Free unused memory for mjpeg format

Signed-off-by: Evan Flynn <[email protected]>

include/usb_cam/formats/mjpeg.hpp

@@ -178,14 +178,29 @@ class MJPEG2RGB : public pixel_format_base
     // deprecated: https://github.com/FFmpeg/FFmpeg/commit/f7db77bd8785d1715d3e7ed7e69bd1cc991f2d07
     av_init_packet(m_avpacket);
     #else
-    av_new_packet(m_avpacket, bytes_used);
+    // Initilize a new packet with defaults
+    m_result = av_new_packet(m_avpacket, bytes_used);
+
+    if (m_result != 0) {
+      std::cerr << "Failed to allocate new AV packet: ";
+      print_av_error_string(m_result);
+    }
     #endif
 
-    av_packet_from_data(
+    // Free all unused memory from AV Packet
+    av_free(m_avpacket->data);
+    av_free(m_avpacket->buf);
+
+    m_result = av_packet_from_data(
       m_avpacket,
       const_cast<uint8_t *>(reinterpret_cast<const uint8_t *>(src)),
       bytes_used);
 
+    if (m_result != 0) {
+      std::cerr << "Failed to initialize AV packet: ";
+      print_av_error_string(m_result);
+    }
+
     // Pass src MJPEG image to decoder
     m_result = avcodec_send_packet(m_avcodec_context, m_avpacket);
 
@@ -195,6 +210,9 @@ class MJPEG2RGB : public pixel_format_base
       print_av_error_string(m_result);
     }
 
+    // After AV packet is sent, free the memory
+    av_free(m_avpacket);
+
     m_result = avcodec_receive_frame(m_avcodec_context, m_avframe_device);
 
     if (m_result == AVERROR(EAGAIN) || m_result == AVERROR_EOF) {