架构大改之前

web_server/src/H264_Encoder.cpp

@@ -32,7 +32,7 @@ struct H264_Encoder::Private {
     std::uint32_t width{};                                  /* 当前编码尺寸；尺寸变化时整体重建编码器。 */
     std::uint32_t height{};                                 /* 当前编码尺寸；H.264 4:2:0 要求偶数。 */
     Video_Pixel_Layout layout{Video_Pixel_Layout::bgra};     /* scaler 当前输入格式。 */
-    bool first_frame{true};                                  /* 编码器重建后必须立即产生可独立解码的关键帧。 */
+    bool key_frame_requested{true};                          /* Track 新建或恢复时，下一 access unit 必须可独立解码。 */
 
     explicit Private(double value_frame_rate) : frame_rate(value_frame_rate) {
         if (!std::isfinite(frame_rate) || frame_rate <= 0.0)
@@ -47,7 +47,7 @@ struct H264_Encoder::Private {
         avcodec_free_context(&codec_context);
         width = 0;
         height = 0;
-        first_frame = true;
+        key_frame_requested = true;
     }
     void configure(std::uint32_t next_width, std::uint32_t next_height,
                    Video_Pixel_Layout next_layout) {
@@ -103,6 +103,10 @@ H264_Encoder::H264_Encoder(double frame_rate)
     : d(std::make_unique<Private>(frame_rate)) {}
 H264_Encoder::~H264_Encoder() = default;
 
+void H264_Encoder::request_key_frame() {
+    d->key_frame_requested = true;
+}
+
 std::shared_ptr<const Encoded_Video_Frame> H264_Encoder::encode(
     std::span<const std::byte> pixels, std::uint32_t width,
     std::uint32_t height, Video_Pixel_Layout layout,
@@ -118,7 +122,9 @@ std::shared_ptr<const Encoded_Video_Frame> H264_Encoder::encode(
                   d->yuv_frame->data, d->yuv_frame->linesize) != static_cast<int>(height))
         throw std::runtime_error("FFmpeg did not convert the complete video frame");
     d->yuv_frame->pts = presentation_time.count();
-    d->yuv_frame->pict_type = d->first_frame ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_NONE;
+    d->yuv_frame->pict_type = d->key_frame_requested
+                                  ? AV_PICTURE_TYPE_I
+                                  : AV_PICTURE_TYPE_NONE;
     require_ffmpeg(avcodec_send_frame(d->codec_context, d->yuv_frame),
                    "submitting frame to H.264 encoder");
     const int received = avcodec_receive_packet(d->codec_context, d->packet);
@@ -130,7 +136,7 @@ std::shared_ptr<const Encoded_Video_Frame> H264_Encoder::encode(
     output->presentation_time = presentation_time;
     output->sequence = sequence;
     output->key_frame = (d->packet->flags & AV_PKT_FLAG_KEY) != 0;
-    d->first_frame = false;
+    d->key_frame_requested = false;
     av_packet_unref(d->packet);
     return output;
 }