modified the audio snippets

Author: imohitmayank

docs/audio_intelligence/audio_snippets.md

@@ -1,11 +1,11 @@
 Audio Intelligence Snippets
 ========================
 
-Here are some code snippets that you might find useful when playing around with audio files :wink:
+Here are some code snippets that you might find useful when playing around with audio files 😉
 
-## Check WAV file's stats
+## Load WAV file and check file stats
 
-- To check some basic stats of a wav file, we can use the following code, 
+- To check some basic stats of a wav file, we can use `wave` package
 
 ``` python linenums="1"
 # import
@@ -20,6 +20,8 @@ with wave.open(file_path, 'rb') as wav_file:
     n_frames = wav_file.getnframes()
     comp_type = wav_file.getcomptype()
     comp_name = wav_file.getcompname()
+    # read the data 
+    data = wav_file.readframes(n_frames)
 # structure the required stats
 wav_file_stats = {
     "Number of Channels": n_channels,
@@ -39,8 +41,43 @@ print(wav_file_stats)
 #  'Compression Type': 'NONE',
 #  'Compression Name': 'not compressed'}
 ```
+
+- We can also `scipy` package for wav file loading and printing stats
+
+``` python linenums="1"
+# import
+from scipy.io import wavfile
+
+# let's define a function to print the stats
+def print_wav_stats(sample_rate, data):
+    print(f"Sample rate: {sample_rate} Hz")
+    print(f"Data type: {data.dtype}")
+    print(f"Duration: {data.shape[0] / sample_rate} seconds")
+    print(f"Number of samples: {data.shape[0]}")
+    print(f"Value range: {data.min()} to {data.max()}")
+    print(f"Channels: {data.shape}")
+
+# Load the wav file
+file_path = f'{dataset_folder}/call_1.wav'
+sample_rate, data = wavfile.read(file_path)
+# print stats, example below
+print_wav_stats(sample_rate, data) 
+# Sample rate: 48000 Hz
+# Data type: int16
+# Duration: 1.18 seconds
+# Number of samples: 56640
+# Value range: -1787 to 1835
+# Channels: (56640, 2)
+``` 
+
+!!! Note
+    `scipy` returns data in an array with shape `(n_samples, n_channels)`. Whereas `wave` package returns data in bytes format.
+
+
 ## Get WAV file duration in seconds
 
+- You can check the above section or below is a readymade function.
+
 ``` python linenums="1"
 # import 
 import wave
@@ -62,6 +99,29 @@ print_wav_duration('path/to/file.wav')
 
 ## Convert Dual Channel WAV file to Mono
 
+- Let's first do this with `scipy` package
+
+``` python linenums="1"
+# import
+from scipy.io import wavfile
+
+def stereo_to_mono(file_path):
+    # Load the stereo wave file
+    sample_rate, data = wavfile.read(file_path)
+    # Check if it's already mono
+    if data.shape[1] != 2:
+        return "The file is not a stereo file."
+    # Convert to mono by taking the mean of the two channels
+    mono_data = data.mean(axis=1) # <--- THIS IS THE ONLY IMPORTANT LINE
+    # Set the file path for output
+    mono_file_path = file_path.replace(".wav", "_mono.wav")
+    # Save the mono file
+    wavfile.write(mono_file_path, sample_rate, mono_data.astype(data.dtype))
+    return f"Stereo file converted to mono: {mono_file_path}"
+```
+
+- Same can be done with `wave` and `numpy` packages
+
 ``` python linenums="1"
 import wave
 import numpy as np
@@ -101,4 +161,44 @@ def stereo_to_mono(file_path):
 # Replace with an actual file path to a stereo wav file
 # e.g., stereo_to_mono("path/to/stereo_file.wav")
 stereo_to_mono(f'{dataset_folder}/call_5.wav')
-```
+```
+
+## Downsample WAV file
+
+- Let's first do this with `scipy` package
+
+``` python linenums="1"
+# import
+from scipy.io import wavfile
+import scipy.signal as sps
+
+# Define a function to downsample a wave file
+def downsample_wav(file_path, target_sample_rate=16000):
+    """Downsample a wave file to a target sample rate.
+
+    Args:
+        file_path (str): The path to the wave file.
+        target_sample_rate (int): The target sample rate to downsample to.
+    
+    Returns:
+        str: A message indicating the success of the operation.
+    """
+    # Load the wave file
+    sample_rate, data = wavfile.read(file_path)
+    # Check if the target sample rate is the same as the original
+    if sample_rate == target_sample_rate:
+        return "The file is already at the target sample rate."
+    # Calculate the new number of samples
+    new_num_samples = int(data.shape[0] * target_sample_rate / sample_rate)
+    # Resample the data
+    new_data = sps.resample(data, number_of_samples)
+    # Set the file path for output
+    downsampled_file_path = file_path.replace(".wav", f"_downsampled_{target_sample_rate}.wav")
+    # Save the downsampled file
+    wavfile.write(downsampled_file_path, target_sample_rate, new_data.astype(data.dtype))
+    # return a message indicating the success of the operation
+    return f"File downsampled to {target_sample_rate} Hz: {downsampled_file_path}"
+```
+
+!!! Warning
+    Before saving `.wav` file using `scipy`, make sure the dtype is `int16`. 

docs/audio_intelligence/interview_questions.md

@@ -1,5 +1,5 @@
 
-- Here are some questions and their answers to make you ready for your next interview. Best of luck :wave:
+- Here are some questions and their answers to make you ready for your next interview. Best of luck 👋
 
 !!! Question ""
     === "Question"