examples : update usage/help in yt-wsp.sh (#3251)

This commit updates the usage/help message to be more readable and include the environment variables available to set options.

examples/yt-wsp.sh

@@ -80,15 +80,41 @@ cleanup() {
 }
 
 print_help() {
-    echo "################################################################################"
+    cat << 'EOF'
-    echo "Usage: ./examples/yt-wsp.sh <video_url>"
+Usage:
-    echo "# See configurable env variables in the script; there are many!"
+  MODEL_PATH=<model> \
-    echo "# This script will produce an MP4 muxed file in the working directory; it will"
+  WHISPER_EXECUTABLE=<whisper-cli> \
-    echo "# be named for the title and id of the video."
+  WHISPER_LANG=en \
-    echo "# passing in https://youtu.be/VYJtb2YXae8 produces a file named";
+  WHISPER_THREAD_COUNT=<int> \
-    echo "# 'Why_we_all_need_subtitles_now-VYJtb2YXae8-res.mp4'"
+  ./examples/yt-wsp.sh <video_url>
-    echo "# Requirements: ffmpeg yt-dlp whisper.cpp"
+
-    echo "################################################################################"
+Description:
+  This script downloads a YouTube video, generates subtitles using Whisper, 
+  and muxes them into an MP4 output file.
+
+Output:
+  An MP4 file with embedded subtitles will be produced in the working directory.
+  The file will be named using the video title and ID.
+  Example: 
+    Input:  https://youtu.be/VYJtb2YXae8
+    Output: Why_we_all_need_subtitles_now-VYJtb2YXae8-res.mp4
+
+Requirements:
+  - ffmpeg
+  - yt-dlp
+  - whisper.cpp
+
+Environment Variables:
+  MODEL_PATH            Path to the Whisper model (e.g., models/ggml-base.en.bin)
+  WHISPER_EXECUTABLE    Path to the Whisper CLI executable
+  WHISPER_LANG          Language code (e.g., 'en' for English)
+  WHISPER_THREAD_COUNT  Number of CPU threads to use
+
+Tip:
+  The script has many configurable environment variables.
+  Review the source code to explore all options.
+
+EOF
 }
 
 check_requirements() {