Fix: copy feature_extractor for whisper model

Signed-off-by: sagewe <sagewe@fastmail.com>

mergekit/merge.py

@@ -136,6 +136,19 @@ def run_merge(
                 "Chat template specified but no tokenizer found. Chat template will not be saved."
             )
 
+    # Copy feature_extractor if it is a whisper model
+    if options.copy_feature_extractor and  arch_info.definition.expected_model_type == "whisper":
+        try:
+            _copy_feature_extractor(
+                merge_config, out_path, trust_remote_code=options.trust_remote_code
+            )
+        except Exception as e:
+            logging.error(
+                "Failed to copy feature_extractor. The merge was still successful, just copy it from somewhere else.",
+                exc_info=e,
+            )
+
+
     if tokenizer:
         logging.info("Saving tokenizer")
         _set_chat_template(tokenizer, merge_config)
@@ -229,6 +242,36 @@ def _copy_tokenizer(
     tokenizer.save_pretrained(out_path, safe_serialization=True)
 
 
+def _copy_feature_extractor(
+    merge_config: MergeConfiguration, out_path: str, trust_remote_code: bool = False
+):
+    donor_model = merge_config.base_model or (merge_config.referenced_models()[0])
+
+    if (os.path.exists(
+            os.path.join(donor_model.model.path, "preprocessor_config.json")
+        )
+    ):
+        logging.info(f"Copying feature_extractor from {donor_model}")
+
+        for file_name in [
+            "preprocessor_config.json",
+        ]:
+            if os.path.exists(os.path.join(donor_model.model.path, file_name)):
+                shutil.copy(
+                    os.path.join(donor_model.model.path, file_name),
+                    os.path.join(out_path, file_name),
+                )
+        return
+
+    # fallback: try actually loading the feature_extractor and saving it
+    logging.info(f"Reserializing feature_extractor from {donor_model}")
+    feature_extractor = transformers.AutoFeatureExtractor.from_pretrained(
+        donor_model.model.path,
+        revision=donor_model.model.revision,
+        trust_remote_code=trust_remote_code,
+    )
+    _set_chat_template(feature_extractor, merge_config)
+    feature_extractor.save_pretrained(out_path, safe_serialization=True)
 def _model_out_config(
     config: MergeConfiguration,
     arch_info: ArchitectureInfo,

mergekit/options.py

@@ -32,6 +32,7 @@ class MergeOptions(BaseModel):
     low_cpu_memory: bool = False
     out_shard_size: int = parse_kmb("5B")
     copy_tokenizer: bool = True
+    copy_feature_extractor: bool = True
     clone_tensors: bool = False
     trust_remote_code: bool = False
     random_seed: Optional[int] = None