AVRational rational = { 1, 25 };
    output_codec_ctx->time_base = rational;
    output_codec_ctx->time_base.num = 1;
    output_codec_ctx->time_base.den = 25;
    output_codec_ctx->ticks_per_frame = 2;
    output_codec_ctx->gop_size = 10;
    output_codec_ctx->max_b_frames = 1;
    output_codec_ctx->debug = 1;

    output_codec_ctx->pix_fmt = AV_PIX_FMT_YUV420P;
    output_codec_ctx->codec_id = AV_CODEC_ID_H264;

    av_opt_set( output_codec_ctx->priv_data, "preset", "slow", 0 );

	while (av_read_frame( input_format_ctx, packet ) >= 0 && running ) {
        if (packet->stream_index == videoIndex) {

            avcodec_decode_video2( input_codec_ctx, pFrame, &got_picture, packet );

            if (got_picture) {

                sws_scale( swsCtx_, pFrame->data, pFrame->linesize, 0, output_codec_ctx->height, outFrame->data, outFrame->linesize );
                outFrame->pts = frame_count++;

                outPacket->stream_index = stream->index;
                outPacket->pts = AV_NOPTS_VALUE;
                outPacket->dts = AV_NOPTS_VALUE;


                avcodec_encode_video2( output_codec_ctx, outPacket, outFrame, &got_output );
                if (got_output) {

                    av_interleaved_write_frame( output_format_ctx, outPacket );
                    av_free_packet( outPacket );
                }
            }
        }
        av_free_packet( packet );
    }