From ff36b01373c09002a996d456993e826ecdcfdaf1 Mon Sep 17 00:00:00 2001
From: Alfred Gutierrez <alfg@users.noreply.github.com>
Date: Mon, 17 Jan 2022 20:02:28 -0800
Subject: [PATCH] feature: add support for displaying chapters (#15)

* feat: add initial code for reading chapters

* feat: add more fields for supporting chapters and chapter tags.
---
 src/ffprobe-wasm-wrapper.cpp    | 66 ++++++++++++++++++++++++++++++++-
 www/package-lock.json           |  2 +-
 www/package.json                |  2 +-
 www/public/ffprobe-worker.js    | 14 +++++++
 www/src/components/Overview.vue | 10 +++++
 5 files changed, 91 insertions(+), 3 deletions(-)

diff --git a/src/ffprobe-wasm-wrapper.cpp b/src/ffprobe-wasm-wrapper.cpp
index d8fc1a2..950f062 100644
--- a/src/ffprobe-wasm-wrapper.cpp
+++ b/src/ffprobe-wasm-wrapper.cpp
@@ -11,6 +11,7 @@ extern "C" {
 #include <libavcodec/avcodec.h>
 #include <libavformat/avformat.h>
 #include <libavutil/avutil.h>
+#include <libavutil/bprint.h>
 #include <libavutil/imgutils.h>
 };
 
@@ -43,6 +44,19 @@ typedef struct Stream {
   int frame_size;
 } Stream;
 
+typedef struct Tag {
+  std::string key;
+  std::string value;
+} Tag;
+
+typedef struct Chapter {
+  int id;
+  std::string time_base;
+  int start;
+  int end;
+  std::vector<Tag> tags;
+} Chapter;
+
 typedef struct Frame {
   int frame_number;
   char pict_type;
@@ -60,6 +74,8 @@ typedef struct FileInfoResponse {
   int nb_streams;
   int flags;
   std::vector<Stream> streams;
+  int nb_chapters;
+  std::vector<Chapter> chapters;
 } FileInfoResponse;
 
 typedef struct FramesResponse {
@@ -103,7 +119,8 @@ FileInfoResponse get_file_info(std::string filename) {
       .duration = (int)pFormatContext->duration,
       .url = pFormatContext->url,
       .nb_streams = (int)pFormatContext->nb_streams,
-      .flags = pFormatContext->flags
+      .flags = pFormatContext->flags,
+      .nb_chapters = (int)pFormatContext->nb_chapters
     };
 
     // Loop through the streams.
@@ -138,6 +155,36 @@ FileInfoResponse get_file_info(std::string filename) {
       r.streams.push_back(stream);
       free(fourcc);
     }
+
+    // Loop through the chapters (if any).
+    for (int i = 0; i < pFormatContext->nb_chapters; i++) {
+      AVChapter *chapter = pFormatContext->chapters[i];
+
+      // Format timebase string to buf.
+      AVBPrint buf;
+      av_bprint_init(&buf, 0, AV_BPRINT_SIZE_AUTOMATIC);
+      av_bprintf(&buf, "%d%s%d", chapter->time_base.num, (char *)"/", chapter->time_base.den);
+
+      Chapter c = {
+        .id = (int)chapter->id,
+        .time_base = buf.str,
+        .start = (int)chapter->start,
+        .end = (int)chapter->end,
+      };
+
+      // Add tags to chapter.
+      const AVDictionaryEntry *tag = NULL;
+      while ((tag = av_dict_get(chapter->metadata, "", tag, AV_DICT_IGNORE_SUFFIX))) {
+        Tag t = {
+          .key = tag->key,
+          .value = tag->value,
+        };
+        c.tags.push_back(t);
+      }
+
+      r.chapters.push_back(c);
+    }
+
     avformat_close_input(&pFormatContext);
     return r;
 }
@@ -293,6 +340,21 @@ EMSCRIPTEN_BINDINGS(structs) {
   ;
   register_vector<Stream>("Stream");
 
+  emscripten::value_object<Tag>("Tag")
+  .field("key", &Tag::key)
+  .field("value", &Tag::value)
+  ;
+  register_vector<Tag>("Tag");
+
+  emscripten::value_object<Chapter>("Chapter")
+  .field("id", &Chapter::id)
+  .field("time_base", &Chapter::time_base)
+  .field("start", &Chapter::start)
+  .field("end", &Chapter::end)
+  .field("tags", &Chapter::tags)
+  ;
+  register_vector<Chapter>("Chapter");
+
   emscripten::value_object<Frame>("Frame")
   .field("frame_number", &Frame::frame_number)
   .field("pict_type", &Frame::pict_type)
@@ -310,6 +372,8 @@ EMSCRIPTEN_BINDINGS(structs) {
   .field("nb_streams", &FileInfoResponse::nb_streams)
   .field("flags", &FileInfoResponse::flags)
   .field("streams", &FileInfoResponse::streams)
+  .field("nb_chapters", &FileInfoResponse::nb_chapters)
+  .field("chapters", &FileInfoResponse::chapters)
   ;
   function("get_file_info", &get_file_info);
 
diff --git a/www/package-lock.json b/www/package-lock.json
index 2d4d8c1..c647218 100644
--- a/www/package-lock.json
+++ b/www/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "ffprobe-wasm",
-  "version": "0.6.0",
+  "version": "0.7.0",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
diff --git a/www/package.json b/www/package.json
index 77cec72..0fb35a8 100644
--- a/www/package.json
+++ b/www/package.json
@@ -1,6 +1,6 @@
 {
   "name": "ffprobe-wasm",
-  "version": "0.6.0",
+  "version": "0.7.0",
   "scripts": {
     "serve": "vue-cli-service serve",
     "build": "vue-cli-service build",
diff --git a/www/public/ffprobe-worker.js b/www/public/ffprobe-worker.js
index 33c32e4..4b33fc2 100644
--- a/www/public/ffprobe-worker.js
+++ b/www/public/ffprobe-worker.js
@@ -21,6 +21,19 @@ onmessage = (e) => {
                 s.push(info.streams.get(i));
             }
 
+            // Remap chapters into collection.
+            const c = [];
+            for (let i = 0; i < info.chapters.size(); i++) {
+                const t = info.chapters.get(i).tags.get(0);
+
+                // Remap tags too.
+                const tags = [];
+                const obj = {};
+                obj[t.key] = t.value;
+                tags.push(obj);
+                c.push({...info.chapters.get(i), ...{tags}});
+            }
+
             const versions = {
                 libavutil:  Module.avutil_version(),
                 libavcodec:  Module.avcodec_version(),
@@ -31,6 +44,7 @@ onmessage = (e) => {
             data = {
                 ...info,
                 streams: s,
+                chapters: c,
                 versions,
             }
             postMessage(data);
diff --git a/www/src/components/Overview.vue b/www/src/components/Overview.vue
index 2f47d35..518d2f4 100644
--- a/www/src/components/Overview.vue
+++ b/www/src/components/Overview.vue
@@ -8,6 +8,15 @@
 
     <h4>Streams</h4>
     <b-table striped hover :items="info.streams"></b-table>
+
+    <div v-show="info.chapters.length > 0">
+      <h4>Chapters</h4>
+      <b-table striped hover :items="info.chapters">
+        <template #cell(tags)="data">
+          <b-table-lite small stacked outlined :items="data.item.tags"></b-table-lite>
+        </template>
+      </b-table>
+    </div>
   </div>
 </template>
 
@@ -25,6 +34,7 @@ export default {
           url: this.info.url,
           nb_streams: this.info.nb_streams,
           flags: this.info.flags,
+          nb_chapters: this.info.nb_chapters,
         },
       ]
     },