Merge pull request #2181 from eggonlea/streaming

Add option to native client binary to print intermediate transcriptions while streaming the input file

native_client/args.h

@@ -30,6 +30,8 @@ bool extended_metadata = false;
 
 bool json_output = false;
 
+int stream_size = 0;
+
 void PrintHelp(const char* bin)
 {
     std::cout <<
@@ -45,6 +47,7 @@ void PrintHelp(const char* bin)
     "	-t			Run in benchmark mode, output mfcc & inference time\n"
     "	--extended		Output string from extended metadata\n"
     "	--json			Extended output, shows word timings as JSON\n"
+    "	--stream size		Run in stream mode, output intermediate results\n"
     "	--help			Show help\n"
     "	--version		Print version and exits\n";
     DS_PrintVersions();
@@ -64,6 +67,7 @@ bool ProcessArgs(int argc, char** argv)
             {"t", no_argument, nullptr, 't'},
             {"extended", no_argument, nullptr, 'e'},
             {"json", no_argument, nullptr, 'j'},
+            {"stream", required_argument, nullptr, 's'},
             {"help", no_argument, nullptr, 'h'},
             {"version", no_argument, nullptr, 'v'},
             {nullptr, no_argument, nullptr, 0}
@@ -118,6 +122,10 @@ bool ProcessArgs(int argc, char** argv)
             json_output = true;
             break;
 
+        case 's':
+            stream_size = atoi(optarg);
+            break;
+
         case 'h': // -h or --help
         case '?': // Unrecognized option
         default:
@@ -136,6 +144,12 @@ bool ProcessArgs(int argc, char** argv)
         return false;
     }
 
+    if (stream_size < 0 || stream_size % 160 != 0) {
+        std::cout <<
+        "Stream buffer size must be multiples of 160\n";
+        return false;
+    }
+
     return true;
 }
 

native_client/client.cc

@@ -70,6 +70,31 @@ LocalDsSTT(ModelState* aCtx, const short* aBuffer, size_t aBufferSize,
     Metadata *metadata = DS_SpeechToTextWithMetadata(aCtx, aBuffer, aBufferSize, aSampleRate);
     res.string = JSONOutput(metadata);
     DS_FreeMetadata(metadata);
+  } else if (stream_size > 0) {
+    StreamingState* ctx;
+    int status = DS_SetupStream(aCtx, 0, aSampleRate, &ctx);
+    if (status != DS_ERR_OK) {
+      res.string = strdup("");
+      return res;
+    }
+    size_t off = 0;
+    const char *last = nullptr;
+    while (off < aBufferSize) {
+      size_t cur = aBufferSize - off > stream_size ? stream_size : aBufferSize - off;
+      DS_FeedAudioContent(ctx, aBuffer + off, cur);
+      off += cur;
+      const char* partial = DS_IntermediateDecode(ctx);
+      if (last == nullptr || strcmp(last, partial)) {
+        printf("%s\n", partial);
+        last = partial;
+      } else {
+        DS_FreeString((char *) partial);
+      }
+    }
+    if (last != nullptr) {
+      DS_FreeString((char *) last);
+    }
+    res.string = DS_FinishStream(ctx);
   } else {
     res.string = DS_SpeechToText(aCtx, aBuffer, aBufferSize, aSampleRate);
   }