diff --git a/Makefile b/Makefile
index 67dd13a..6dc3182 100644
--- a/Makefile
+++ b/Makefile
@@ -31,6 +31,7 @@ WEB_DEMUXER_ARGS = \
 		-s EXPORTED_RUNTIME_METHODS=cwrap,getValue,UTF8ToString \
 		-s EXPORTED_FUNCTIONS=_free \
 		-s ASYNCIFY \
+		-s WASM_BIGINT \
 		-s ALLOW_MEMORY_GROWTH=1
 
 clean:
diff --git a/lib/web-demuxer/post.js b/lib/web-demuxer/post.js
index 50d16cd..00e5ead 100644
--- a/lib/web-demuxer/post.js
+++ b/lib/web-demuxer/post.js
@@ -29,7 +29,8 @@ function getAVStream(file, type = 0, streamIndex = -1) {
   const id = Module.getValue(av_stream_ptr + 4, "i32");
   const start_time = Module.getValue(av_stream_ptr + 8, "double");
   const duration = Module.getValue(av_stream_ptr + 16, "double");
-  const codecpar_ptr = Module.getValue(av_stream_ptr + 24, "*");
+  const nb_frames = Module.getValue(av_stream_ptr + 24, "i64");
+  const codecpar_ptr = Module.getValue(av_stream_ptr + 32, "*");
   const codecpar_codec_string_ptr = Module.getValue(codecpar_ptr + 8, "i8*");
   let codecpar = {
     codec_type: Module.getValue(codecpar_ptr, "i32"),
@@ -63,6 +64,7 @@ function getAVStream(file, type = 0, streamIndex = -1) {
     codecpar,
     start_time,
     duration,
+    nb_frames
   };
 
   // free wasm memory
diff --git a/lib/web-demuxer/web_demuxer.c b/lib/web-demuxer/web_demuxer.c
index 11195d8..6412a78 100644
--- a/lib/web-demuxer/web_demuxer.c
+++ b/lib/web-demuxer/web_demuxer.c
@@ -86,6 +86,7 @@ WebAVStream *EMSCRIPTEN_KEEPALIVE get_av_stream(const char *filename, int type,
     stream->id = raw_stream->id;
     stream->start_time = raw_stream->start_time * av_q2d(raw_stream->time_base);
     stream->duration = raw_stream->duration > 0 ? raw_stream->duration * av_q2d(raw_stream->time_base) : fmt_ctx->duration * av_q2d(AV_TIME_BASE_Q); // TODO: some file type can not get stream duration
+    stream->nb_frames = raw_stream->nb_frames;
 
     avformat_close_input(&fmt_ctx);
 
diff --git a/lib/web-demuxer/web_demuxer.h b/lib/web-demuxer/web_demuxer.h
index 66652f6..fd960bd 100644
--- a/lib/web-demuxer/web_demuxer.h
+++ b/lib/web-demuxer/web_demuxer.h
@@ -26,6 +26,7 @@ typedef struct {
     int id;
     double start_time;
     double duration;
+    int64_t nb_frames;
     WebAVCodecParameters *codecpar;
 } WebAVStream;
 
diff --git a/src/types/demuxer.ts b/src/types/demuxer.ts
index cd0bc2a..9dcc077 100644
--- a/src/types/demuxer.ts
+++ b/src/types/demuxer.ts
@@ -23,6 +23,7 @@ export interface WebAVStream {
   id: number;
   start_time: number;
   duration: number;
+  nb_frames: number;
   codecpar: WebAVCodecParameters;
 }