s->bitstream_buffer_size=0;
void ff_mpeg_flush(AVCodecContext *avctx){    int i;    MpegEncContext *s = avctx->priv_data;        if(s==NULL || s->picture==NULL)         return;        for(i=0; i<MAX_PICTURE_COUNT; i++){       if(s->picture[i].data[0] && (   s->picture[i].type == FF_BUFFER_TYPE_INTERNAL                                    || s->picture[i].type == FF_BUFFER_TYPE_USER))        avctx->release_buffer(avctx, (AVFrame*)&s->picture[i]);    }    s->current_picture_ptr = s->last_picture_ptr = s->next_picture_ptr = NULL;        s->parse_context.state= -1;    s->parse_context.frame_start_found= 0;    s->parse_context.overread= 0;    s->parse_context.overread_index= 0;    s->parse_context.index= 0;    s->parse_context.last_index= 0;}