WavSampleProvider: Add a warning when channel_ids are duplicated.

  - Duplicating channel IDs means the same audio channel from a wav file represents multiple labels.
    - E.g. the user provides a one channel wav file and maps the single channel to both L2 and R2.
    - This is strange, but we can and have safely handled it for a while. Log and warn when this occurs.
  - Add tests for existing behavior:
    - `channel_ids` may be duplicated.
    - `channel_labels` may not be duplicated.
  - Drive-by: Update some names that are really just testing `Initialize`.

PiperOrigin-RevId: 686896385

iamf/cli/BUILD

@@ -446,6 +446,7 @@ cc_library(
         ":wav_reader",
         "//iamf/cli/proto:audio_frame_cc_proto",
         "//iamf/common:macros",
+        "//iamf/common:obu_util",
         "//iamf/obu:types",
         "@com_google_absl//absl/container:flat_hash_map",
         "@com_google_absl//absl/log",

iamf/cli/tests/wav_sample_provider_test.cc

@@ -98,6 +98,36 @@ TEST(Initialize, FailsForUnknownLabels) {
       wav_sample_provider.Initialize(GetInputWavDir(), audio_elements).ok());
 }
 
+TEST(Initialize, SucceedsForDuplicateChannelIds) {
+  constexpr uint32_t kDuplicateChannelId = 0;
+  iamf_tools_cli_proto::UserMetadata user_metadata;
+  absl::flat_hash_map<DecodedUleb128, AudioElementWithData> audio_elements;
+  InitializeTestData(kSampleRate, user_metadata, audio_elements);
+  user_metadata.mutable_audio_frame_metadata(0)->set_channel_ids(
+      0, kDuplicateChannelId);
+  user_metadata.mutable_audio_frame_metadata(0)->set_channel_ids(
+      1, kDuplicateChannelId);
+  WavSampleProvider wav_sample_provider(user_metadata.audio_frame_metadata());
+
+  EXPECT_THAT(wav_sample_provider.Initialize(GetInputWavDir(), audio_elements),
+              IsOk());
+}
+
+TEST(Initialize, FailsForDuplicateChannelLabels) {
+  constexpr absl::string_view kDuplicateLabel = "L2";
+  iamf_tools_cli_proto::UserMetadata user_metadata;
+  absl::flat_hash_map<DecodedUleb128, AudioElementWithData> audio_elements;
+  InitializeTestData(kSampleRate, user_metadata, audio_elements);
+  user_metadata.mutable_audio_frame_metadata(0)->set_channel_labels(
+      0, kDuplicateLabel);
+  user_metadata.mutable_audio_frame_metadata(0)->set_channel_labels(
+      1, kDuplicateLabel);
+  WavSampleProvider wav_sample_provider(user_metadata.audio_frame_metadata());
+
+  EXPECT_FALSE(
+      wav_sample_provider.Initialize(GetInputWavDir(), audio_elements).ok());
+}
+
 TEST(Initialize, FailsForChannelIdTooLarge) {
   iamf_tools_cli_proto::UserMetadata user_metadata;
   absl::flat_hash_map<DecodedUleb128, AudioElementWithData> audio_elements;
@@ -114,7 +144,7 @@ TEST(Initialize, FailsForChannelIdTooLarge) {
       wav_sample_provider.Initialize(GetInputWavDir(), audio_elements).ok());
 }
 
-TEST(WavSampleProviderTest, MismatchingChannelIdsAndLabels) {
+TEST(Initialize, FailsForDifferentSizedChannelIdsAndChannelLabels) {
   iamf_tools_cli_proto::UserMetadata user_metadata;
   absl::flat_hash_map<DecodedUleb128, AudioElementWithData> audio_elements;
   InitializeTestData(kSampleRate, user_metadata, audio_elements);
@@ -128,7 +158,7 @@ TEST(WavSampleProviderTest, MismatchingChannelIdsAndLabels) {
       wav_sample_provider.Initialize(GetInputWavDir(), audio_elements).ok());
 }
 
-TEST(WavSampleProviderTest, BitDepthLowerThanFile) {
+TEST(Initialize, FailsForBitDepthLowerThanFile) {
   iamf_tools_cli_proto::UserMetadata user_metadata;
   absl::flat_hash_map<DecodedUleb128, AudioElementWithData> audio_elements;
   InitializeTestData(kSampleRate, user_metadata, audio_elements);
@@ -143,7 +173,7 @@ TEST(WavSampleProviderTest, BitDepthLowerThanFile) {
       wav_sample_provider.Initialize(GetInputWavDir(), audio_elements).ok());
 }
 
-TEST(WavSampleProviderTest, MismatchingSampleRates) {
+TEST(Initialize, FailsForMismatchingSampleRates) {
   iamf_tools_cli_proto::UserMetadata user_metadata;
   absl::flat_hash_map<DecodedUleb128, AudioElementWithData> audio_elements;
 

iamf/cli/wav_sample_provider.cc

@@ -28,6 +28,7 @@
 #include "iamf/cli/demixing_module.h"
 #include "iamf/cli/wav_reader.h"
 #include "iamf/common/macros.h"
+#include "iamf/common/obu_util.h"
 #include "iamf/obu/types.h"
 
 namespace iamf_tools {
@@ -45,6 +46,15 @@ absl::Status WavSampleProvider::Initialize(
                        audio_frame_metadata.channel_ids_size(), " vs ",
                        audio_frame_metadata.channel_labels_size(), ")"));
     }
+    if (!ValidateUnique(audio_frame_metadata.channel_ids().begin(),
+                        audio_frame_metadata.channel_ids().end(), "channel ids")
+             .ok()) {
+      // OK. The user is claiming some channel IDs are shared between labels.
+      // This is strange, but permitted.
+      LOG(WARNING) << "Usually channel labels should be unique. Did you use "
+                      "the same channel ID for different channels?";
+    }
+
     // Precompute the `ChannelLabel::Label` for each channel label string.
     RETURN_IF_NOT_OK(ChannelLabel::ConvertAndFillLabels(
         audio_frame_metadata.channel_labels(),