[WIP] Implementing No Speech Processor elixir-nx#379

lib/bumblebee/audio/speech_to_text_whisper.ex

@@ -23,7 +23,9 @@ defmodule Bumblebee.Audio.SpeechToTextWhisper do
         defn_options: [],
         preallocate_params: false,
         task: :transcribe,
-        stream: false
+        stream: false,
+        logprob_threshold: 0.6,
+        no_speech_threshold: -1.0
       ])
 
     %{model: model, params: params, spec: spec} = model_info
@@ -59,7 +61,7 @@ defmodule Bumblebee.Audio.SpeechToTextWhisper do
       context_num_seconds: context_num_seconds
     }
 
-    {generate_opts, generation_config} = generate_opts(generation_config, opts)
+    {generate_opts, generation_config} = generate_opts(model_info, generation_config, opts)
     generate_fun = Text.Generation.build_generate(model, spec, generation_config, generate_opts)
 
     generate_fun = fn params, {inputs, seed} ->
@@ -210,27 +212,68 @@ defmodule Bumblebee.Audio.SpeechToTextWhisper do
     end
   end
 
-  defp generate_opts(generation_config, opts) do
+  defp generate_opts(model_info, generation_config, opts) do
     forced_token_ids = forced_token_ids(opts, generation_config.extra_config)
     generation_config = %{generation_config | forced_token_ids: forced_token_ids}
 
     logits_processors =
-      if opts[:timestamps] do
-        [
-          &Bumblebee.Text.Generation.LogitsProcessing.whisper_timestamp_processor(&1, &2,
-            eos_token_id: generation_config.eos_token_id,
-            forced_token_ids: generation_config.forced_token_ids,
-            no_timestamps_token_id: generation_config.extra_config.no_timestamps_token_id,
-            timestamp_begin_id: generation_config.extra_config.no_timestamps_token_id + 1
-          )
-        ]
-      else
-        []
-      end
+      []
+      |> add_no_speech_detection_processor(opts, model_info, generation_config)
+      |> add_timestamp_processor(opts, generation_config)
+      |> add_suppress_tokens_at_begin_processor(opts, model_info)
 
-    opts = [logits_processors: logits_processors]
+    {[logits_processors: logits_processors], generation_config}
+  end
+
+  defp add_timestamp_processor(processors, opts, generation_config) do
+    timestamp_processor =
+      &Bumblebee.Text.Generation.LogitsProcessing.whisper_timestamp_processor(&1, &2,
+        eos_token_id: generation_config.eos_token_id,
+        forced_token_ids: generation_config.forced_token_ids,
+        no_timestamps_token_id: generation_config.extra_config.no_timestamps_token_id,
+        timestamp_begin_id: generation_config.extra_config.no_timestamps_token_id + 1
+      )
+
+    if opts[:timestamps] do
+      [timestamp_processor | processors]
+    else
+      processors
+    end
+  end
 
-    {opts, generation_config}
+  defp add_suppress_tokens_at_begin_processor(processors, opts, model_info) do
+    suppress_tokens_at_begin_processor =
+      &Bumblebee.Text.Generation.LogitsProcessing.suppress_tokens_at_begin_processor(
+        &1,
+        &2,
+        begin_suppress_tokens:
+          Nx.tensor(model_info.spec.begin_suppress_tokens) |> Nx.new_axis(-1),
+        begin_index: opts[:begin_index] || 1
+      )
+
+    [suppress_tokens_at_begin_processor | processors]
+  end
+
+  defp add_no_speech_detection_processor(processors, opts, model_info, generation_config) do
+    no_speech_detection_processor = fn logits, context ->
+      %{logits: processed_logits, skip: should_skip} =
+        Bumblebee.Text.Generation.LogitsProcessing.whisper_no_speech_detection(
+          logits,
+          context,
+          no_speech_token: List.first(model_info.spec.begin_suppress_tokens),
+          forced_token_ids: generation_config.forced_token_ids,
+          no_speech_threshold: opts[:no_speech_threshold],
+          logprob_threshold: opts[:logprob_threshold]
+        )
+
+      Nx.select(should_skip, logits, processed_logits)
+    end
+
+    if opts[:no_speech_threshold] && opts[:logprob_threshold] do
+      [no_speech_detection_processor | processors]
+    else
+      processors
+    end
   end
 
   defp forced_token_ids(opts, extra_config) do

lib/bumblebee/audio/whisper.ex

@@ -166,7 +166,13 @@ defmodule Bumblebee.Audio.Whisper do
   #{Shared.options_doc(options)}
   """
 
-  defstruct [architecture: :base] ++ Shared.option_defaults(options)
+  defstruct [
+              architecture: :base,
+              suppress_tokens: [],
+              begin_suppress_tokens: [],
+              forced_decoder_ids: [],
+              no_timestamps_token_id: nil
+            ] ++ Shared.option_defaults(options)
 
   @behaviour Bumblebee.ModelSpec
   @behaviour Bumblebee.Configurable
@@ -520,7 +526,11 @@ defmodule Bumblebee.Audio.Whisper do
           dropout_rate: {"dropout", number()},
           attention_dropout_rate: {"attention_dropout", number()},
           activation_dropout_rate: {"activation_dropout", number()},
-          initializer_scale: {"init_std", number()}
+          initializer_scale: {"init_std", number()},
+          suppress_tokens: {"suppress_tokens", list(number())},
+          begin_suppress_tokens: {"begin_suppress_tokens", list(number())},
+          forced_decoder_ids: {"forced_decoder_ids", list(list(number()))},
+          no_timestamps_token_id: {"no_timestamps_token", number()}
         ) ++ Shared.common_options_from_transformers(data, spec)
 
       @for.config(spec, opts)

lib/bumblebee/text/generation/logits_processing.ex

@@ -201,6 +201,43 @@ defmodule Bumblebee.Text.Generation.LogitsProcessing do
     end
   end
 
+  defn whisper_no_speech_detection(logits, context, opts \\ []) do
+    opts =
+      keyword!(opts, [
+        :no_speech_token,
+        :forced_token_ids,
+        :no_speech_threshold,
+        :logprob_threshold
+      ])
+
+    no_speech_token = opts[:no_speech_token]
+    begin_idx = begin_idx(opts[:forced_token_ids])
+    no_speech_threshold = opts[:no_speech_threshold]
+    logprob_threshold = opts[:logprob_threshold]
+
+    if context.length == begin_idx do
+      scores = Axon.Activations.log_softmax(logits)
+      no_speech_logprob = scores[no_speech_token]
+      avg_logprob = compute_avg_logprob(scores, context.sequence)
+
+      should_skip =
+        Nx.logical_and(
+          Nx.greater(no_speech_logprob, Nx.log(no_speech_threshold)),
+          Nx.less(avg_logprob, Nx.log(logprob_threshold))
+        )
+
+      %{logits: logits, skip: should_skip}
+    else
+      %{logits: logits, skip: Nx.tensor(false)}
+    end
+  end
+
+  defnp compute_avg_logprob(scores, sequence) do
+    sequence_length = Nx.size(sequence)
+    total_logprob = Nx.sum(Nx.take(scores, sequence))
+    Nx.divide(total_logprob, sequence_length)
+  end
+
   defnp force_timestamp_pair(logits, context, begin_idx, eos_token_id, timestamp_begin_id) do
     # Force timestamp tokens to appear in pairs, end followed by
     # start, except directly before the EOS token
@@ -253,6 +290,22 @@ defmodule Bumblebee.Text.Generation.LogitsProcessing do
     Nx.select(ignore_mask, Nx.Constants.neg_infinity(Nx.type(logits)), logits)
   end
 
+  defn suppress_tokens_at_begin_processor(logits, context, opts \\ []) do
+    opts = keyword!(opts, [:begin_suppress_tokens, :begin_index])
+    begin_suppress_tokens = opts[:begin_suppress_tokens]
+    begin_index = opts[:begin_index]
+
+    if context.length == begin_index do
+      # Set the logits for the suppressed tokens to negative infinity
+      values =
+        Nx.broadcast(Nx.Constants.neg_infinity(Nx.type(logits)), {Nx.size(begin_suppress_tokens)})
+
+      Nx.indexed_put(logits, begin_suppress_tokens, values)
+    else
+      logits
+    end
+  end
+
   deftransformp begin_idx(forced_token_ids) do
     case List.last(forced_token_ids) do
       nil -> 1

mix.exs

@@ -1,7 +1,7 @@
 defmodule Bumblebee.MixProject do
   use Mix.Project
 
-  @version "0.5.3"
+  @version "0.5.4"
   @description "Pre-trained and transformer Neural Network models in Axon"
 
   def project do