youtube-dl 下载youtube上的视频

进行下边操作之前，要按照使用youtube-dl下载国外视频中下载ffmpeg和配置环境变量。及下载youtube-dl。
https://yt-dl.org/

youtube-dl的开源地址: https://github.com/rg3/youtube-dl
可以通过该地址查看youtube-dl的用法。后续研发也可以用到。

查看视频所有类型,只看不下载

youtube-dl -F [url]

举例:
youtube-dl -F https://www.youtube.com/watch?v=AbvjWY6tMyg

运行之后:

>youtube-dl -F https://www.youtube.com/watch?v=AbvjWY6tMyg

[youtube] AbvjWY6tMyg: Downloading webpage
[youtube] AbvjWY6tMyg: Downloading video info webpage
[info] Available formats for AbvjWY6tMyg:
format code  extension  resolution note
249          webm       audio only DASH audio   65k , opus @ 50k, 4.31MiB
250          webm       audio only DASH audio   85k , opus @ 70k, 5.67MiB
140          m4a        audio only DASH audio  128k , m4a_dash container, mp4a.4
0.2@128k, 9.99MiB
171          webm       audio only DASH audio  146k , vorbis@128k, 10.04MiB
251          webm       audio only DASH audio  159k , opus @160k, 11.07MiB
278          webm       256x144    144p  100k , webm container, vp9, 30fps, vide
o only, 7.06MiB
160          mp4        256x144    144p  116k , avc1.4d400c, 30fps, video only,
5.24MiB
242          webm       426x240    240p  237k , vp9, 30fps, video only, 15.04MiB

133          mp4        426x240    240p  255k , avc1.4d4015, 30fps, video only,
11.18MiB
243          webm       640x360    360p  532k , vp9, 30fps, video only, 28.06MiB

134          mp4        640x360    360p  737k , avc1.4d401e, 30fps, video only,
32.50MiB
244          webm       854x480    480p  944k , vp9, 30fps, video only, 51.11MiB

135          mp4        854x480    480p 1389k , avc1.4d401f, 30fps, video only,
66.91MiB
247          webm       1280x720   720p 1955k , vp9, 30fps, video only, 105.76Mi
B
136          mp4        1280x720   720p 2791k , avc1.4d401f, 30fps, video only,
134.21MiB
248          webm       1920x1080  1080p 3341k , vp9, 30fps, video only, 187.42M
iB
137          mp4        1920x1080  1080p 5020k , avc1.640028, 30fps, video only,
 239.78MiB
271          webm       2560x1440  1440p 9026k , vp9, 30fps, video only, 579.91M
iB
313          webm       3840x2160  2160p 18262k , vp9, 30fps, video only, 1.24Gi
B
272          webm       7680x4320  4320p 25530k , vp9, 30fps, video only, 1.68Gi
B
17           3gp        176x144    small , mp4v.20.3, mp4a.40.2@ 24k, 6.00MiB
36           3gp        320x180    small , mp4v.20.3, mp4a.40.2, 17.72MiB
18           mp4        640x360    medium , avc1.42001E, mp4a.40.2@ 96k, 54.60Mi
B
43           webm       640x360    medium , vp8.0, vorbis@128k, 63.72MiB
22           mp4        1280x720   hd720 , avc1.64001F, mp4a.40.2@192k (best)

出现audio only的只有音频。
出现video only的只有视频。
否则音视频都有。

下载指定文件

比如要下载8k的视频
通过上一步获取到:

272          webm       7680x4320  4320p 25530k , vp9, 30fps, video only, 1.68GiB

可见8k格式的index是272.

可以用以下命令:

youtube-dl -f 272 https://www.youtube.com/watch?v=AbvjWY6tMyg

运行结果:

[youtube] AbvjWY6tMyg: Downloading webpage
[youtube] AbvjWY6tMyg: Downloading video info webpage
[download] Destination: Amazing 8K Ultra-HD-AbvjWY6tMyg.webm
[download] 100% of 1.68GiB in 04:34

下载指定文件并合并

251          webm       audio only DASH audio  159k , opus @160k, 11.07MiB
...
272          webm       7680x4320  4320p 25530k , vp9, 30fps, video only, 1.68GiB

如果想要以上的视频和音频合并，可以用一下命令。（前提已经下载了ffmpeg并配置了环境变量，过程参见https://www.jianshu.com/p/8817a7b0c8d6）

youtube-dl -f 272+251 https://www.youtube.com/watch?v=AbvjWY6tMyg

注意: 视频在前 音频在后 272是视频的编号 251是音频的编号。

运行结果:

[youtube] AbvjWY6tMyg: Downloading webpage
[youtube] AbvjWY6tMyg: Downloading video info webpage
[download] Destination: Amazing 8K Ultra-HD-AbvjWY6tMyg.f272.webm
[download] 100% of 1.68GiB in 03:37
[download] Destination: Amazing 8K Ultra-HD-AbvjWY6tMyg.f251.webm
[download] 100% of 11.07MiB in 00:02
[ffmpeg] Merging formats into "Amazing 8K Ultra-HD-AbvjWY6tMyg.webm"
Deleting original file Amazing 8K Ultra-HD-AbvjWY6tMyg.f272.webm (pass -k to keep)
Deleting original file Amazing 8K Ultra-HD-AbvjWY6tMyg.f251.webm (pass -k to keep)

可见下载完之后，原始的视频和音频文件被删除了。
如果想要保存单独的视频和音频文件，可以加上-k参数。

References:

https://www.jianshu.com/p/8817a7b0c8d6
https://yt-dl.org/