HLS TS 切片下载失败后清除该切片遗留的解复用输入缓存 (#4786)

在 HLS TS 切片下载失败后清除该切片遗留的解复用输入缓存，防止其与下一切片拼接导致错误的包或者损坏的包出现.

src/Http/HlsPlayer.cpp

@@ -153,6 +153,7 @@ void HlsPlayer::fetchSegment() {
             return;
         }
         if (err) {
+            strong_self->onSegmentDownloadFailed(err);
             WarnL << "Download ts segment " << url << " failed:" << err;
             if (err.getErrCode() == Err_timeout) {
                 strong_self->_timeout_multiple = MAX(strong_self->_timeout_multiple + 1, MAX_TIMEOUT_MULTIPLE);
@@ -492,6 +493,14 @@ void HlsPlayerImp::onPacket(const char *data, size_t len) {
     _recvtotalbytes += HlsPlayer::getRecvTotalBytes();
 }
 
+void HlsPlayerImp::onSegmentDownloadFailed(const toolkit::SockException &ex) {
+    if (_decoder && ex) {
+        // 失败切片的输入残片不能与下一切片拼接；这里只清输入缓存，不 flush 解码帧。
+        // Input left by a failed segment must not join the next one; clear it without flushing decoded frames.
+        _decoder->clearInputCache();
+    }
+}
+
 void HlsPlayerImp::addTrackCompleted() {
     PlayerImp<HlsPlayer, PlayerBase>::onPlayResult(SockException(Err_success, "play hls success"));
 }

src/Http/HlsPlayer.h

@@ -90,6 +90,9 @@ protected:
      * [AUTO-TRANSLATED:159a6559]
      */
     virtual void onPacket(const char *data, size_t len) = 0;
+    // TS 切片下载失败通知；派生类可清理该切片遗留的输入状态。
+    // Notify derived classes to clear input state left by a failed TS segment.
+    virtual void onSegmentDownloadFailed(const toolkit::SockException &ex) {}
 
 private:
     bool onParsed(bool is_m3u8_inner, int64_t sequence, const map<int, ts_segment> &ts_map) override;
@@ -149,6 +152,7 @@ public:
 private:
     //// HlsPlayer override////
     void onPacket(const char *data, size_t len) override;
+    void onSegmentDownloadFailed(const toolkit::SockException &ex) override;
 
 private:
     //// PlayerBase override////

src/Rtp/Decoder.cpp

@@ -72,6 +72,10 @@ ssize_t DecoderImp::input(const uint8_t *data, size_t bytes){
     return _decoder->input(data, bytes);
 }
 
+void DecoderImp::clearInputCache() {
+    _decoder->clearInputCache();
+}
+
 DecoderImp::DecoderImp(const Decoder::Ptr &decoder, MediaSinkInterface *sink){
     _decoder = decoder;
     _sink = sink;

src/Rtp/Decoder.h

@@ -25,6 +25,9 @@ public:
     using onStream = std::function<void(int stream, int codecid, const void *extra, size_t bytes, int finish)>;
 
     virtual ssize_t input(const uint8_t *data, size_t bytes) = 0;
+    // 清理未完成的输入缓存，但不 flush 已解析的帧。
+    // Clear incomplete input cache without flushing parsed frames.
+    virtual void clearInputCache() {}
     void setOnDecode(onDecode cb);
     void setOnStream(onStream cb);
 
@@ -45,6 +48,7 @@ public:
 
     static Ptr createDecoder(Type type, MediaSinkInterface *sink);
     ssize_t input(const uint8_t *data, size_t bytes);
+    void clearInputCache();
     void flush();
 
 protected:

src/Rtp/TSDecoder.cpp

@@ -146,6 +146,12 @@ ssize_t TSDecoder::input(const uint8_t *data, size_t bytes) {
     return bytes;
 }
 
+void TSDecoder::clearInputCache() {
+    // 只清理未完成的 TS 输入缓存，不重置 libmpegts 或 flush 残留帧。
+    // Clear only incomplete TS input; do not reset libmpegts or flush pending frames.
+    _ts_segment.reset();
+}
+
 #endif//defined(ENABLE_HLS)
 
 }//namespace mediakit

src/Rtp/TSDecoder.h

@@ -49,6 +49,7 @@ public:
     TSDecoder();
     ~TSDecoder();
     ssize_t input(const uint8_t* data, size_t bytes) override ;
+    void clearInputCache() override;
 
 private:
     TSSegment _ts_segment;