Change gain map parsing API.

CHANGELOG.md

@@ -17,6 +17,11 @@ 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.
+ The combination of settings enableParsingGainMapMetadata=false with
+ enableDecodingGainMap=true is no longer allowed and returns and invalid argument
+ error.
+ The `gainMapPresent` field is now only populated if enableParsingGainMapMetadata
+ is true.
 
 ## [1.1.1] - 2024-07-30
 

apps/avifgainmaputil/extractgainmap_command.cc

@@ -21,6 +21,7 @@ avifResult ExtractGainMapCommand::Run() {
  if (decoder == NULL) {
  return AVIF_RESULT_OUT_OF_MEMORY;
  }
+ decoder->enableParsingGainMapMetadata = true;
  decoder->enableDecodingGainMap = true;
  decoder->ignoreColorAndAlpha = true;
 

include/avif/avif.h

@@ -1312,28 +1312,20 @@ typedef struct avifDecoder
  // Version 1.1.0 ends here. Add any new members after this line.
 
 #if defined(AVIF_ENABLE_EXPERIMENTAL_GAIN_MAP)
- // Enable decoding the gain map image if present (defaults to AVIF_FALSE)
- // (see also 'enableParsingGainMapMetadata' below).
- // If 'enableParsingGainMapMetadata' is also true, the gain map is only decoded if
- // the gan map's metadata is a supported version.
- // 'gainMapPresent' is still set if the presence of a gain map is detected, regardless
- // of this setting.
- avifBool enableDecodingGainMap;
  // Enable parsing the gain map metadata if present (defaults to AVIF_FALSE).
- // This setting can affect the value of 'gainMapPresent', see the description of
- // 'gainMapPresent' below.
  // Gain map metadata is read during avifDecoderParse(). Like Exif and XMP, this data
  // can be (unfortunately) packed at the end of the file, which will cause
  // avifDecoderParse() to return AVIF_RESULT_WAITING_ON_IO until it finds it.
  // If you don't actually use this data, it's best to leave this to AVIF_FALSE (default).
  avifBool enableParsingGainMapMetadata;
+ // Enable decoding the gain map image if present (defaults to AVIF_FALSE).
+ // If set to true, enableParsingGainMapMetadata must also be true.
+ avifBool enableDecodingGainMap;
  // Do not decode the color/alpha planes of the main image.
  // Can be useful to decode the gain map image only.
  avifBool ignoreColorAndAlpha;
- // If 'enableParsingGainMapMetadata' is false: gainMapPresent is true when avifDecoderParse()
- // detects a gain map.
- // If 'enableParsingGainMapMetadata' is true: gainMapPresent is true when avifDecoderParse()
- // detects a gain map whose metadata is a supported version.
+ // True when avifDecoderParse() detects a supported gain map.
+ // Requires enableParsingGainMapMetadata to be set to true.
  avifBool gainMapPresent;
 #endif
 } avifDecoder;

src/read.c

@@ -4495,6 +4495,12 @@ avifResult avifDecoderParse(avifDecoder * decoder)
  if (!decoder->io || !decoder->io->read) {
  return AVIF_RESULT_IO_NOT_SET;
  }
+#if defined(AVIF_ENABLE_EXPERIMENTAL_GAIN_MAP)
+ if (decoder->enableDecodingGainMap && !decoder->enableParsingGainMapMetadata) {
+ avifDiagnosticsPrintf(&decoder->diag, "If enableDecodingGainMap is true, enableParsingGainMapMetadata must also be true");
+ return AVIF_RESULT_INVALID_ARGUMENT;
+ }
+#endif
 
  // Cleanup anything lingering in the decoder
  avifDecoderCleanup(decoder);
@@ -5367,46 +5373,36 @@ avifResult avifDecoderReset(avifDecoder * decoder)
  }
 
 #if defined(AVIF_ENABLE_EXPERIMENTAL_GAIN_MAP)
- avifDecoderItem * toneMappedImageItem;
- const avifResult findGainMapResult = avifDecoderFindGainMapItem(decoder,
- mainItems[AVIF_ITEM_COLOR],
- &toneMappedImageItem,
- &mainItems[AVIF_ITEM_GAIN_MAP],
- &codecType[AVIF_ITEM_GAIN_MAP]);
- if (!decoder->enableDecodingGainMap) {
- // When ignoring the gain map, we still report whether one is present or not,
- // but do not fail if there was any error with the gain map.
- if (findGainMapResult != AVIF_RESULT_OK) {
- // Only ignore reproducible errors (caused by the bitstream and not by the environment).
- AVIF_CHECKERR(findGainMapResult != AVIF_RESULT_OUT_OF_MEMORY, findGainMapResult);
- // Clear diagnostic message.
- avifDiagnosticsClearError(data->diag);
- }
- decoder->gainMapPresent = (mainItems[AVIF_ITEM_GAIN_MAP] != NULL);
- // We also ignore the actual item and don't decode it.
- mainItems[AVIF_ITEM_GAIN_MAP] = NULL;
- } else {
- AVIF_CHECKRES(findGainMapResult);
- }
- if (toneMappedImageItem != NULL && decoder->enableParsingGainMapMetadata) {
- // Read the gain map's metadata.
- avifROData tmapData;
- AVIF_CHECKRES(avifDecoderItemRead(toneMappedImageItem, decoder->io, &tmapData, 0, 0, data->diag));
- if (decoder->image->gainMap == NULL) {
- decoder->image->gainMap = avifGainMapCreate();
- AVIF_CHECKERR(decoder->image->gainMap, AVIF_RESULT_OUT_OF_MEMORY);
- }
- const avifResult tmapParsingRes =
- avifParseToneMappedImageBox(&decoder->image->gainMap->metadata, tmapData.data, tmapData.size, data->diag);
- if (tmapParsingRes == AVIF_RESULT_NOT_IMPLEMENTED) {
- // Forget about the gain map.
- toneMappedImageItem = NULL;
- mainItems[AVIF_ITEM_GAIN_MAP] = NULL;
- avifGainMapDestroy(decoder->image->gainMap);
- decoder->image->gainMap = NULL;
- decoder->gainMapPresent = AVIF_FALSE;
- } else {
- AVIF_CHECKRES(tmapParsingRes);
+ if (decoder->enableParsingGainMapMetadata) {
+ avifDecoderItem * toneMappedImageItem;
+ avifDecoderItem * gainMapItem;
+ avifCodecType gainMapCodecType;
+ AVIF_CHECKRES(
+ avifDecoderFindGainMapItem(decoder, mainItems[AVIF_ITEM_COLOR], &toneMappedImageItem, &gainMapItem, &gainMapCodecType));
+ if (toneMappedImageItem != NULL) {
+ // Read the gain map's metadata.
+ avifROData tmapData;
+ AVIF_CHECKRES(avifDecoderItemRead(toneMappedImageItem, decoder->io, &tmapData, 0, 0, data->diag));
+ if (decoder->image->gainMap == NULL) {
+ decoder->image->gainMap = avifGainMapCreate();
+ AVIF_CHECKERR(decoder->image->gainMap, AVIF_RESULT_OUT_OF_MEMORY);
+ }
+ const avifResult tmapParsingRes =
+ avifParseToneMappedImageBox(&decoder->image->gainMap->metadata, tmapData.data, tmapData.size, data->diag);
+ if (tmapParsingRes != AVIF_RESULT_OK) {
+ avifGainMapDestroy(decoder->image->gainMap);
+ decoder->image->gainMap = NULL;
+ }
+ if (tmapParsingRes == AVIF_RESULT_NOT_IMPLEMENTED) {
+ // Unsupported gain map version. Simply ignore the gain map.
+ } else {
+ AVIF_CHECKRES(tmapParsingRes);
+ decoder->gainMapPresent = AVIF_TRUE;
+ if (decoder->enableDecodingGainMap) {
+ mainItems[AVIF_ITEM_GAIN_MAP] = gainMapItem;
+ codecType[AVIF_ITEM_GAIN_MAP] = gainMapCodecType;
+ }
+ }
  }
  }
 #endif // AVIF_ENABLE_EXPERIMENTAL_GAIN_MAP

tests/gtest/avifgainmaptest.cc

@@ -576,9 +576,9 @@ TEST(GainMapTest, IgnoreGainMap) {
 
  // Verify that the input and decoded images are close.
  EXPECT_GT(testutil::GetPsnr(*image, *decoded), 40.0);
- // Verify that the gain map was detected...
- EXPECT_TRUE(decoder->gainMapPresent);
- // ... but not decoded because enableDecodingGainMap is false by default.
+ // Verify that the gain map is not detected.
+ EXPECT_FALSE(decoder->gainMapPresent);
+ // And not decoded because enableDecodingGainMap is false by default.
  EXPECT_EQ(decoded->gainMap, nullptr);
 }
 
@@ -624,7 +624,7 @@ TEST(GainMapTest, IgnoreGainMapButReadMetadata) {
  image->gainMap->altMatrixCoefficients);
 }
 
-TEST(GainMapTest, DecodeGainMapButIgnoreMetadata) {
+TEST(GainMapTest, DecodeGainMapTrueParseMetadataFalse) {
  ImagePtr image = CreateTestImageWithGainMap(/*base_rendition_is_hdr=*/false);
  ASSERT_NE(image, nullptr);
 
@@ -643,27 +643,11 @@ TEST(GainMapTest, DecodeGainMapButIgnoreMetadata) {
  decoder->enableDecodingGainMap = AVIF_TRUE;
  result = avifDecoderReadMemory(decoder.get(), decoded.get(), encoded.data,
  encoded.size);
- ASSERT_EQ(result, AVIF_RESULT_OK)
+ // Verify we get an error because the combination of
+ // enableDecodingGainMap=false and enableParsingGainMapMetadata=true
+ // is not allowed.
+ ASSERT_EQ(result, AVIF_RESULT_INVALID_ARGUMENT)
  << avifResultToString(result) << " " << decoder->diag.error;
-
- // Verify that the gain map was detected...
- EXPECT_TRUE(decoder->gainMapPresent);
- ASSERT_NE(decoded->gainMap, nullptr);
- ASSERT_NE(decoded->gainMap->image, nullptr);
- EXPECT_GT(testutil::GetPsnr(*image->gainMap->image, *decoded->gainMap->image),
- 40.0);
-
- // Check that the gain map metadata was not populated.
- CheckGainMapMetadataMatches(decoded->gainMap->metadata,
- avifGainMapMetadata());
- EXPECT_EQ(decoded->gainMap->altDepth, 0);
- EXPECT_EQ(decoded->gainMap->altPlaneCount, 0);
- EXPECT_EQ(decoded->gainMap->altColorPrimaries,
- AVIF_COLOR_PRIMARIES_UNSPECIFIED);
- EXPECT_EQ(decoded->gainMap->altTransferCharacteristics,
- AVIF_TRANSFER_CHARACTERISTICS_UNSPECIFIED);
- EXPECT_EQ(decoded->gainMap->altMatrixCoefficients,
- AVIF_MATRIX_COEFFICIENTS_UNSPECIFIED);
 }
 
 TEST(GainMapTest, IgnoreColorAndAlpha) {
@@ -884,9 +868,8 @@ TEST(GainMapTest, DecodeUnsupportedVersion) {
  decoder->enableParsingGainMapMetadata = false;
  ASSERT_EQ(avifDecoderReadFile(decoder.get(), decoded.get(), path.c_str()),
  AVIF_RESULT_OK);
- // Gain map marked as present because the metadata was not parsed, so we
- // don't know it's not supported.
- EXPECT_EQ(decoder->gainMapPresent, true);
+ // Gain map not found since enableParsingGainMapMetadata is false.
+ EXPECT_EQ(decoder->gainMapPresent, false);
  ASSERT_EQ(decoded->gainMap, nullptr);
 
  ASSERT_EQ(avifDecoderReset(decoder.get()), AVIF_RESULT_OK);
@@ -901,12 +884,10 @@ TEST(GainMapTest, DecodeUnsupportedVersion) {
  ASSERT_EQ(avifDecoderReset(decoder.get()), AVIF_RESULT_OK);
  decoder->enableDecodingGainMap = true;
  decoder->enableParsingGainMapMetadata = false;
+ // Invalid enableDecodingGainMap=true and enableParsingGainMapMetadata
+ // combination.
  ASSERT_EQ(avifDecoderReadFile(decoder.get(), decoded.get(), path.c_str()),
- AVIF_RESULT_OK);
- // Gain map marked as present because the metadata was not parsed, so we
- // don't know it's not supported.
- EXPECT_EQ(decoder->gainMapPresent, true);
- ASSERT_NE(decoded->gainMap, nullptr);
+ AVIF_RESULT_INVALID_ARGUMENT);
 
  ASSERT_EQ(avifDecoderReset(decoder.get()), AVIF_RESULT_OK);
  decoder->enableDecodingGainMap = true;