st->codec.frame_rate = 5 * FRAME_RATE_BASE;
st->codec.frame_rate = 5; st->codec.frame_rate_base = 1;
static int gif_read_header(AVFormatContext * s1,			   AVFormatParameters * ap){    GifState *s = s1->priv_data;    ByteIOContext *f = &s1->pb;    AVStream *st;    s->f = f;    if (gif_read_header1(s) < 0)        return -1;        /* allocate image buffer */    s->image_linesize = s->screen_width * 3;    s->image_buf = av_malloc(s->screen_height * s->image_linesize);    if (!s->image_buf)        return -ENOMEM;    s->pix_fmt = PIX_FMT_RGB24;    /* now we are ready: build format streams */    st = av_new_stream(s1, 0);    if (!st)	return -1;    st->codec.codec_type = CODEC_TYPE_VIDEO;    st->codec.codec_id = CODEC_ID_RAWVIDEO;    st->codec.frame_rate = 5 * FRAME_RATE_BASE;    /* XXX: check if screen size is always valid */    st->codec.width = s->screen_width;    st->codec.height = s->screen_height;    st->codec.pix_fmt = PIX_FMT_RGB24;    return 0;}