color: Clarify default behaviors

media/formats/webm/webm_colour_parser.cc

Index: media/formats/webm/webm_colour_parser.cc
diff --git a/media/formats/webm/webm_colour_parser.cc b/media/formats/webm/webm_colour_parser.cc
index ddc9b931f304efdc4fb965b965a6688cde0d6ae4..846fa092f1dfcc5376fd6fab11ade216dcf6288c 100644
--- a/media/formats/webm/webm_colour_parser.cc
+++ b/media/formats/webm/webm_colour_parser.cc
@@ -15,68 +15,6 @@ namespace media {
 // ---- Begin copy/paste from libwebm/webm_parser/include/webm/dom_types.h ----
 
 /**
- A parsed \WebMID{MatrixCoefficients} element.
-
- Matroska/WebM adopted these values from Table 4 of ISO/IEC 23001-8:2013/DCOR1.
- See that document for further details.
- */
-enum class MatrixCoefficients : std::uint64_t {
-  /**
-   The identity matrix.
-
-   Typically used for GBR (often referred to as RGB); however, may also be used
-   for YZX (often referred to as XYZ).
-   */
-  kRgb = 0,
-
-  /**
-   Rec. ITU-R BT.709-5.
-   */
-  kBt709 = 1,
-
-  /**
-   Image characteristics are unknown or are determined by the application.
-   */
-  kUnspecified = 2,
-
-  /**
-   United States Federal Communications Commission Title 47 Code of Federal
-   Regulations (2003) 73.682 (a) (20).
-   */
-  kFcc = 4,
-
-  /**
-   Rec. ITU-R BT.470‑6 System B, G (historical).
-   */
-  kBt470Bg = 5,
-
-  /**
-   Society of Motion Picture and Television Engineers 170M (2004).
-   */
-  kSmpte170M = 6,
-
-  /**
-   Society of Motion Picture and Television Engineers 240M (1999).
-   */
-  kSmpte240M = 7,
-
-  /**
-   YCgCo.
-   */
-  kYCgCo = 8,
-
-  /**
-   Rec. ITU-R BT.2020 (non-constant luminance).
-   */
-  kBt2020NonconstantLuminance = 9,
-
-  /**
-   Rec. ITU-R BT.2020 (constant luminance).
-   */
-  kBt2020ConstantLuminance = 10,
-};
-
-/**
  A parsed \WebMID{Range} element.
  */
 enum class Range : std::uint64_t {
@@ -101,236 +39,8 @@ enum class Range : std::uint64_t {
   kDerived = 3,
 };
 
-/**
- A parsed \WebMID{TransferCharacteristics} element.
-
- Matroska/WebM adopted these values from Table 3 of ISO/IEC 23001-8:2013/DCOR1.
- See that document for further details.
- */
-enum class TransferCharacteristics : std::uint64_t {
-  /**
-   Rec. ITU-R BT.709-6.
-   */
-  kBt709 = 1,
-
-  /**
-   Image characteristics are unknown or are determined by the application.
-   */
-  kUnspecified = 2,
-
-  /**
-   Rec. ITU‑R BT.470‑6 System M (historical) with assumed display gamma 2.2.
-   */
-  kGamma22curve = 4,
-
-  /**
-   Rec. ITU‑R BT.470-6 System B, G (historical) with assumed display gamma 2.8.
-   */
-  kGamma28curve = 5,
-
-  /**
-   Society of Motion Picture and Television Engineers 170M (2004).
-   */
-  kSmpte170M = 6,
-
-  /**
-   Society of Motion Picture and Television Engineers 240M (1999).
-   */
-  kSmpte240M = 7,
-
-  /**
-   Linear transfer characteristics.
-   */
-  kLinear = 8,
-
-  /**
-   Logarithmic transfer characteristic (100:1 range).
-   */
-  kLog = 9,
-
-  /**
-   Logarithmic transfer characteristic (100 * Sqrt(10) : 1 range).
-   */
-  kLogSqrt = 10,
-
-  /**
-   IEC 61966-2-4.
-   */
-  kIec6196624 = 11,
-
-  /**
-   Rec. ITU‑R BT.1361-0 extended colour gamut system (historical).
-   */
-  kBt1361ExtendedColourGamut = 12,
-
-  /**
-   IEC 61966-2-1 sRGB or sYCC.
-   */
-  kIec6196621 = 13,
-
-  /**
-   Rec. ITU-R BT.2020-2 (10-bit system).
-   */
-  k10BitBt2020 = 14,
-
-  /**
-   Rec. ITU-R BT.2020-2 (12-bit system).
-   */
-  k12BitBt2020 = 15,
-
-  /**
-   Society of Motion Picture and Television Engineers ST 2084.
-   */
-  kSmpteSt2084 = 16,
-
-  /**
-   Society of Motion Picture and Television Engineers ST 428-1.
-   */
-  kSmpteSt4281 = 17,
-
-  /**
-   Association of Radio Industries and Businesses (ARIB) STD-B67.
-   */
-  kAribStdB67Hlg = 18,
-};
-
-/**
- A parsed \WebMID{Primaries} element.
-
- Matroska/WebM adopted these values from Table 2 of ISO/IEC 23001-8:2013/DCOR1.
- See that document for further details.
- */
-enum class Primaries : std::uint64_t {
-  /**
-   Rec. ITU‑R BT.709-6.
-   */
-  kBt709 = 1,
-
-  /**
-   Image characteristics are unknown or are determined by the application.
-   */
-  kUnspecified = 2,
-
-  /**
-   Rec. ITU‑R BT.470‑6 System M (historical).
-   */
-  kBt470M = 4,
-
-  /**
-   Rec. ITU‑R BT.470‑6 System B, G (historical).
-   */
-  kBt470Bg = 5,
-
-  /**
-   Society of Motion Picture and Television Engineers 170M (2004).
-   */
-  kSmpte170M = 6,
-
-  /**
-   Society of Motion Picture and Television Engineers 240M (1999).
-   */
-  kSmpte240M = 7,
-
-  /**
-   Generic film.
-   */
-  kFilm = 8,
-
-  /**
-   Rec. ITU-R BT.2020-2.
-   */
-  kBt2020 = 9,
-
-  /**
-   Society of Motion Picture and Television Engineers ST 428-1.
-   */
-  kSmpteSt4281 = 10,
-
-  /**
-   JEDEC P22 phosphors/EBU Tech. 3213-E (1975).
-   */
-  kJedecP22Phosphors = 22,
-};
-
 // ---- End copy/paste from libwebm/webm_parser/include/webm/dom_types.h ----
 
-// Ensure that libwebm enum values match enums in gfx::ColorSpace.
-#define STATIC_ASSERT_ENUM(a, b)                                             \
-  static_assert(static_cast<int>(a) == static_cast<int>(gfx::ColorSpace::b), \
-                "mismatching enums: " #a " and " #b)
-
-STATIC_ASSERT_ENUM(MatrixCoefficients::kRgb, MatrixID::RGB);
-STATIC_ASSERT_ENUM(MatrixCoefficients::kBt709, MatrixID::BT709);
-STATIC_ASSERT_ENUM(MatrixCoefficients::kUnspecified, MatrixID::UNSPECIFIED);
-STATIC_ASSERT_ENUM(MatrixCoefficients::kFcc, MatrixID::FCC);
-STATIC_ASSERT_ENUM(MatrixCoefficients::kBt470Bg, MatrixID::BT470BG);
-STATIC_ASSERT_ENUM(MatrixCoefficients::kSmpte170M, MatrixID::SMPTE170M);
-STATIC_ASSERT_ENUM(MatrixCoefficients::kSmpte240M, MatrixID::SMPTE240M);
-STATIC_ASSERT_ENUM(MatrixCoefficients::kYCgCo, MatrixID::YCOCG);
-STATIC_ASSERT_ENUM(MatrixCoefficients::kBt2020NonconstantLuminance,
-                   MatrixID::BT2020_NCL);
-STATIC_ASSERT_ENUM(MatrixCoefficients::kBt2020ConstantLuminance,
-                   MatrixID::BT2020_CL);
-
-gfx::ColorSpace::MatrixID FromWebMMatrixCoefficients(MatrixCoefficients c) {
-  return static_cast<gfx::ColorSpace::MatrixID>(c);
-}
-
-STATIC_ASSERT_ENUM(Range::kUnspecified, RangeID::UNSPECIFIED);
-STATIC_ASSERT_ENUM(Range::kBroadcast, RangeID::LIMITED);
-STATIC_ASSERT_ENUM(Range::kFull, RangeID::FULL);
-STATIC_ASSERT_ENUM(Range::kDerived, RangeID::DERIVED);
-
-gfx::ColorSpace::RangeID FromWebMRange(Range range) {
-  return static_cast<gfx::ColorSpace::RangeID>(range);
-}
-
-STATIC_ASSERT_ENUM(TransferCharacteristics::kBt709, TransferID::BT709);
-STATIC_ASSERT_ENUM(TransferCharacteristics::kUnspecified,
-                   TransferID::UNSPECIFIED);
-STATIC_ASSERT_ENUM(TransferCharacteristics::kGamma22curve, TransferID::GAMMA22);
-STATIC_ASSERT_ENUM(TransferCharacteristics::kGamma28curve, TransferID::GAMMA28);
-STATIC_ASSERT_ENUM(TransferCharacteristics::kSmpte170M, TransferID::SMPTE170M);
-STATIC_ASSERT_ENUM(TransferCharacteristics::kSmpte240M, TransferID::SMPTE240M);
-STATIC_ASSERT_ENUM(TransferCharacteristics::kLinear, TransferID::LINEAR);
-STATIC_ASSERT_ENUM(TransferCharacteristics::kLog, TransferID::LOG);
-STATIC_ASSERT_ENUM(TransferCharacteristics::kLogSqrt, TransferID::LOG_SQRT);
-STATIC_ASSERT_ENUM(TransferCharacteristics::kIec6196624,
-                   TransferID::IEC61966_2_4);
-STATIC_ASSERT_ENUM(TransferCharacteristics::kBt1361ExtendedColourGamut,
-                   TransferID::BT1361_ECG);
-STATIC_ASSERT_ENUM(TransferCharacteristics::kIec6196621,
-                   TransferID::IEC61966_2_1);
-STATIC_ASSERT_ENUM(TransferCharacteristics::k10BitBt2020,
-                   TransferID::BT2020_10);
-STATIC_ASSERT_ENUM(TransferCharacteristics::k12BitBt2020,
-                   TransferID::BT2020_12);
-STATIC_ASSERT_ENUM(TransferCharacteristics::kSmpteSt2084,
-                   TransferID::SMPTEST2084);
-STATIC_ASSERT_ENUM(TransferCharacteristics::kSmpteSt4281,
-                   TransferID::SMPTEST428_1);
-STATIC_ASSERT_ENUM(TransferCharacteristics::kAribStdB67Hlg,
-                   TransferID::ARIB_STD_B67);
-
-gfx::ColorSpace::TransferID FromWebMTransferCharacteristics(
-    TransferCharacteristics tc) {
-  return static_cast<gfx::ColorSpace::TransferID>(tc);
-}
-
-STATIC_ASSERT_ENUM(Primaries::kBt709, PrimaryID::BT709);
-STATIC_ASSERT_ENUM(Primaries::kUnspecified, PrimaryID::UNSPECIFIED);
-STATIC_ASSERT_ENUM(Primaries::kBt470M, PrimaryID::BT470M);
-STATIC_ASSERT_ENUM(Primaries::kBt470Bg, PrimaryID::BT470BG);
-STATIC_ASSERT_ENUM(Primaries::kSmpte170M, PrimaryID::SMPTE170M);
-STATIC_ASSERT_ENUM(Primaries::kSmpte240M, PrimaryID::SMPTE240M);
-STATIC_ASSERT_ENUM(Primaries::kFilm, PrimaryID::FILM);
-STATIC_ASSERT_ENUM(Primaries::kBt2020, PrimaryID::BT2020);
-STATIC_ASSERT_ENUM(Primaries::kSmpteSt4281, PrimaryID::SMPTEST428_1);
-
-gfx::ColorSpace::PrimaryID FromWebMPrimaries(Primaries primaries) {
-  return static_cast<gfx::ColorSpace::PrimaryID>(primaries);
-}
-
 WebMColorMetadata::WebMColorMetadata() {}
 WebMColorMetadata::WebMColorMetadata(const WebMColorMetadata& rhs) = default;
 
@@ -490,26 +200,27 @@ WebMColorMetadata WebMColourParser::GetWebMColorMetadata() const {
   if (chroma_siting_vert_ != -1)
     color_metadata.ChromaSitingVert = chroma_siting_vert_;
 
-  gfx::ColorSpace::MatrixID matrix_id = gfx::ColorSpace::MatrixID::UNSPECIFIED;
-  if (matrix_coefficients_ != -1)
-    matrix_id = FromWebMMatrixCoefficients(
-        static_cast<MatrixCoefficients>(matrix_coefficients_));
-
-  gfx::ColorSpace::RangeID range_id = gfx::ColorSpace::RangeID::UNSPECIFIED;
-  if (range_ != -1)
-    range_id = FromWebMRange(static_cast<Range>(range_));
-
-  gfx::ColorSpace::TransferID transfer_id =
-      gfx::ColorSpace::TransferID::UNSPECIFIED;
-  if (transfer_characteristics_ != -1)
-    transfer_id = FromWebMTransferCharacteristics(
-        static_cast<TransferCharacteristics>(transfer_characteristics_));
-
   gfx::ColorSpace::PrimaryID primary_id =
-      gfx::ColorSpace::PrimaryID::UNSPECIFIED;
-  if (primaries_ != -1)
-    primary_id = FromWebMPrimaries(static_cast<Primaries>(primaries_));
-
+      gfx::ColorSpace::PrimaryIDFromH264(primaries_);
+  gfx::ColorSpace::TransferID transfer_id =
+      gfx::ColorSpace::TransferIDFromH264(transfer_characteristics_);
+  gfx::ColorSpace::MatrixID matrix_id =
+      gfx::ColorSpace::MatrixIDFromH264(matrix_coefficients_);
+  gfx::ColorSpace::RangeID range_id = gfx::ColorSpace::RangeID::FULL;
+  switch (static_cast<Range>(range_)) {
+    case Range::kUnspecified:
+      range_id = gfx::ColorSpace::RangeID::FULL;
+      break;
+    case Range::kBroadcast:
+      range_id = gfx::ColorSpace::RangeID::LIMITED;
+      break;
+    case Range::kFull:
+      range_id = gfx::ColorSpace::RangeID::FULL;
+      break;
+    case Range::kDerived:
+      range_id = gfx::ColorSpace::RangeID::DERIVED;
+      break;
+  }
   color_metadata.color_space =
       gfx::ColorSpace(primary_id, transfer_id, matrix_id, range_id);