fix: memory leak while recording audio

Author: TzuHuanTai

doc/USE_GPERFTOOLS.md

@@ -29,7 +29,7 @@ sudo apt-get install ghostscript graphviz
 ## 3. Run the Program and Generate Performance Data
 Execute program and output the performance data to a specified file, for example:
 ```bash
-CPUPROFILE=./prof.out CPUPROFILESIGNAL=12 ./pi_webrtc --camera=v4l2:0 --fps=30 --width=1280 --height=960 --v4l2_format=h264 --hw_accel --uid=home-pi-3b
+CPUPROFILE=./prof.out HEAPPROFILE=heap CPUPROFILESIGNAL=12 ./pi_webrtc --camera=v4l2:0 --fps=30 --width=1280 --height=960 --v4l2_format=h264 --hw_accel --uid=home-pi-3b
 ```
 
 Send a signal to the process to start/stop collect performance data:
@@ -43,6 +43,7 @@ Convert the performance data into a PDF report using the pprof tool:
 
 ```bash
 pprof /home/pi/IoT/RaspberryPi_WebRTC/build/pi_webrtc prof.out.0 --pdf > prof_0.pdf
+pprof --pdf --base=heap.0001.heap ./test_recorder heap.0003.heap > heap_diff.pdf
 ```
 
 # Reference

src/recorder/audio_recorder.cpp

@@ -63,8 +63,8 @@ void AudioRecorder::Encode() {
         return;
     }
 
+    AVPacket *pkt = av_packet_alloc();
     while (ret >= 0) {
-        AVPacket *pkt = av_packet_alloc();
         ret = avcodec_receive_packet(encoder, pkt);
         if (ret == AVERROR(EAGAIN)) {
             break;
@@ -79,10 +79,9 @@ void AudioRecorder::Encode() {
         pkt->duration = av_rescale_q(pkt->duration, encoder->time_base, st->time_base);
 
         OnPacketed(pkt);
-
-        av_packet_unref(pkt);
-        av_packet_free(&pkt);
     }
+    av_packet_unref(pkt);
+    av_packet_free(&pkt);
 }
 
 void AudioRecorder::OnBuffer(PaBuffer &buffer) {
@@ -106,7 +105,7 @@ void AudioRecorder::OnBuffer(PaBuffer &buffer) {
 
     if (fifo_buffer.write(reinterpret_cast<void **>(converted_input_samples), samples_per_channel) <
         samples_per_channel) {
-        DEBUG_PRINT("Failed to write audio date into fifo buffer.");
+        DEBUG_PRINT("Failed to write audio data into fifo buffer.");
     }
 
     if (converted_input_samples) {