From eb2a3e30c359003cd595b8aa5a883c68d40d905b Mon Sep 17 00:00:00 2001
From: Sanchit Gandhi <sanchit-gandhi@users.noreply.huggingface.co>
Date: Mon, 5 Dec 2022 12:28:32 +0000
Subject: [PATCH] Force <|startoftranscript|>

Updates the `forced_decoder_ids` to force the `<|startoftranscript|>` token at position 1. This is to match the official Whisper implementation, which always predicts `<|startoftranscript|>` at position 1:
```python
#!pip install git+https://github.com/openai/whisper.git

import whisper
from datasets import load_dataset

import torch

device = "cuda" if torch.cuda.is_available() else "cpu"

model = whisper.load_model("tiny.en").to(device)

tokenizer = whisper.tokenizer.get_tokenizer(False, task="transcribe", language="en")
tokenizer = tokenizer.tokenizer

librispeech = load_dataset("hf-internal-testing/librispeech_asr_dummy", "clean", split="validation")

def to_pad_to_mel(array):
    """Static function which:
        1. Pads/trims a list of audio arrays to a max length of 30s
        2. Computes log-mel filter coefficients from padded/trimmed audio sequences
        Inputs:
            array: list of audio arrays
        Returns:
            input_ids: torch.tensor of log-mel filter bank coefficients
    """
    padded_input = whisper.pad_or_trim(np.asarray(array, dtype=np.float32))
    input_ids = whisper.log_mel_spectrogram(padded_input)
    return input_ids

audio_array = librispeech[0]["audio"]["array"]
log_mel = to_pad_to_mel(audio_array).unsqueeze(0)

tokens = model.generate(log_mel.to(device))[0]
transcript = tokenizer.decode(tokens, skip_special_tokens=False)
print(transcript)
```
**Print Output:**
```
<|startoftranscript|><|notimestamps|> Mr. Quilter is the apostle of the middle classes, and we are glad to
```
---
 config.json | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/config.json b/config.json
index 18c737b..4a0f799 100644
--- a/config.json
+++ b/config.json
@@ -26,6 +26,10 @@
   "forced_decoder_ids": [
     [
       1,
+      50257
+    ]
+    [
+      2,
       50362
     ]
   ],