avconv.c:3170: error: Null Dereference
  pointer `st` last assigned on line 3156 could be null and is dereferenced at line 3170, column 9.

avconv.c:3153:1: start of procedure new_output_stream()
3151. }
3152. 
3153. static OutputStream *new_output_stream(OptionsContext *o, AVFormatContext *oc, enum AVMediaType type)
      ^
3154. {
3155.     OutputStream *ost;

avconv.c:3156:5: 
3154. {
3155.     OutputStream *ost;
3156.     AVStream *st = avformat_new_stream(oc, NULL);
          ^
3157.     int idx      = oc->nb_streams - 1, ret = 0;
3158.     char *bsf = NULL, *next, *codec_tag = NULL;

libavformat/utils.c:2701:1: start of procedure avformat_new_stream()
  2699. #endif
  2700. 
  2701. AVStream *avformat_new_stream(AVFormatContext *s, AVCodec *c)
        ^
  2702. {
  2703.     AVStream *st;

libavformat/utils.c:2707:9: Taking true branch
  2705.     AVStream **streams;
  2706. 
  2707.     if (s->nb_streams >= INT_MAX/sizeof(*streams))
                ^
  2708.         return NULL;
  2709.     streams = av_realloc(s->streams, (s->nb_streams + 1) * sizeof(*streams));

libavformat/utils.c:2708:9: 
  2706. 
  2707.     if (s->nb_streams >= INT_MAX/sizeof(*streams))
  2708.         return NULL;
                ^
  2709.     streams = av_realloc(s->streams, (s->nb_streams + 1) * sizeof(*streams));
  2710.     if (!streams)

libavformat/utils.c:2749:1: return from a call to avformat_new_stream
  2747.     s->streams[s->nb_streams++] = st;
  2748.     return st;
  2749. }
        ^
  2750. 
  2751. AVProgram *av_new_program(AVFormatContext *ac, int id)

avconv.c:3157:5: 
3155.     OutputStream *ost;
3156.     AVStream *st = avformat_new_stream(oc, NULL);
3157.     int idx      = oc->nb_streams - 1, ret = 0;
          ^
3158.     char *bsf = NULL, *next, *codec_tag = NULL;
3159.     AVBitStreamFilterContext *bsfc, *bsfc_prev = NULL;

avconv.c:3158:5: 
3156.     AVStream *st = avformat_new_stream(oc, NULL);
3157.     int idx      = oc->nb_streams - 1, ret = 0;
3158.     char *bsf = NULL, *next, *codec_tag = NULL;
          ^
3159.     AVBitStreamFilterContext *bsfc, *bsfc_prev = NULL;
3160.     double qscale = -1;

avconv.c:3159:5: 
3157.     int idx      = oc->nb_streams - 1, ret = 0;
3158.     char *bsf = NULL, *next, *codec_tag = NULL;
3159.     AVBitStreamFilterContext *bsfc, *bsfc_prev = NULL;
          ^
3160.     double qscale = -1;
3161.     char *buf = NULL, *arg = NULL, *preset = NULL;

avconv.c:3160:5: 
3158.     char *bsf = NULL, *next, *codec_tag = NULL;
3159.     AVBitStreamFilterContext *bsfc, *bsfc_prev = NULL;
3160.     double qscale = -1;
          ^
3161.     char *buf = NULL, *arg = NULL, *preset = NULL;
3162.     AVIOContext *s = NULL;

avconv.c:3161:5: 
3159.     AVBitStreamFilterContext *bsfc, *bsfc_prev = NULL;
3160.     double qscale = -1;
3161.     char *buf = NULL, *arg = NULL, *preset = NULL;
          ^
3162.     AVIOContext *s = NULL;
3163. 

avconv.c:3162:5: 
3160.     double qscale = -1;
3161.     char *buf = NULL, *arg = NULL, *preset = NULL;
3162.     AVIOContext *s = NULL;
          ^
3163. 
3164.     if (!st) {

avconv.c:3164:10: Taking true branch
3162.     AVIOContext *s = NULL;
3163. 
3164.     if (!st) {
               ^
3165.         av_log(NULL, AV_LOG_FATAL, "Could not alloc stream.\n");
3166.         exit_program(1);

avconv.c:3165:9: Skipping av_log(): empty list of specs
3163. 
3164.     if (!st) {
3165.         av_log(NULL, AV_LOG_FATAL, "Could not alloc stream.\n");
              ^
3166.         exit_program(1);
3167.     }

avconv.c:3166:9: Skipping exit_program(): empty list of specs
3164.     if (!st) {
3165.         av_log(NULL, AV_LOG_FATAL, "Could not alloc stream.\n");
3166.         exit_program(1);
              ^
3167.     }
3168. 

avconv.c:3169:9: Taking true branch
3167.     }
3168. 
3169.     if (oc->nb_streams - 1 < o->nb_streamid_map)
              ^
3170.         st->id = o->streamid_map[oc->nb_streams - 1];
3171. 

avconv.c:3170:9: 
3168. 
3169.     if (oc->nb_streams - 1 < o->nb_streamid_map)
3170.         st->id = o->streamid_map[oc->nb_streams - 1];
              ^
3171. 
3172.     output_streams = grow_array(output_streams, sizeof(*output_streams), &nb_output_streams,
