ffmpeg.c:1361: error: Null Dereference
  pointer `vstats_file` last assigned on line 1351 could be null and is dereferenced by call to `fprintf()` at line 1361, column 9.

ffmpeg.c:1342:1: start of procedure do_video_stats()
1340. }
1341. 
1342. static void do_video_stats(AVFormatContext *os, AVOutputStream *ost,
      ^
1343.                            int frame_size)
1344. {

ffmpeg.c:1350:10: Taking true branch
1348. 
1349.     /* this is executed just the first time do_video_stats is called */
1350.     if (!vstats_file) {
               ^
1351.         vstats_file = fopen(vstats_filename, "w");
1352.         if (!vstats_file) {

ffmpeg.c:1351:9: 
1349.     /* this is executed just the first time do_video_stats is called */
1350.     if (!vstats_file) {
1351.         vstats_file = fopen(vstats_filename, "w");
              ^
1352.         if (!vstats_file) {
1353.             perror("fopen");

ffmpeg.c:1352:14: Taking true branch
1350.     if (!vstats_file) {
1351.         vstats_file = fopen(vstats_filename, "w");
1352.         if (!vstats_file) {
                   ^
1353.             perror("fopen");
1354.             av_exit(1);

ffmpeg.c:1353:13: 
1351.         vstats_file = fopen(vstats_filename, "w");
1352.         if (!vstats_file) {
1353.             perror("fopen");
                  ^
1354.             av_exit(1);
1355.         }

ffmpeg.c:1354:13: Skipping av_exit(): empty list of specs
1352.         if (!vstats_file) {
1353.             perror("fopen");
1354.             av_exit(1);
                  ^
1355.         }
1356.     }

ffmpeg.c:1358:5: 
1356.     }
1357. 
1358.     enc = ost->st->codec;
          ^
1359.     if (enc->codec_type == AVMEDIA_TYPE_VIDEO) {
1360.         frame_number = ost->frame_number;

ffmpeg.c:1359:9: Taking true branch
1357. 
1358.     enc = ost->st->codec;
1359.     if (enc->codec_type == AVMEDIA_TYPE_VIDEO) {
              ^
1360.         frame_number = ost->frame_number;
1361.         fprintf(vstats_file, "frame= %5d q= %2.1f ", frame_number, enc->coded_frame->quality/(float)FF_QP2LAMBDA);

ffmpeg.c:1360:9: 
1358.     enc = ost->st->codec;
1359.     if (enc->codec_type == AVMEDIA_TYPE_VIDEO) {
1360.         frame_number = ost->frame_number;
              ^
1361.         fprintf(vstats_file, "frame= %5d q= %2.1f ", frame_number, enc->coded_frame->quality/(float)FF_QP2LAMBDA);
1362.         if (enc->flags&CODEC_FLAG_PSNR)

ffmpeg.c:1361:9: 
1359.     if (enc->codec_type == AVMEDIA_TYPE_VIDEO) {
1360.         frame_number = ost->frame_number;
1361.         fprintf(vstats_file, "frame= %5d q= %2.1f ", frame_number, enc->coded_frame->quality/(float)FF_QP2LAMBDA);
              ^
1362.         if (enc->flags&CODEC_FLAG_PSNR)
1363.             fprintf(vstats_file, "PSNR= %6.2f ", psnr(enc->coded_frame->error[0]/(enc->width*enc->height*255.0*255.0)));
