ffmpegencoder: fixed bug that failed to flush the audio encoder

For some reason, when the encoder closed it only flushed the video encoder and
not the audio encoder. Now it does both.

app/codec/ffmpeg/ffmpegencoder.cpp

@@ -422,25 +422,34 @@ bool FFmpegEncoder::SetupCodecContext(AVStream* stream, AVCodecContext* codec_ct
 void FFmpegEncoder::FlushEncoders()
 {
   if (video_codec_ctx_) {
-    avcodec_send_frame(video_codec_ctx_, nullptr);
+    FlushCodecCtx(video_codec_ctx_, video_stream_);
+  }
+
+  if (audio_codec_ctx_) {
+    FlushCodecCtx(audio_codec_ctx_, audio_stream_);
+  }
+}
+
+void FFmpegEncoder::FlushCodecCtx(AVCodecContext *codec_ctx, AVStream* stream)
+{
+  avcodec_send_frame(codec_ctx, nullptr);
   AVPacket* pkt = av_packet_alloc();
 
   int error_code;
   do {
-      error_code = avcodec_receive_packet(video_codec_ctx_, pkt);
+    error_code = avcodec_receive_packet(codec_ctx, pkt);
 
     if (error_code < 0) {
       break;
     }
 
-      pkt->stream_index = video_stream_->index;
-      av_packet_rescale_ts(pkt, video_codec_ctx_->time_base, video_stream_->time_base);
+    pkt->stream_index = stream->index;
+    av_packet_rescale_ts(pkt, codec_ctx->time_base, stream->time_base);
     av_interleaved_write_frame(fmt_ctx_, pkt);
     av_packet_unref(pkt);
   } while (error_code >= 0);
 
   av_packet_free(&pkt);
-  }
 }
 
 void FFmpegEncoder::Error(const QString &s)

app/codec/ffmpeg/ffmpegencoder.h

@@ -51,6 +51,7 @@ private:
   bool SetupCodecContext(AVStream *stream, AVCodecContext *codec_ctx, AVCodec *codec);
 
   void FlushEncoders();
+  void FlushCodecCtx(AVCodecContext* codec_ctx, AVStream *stream);
 
   AVFormatContext* fmt_ctx_;