ffmpeg 视频过度滤镜 gltransition

上次随笔中提到的 ffmpeg-concat 可以处理视频过度，但是缺点是临时文件超大。

经过查找 ffmpeg 还有 gltransition 滤镜，但是 ffmpeg 的正式版中还没有加进去。

github 上有 ffmpeg-gl-transition 项目，有详细的添加滤镜的说明，参见以下地址

https://github.com/transitive-bullshit/ffmpeg-gl-transition

这个滤镜依赖的库包括 GLEW + glfw3

想静态编译 GLEW 需要加 #define GLEW_STATIC

ffmpeg -i 1.mp4 -i 2.mp4 -filter_complex "gltransition=duration=4:offset=1.5:source=crosswarp.glsl" -y out.mp4

通过下面的脚本可以使用不同视频过度方式

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ffmpeg-gl-transition-concat.sh

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#!/bin/bash

# Example of concatenating 3 mp4s together with 1-second transitions between them.

tpath="/ffmpeg/transitions/"

x264="-look_ahead 0 -ac 2 -c:v h264_qsv -profile:v high -level 3.1 -preset:v veryfast"

ki="-keyint_min 72 -g 72 -sc_threshold 0"

br="-b:v 3000k -minrate 3000k -maxrate 6000k -bufsize 6000k -b:a 128k"

ffmpeg -hide_banner \

  -i 1.mp4 \

  -i 2.mp4 \

  -i 3.mp4 \

  -filter_complex " \

    [0:a]   atrim=0:5  [a0]; \

    [1:a]   atrim=0:5  [a1]; \

    [2:a]   atrim=0:6  [a2]; \

    \

	[0:v]   split  [v000] [v010]; \

    [1:v]   split  [v100] [v110]; \

    [2:v]   split  [v200] [v210]; \

	\

    [v000]  trim=0:5                [v001];  \

    [v010]  trim=5:6                [v011t]; \

    [v011t] setpts=PTS-STARTPTS     [v011];  \

	\

    [v100]   trim=0:5               [v101];  \

    [v110]   trim=5:6               [v111t]; \

    [v111t]  setpts=PTS-STARTPTS    [v111];  \

	\

    [v200]     trim=0:5             [v201];  \

    [v210]     trim=5:6             [v211t]; \

    [v211t]    setpts=PTS-STARTPTS  [v211];  \

	\

    [v011] [v101] gltransition=duration=1:source=${tpath}WaterDrop.glsl  [vt0]; \

    [v111] [v201] gltransition=duration=1:source=${tpath}crosswarp.glsl  [vt1]; \

    \

	[v001] [vt0] [vt1] [v211]  concat=n=4          [outv]; \

	[a0] [a1] [a2]             concat=n=3:v=0:a=1  [outa]" \

  -map [outv] -map [outa] \

  ${x264} ${ki} ${br} \

  -y ffmpeg-gl-transition-concat.mp4

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