int av_index_search_timestamp(AVStream *st, int wanted_timestamp, int backward)
int av_index_search_timestamp(AVStream *st, int64_t wanted_timestamp, int backward)
int av_index_search_timestamp(AVStream *st, int wanted_timestamp, int backward){    AVIndexEntry *entries= st->index_entries;    int nb_entries= st->nb_index_entries;    int a, b, m;    int64_t timestamp;    a = - 1;    b = nb_entries;    while (b - a > 1) {        m = (a + b) >> 1;        timestamp = entries[m].timestamp;        if(timestamp >= wanted_timestamp)            b = m;        if(timestamp <= wanted_timestamp)            a = m;    }    m= backward ? a : b;    if(m == nb_entries)         return -1;    return  m;}