[Libav-user] bitrate and delay of h264

[hz nan]

Hi all.
I'm using ffmpeg to encode screen image and send to other computer .
But I found the bitrate is very large. It is nearly 300KB/s which need
to be below 100KB/s. And if i decrease the bitrate,the quality of
image become very bad.
And I encode 5image in 1s, because if I only encode 1image in 1s, the
delay of the image will become about 6s which is very large.
Anyone has advice to decrease the bitrate and the delay of the image?
Thanks
Hongzhen Nan
            pCodec = avcodec_find_encoder(CODEC_ID_H264);
        pCodecCtx= avcodec_alloc_context();
        pCodecCtx->width = 800;
        pCodecCtx->height = 600;
        pCodecCtx->pix_fmt = PIX_FMT_YUV420P;
        pCodecCtx->time_base.den = 1;
        pCodecCtx->time_base.num = 5;
        pCodecCtx->coder_type=1;
        pCodecCtx->flags|=(CODEC_FLAG_LOOP_FILTER);
        pCodecCtx->me_cmp|=FF_CMP_CHROMA;
        pCodecCtx->partitions|=(X264_PART_I8X8|X264_PART_I4X4|X264_PART_P8X8|X264_PART_B8X8);
        pCodecCtx->me_method=ME_HEX;
        pCodecCtx->me_subpel_quality=4;
        pCodecCtx->me_range=16;
        pCodecCtx->gop_size=2;
        pCodecCtx->keyint_min=25;
        pCodecCtx->scenechange_threshold=40;
        pCodecCtx->i_quant_factor=(float)1/0.71;
        pCodecCtx->b_frame_strategy=1;
        pCodecCtx->qcompress=0.6;
        pCodecCtx->qmin=10;
        pCodecCtx->qmax=51;
        pCodecCtx->max_qdiff=4;
        pCodecCtx->max_b_frames=3;
        pCodecCtx->refs=2;
        pCodecCtx->directpred=1;
        pCodecCtx->trellis=1;
        pCodecCtx->flags2
|=(CODEC_FLAG2_BPYRAMID|CODEC_FLAG2_WPRED|CODEC_FLAG2_8X8DCT|CODEC_FLAG2_FASTPSKIP);
        pCodecCtx->flags2 &=~(CODEC_FLAG2_MIXED_REFS|CODEC_FLAG2_MBTREE);
        pCodecCtx->weighted_p_pred=1;
        pCodecCtx->rc_lookahead=0;
        pCodecCtx->bit_rate=300000;
        pCodecCtx->bit_rate_tolerance = 800;