Supress avcodec_close() deprecation warning

Note, CodecContext2::close() function marked as deprecated for a long
time.

CMakeLists.txt

@@ -23,7 +23,7 @@ set(CMAKE_CXX_STANDARD_REQUIRED yes)
 # Warnings
 set (AVCPP_WARNING_OPTIONS
      $<$<OR:$<CXX_COMPILER_ID:Clang>,$<CXX_COMPILER_ID:AppleClang>,$<CXX_COMPILER_ID:GNU>>:
-       -Wall -Wextra>
+       -Wall -Wextra -Werror=return-type -Wwrite-strings>
      $<$<CXX_COMPILER_ID:MSVC>:
        /W4>)
 

src/avutils.h

@@ -28,6 +28,8 @@ extern "C" {
 #define API_AVFORMAT_URL       ((LIBAVFORMAT_VERSION_MAJOR > 58) || (LIBAVFORMAT_VERSION_MAJOR == 58 && LIBAVFORMAT_VERSION_MINOR >= 7))
 // net key frame flags: AV_FRAME_FLAG_KEY (FFmpeg 6.1)
 #define API_FRAME_KEY          ((LIBAVUTIL_VERSION_MAJOR > 58) || (LIBAVUTIL_VERSION_MAJOR == 58 && LIBAVUTIL_VERSION_MINOR >= 29))
+// avcodec_close() support
+#define API_AVCODEC_CLOSE      (LIBAVCODEC_VERSION_MAJOR < 61)
 
 #if defined(__ICL) || defined (__INTEL_COMPILER)
 #    define FF_DISABLE_DEPRECATION_WARNINGS __pragma(warning(push)) __pragma(warning(disable:1478))

src/codeccontext.cpp

@@ -448,12 +448,71 @@ void CodecContext2::open(Dictionary &options, const Codec &codec, OptionalErrorC
     options.assign(prt);
 }
 
+namespace {
+// Close code in new way: recreate context with parameters coping
+// Use legacy avcodec_close() for old ffmpeg versions.
+int codec_close(AVCodecContext*& ctx)
+{
+#if API_AVCODEC_CLOSE
+    return avcodec_close(ctx);
+#else
+    AVCodecContext *ctxNew = nullptr;
+    AVCodecParameters *parTmp = nullptr;
+
+    int ret;
+
+    ctxNew = avcodec_alloc_context3(ctx->codec);
+    if (!ctxNew) {
+        ret = AVERROR(ENOMEM);
+        goto fail;
+    }
+
+    parTmp = avcodec_parameters_alloc();
+    if (!parTmp) {
+        ret = AVERROR(ENOMEM);
+        goto fail;
+    }
+
+    ret = avcodec_parameters_from_context(parTmp, ctx);
+    if (ret < 0)
+        goto fail;
+
+    ret = avcodec_parameters_to_context(ctxNew, parTmp);
+    if (ret < 0)
+        goto fail;
+
+    ctxNew->pkt_timebase = ctx->pkt_timebase;
+
+
+#if (LIBAVCODEC_VERSION_MAJOR < 61) || (defined(FF_API_TICKS_PER_FRAME) && FF_API_TICKS_PER_FRAME)
+FF_DISABLE_DEPRECATION_WARNINGS
+    ctxNew->ticks_per_frame = ctx->ticks_per_frame;
+FF_ENABLE_DEPRECATION_WARNINGS
+#endif
+
+    avcodec_free_context(&ctx);
+    ctx = ctxNew;
+
+    ctxNew = nullptr;
+    ret      = 0;
+
+fail:
+    avcodec_free_context(&ctxNew);
+    avcodec_parameters_free(&parTmp);
+
+    return ret;
+#endif
+}
+}
+
 void CodecContext2::close(OptionalErrorCode ec)
 {
     clear_if(ec);
     if (isOpened())
     {
-        avcodec_close(m_raw);
+        if (auto sts = codec_close(m_raw); sts) {
+            throws_if(ec, sts, ffmpeg_category());
+        }
         return;
     }
     throws_if(ec, Errors::CodecNotOpened);