Update README

Author: KitaitiMakoto

bindings/ruby/README.md

@@ -19,8 +19,6 @@ If bundler is not being used to manage dependencies, install the gem by executin
 Usage
 -----
 
-NOTE: This gem is still in development. API is not stable for now.
-
 ```ruby
 require "whisper"
 
@@ -33,9 +31,6 @@ params.duration = 60_000
 params.max_text_tokens = 300
 params.translate = true
 params.print_timestamps = false
-params.new_segment_callback = ->(output, t0, t1, index) {
-  puts "segment #{index}: #{t0}ms -> #{t1}ms: #{output}"
-}
 
 whisper.transcribe("path/to/audio.wav", params) do |whole_text|
   puts whole_text
@@ -59,5 +54,57 @@ There are some types of models. See [models][] page for details.
 
 Currently, whisper.cpp accepts only 16-bit WAV files.
 
+### API ###
+
+Once `Whisper::Context#transcribe` called, you can retrieve segments by `#each_segment`:
+
+```ruby
+def format_time(time_ms)
+  sec, decimal_part = time_ms.divmod(1000)
+  min, sec = sec.divmod(60)
+  hour, min = min.divmod(60)
+  "%02d:%02d:%02d.%03d" % [hour, min, sec, decimal_part]
+end
+
+whisper.transcribe("path/to/audio.wav", params)
+
+whisper.each_segment.with_index do |segment, index|
+  line = "[%{nth}: %{st} --> %{ed}] %{text}" % {
+    nth: index + 1,
+    st: format_time(segment.start_time),
+    ed: format_time(segment.end_time),
+    text: segment.text
+  }
+  line << " (speaker turned)" if segment.speaker_next_turn?
+  puts line
+end
+
+```
+
+You can also add hook to params called on new segment:
+
+```ruby
+def format_time(time_ms)
+  sec, decimal_part = time_ms.divmod(1000)
+  min, sec = sec.divmod(60)
+  hour, min = min.divmod(60)
+  "%02d:%02d:%02d.%03d" % [hour, min, sec, decimal_part]
+end
+
+# Add hook before calling #transcribe
+params.on_new_segment do |segment|
+  line = "[%{st} --> %{ed}] %{text}" % {
+    st: format_time(segment.start_time),
+    ed: format_time(segment.end_time),
+    text: segment.text
+  }
+  line << " (speaker turned)" if segment.speaker_next_turn?
+  puts line
+end
+
+whisper.transcribe("path/to/audio.wav", params)
+
+```
+
 [whisper.cpp]: https://github.com/ggerganov/whisper.cpp
 [models]: https://github.com/ggerganov/whisper.cpp/tree/master/models