avconv.c:1480: error: Null Dereference
  pointer `vstats_file` last assigned on line 1470 could be null and is dereferenced by call to `fprintf()` at line 1480, column 9.

avconv.c:1461:1: start of procedure do_video_stats()
1459. }
1460. 
1461. static void do_video_stats(AVFormatContext *os, OutputStream *ost,
      ^
1462.                            int frame_size)
1463. {

avconv.c:1469:10: Taking true branch
1467. 
1468.     /* this is executed just the first time do_video_stats is called */
1469.     if (!vstats_file) {
               ^
1470.         vstats_file = fopen(vstats_filename, "w");
1471.         if (!vstats_file) {

avconv.c:1470:9: 
1468.     /* this is executed just the first time do_video_stats is called */
1469.     if (!vstats_file) {
1470.         vstats_file = fopen(vstats_filename, "w");
              ^
1471.         if (!vstats_file) {
1472.             perror("fopen");

avconv.c:1471:14: Taking true branch
1469.     if (!vstats_file) {
1470.         vstats_file = fopen(vstats_filename, "w");
1471.         if (!vstats_file) {
                   ^
1472.             perror("fopen");
1473.             exit_program(1);

avconv.c:1472:13: 
1470.         vstats_file = fopen(vstats_filename, "w");
1471.         if (!vstats_file) {
1472.             perror("fopen");
                  ^
1473.             exit_program(1);
1474.         }

avconv.c:1473:13: Skipping exit_program(): empty list of specs
1471.         if (!vstats_file) {
1472.             perror("fopen");
1473.             exit_program(1);
                  ^
1474.         }
1475.     }

avconv.c:1477:5: 
1475.     }
1476. 
1477.     enc = ost->st->codec;
          ^
1478.     if (enc->codec_type == AVMEDIA_TYPE_VIDEO) {
1479.         frame_number = ost->frame_number;

avconv.c:1478:9: Taking true branch
1476. 
1477.     enc = ost->st->codec;
1478.     if (enc->codec_type == AVMEDIA_TYPE_VIDEO) {
              ^
1479.         frame_number = ost->frame_number;
1480.         fprintf(vstats_file, "frame= %5d q= %2.1f ", frame_number, enc->coded_frame->quality / (float)FF_QP2LAMBDA);

avconv.c:1479:9: 
1477.     enc = ost->st->codec;
1478.     if (enc->codec_type == AVMEDIA_TYPE_VIDEO) {
1479.         frame_number = ost->frame_number;
              ^
1480.         fprintf(vstats_file, "frame= %5d q= %2.1f ", frame_number, enc->coded_frame->quality / (float)FF_QP2LAMBDA);
1481.         if (enc->flags&CODEC_FLAG_PSNR)

avconv.c:1480:9: 
1478.     if (enc->codec_type == AVMEDIA_TYPE_VIDEO) {
1479.         frame_number = ost->frame_number;
1480.         fprintf(vstats_file, "frame= %5d q= %2.1f ", frame_number, enc->coded_frame->quality / (float)FF_QP2LAMBDA);
              ^
1481.         if (enc->flags&CODEC_FLAG_PSNR)
1482.             fprintf(vstats_file, "PSNR= %6.2f ", psnr(enc->coded_frame->error[0] / (enc->width * enc->height * 255.0 * 255.0)));
