avconv.c:4183: error: Uninitialized Value
  The value read from ost was never initialized.

avconv.c:4183:5: 
4181.     ost->filter       = ofilter;
4182. 
4183.     ofilter->ost      = ost;
          ^
4184. 
4185.     if (ost->stream_copy) {

static void init_output_filter(OutputFilter *ofilter, OptionsContext *o,
                               AVFormatContext *oc)
{
    OutputStream *ost;
    switch (ofilter->out_tmp->filter_ctx->output_pads[ofilter->out_tmp->pad_idx].type) {
    case AVMEDIA_TYPE_VIDEO: ost = new_video_stream(o, oc); break;
    case AVMEDIA_TYPE_AUDIO: ost = new_audio_stream(o, oc); break;
    default:
        av_log(NULL, AV_LOG_FATAL, "Only video and audio filters are supported "
               "currently.\n");
        exit_program(1);
    }
    ost->source_index = -1;
    ost->filter       = ofilter;
    ofilter->ost      = ost;
    if (ost->stream_copy) {
        av_log(NULL, AV_LOG_ERROR, "Streamcopy requested for output stream %d:%d, "
               "which is fed from a complex filtergraph. Filtering and streamcopy "
               "cannot be used together.\n", ost->file_index, ost->index);
        exit_program(1);
    }
    if (configure_output_filter(ofilter->graph, ofilter, ofilter->out_tmp) < 0) {
        av_log(NULL, AV_LOG_FATAL, "Error configuring filter.\n");
        exit_program(1);
    }
    avfilter_inout_free(&ofilter->out_tmp);
}
['static void init_output_filter(OutputFilter *ofilter, OptionsContext *o,\n                               AVFormatContext *oc)\n{\n    OutputStream *ost;\n    switch (ofilter->out_tmp->filter_ctx->output_pads[ofilter->out_tmp->pad_idx].type) {\n    case AVMEDIA_TYPE_VIDEO: ost = new_video_stream(o, oc); break;\n    case AVMEDIA_TYPE_AUDIO: ost = new_audio_stream(o, oc); break;\n    default:\n        av_log(NULL, AV_LOG_FATAL, "Only video and audio filters are supported "\n               "currently.\\n");\n        exit_program(1);\n    }\n    ost->source_index = -1;\n    ost->filter       = ofilter;\n    ofilter->ost      = ost;\n    if (ost->stream_copy) {\n        av_log(NULL, AV_LOG_ERROR, "Streamcopy requested for output stream %d:%d, "\n               "which is fed from a complex filtergraph. Filtering and streamcopy "\n               "cannot be used together.\\n", ost->file_index, ost->index);\n        exit_program(1);\n    }\n    if (configure_output_filter(ofilter->graph, ofilter, ofilter->out_tmp) < 0) {\n        av_log(NULL, AV_LOG_FATAL, "Error configuring filter.\\n");\n        exit_program(1);\n    }\n    avfilter_inout_free(&ofilter->out_tmp);\n}']