refactor ffmpeg super class into more maintainable package, cmake is catigorized now ; removed old engine, replaced with new one

src/engine/ffmpeg/CodecContext.cpp

@@ -0,0 +1,67 @@
+#include "CodecContext.h"
+#include <QDebug>
+
+extern "C" {
+#include <libavcodec/avcodec.h>
+}
+
+namespace engine {
+
+void CodecContext::Deleter::operator()(AVCodecContext *p) const {
+    avcodec_free_context(&p);
+}
+
+bool CodecContext::open(const AVCodecParameters *par) {
+    close();
+
+    const AVCodec *dec = avcodec_find_decoder(par->codec_id);
+    if (!dec) {
+        qWarning() << "[CodecContext] No decoder found for codec_id" << par->codec_id;
+        return false;
+    }
+
+    AVCodecContext *raw = avcodec_alloc_context3(dec);
+    if (!raw) {
+        qWarning() << "[CodecContext] Failed to allocate codec context";
+        return false;
+    }
+
+    avcodec_parameters_to_context(raw, par);
+
+    if (avcodec_open2(raw, dec, nullptr) < 0) {
+        avcodec_free_context(&raw);
+        qWarning() << "[CodecContext] Cannot open codec";
+        return false;
+    }
+
+    m_ctx.reset(raw);
+    return true;
+}
+
+void CodecContext::close() {
+    m_ctx.reset();
+}
+
+bool CodecContext::sendPacket(const AVPacket *pkt) const {
+    return m_ctx && avcodec_send_packet(m_ctx.get(), pkt) >= 0;
+}
+
+bool CodecContext::receiveFrame(AVFrame *frame) const {
+    if (!m_ctx) return false;
+    int ret = avcodec_receive_frame(m_ctx.get(), frame);
+    return ret == 0;
+}
+
+void CodecContext::flush() {
+    if (m_ctx) avcodec_flush_buffers(m_ctx.get());
+}
+
+int CodecContext::sampleRate() const {
+    return m_ctx ? m_ctx->sample_rate : 0;
+}
+
+int CodecContext::channels() const {
+    return m_ctx ? m_ctx->ch_layout.nb_channels : 0;
+}
+
+} // namespace engine