ffmpeg.c:3755: error: Null Dereference
  pointer `file_oformat` last assigned on line 3744 could be null and is dereferenced at line 3755, column 17.

ffmpeg.c:3719:1: start of procedure opt_output_file()
3717. }
3718. 
3719. static void opt_output_file(const char *filename)
      ^
3720. {
3721.     AVFormatContext *oc;

ffmpeg.c:3724:5: 
3722.     int err, use_video, use_audio, use_subtitle, use_data;
3723.     int input_has_video, input_has_audio, input_has_subtitle, input_has_data;
3724.     AVFormatParameters params, *ap = &params;
          ^
3725.     AVOutputFormat *file_oformat;
3726. 

ffmpeg.c:3727:10: Taking false branch
3725.     AVOutputFormat *file_oformat;
3726. 
3727.     if (!strcmp(filename, "-"))
               ^
3728.         filename = "pipe:";
3729. 

ffmpeg.c:3730:5: 
3728.         filename = "pipe:";
3729. 
3730.     oc = avformat_alloc_context();
          ^
3731.     if (!oc) {
3732.         print_error(filename, AVERROR(ENOMEM));

libavformat/options.c:78:1: start of procedure avformat_alloc_context()
  76. }
  77. 
  78. AVFormatContext *avformat_alloc_context(void)
      ^
  79. {
  80.     AVFormatContext *ic;

libavformat/options.c:81:5: 
  79. {
  80.     AVFormatContext *ic;
  81.     ic = av_malloc(sizeof(AVFormatContext));
          ^
  82.     if (!ic) return ic;
  83.     avformat_get_context_defaults(ic);

libavutil/mem.c:64:1: start of procedure av_malloc()
    62.    linker will do it automatically. */
    63. 
    64. void *av_malloc(size_t size)
        ^
    65. {
    66.     void *ptr = NULL;

libavutil/mem.c:66:5: 
    64. void *av_malloc(size_t size)
    65. {
    66.     void *ptr = NULL;
            ^
    67. #if CONFIG_MEMALIGN_HACK
    68.     long diff;

libavutil/mem.c:72:8: Taking false branch
    70. 
    71.     /* let's disallow possible ambiguous cases */
    72.     if(size > (INT_MAX-32) )
               ^
    73.         return NULL;
    74. 

libavutil/mem.c:83:9: Taking false branch
    81.     ((char*)ptr)[-1]= diff;
    82. #elif HAVE_POSIX_MEMALIGN
    83.     if (posix_memalign(&ptr,32,size))
                ^
    84.         ptr = NULL;
    85. #elif HAVE_MEMALIGN

libavutil/mem.c:114:5: 
    112.     ptr = malloc(size);
    113. #endif
    114.     return ptr;
             ^
    115. }
    116. 

libavutil/mem.c:115:1: return from a call to av_malloc
    113. #endif
    114.     return ptr;
    115. }
         ^
    116. 
    117. void *av_realloc(void *ptr, size_t size)

libavformat/options.c:82:10: Taking false branch
  80.     AVFormatContext *ic;
  81.     ic = av_malloc(sizeof(AVFormatContext));
  82.     if (!ic) return ic;
               ^
  83.     avformat_get_context_defaults(ic);
  84.     ic->av_class = &av_format_context_class;

libavformat/options.c:83:5: Skipping avformat_get_context_defaults(): empty list of specs
  81.     ic = av_malloc(sizeof(AVFormatContext));
  82.     if (!ic) return ic;
  83.     avformat_get_context_defaults(ic);
          ^
  84.     ic->av_class = &av_format_context_class;
  85.     return ic;

libavformat/options.c:84:5: 
  82.     if (!ic) return ic;
  83.     avformat_get_context_defaults(ic);
  84.     ic->av_class = &av_format_context_class;
          ^
  85.     return ic;
  86. }

libavformat/options.c:85:5: 
  83.     avformat_get_context_defaults(ic);
  84.     ic->av_class = &av_format_context_class;
  85.     return ic;
          ^
  86. }

libavformat/options.c:86:1: return from a call to avformat_alloc_context
  84.     ic->av_class = &av_format_context_class;
  85.     return ic;
  86. }
      ^

ffmpeg.c:3731:10: Taking false branch
3729. 
3730.     oc = avformat_alloc_context();
3731.     if (!oc) {
               ^
3732.         print_error(filename, AVERROR(ENOMEM));
3733.         ffmpeg_exit(1);

ffmpeg.c:3736:9: Taking false branch
3734.     }
3735. 
3736.     if (last_asked_format) {
              ^
3737.         file_oformat = av_guess_format(last_asked_format, NULL, NULL);
3738.         if (!file_oformat) {

ffmpeg.c:3744:9: Skipping av_guess_format(): empty list of specs
3742.         last_asked_format = NULL;
3743.     } else {
3744.         file_oformat = av_guess_format(NULL, filename, NULL);
              ^
3745.         if (!file_oformat) {
3746.             fprintf(stderr, "Unable to find a suitable output format for '%s'\n",

ffmpeg.c:3745:14: Taking true branch
3743.     } else {
3744.         file_oformat = av_guess_format(NULL, filename, NULL);
3745.         if (!file_oformat) {
                   ^
3746.             fprintf(stderr, "Unable to find a suitable output format for '%s'\n",
3747.                     filename);

ffmpeg.c:3746:13: 
3744.         file_oformat = av_guess_format(NULL, filename, NULL);
3745.         if (!file_oformat) {
3746.             fprintf(stderr, "Unable to find a suitable output format for '%s'\n",
                  ^
3747.                     filename);
3748.             ffmpeg_exit(1);

ffmpeg.c:3748:13: Skipping ffmpeg_exit(): empty list of specs
3746.             fprintf(stderr, "Unable to find a suitable output format for '%s'\n",
3747.                     filename);
3748.             ffmpeg_exit(1);
                  ^
3749.         }
3750.     }

ffmpeg.c:3752:5: 
3750.     }
3751. 
3752.     oc->oformat = file_oformat;
          ^
3753.     av_strlcpy(oc->filename, filename, sizeof(oc->filename));
3754. 

ffmpeg.c:3753:5: 
3751. 
3752.     oc->oformat = file_oformat;
3753.     av_strlcpy(oc->filename, filename, sizeof(oc->filename));
          ^
3754. 
3755.     if (!strcmp(file_oformat->name, "ffm") &&

libavutil/avstring.c:64:1: start of procedure av_strlcpy()
  62. }
  63. 
  64. size_t av_strlcpy(char *dst, const char *src, size_t size)
      ^
  65. {
  66.     size_t len = 0;

libavutil/avstring.c:66:5: 
  64. size_t av_strlcpy(char *dst, const char *src, size_t size)
  65. {
  66.     size_t len = 0;
          ^
  67.     while (++len < size && *src)
  68.         *dst++ = *src++;

libavutil/avstring.c:67:12: Loop condition is true. Entering loop body
  65. {
  66.     size_t len = 0;
  67.     while (++len < size && *src)
                 ^
  68.         *dst++ = *src++;
  69.     if (len <= size)

libavutil/avstring.c:67:28: Loop condition is false. Leaving loop
  65. {
  66.     size_t len = 0;
  67.     while (++len < size && *src)
                                 ^
  68.         *dst++ = *src++;
  69.     if (len <= size)

libavutil/avstring.c:69:9: Taking true branch
  67.     while (++len < size && *src)
  68.         *dst++ = *src++;
  69.     if (len <= size)
              ^
  70.         *dst = 0;
  71.     return len + strlen(src) - 1;

libavutil/avstring.c:70:9: 
  68.         *dst++ = *src++;
  69.     if (len <= size)
  70.         *dst = 0;
              ^
  71.     return len + strlen(src) - 1;
  72. }

libavutil/avstring.c:71:5: 
  69.     if (len <= size)
  70.         *dst = 0;
  71.     return len + strlen(src) - 1;
          ^
  72. }
  73. 

libavutil/avstring.c:72:1: return from a call to av_strlcpy
  70.         *dst = 0;
  71.     return len + strlen(src) - 1;
  72. }
      ^
  73. 
  74. size_t av_strlcat(char *dst, const char *src, size_t size)

ffmpeg.c:3755:10: 
3753.     av_strlcpy(oc->filename, filename, sizeof(oc->filename));
3754. 
3755.     if (!strcmp(file_oformat->name, "ffm") &&
               ^
3756.         av_strstart(filename, "http:", NULL)) {
3757.         /* special case for files sent to ffserver: we get the stream
