Read video I/P/B frames.

src/ffprobe-wasm-wrapper.cpp

@@ -128,7 +128,7 @@ FileInfoResponse get_file_info() {
     return r;
 }
 
-FramesResponse get_frames() {
+FramesResponse get_frames(int offset) {
     av_log_set_level(AV_LOG_QUIET); // No logging output for libav.
 
     FILE *file = fopen("file", "rb");
@@ -190,22 +190,39 @@ FramesResponse get_frames() {
     AVPacket *pPacket = av_packet_alloc();
     AVFrame *pFrame = av_frame_alloc();
 
-    int how_many_packets_to_process = 100;
+    int how_many_packets_to_process = 300;
-    // av_seek_frame(pFormatContext, 1, 1001*30, AVSEEK_FLAG_ANY);
+    int frame_count = 0;
+
+    // Read video frames.
+    // TODO: Support seek so we don't have to cap at 300 frames.
     while (av_read_frame(pFormatContext, pPacket) >= 0) {
+      if (frame_count >= offset) {
         if (pPacket->stream_index == video_stream_index) {
 
-        avcodec_send_packet(pCodecContext, pPacket);
+          int response = 0;
-        avcodec_receive_frame(pCodecContext, pFrame);
+          response = avcodec_send_packet(pCodecContext, pPacket);
+
+          if (response >= 0) {
+            response = avcodec_receive_frame(pCodecContext, pFrame);
+            if (response == AVERROR(EAGAIN) || response == AVERROR_EOF) {
+              continue;
+            }
+
             Frame f = {
               .pict_type = (char) av_get_picture_type_char(pFrame->pict_type),
               .frame_number = pCodecContext->frame_number,
               .pkt_size = pFrame->pkt_size,
             };
             r.frames.push_back(f);
-      }
+
             if (--how_many_packets_to_process <= 0) break;
           }
+        }
+      }
+
+      frame_count++;
+    }
+
     return r;
 }
 
@@ -234,9 +251,9 @@ EMSCRIPTEN_BINDINGS(FileInfoResponse_struct) {
   register_vector<Stream>("Stream");
 
   emscripten::value_object<Frame>("Frame")
-  .field("frame_type", &Frame::pict_type)
+  .field("pict_type", &Frame::pict_type)
   .field("frame_number", &Frame::frame_number)
-  .field("frame_size", &Frame::pkt_size);
+  .field("pkt_size", &Frame::pkt_size);
   register_vector<Frame>("Frame");
 
   emscripten::value_object<FileInfoResponse>("FileInfoResponse")

www/src/components/Frames.vue

@@ -2,7 +2,7 @@
   <div>
     <h4>Frames</h4>
     <b-table striped hover :items="frames">
-      <template #cell(frame_type)="data">
+      <template #cell(pict_type)="data">
         {{ String.fromCharCode(data.value) }}
       </template>
 
@@ -13,7 +13,6 @@
 <script>
 export default {
   name: 'Frames',
-  props: [''],
   data() {
     return {
       data: null,
@@ -21,6 +20,8 @@ export default {
   },
   computed: {
     frames() {
+      if (!this.data) return [];
+
       const s = [];
       for (let i = 0; i < this.data.frames.size(); i++) {
         s.push(this.data.frames.get(i));
@@ -29,7 +30,7 @@ export default {
     },
   },
   created() {
-    this.data = window.Module.get_frames();
+    this.data = window.Module.get_frames(0);
   },
 }
 </script>