From bb6c627fad9683e67b266e741bebf99f60963bb4 Mon Sep 17 00:00:00 2001
From: linbo <1034003879@qq.com>
Date: Wed, 12 Aug 2026 10:37:18 +0800
Subject: [PATCH] fix(camera): preserve UVC recording timing

---
 .../camera/uvc_camera/src/uvc_camera.cpp      | 34 +++++++++++++------
 1 file changed, 24 insertions(+), 10 deletions(-)

diff --git a/cmvr-es/devices/camera/uvc_camera/src/uvc_camera.cpp b/cmvr-es/devices/camera/uvc_camera/src/uvc_camera.cpp
index 362a6c94..4086c473 100644
--- a/cmvr-es/devices/camera/uvc_camera/src/uvc_camera.cpp
+++ b/cmvr-es/devices/camera/uvc_camera/src/uvc_camera.cpp
@@ -3,6 +3,8 @@
 // Created by xtkuang on 2025/5/30.
 //
 
+#include <algorithm>
+
 #include "../include/uvc_camera.h"
 
 using namespace std;
@@ -361,7 +363,9 @@ void UVCCamera::startRecording(const std::string &video_path) {
         codecpar->codec_id = codec_id;
         codecpar->width = width_;
         codecpar->height = height_;
-        stream->time_base = {1, fps_}; // 时间基：1/fps（每帧间隔1个时间单位）
+        // Use a fine-grained time base because the actual UVC frame rate can
+        // differ significantly from the configured frame rate.
+        stream->time_base = {1, 1'000'000};
 
         // 4. 复制编码器的extradata（如H.264的SPS/PPS，确保播放器能解析）
         if (rgbEncoder_ && rgbEncoder_->codec_context && rgbEncoder_->codec_context->extradata) {
@@ -665,6 +669,8 @@ void UVCCamera::recording_worker_() {
     is_recording_running = true;
     const int frame_interval = 1000 / fps_;
     bool is_first_key = false;
+    int64_t first_capture_monotonic_ns = 0;
+    int64_t last_packet_pts = AV_NOPTS_VALUE;
     try {
         //保证当前采集线程正常运行
         while (state_.is_recording && is_streaming_running) {
@@ -707,25 +713,33 @@ void UVCCamera::recording_worker_() {
             packet_->size = static_cast<int>(frame_data.rgbFrame.size());
             packet_->stream_index = stream_->index;      // 指定流索引
 
-            // 设置时间戳（递增）
-            packet_->pts = frame_count_++;
-            packet_->dts = packet_->pts;
-            packet_->duration = 1;  // 每帧持续1个时间单位（根据time_base）
+            // Preserve real capture time so dropped/late frames do not speed up playback.
+            if (first_capture_monotonic_ns == 0) {
+                first_capture_monotonic_ns = frame_data.capture_monotonic_ns;
+            }
+            const int64_t elapsed_ns = std::max<int64_t>(
+                0, frame_data.capture_monotonic_ns - first_capture_monotonic_ns);
+            int64_t packet_pts = av_rescale_q(
+                elapsed_ns, AVRational{1, 1'000'000'000}, stream_->time_base);
+            if (last_packet_pts != AV_NOPTS_VALUE && packet_pts <= last_packet_pts) {
+                packet_pts = last_packet_pts + 1;
+            }
+            packet_->pts = packet_pts;
+            packet_->dts = packet_pts;
+            packet_->duration = av_rescale_q(
+                1, AVRational{1, fps_}, stream_->time_base);
+            last_packet_pts = packet_pts;
+            ++frame_count_;
 
             // 标记关键帧
             if (frame_data.bKey) {
                 packet_->flags |= AV_PKT_FLAG_KEY;
             }
 
-            // 转换时间基
-            av_packet_rescale_ts(packet_, {1, fps_}, stream_->time_base);
-
             // 写入帧
             if (av_interleaved_write_frame(format_context_, packet_) < 0) {
                 CMVR_LOG(ERROR) << "写入第" << frame_count_ << "帧失败";
             }
-
-            std::this_thread::sleep_for(std::chrono::milliseconds(33));
         }
 
         // 7. 写入文件尾（完成封装）