printf("hello state=%d\n", rt->state);
av_log(s, AV_LOG_DEBUG, "hello state=%d\n", rt->state);
static int rtsp_read_play(AVFormatContext *s){    RTSPState *rt = s->priv_data;    RTSPHeader reply1, *reply = &reply1;    char cmd[1024];    printf("hello state=%d\n", rt->state);    if (rt->state == RTSP_STATE_PAUSED) {        snprintf(cmd, sizeof(cmd),                  "PLAY %s RTSP/1.0\r\n",                 s->filename);    } else {        snprintf(cmd, sizeof(cmd),                  "PLAY %s RTSP/1.0\r\n"                 "Range: npt=%0.3f-\r\n",                 s->filename,                 (double)rt->seek_timestamp / AV_TIME_BASE);    }    rtsp_send_cmd(s, cmd, reply, NULL);    if (reply->status_code != RTSP_STATUS_OK) {        return -1;    } else {        rt->state = RTSP_STATE_PLAYING;        return 0;    }}