ref #10 : option to keep context in "stream" example

Seems the results become worse when we keep the context, so by default
this is not enabled

stream.cpp

@@ -40,6 +40,7 @@ struct whisper_params {
 
  bool verbose = false;
  bool translate = false;
+ bool no_context = true;
  bool print_special_tokens = false;
  bool no_timestamps = true;
 
@@ -64,6 +65,8 @@ bool whisper_params_parse(int argc, char ** argv, whisper_params & params) {
  params.verbose = true;
  } else if (arg == "--translate") {
  params.translate = true;
+ } else if (arg == "-kc" || arg == "--keep-context") {
+ params.no_context = false;
  } else if (arg == "-l" || arg == "--language") {
  params.language = argv[++i];
  if (whisper_lang_id(params.language.c_str()) == -1) {
@@ -103,6 +106,7 @@ void whisper_print_usage(int argc, char ** argv, const whisper_params & params)
  fprintf(stderr, " --step N audio step size in milliseconds (default: %d)\n", params.step_ms);
  fprintf(stderr, " -v, --verbose verbose output\n");
  fprintf(stderr, " --translate translate from source language to english\n");
+ fprintf(stderr, " -nc, --no-context disable context from earlier audio (default: false)\n");
  fprintf(stderr, " -ps, --print_special print special tokens\n");
  fprintf(stderr, " -nt, --no_timestamps do not print timestamps\n");
  fprintf(stderr, " -l LANG, --language LANG spoken language (default: %s)\n", params.language.c_str());
@@ -273,6 +277,7 @@ int main(int argc, char ** argv) {
  wparams.print_realtime = false;
  wparams.print_timestamps = !params.no_timestamps;
  wparams.translate = params.translate;
+ wparams.no_context = params.no_context;
  wparams.language = params.language.c_str();
  wparams.n_threads = params.n_threads;
 

whisper.cpp

@@ -405,6 +405,8 @@ struct whisper_context {
 
  std::vector<whisper_result> result_cur;
  std::vector<whisper_segment> result_all;
+
+ std::vector<whisper_token> prompt_past;
 };
 
 // load the model from a ggml file
@@ -1020,8 +1022,6 @@ bool whisper_model_load(const std::string & fname, whisper_context & wctx) {
 // - model: the model
 // - n_threads: number of threads to use
 // - mel_offset: offset in the mel spectrogram (i.e. audio offset)
-// - mel_inp: input mel spectrogram
-// - features: output encoded features
 //
 bool whisper_encode(
  whisper_context & wctx,
@@ -1405,10 +1405,9 @@ bool whisper_encode(
 //
 // - model: the model
 // - n_threads: number of threads to use
-// - n_past: prompt length
-// - prompt: text prompt
-// - logits_out: output logits
-// - probs_out: output probabilities
+// - tokens: text prompt
+// - n_tokens: number of tokens in the prompt
+// - n_past: number of past tokens to prefix the prompt with
 //
 bool whisper_decode(
  whisper_context & wctx,
@@ -2259,6 +2258,7 @@ struct whisper_full_params whisper_full_default_params(enum whisper_decode_strat
  .offset_ms = 0,
 
  .translate = false,
+ .no_context = false,
  .print_special_tokens = false,
  .print_progress = true,
  .print_realtime = false,
@@ -2279,6 +2279,7 @@ struct whisper_full_params whisper_full_default_params(enum whisper_decode_strat
  .offset_ms = 0,
 
  .translate = false,
+ .no_context = false,
  .print_special_tokens = false,
  .print_progress = true,
  .print_realtime = false,
@@ -2297,6 +2298,7 @@ struct whisper_full_params whisper_full_default_params(enum whisper_decode_strat
 
  return result;
 }
+
 int whisper_full(
  struct whisper_context * ctx,
  struct whisper_full_params params,
@@ -2309,7 +2311,10 @@ int whisper_full(
  }
 
  // the accumulated text context so far
- std::vector<whisper_token> prompt_past = { };
+ auto & prompt_past = ctx->prompt_past;
+ if (params.no_context) {
+ prompt_past.clear();
+ }
 
  // these tokens determine the task that will be performed
  std::vector<whisper_token> prompt_init = { whisper_token_sot(ctx) };

whisper.h

@@ -105,6 +105,7 @@ extern "C" {
  int offset_ms;
 
  bool translate;
+ bool no_context;
  bool print_special_tokens;
  bool print_progress;
  bool print_realtime;