avconv.c:1457: error: Null Dereference
  pointer `vstats_file` last assigned on line 1447 could be null and is dereferenced by call to `fprintf()` at line 1457, column 9.

avconv.c:1438:1: start of procedure do_video_stats()
1436. }
1437. 
1438. static void do_video_stats(AVFormatContext *os, OutputStream *ost,
      ^
1439.                            int frame_size)
1440. {

avconv.c:1446:10: Taking true branch
1444. 
1445.     /* this is executed just the first time do_video_stats is called */
1446.     if (!vstats_file) {
               ^
1447.         vstats_file = fopen(vstats_filename, "w");
1448.         if (!vstats_file) {

avconv.c:1447:9: 
1445.     /* this is executed just the first time do_video_stats is called */
1446.     if (!vstats_file) {
1447.         vstats_file = fopen(vstats_filename, "w");
              ^
1448.         if (!vstats_file) {
1449.             perror("fopen");

avconv.c:1448:14: Taking true branch
1446.     if (!vstats_file) {
1447.         vstats_file = fopen(vstats_filename, "w");
1448.         if (!vstats_file) {
                   ^
1449.             perror("fopen");
1450.             exit_program(1);

avconv.c:1449:13: 
1447.         vstats_file = fopen(vstats_filename, "w");
1448.         if (!vstats_file) {
1449.             perror("fopen");
                  ^
1450.             exit_program(1);
1451.         }

avconv.c:1450:13: Skipping exit_program(): empty list of specs
1448.         if (!vstats_file) {
1449.             perror("fopen");
1450.             exit_program(1);
                  ^
1451.         }
1452.     }

avconv.c:1454:5: 
1452.     }
1453. 
1454.     enc = ost->st->codec;
          ^
1455.     if (enc->codec_type == AVMEDIA_TYPE_VIDEO) {
1456.         frame_number = ost->frame_number;

avconv.c:1455:9: Taking true branch
1453. 
1454.     enc = ost->st->codec;
1455.     if (enc->codec_type == AVMEDIA_TYPE_VIDEO) {
              ^
1456.         frame_number = ost->frame_number;
1457.         fprintf(vstats_file, "frame= %5d q= %2.1f ", frame_number, enc->coded_frame->quality/(float)FF_QP2LAMBDA);

avconv.c:1456:9: 
1454.     enc = ost->st->codec;
1455.     if (enc->codec_type == AVMEDIA_TYPE_VIDEO) {
1456.         frame_number = ost->frame_number;
              ^
1457.         fprintf(vstats_file, "frame= %5d q= %2.1f ", frame_number, enc->coded_frame->quality/(float)FF_QP2LAMBDA);
1458.         if (enc->flags&CODEC_FLAG_PSNR)

avconv.c:1457:9: 
1455.     if (enc->codec_type == AVMEDIA_TYPE_VIDEO) {
1456.         frame_number = ost->frame_number;
1457.         fprintf(vstats_file, "frame= %5d q= %2.1f ", frame_number, enc->coded_frame->quality/(float)FF_QP2LAMBDA);
              ^
1458.         if (enc->flags&CODEC_FLAG_PSNR)
1459.             fprintf(vstats_file, "PSNR= %6.2f ", psnr(enc->coded_frame->error[0]/(enc->width*enc->height*255.0*255.0)));
