fix: video duration accuracy

wanwu · May 22, 2024 · e45d8db · e45d8db
1 parent e0dc3af
commit e45d8db
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Showing 4 changed files with 24 additions and 4 deletions.
diff --git a/README.md b/README.md
@@ -38,6 +38,7 @@
 * 编译前需要下载 [ffmpeg-3.4.8.tar.xz](http://ffmpeg.org/releases/ffmpeg-3.4.8.tar.xz) 并解压至 `script` 目录下方。
 
 * emcc下载:git clone https://github.com/emscripten-core/emsdk.git
+* 安装emsdk，在emsdk目录下执行
 
 ```shell
   git pull
@@ -52,7 +53,7 @@
 * `emsdk` 需要安装于代码库根目录
 
 ## 编译脚本
-
+* 安装依赖 `npm i`，执行script目录下的脚本
 `script`下面是编译脚本
 `build_ffmpeg-3.4.8.sh` 编译本地c编译环境的ffmpeg的lib库
 `build-emcc.sh` 编译emcc环境需要的ffmpeg的lib库，编译结果lib/ffmpeg-emcc

diff --git a/package.json b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "cheetah-capture",
-  "version": "0.1.5",
+  "version": "0.1.6",
   "description": "cheetah-capture是基于ffmpeg的wasm截取视频帧工具",
   "keywords": [
     "ffmpeg",

diff --git a/src/capture.c b/src/capture.c
@@ -4,6 +4,7 @@
 #include <libavformat/avformat.h>
 #include <libavutil/imgutils.h>
 #include <libswscale/swscale.h>
+#include <libavutil/avutil.h>
 
 typedef struct
 {
@@ -19,6 +20,10 @@ typedef struct
     int lastIframe;
 } FrameInfo;
 
+// double av_q2d(AVRational r) {
+//     return r.num / (double) r.den;
+// }
+
 AVFrame *initAVFrame(AVCodecContext *pCodecCtx, uint8_t **frameBuffer)
 {
     AVFrame *pFrameRGB = av_frame_alloc();
@@ -227,7 +232,21 @@ int videoStream, int time, FrameInfo *frameInfo, int *Iframe, int counts, int id
     imageData = (ImageData *)malloc(sizeof(ImageData));
     imageData->width = (uint32_t)pNewCodecCtx->width;
     imageData->height = (uint32_t)pNewCodecCtx->height;
-    imageData->duration = (uint32_t)pFormatCtx->duration;
+    // 计算视频的实际时长
+    if(pFormatCtx->duration!=AV_NOPTS_VALUE){
+        int hours,mins,secs,us;
+        int64_t duration=pFormatCtx->duration+5000;
+        secs=duration/AV_TIME_BASE;
+        us=duration%AV_TIME_BASE;//1000000
+        mins=secs/60;
+        secs%=60;
+        hours=mins/60;
+        mins%=60;
+        int totalMilliseconds = (hours * 3600000) + (mins * 60000) + (secs * 1000) + (100 * us / AV_TIME_BASE);
+        imageData->duration = (uint32_t)totalMilliseconds;
+    } else {
+        imageData->duration = 0;
+    }
     imageData->data = getFrameBuffer(pFrameRGB, pNewCodecCtx);
     emscripten_run_script(get_js_code(*imageData, id));
     av_frame_free(&pFrameRGB);

diff --git a/src/index.ts b/src/index.ts
@@ -176,7 +176,7 @@ export async function initCapture({
                 const img = await getUrl(width, height, imageDataBuffer, angle);
                 const cbk = pool.getCbk(id);
                 const {onChange} = cbk;
-                const info = {width, height, duration: duration / 1000000};
+                const info = {width, height, duration: Number(duration) / 1000};
                 const {url} = pool.getCbk(id);
                 onChange && onChange({url}, img, info);
                 url.push(img.url);