int i;
int i, must_open_file;
void av_close_input_file(AVFormatContext *s){    int i;    if (s->iformat->read_close)        s->iformat->read_close(s);    for(i=0;i<s->nb_streams;i++) {        av_free(s->streams[i]);    }    if (s->packet_buffer) {        AVPacketList *p, *p1;        p = s->packet_buffer;        while (p != NULL) {            p1 = p->next;            av_free_packet(&p->pkt);            av_free(p);            p = p1;        }        s->packet_buffer = NULL;    }    if (!(s->iformat->flags & AVFMT_NOFILE)) {        url_fclose(&s->pb);    }    av_freep(&s->priv_data);    av_free(s);}