Software: Love editing, MP4/RM conversion expert.

1. Step 1: First, import the horizontal video into the software, open the MP4/RM conversion expert and import your own horizontal video.

2. Step 2: Select the exported video format, and then export it as "AVI/MPEG4 format used on the computer".

3. Step 3: Set the parameters of the video and export the high-definition image quality. You can choose the popular H.264 encoder, and then the bit rate and resolution of the video can be adjusted by yourself. I usually export 1080P HD video.

4. Step 4: Cut the picture directly, and cut the horizontal video to the size of the vertical video. Use "Humanized Movie Screen Editing Function" to set the desired vertical screen ratio in the width and height, such as 720× 1080, and click OK. Start the conversion directly.