youtube-dl for Muxing Streams

Let's say we need to download videos from youtube with the highest audio and video quality. Sometimes, the combination is not available with most downloaders. But youtube-dl can download separate audio and video streams and mux them together. Here are some commands to do that.

# List all available streams for a video
➜ youtube-dl -F "https://www.youtube.com/watch?v=abcd1234"

Outputs

[youtube] abcd1234: Downloading webpage
[youtube] abcd1234: Downloading video info webpage
[youtube] abcd1234: Extracting video information
[youtube] abcd1234: Downloading js player en_US-vfl5-0t5t
[youtube] abcd1234: Downloading js player en_US-vfl5-0t5t
[info] Available formats for abcd1234:
format code  extension  resolution note
249          webm       audio only DASH audio   56k , opus @ 50k, 1.52MiB
250          webm       audio only DASH audio   84k , opus @ 70k, 2.10MiB
171          webm       audio only DASH audio  126k , vorbis@128k, 3.36MiB
140          m4a        audio only DASH audio  127k , m4a_dash container, mp4a.40.2@128k, 3.69MiB
251          webm       audio only DASH audio  161k , opus @160k, 4.03MiB
278          webm       256x144    144p  101k , webm container, vp9, 13fps, video only, 2.41MiB
160          mp4        256x144    144p  112k , avc1.4d400c, 25fps, video only, 3.19MiB
242          webm       426x240    240p  140k , vp9, 25fps, video only, 2.34MiB
243          webm       640x360    360p  234k , vp9, 25fps, video only, 3.98MiB
133          mp4        426x240    240p  248k , avc1.4d4015, 25fps, video only, 7.13MiB
134          mp4        640x360    360p  254k , avc1.4d401e, 25fps, video only, 6.49MiB
244          webm       854x480    480p  355k , vp9, 25fps, video only, 6.22MiB
135          mp4        854x480    480p  559k , avc1.4d401e, 25fps, video only, 13.74MiB
247          webm       1280x720   720p  601k , vp9, 25fps, video only, 11.70MiB
136          mp4        1280x720   720p 1171k , avc1.4d401f, 25fps, video only, 28.41MiB
248          webm       1920x1080  1080p 1220k , vp9, 25fps, video only, 23.32MiB
137          mp4        1920x1080  1080p 2258k , avc1.640028, 25fps, video only, 57.07MiB
17           3gp        176x144    small , mp4v.20.3, mp4a.40.2@ 24k
36           3gp        320x180    small , mp4v.20.3, mp4a.40.2
43           webm       640x360    medium , vp8.0, vorbis@128k
18           mp4        640x360    medium , avc1.42001E, mp4a.40.2@ 96k
22           mp4        1280x720   hd720 , avc1.64001F, mp4a.40.2@192k (best)
➜

We can see that the highest quality video is 137 with 1080p 2258k and audio is 251 with 161k. But these are video only and audio only streams. Let's combine them.

➜ youtube-dl -f 137+251 "https://www.youtube.com/watch?v=abcd1234"

It will pick a compatible format when merging. If mp4 doesn't work it gets converted into mkv mostly.

Misc
Automatically choose best video and audio: -f bestvideo+bestaudio
Download subtitle if the video has one already uploaded: --write-srt --sub-lang en