1.將要做效果的視頻拉進PR裏面，如下圖紅框所示；
/iknow-pic.cdn.bcebos.com/77094b36acaf2edd97d24a5d801001e939019366"target="_blank"title=""class="ikqb_img_alink">/iknow-pic.cdn.bcebos.com/77094b36acaf2edd97d24a5d801001e939019366?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto"esrc="/77094b36acaf2edd97d24a5d801001e939019366"/>
2.然後將視頻拉進時間軸，如下圖紅框所示；
/iknow-pic.cdn.bcebos.com/9f510fb30f2442a77c15fe11dc43ad4bd113026e"target="_blank"title=""class="ikqb_img_alink">/iknow-pic.cdn.bcebos.com/9f510fb30f2442a77c15fe11dc43ad4bd113026e?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto"esrc="/9f510fb30f2442a77c15fe11dc43ad4bd113026e"/>
3.點擊時間軸左側框裏面的“效果”，如下圖紅框所示；
/iknow-pic.cdn.bcebos.com/7acb0a46f21fbe09694ec0a066600c338744ad75"target="_blank"title=""class="ikqb_img_alink">/iknow-pic.cdn.bcebos.com/7acb0a46f21fbe09694ec0a066600c338744ad75?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto"esrc="/7acb0a46f21fbe09694ec0a066600c338744ad75"/>
4.在效果裏面選擇“視頻效果”，如下圖紅框所示；
/iknow-pic.cdn.bcebos.com/91ef76c6a7efce1bd7a7cb7ea251f3deb58f65f1"target="_blank"title=""class="ikqb_img_alink">/iknow-pic.cdn.bcebos.com/91ef76c6a7efce1bd7a7cb7ea251f3deb58f65f1?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto"esrc="/91ef76c6a7efce1bd7a7cb7ea251f3deb58f65f1"/>
5.選擇視頻效果裏面的“變換”，如下圖紅框所示；
/iknow-pic.cdn.bcebos.com/203fb80e7bec54e70b1819aab4389b504ec26a89"target="_blank"title=""class="ikqb_img_alink">/iknow-pic.cdn.bcebos.com/203fb80e7bec54e70b1819aab4389b504ec26a89?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto"esrc="/203fb80e7bec54e70b1819aab4389b504ec26a89"/>
6.然後選擇變換效果裏面的“裁剪”，如下圖紅框所示；
/iknow-pic.cdn.bcebos.com/7a899e510fb30f24e18ceeb7c595d143ad4b036b"target="_blank"title=""class="ikqb_img_alink">/iknow-pic.cdn.bcebos.com/7a899e510fb30f24e18ceeb7c595d143ad4b036b?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto"esrc="/7a899e510fb30f24e18ceeb7c595d143ad4b036b"/>
7.將裁剪效果直接拖動到視頻的時間軸裏面，如下圖紅框所示；
/iknow-pic.cdn.bcebos.com/0d338744ebf81a4c5904ee7dda2a6059252da64b"target="_blank"title=""class="ikqb_img_alink">/iknow-pic.cdn.bcebos.com/0d338744ebf81a4c5904ee7dda2a6059252da64b?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto"esrc="/0d338744ebf81a4c5904ee7dda2a6059252da64b"/>
8.然後點擊左上角操作框的“效果控件”，如下圖紅框所示；
/iknow-pic.cdn.bcebos.com/ae51f3deb48f8c54db9dc79b37292df5e0fe7f33"target="_blank"title=""class="ikqb_img_alink">/iknow-pic.cdn.bcebos.com/ae51f3deb48f8c54db9dc79b37292df5e0fe7f33?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto"esrc="/ae51f3deb48f8c54db9dc79b37292df5e0fe7f33"/>
9.效果控件會默認打開“裁剪”菜單，如下圖紅框所示；
/iknow-pic.cdn.bcebos.com/024f78f0f736afc3cd4c3dd1be19ebc4b64512c5"target="_blank"title=""class="ikqb_img_alink">/iknow-pic.cdn.bcebos.com/024f78f0f736afc3cd4c3dd1be19ebc4b64512c5?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto"esrc="/024f78f0f736afc3cd4c3dd1be19ebc4b64512c5"/>
10.設置裁剪菜單的“頂部”和“底部”參數，這裏設置為15%，如果想要黑邊大就將參數設置大，反之設置小，如下圖紅框所示；
/iknow-pic.cdn.bcebos.com/9a504fc2d5628535a659d0959def76c6a6ef63cc"target="_blank"title=""class="ikqb_img_alink">/iknow-pic.cdn.bcebos.com/9a504fc2d5628535a659d0959def76c6a6ef63cc?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto"esrc="/9a504fc2d5628535a659d0959def76c6a6ef63cc"/>
11.就這樣，只調節上下參數，不調節左右參數，如下圖紅框所示；
/iknow-pic.cdn.bcebos.com/95eef01f3a292df5b328aea1b1315c6035a8739e"target="_blank"title=""class="ikqb_img_alink">/iknow-pic.cdn.bcebos.com/95eef01f3a292df5b328aea1b1315c6035a8739e?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto"esrc="/95eef01f3a292df5b328aea1b1315c6035a8739e"/>
12.然後視頻上下的黑邊就加好了，如下圖紅框所示。
/iknow-pic.cdn.bcebos.com/dcc451da81cb39db200565e2dd160924aa1830b8"target="_blank"title=""class="ikqb_img_alink">/iknow-pic.cdn.bcebos.com/dcc451da81cb39db200565e2dd160924aa1830b8?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto"esrc="/dcc451da81cb39db200565e2dd160924aa1830b8"/>