如何用 gstreamer 进行 mp4 视频拼接？

两个视频信息如下：

Properties: Duration: 0:01:12.100000000 Seekable: yes Live: no Tags: video codec: H.264 / AVC container-specific-track-id: 1 bitrate: 286767 datetime: 2023-08-27T00:21:51Z container format: ISO MP4/M4A container #0: video/quicktime, variant=(string)iso Tags: datetime: 2023-08-27T00:21:51Z container format: ISO MP4/M4A video #1: video/x-h264, stream-format=(string)avc, alignment=(string)au, level=(string)4.2, profile=(string)constrained-baseline, codec_data=(buffer)0142402affe1001b2742402a95a01a80a1e693011000000300100000030288da1c32a001000428ce3c80, width=(int)1686, height=(int)1274, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)20/1, coded-picture-structure=(string)frame, chroma-format=(string)4:2:0, bit-depth-luma=(uint)8, bit-depth-chroma=(uint)8, parsed=(boolean)true Tags: video codec: H.264 / AVC container-specific-track-id: 1 bitrate: 286767 Codec: video/x-h264, stream-format=(string)avc, alignment=(string)au, level=(string)4.2, profile=(string)constrained-baseline, codec_data=(buffer)0142402affe1001b2742402a95a01a80a1e693011000000300100000030288da1c32a001000428ce3c80, width=(int)1686, height=(int)1274, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)20/1, coded-picture-structure=(string)frame, chroma-format=(string)4:2:0, bit-depth-luma=(uint)8, bit-depth-chroma=(uint)8, parsed=(boolean)true Stream ID: 300fa2d73257adb55ba1f7b66d59e5f3a02d95809b27cad83b8aeee34ca206d7/001 Width: 1686 Height: 1274 Depth: 24 Frame rate: 20/1 Pixel aspect ratio: 1/1 Interlaced: false Bitrate: 286767 Max bitrate: 0 

Properties: Duration: 0:00:08.541000000 Seekable: yes Live: no Tags: audio codec: MPEG-4 AAC audio maximum bitrate: 64000 bitrate: 64000 language code: en container-specific-track-id: 1 datetime: 2018-06-14T03:53:44Z QT atom: buffer of 33 bytes container format: ISO MP4/M4A video codec: H.264 / AVC container #0: video/quicktime, variant=(string)iso Tags: datetime: 2018-06-14T03:53:44Z QT atom: buffer of 33 bytes container format: ISO MP4/M4A audio #1: audio/mpeg, mpegversion=(int)4, framed=(boolean)true, stream-format=(string)raw, level=(string)2, base-profile=(string)lc, profile=(string)lc, codec_data=(buffer)1208, rate=(int)44100, channels=(int)1 Tags: audio codec: MPEG-4 AAC audio maximum bitrate: 64000 bitrate: 64000 language code: en container-specific-track-id: 1 Codec: audio/mpeg, mpegversion=(int)4, framed=(boolean)true, stream-format=(string)raw, level=(string)2, base-profile=(string)lc, profile=(string)lc, codec_data=(buffer)1208, rate=(int)44100, channels=(int)1 Stream ID: ce71f7e55d3b89b717642b27ff2725345d4ecdc789036440d8e659aa9c8e39d0/001 Language: en Channels: 1 (unknown layout) Sample rate: 44100 Depth: 32 Bitrate: 64000 Max bitrate: 64000 video #2: video/x-h264, stream-format=(string)avc, alignment=(string)au, level=(string)4, profile=(string)baseline, codec_data=(buffer)01428028ffe1001267428028da01100f1e5e520a0c0c0da1426a01000468ce06e2, width=(int)1080, height=(int)1920, pixel-aspect-ratio=(fraction)1/1, colorimetry=(string)bt709, framerate=(fraction)0/1, coded-picture-structure=(string)frame, chroma-format=(string)4:2:0, bit-depth-luma=(uint)8, bit-depth-chroma=(uint)8, parsed=(boolean)true Tags: video codec: H.264 / AVC language code: en container-specific-track-id: 2 bitrate: 13165685 Codec: video/x-h264, stream-format=(string)avc, alignment=(string)au, level=(string)4, profile=(string)baseline, codec_data=(buffer)01428028ffe1001267428028da01100f1e5e520a0c0c0da1426a01000468ce06e2, width=(int)1080, height=(int)1920, pixel-aspect-ratio=(fraction)1/1, colorimetry=(string)bt709, framerate=(fraction)0/1, coded-picture-structure=(string)frame, chroma-format=(string)4:2:0, bit-depth-luma=(uint)8, bit-depth-chroma=(uint)8, parsed=(boolean)true Stream ID: ce71f7e55d3b89b717642b27ff2725345d4ecdc789036440d8e659aa9c8e39d0/002 Width: 1080 Height: 1920 Depth: 24 Frame rate: 0/1 Pixel aspect ratio: 1/1 Interlaced: false Bitrate: 13165685 Max bitrate: 0 

需求如下：

• 把第二个视频放到第一个视频的后面然后拼接成一个 mp4 视频。不是同一个画面内左右拼接两个视频。
• 只用 gstreamer 相关的，代码也可以，命令行也行。

问了 chatgpt 也没问出个所以然来，谷歌也没搜到正确的答案。