avconv.c:1474: error: Null Dereference
  pointer `vstats_file` last assigned on line 1464 could be null and is dereferenced by call to `fprintf()` at line 1474, column 9.

avconv.c:1455:1: start of procedure do_video_stats()
1453. }
1454. 
1455. static void do_video_stats(AVFormatContext *os, OutputStream *ost,
      ^
1456.                            int frame_size)
1457. {

avconv.c:1463:10: Taking true branch
1461. 
1462.     /* this is executed just the first time do_video_stats is called */
1463.     if (!vstats_file) {
               ^
1464.         vstats_file = fopen(vstats_filename, "w");
1465.         if (!vstats_file) {

avconv.c:1464:9: 
1462.     /* this is executed just the first time do_video_stats is called */
1463.     if (!vstats_file) {
1464.         vstats_file = fopen(vstats_filename, "w");
              ^
1465.         if (!vstats_file) {
1466.             perror("fopen");

avconv.c:1465:14: Taking true branch
1463.     if (!vstats_file) {
1464.         vstats_file = fopen(vstats_filename, "w");
1465.         if (!vstats_file) {
                   ^
1466.             perror("fopen");
1467.             exit_program(1);

avconv.c:1466:13: 
1464.         vstats_file = fopen(vstats_filename, "w");
1465.         if (!vstats_file) {
1466.             perror("fopen");
                  ^
1467.             exit_program(1);
1468.         }

avconv.c:1467:13: Skipping exit_program(): empty list of specs
1465.         if (!vstats_file) {
1466.             perror("fopen");
1467.             exit_program(1);
                  ^
1468.         }
1469.     }

avconv.c:1471:5: 
1469.     }
1470. 
1471.     enc = ost->st->codec;
          ^
1472.     if (enc->codec_type == AVMEDIA_TYPE_VIDEO) {
1473.         frame_number = ost->frame_number;

avconv.c:1472:9: Taking true branch
1470. 
1471.     enc = ost->st->codec;
1472.     if (enc->codec_type == AVMEDIA_TYPE_VIDEO) {
              ^
1473.         frame_number = ost->frame_number;
1474.         fprintf(vstats_file, "frame= %5d q= %2.1f ", frame_number, enc->coded_frame->quality / (float)FF_QP2LAMBDA);

avconv.c:1473:9: 
1471.     enc = ost->st->codec;
1472.     if (enc->codec_type == AVMEDIA_TYPE_VIDEO) {
1473.         frame_number = ost->frame_number;
              ^
1474.         fprintf(vstats_file, "frame= %5d q= %2.1f ", frame_number, enc->coded_frame->quality / (float)FF_QP2LAMBDA);
1475.         if (enc->flags&CODEC_FLAG_PSNR)

avconv.c:1474:9: 
1472.     if (enc->codec_type == AVMEDIA_TYPE_VIDEO) {
1473.         frame_number = ost->frame_number;
1474.         fprintf(vstats_file, "frame= %5d q= %2.1f ", frame_number, enc->coded_frame->quality / (float)FF_QP2LAMBDA);
              ^
1475.         if (enc->flags&CODEC_FLAG_PSNR)
1476.             fprintf(vstats_file, "PSNR= %6.2f ", psnr(enc->coded_frame->error[0] / (enc->width * enc->height * 255.0 * 255.0)));
