From bb8c47519d5badf4bbd8a12e482fa596e90a4e7b Mon Sep 17 00:00:00 2001
From: Alexander Kuznetsov <alex@beershire.ru>
Date: Fri, 1 Nov 2024 20:16:57 +0300
Subject: [PATCH] Add compression_ratio_hallucination_threshold

Add compression_ratio_hallucination_threshold to Discard High Compression Ratio Segments in transcribe()

https://github.com/openai/whisper/discussions/2420
---
 whisper/transcribe.py | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/whisper/transcribe.py b/whisper/transcribe.py
index 8eb6a71..3c510e7 100644
--- a/whisper/transcribe.py
+++ b/whisper/transcribe.py
@@ -42,11 +42,11 @@ def transcribe(
     verbose: Optional[bool] = None,
     temperature: Union[float, Tuple[float, ...]] = (0.0, 0.2, 0.4, 0.6, 0.8, 1.0),
     compression_ratio_threshold: Optional[float] = 2.4,
+    compression_ratio_halucination_threshold: Optional[float] = 3,
     logprob_threshold: Optional[float] = -1.0,
     no_speech_threshold: Optional[float] = 0.6,
     condition_on_previous_text: bool = True,
     initial_prompt: Optional[str] = None,
-    carry_initial_prompt: bool = False,
     word_timestamps: bool = False,
     prepend_punctuations: str = "\"'“¿([{-",
     append_punctuations: str = "\"'.。,，!！?？:：”)]}、",
@@ -76,6 +76,9 @@ def transcribe(
     compression_ratio_threshold: float
         If the gzip compression ratio is above this value, treat as failed
 
+    compression_ratio_halcination_threshold: float
+        If the gzip compression ratio is above this value after all attempts to decode, treat as a halucination and skip
+
     logprob_threshold: float
         If the average log probability over sampled tokens is below this value, treat as failed
 
@@ -205,7 +208,7 @@ def transcribe(
                 compression_ratio_threshold is not None
                 and decode_result.compression_ratio > compression_ratio_threshold
             ):
-                needs_fallback = True  # too repetitive
+                needs_fallback = True  # too repetitive <-- We can inprove it...
             if (
                 logprob_threshold is not None
                 and decode_result.avg_logprob < logprob_threshold
@@ -216,6 +219,13 @@ def transcribe(
                 and decode_result.no_speech_prob > no_speech_threshold
             ):
                 needs_fallback = False  # silence
+            if (
+            compression_ratio_halucination_threshold is not None
+            and decode_result.compression_ratio > compression_ratio_halucination_threshold
+            and t == temperatures[-1]
+            ):
+            # Discard the segment
+                continue  # Skip to the next segment
             if not needs_fallback:
                 break