@ avifResult DecodeIncrementally(const avifRWData& encoded_avif,
       std::cerr << (use_nth_image_api ? "avifDecoderNthImage(0)"
                                       : "avifDecoderNextImage()")
                 << " returned WAITING_ON_IO instead of OK";
-      return AVIF_RESULT_INVALID_ARGUMENT;
+      AVIF_CHECKERR(false, AVIF_RESULT_INVALID_ARGUMENT);
     }
     const uint32_t decoded_row_count = avifDecoderDecodedRowCount(decoder);
-    AVIF_CHECKERR(decoded_row_count >= previously_decoded_row_count,
-                  AVIF_RESULT_INVALID_ARGUMENT);
+    if (decoded_row_count < previously_decoded_row_count) {
+      printf("ERROR: decoded row count decreased from %d to %d\n",
+             previously_decoded_row_count, decoded_row_count);
+      AVIF_CHECKERR(false, AVIF_RESULT_INVALID_ARGUMENT);
+    }
+    bool has_gain_map = false;
+#if defined(AVIF_ENABLE_EXPERIMENTAL_GAIN_MAP)
+    has_gain_map = (reference.gainMap != nullptr);
+#endif
     const uint32_t min_decoded_row_count = GetMinDecodedRowCount(
         reference.height, cell_height, reference.alphaPlane != nullptr,
-        data.available.size, data.full_size, enable_fine_incremental_check);
-    AVIF_CHECKERR(decoded_row_count >= min_decoded_row_count,
-                  AVIF_RESULT_INVALID_ARGUMENT);
+        has_gain_map, data.available.size, data.full_size,
+        enable_fine_incremental_check);
+    if (decoded_row_count < min_decoded_row_count) {
+      printf(
+          "ERROR: expected to have decoded at least %d rows with %zu available "
+          "bytes, but only %d were decoded\n",
+          min_decoded_row_count, data.available.size, decoded_row_count);
+      AVIF_CHECKERR(false, AVIF_RESULT_INVALID_ARGUMENT);
+    }
     ComparePartialYuva(reference, *decoder->image, decoded_row_count);
 
     previously_decoded_row_count = decoded_row_count;
@@ -376,19 +401,18 @@ avifResult DecodeIncrementally(const avifRWData& encoded_avif,
 avifResult DecodeNonIncrementallyAndIncrementally(
     const avifRWData& encoded_avif, avifDecoder* decoder, bool is_persistent,
     bool give_size_hint, bool use_nth_image_api, uint32_t cell_height,
-    bool enable_fine_incremental_check, bool expect_whole_file_read) {
+    bool enable_fine_incremental_check, bool expect_whole_file_read,
+    bool expect_parse_success_from_partial_file) {
   ImagePtr reference(avifImageCreateEmpty());
   if (reference == nullptr) return AVIF_RESULT_INVALID_ARGUMENT;
   decoder->allowIncremental = AVIF_FALSE;
-  if (avifDecoderReadMemory(decoder, reference.get(), encoded_avif.data,
-                            encoded_avif.size) != AVIF_RESULT_OK) {
-    return AVIF_RESULT_INVALID_ARGUMENT;
-  }
+  AVIF_CHECKRES(avifDecoderReadMemory(decoder, reference.get(),
+                                      encoded_avif.data, encoded_avif.size));
 
   const avifResult result = DecodeIncrementally(
       encoded_avif, decoder, is_persistent, give_size_hint, use_nth_image_api,
       *reference, cell_height, enable_fine_incremental_check,
-      expect_whole_file_read);
+      expect_whole_file_read, expect_parse_success_from_partial_file);
   return result;
 }
 

tests/gtest/avifincrtest_helpers.h

@@ -52,20 +52,26 @@ void EncodeRectAsIncremental(const avifImage& image, uint32_t width,
 // incremental granularity. enable_fine_incremental_check checks that sample
 // rows are gradually output when feeding more and more input bytes to the
 // decoder.
-avifResult DecodeIncrementally(const avifRWData& encoded_avif,
-                               avifDecoder* decoder, bool is_persistent,
-                               bool give_size_hint, bool use_nth_image_api,
-                               const avifImage& reference, uint32_t cell_height,
-                               bool enable_fine_incremental_check = false,
-                               bool expect_whole_file_read = true);
+// If 'expect_parse_success_from_partial_file' is true, avifDecoderParse
+// should succeed before the whole file is available. Returns an error
+// if avifDecoderParse fails until all the bytes are available.
+// `expect_parse_success_from_partial_file` should be set to false if the file
+// may be using 'idat' or may have some metadata at the end of the file.
+avifResult DecodeIncrementally(
+    const avifRWData& encoded_avif, avifDecoder* decoder, bool is_persistent,
+    bool give_size_hint, bool use_nth_image_api, const avifImage& reference,
+    uint32_t cell_height, bool enable_fine_incremental_check = false,
+    bool expect_whole_file_read = true,
+    bool expect_parse_success_from_partial_file = true);
 
 // Calls DecodeIncrementally() with the reference being a regular decoding of
 // encoded_avif.
 avifResult DecodeNonIncrementallyAndIncrementally(
     const avifRWData& encoded_avif, avifDecoder* decoder, bool is_persistent,
     bool give_size_hint, bool use_nth_image_api, uint32_t cell_height,
     bool enable_fine_incremental_check = false,
-    bool expect_whole_file_read = true);
+    bool expect_whole_file_read = true,
+    bool expect_parse_success_from_partial_file = true);
 
 }  // namespace testutil
 }  // namespace avif

tests/gtest/aviftest_helpers.cc

@@ -145,7 +145,7 @@ void FillImagePlain(avifImage* image, const uint32_t yuva[4]) {
   }
 }
 
-void FillImageGradient(avifImage* image) {
+void FillImageGradient(avifImage* image, int offset) {
   for (avifChannelIndex c :
        {AVIF_CHAN_Y, AVIF_CHAN_U, AVIF_CHAN_V, AVIF_CHAN_A}) {
     const uint32_t limitedRangeMin =
@@ -158,16 +158,17 @@ void FillImageGradient(avifImage* image) {
     const uint32_t plane_height = avifImagePlaneHeight(image, c);
     uint8_t* row = avifImagePlane(image, c);
     const uint32_t row_bytes = avifImagePlaneRowBytes(image, c);
+    const uint32_t max_xy_sum = plane_width + plane_height - 2;
     for (uint32_t y = 0; y < plane_height; ++y) {
       for (uint32_t x = 0; x < plane_width; ++x) {
-        uint32_t value;
+        uint32_t value = (x + y + offset) % (max_xy_sum + 1);
         if (image->yuvRange == AVIF_RANGE_FULL || c == AVIF_CHAN_A) {
-          value = (x + y) * ((1u << image->depth) - 1u) /
-                  std::max(1u, plane_width + plane_height - 2);
+          value =
+              value * ((1u << image->depth) - 1u) / std::max(1u, max_xy_sum);
         } else {
-          value = limitedRangeMin +
-                  (x + y) * (limitedRangeMax - limitedRangeMin) /
-                      std::max(1u, plane_width + plane_height - 2);
+          value = limitedRangeMin + value *
+                                        (limitedRangeMax - limitedRangeMin) /
+                                        std::max(1u, max_xy_sum);
         }
         if (avifImageUsesU16(image)) {
           reinterpret_cast<uint16_t*>(row)[x] = static_cast<uint16_t>(value);

tests/gtest/aviftest_helpers.h

@@ -115,7 +115,9 @@ ImagePtr CreateImage(int width, int height, int depth,
 
 // Set all pixels of each plane of an image.
 void FillImagePlain(avifImage* image, const uint32_t yuva[4]);
-void FillImageGradient(avifImage* image);
+// 'offset' is a value to spatially offset the gradient, useful to create
+// distinct images.
+void FillImageGradient(avifImage* image, int offset = 0);
 void FillImageChannel(avifRGBImage* image, uint32_t channel_offset,
                       uint32_t value);