It all started with a wedding. You hire a videographer, you wait patiently for several weeks, and finally your video is available. It's hosted on YouTube, quick and easy to start watching right away! However I can never know if this precious video may disappear, if their account may get deleted, or some other event may occur that causes such an important moment in our lives to disappear. This post provides a straightforward solution to archiving YouTube videos, in my case with a focus on retaining as high of quality as possible.
Downloading content from YouTube
We are not pirating content, and have permission from our videographer to store this video. I may even have an external hard drive sitting around with it. But who wants to risk that breaking or disappearing? There is an existing open source project for downloading videos from YouTube and other sites called yt-dlp. This works perfectly for our scenario.
Without diving too deep into the specifics, there are many formats of content available from YouTube even for a single "video". Each video on YouTube can be accessed at various resolutions and audio qualities. We start off by listing what is available with the following command:
yt-dlp --list-formats 'https://www.youtube.com/watch?v=deadbeef'
This will output a table with the available audio and video formats for the YouTube video. It is not uncommon for the formats to be completely separate, as in you have audio-only and video-only formats. We will cover the steps necessary for this scenario.
Let's suppose the output from the command looked something like this:
ID EXT RESOLUTION FPS CH │ FILESIZE TBR PROTO │ VCODEC VBR ACODEC ABR ASR MORE INFO
───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
sb2 mhtml 48x27 0 │ mhtml │ images storyboard
sb1 mhtml 80x45 0 │ mhtml │ images storyboard
sb0 mhtml 160x90 0 │ mhtml │ images storyboard
233 mp4 audio only │ m3u8 │ audio only unknown [en] Default
234 mp4 audio only │ m3u8 │ audio only unknown [en] Default
139 m4a audio only 2 │ 2.12MiB 49k https │ audio only mp4a.40.5 49k 22k [en] low, m4a_dash
249 webm audio only 2 │ 2.16MiB 50k https │ audio only opus 50k 48k [en] low, webm_dash
250 webm audio only 2 │ 2.87MiB 66k https │ audio only opus 66k 48k [en] low, webm_dash
140 m4a audio only 2 │ 5.63MiB 129k https │ audio only mp4a.40.2 129k 44k [en] medium, m4a_dash
251 webm audio only 2 │ 5.64MiB 130k https │ audio only opus 130k 48k [en] medium, webm_dash
602 mp4 256x144 12 │ ~ 4.00MiB 92k m3u8 │ vp09.00.10.08 92k video only
269 mp4 256x144 24 │ ~ 7.76MiB 179k m3u8 │ avc1.4D400C 179k video only
160 mp4 256x144 24 │ 3.53MiB 81k https │ avc1.4D400C 81k video only 144p, mp4_dash
603 mp4 256x144 24 │ ~ 7.32MiB 169k m3u8 │ vp09.00.11.08 169k video only
278 webm 256x144 24 │ 3.71MiB 85k https │ vp09.00.11.08 85k video only 144p, webm_dash
229 mp4 426x240 24 │ ~ 13.83MiB 319k m3u8 │ avc1.4D4015 319k video only
133 mp4 426x240 24 │ 7.99MiB 184k https │ avc1.4D4015 184k video only 240p, mp4_dash
604 mp4 426x240 24 │ ~ 13.51MiB 311k m3u8 │ vp09.00.20.08 311k video only
242 webm 426x240 24 │ 6.30MiB 145k https │ vp09.00.20.08 145k video only 240p, webm_dash
230 mp4 640x360 24 │ ~ 31.52MiB 726k m3u8 │ avc1.4D401E 726k video only
134 mp4 640x360 24 │ 15.18MiB 349k https │ avc1.4D401E 349k video only 360p, mp4_dash
605 mp4 640x360 24 │ ~ 26.07MiB 601k m3u8 │ vp09.00.21.08 601k video only
243 webm 640x360 24 │ 10.97MiB 253k https │ vp09.00.21.08 253k video only 360p, webm_dash
231 mp4 854x480 24 │ ~ 58.71MiB 1353k m3u8 │ avc1.4D401E 1353k video only
135 mp4 854x480 24 │ 31.68MiB 729k https │ avc1.4D401E 729k video only 480p, mp4_dash
606 mp4 854x480 24 │ ~ 41.26MiB 951k m3u8 │ vp09.00.30.08 951k video only
244 webm 854x480 24 │ 18.21MiB 419k https │ vp09.00.30.08 419k video only 480p, webm_dash
232 mp4 1280x720 24 │ ~106.77MiB 2460k m3u8 │ avc1.64001F 2460k video only
136 mp4 1280x720 24 │ 61.14MiB 1408k https │ avc1.64001F 1408k video only 720p, mp4_dash
609 mp4 1280x720 24 │ ~ 76.00MiB 1752k m3u8 │ vp09.00.31.08 1752k video only
247 webm 1280x720 24 │ 32.92MiB 758k https │ vp09.00.31.08 758k video only 720p, webm_dash
270 mp4 1920x1080 24 │ ~215.93MiB 4976k m3u8 │ avc1.640028 4976k video only
137 mp4 1920x1080 24 │ 115.89MiB 2668k https │ avc1.640028 2668k video only 1080p, mp4_dash
614 mp4 1920x1080 24 │ ~124.34MiB 2865k m3u8 │ vp09.00.40.08 2865k video only
248 webm 1920x1080 24 │ 56.64MiB 1304k https │ vp09.00.40.08 1304k video only 1080p, webm_dash
620 mp4 2560x1440 24 │ ~352.28MiB 8118k m3u8 │ vp09.00.50.08 8118k video only
271 webm 2560x1440 24 │ 172.62MiB 3974k https │ vp09.00.50.08 3974k video only 1440p, webm_dash
625 mp4 3840x2160 24 │ ~634.40MiB 14620k m3u8 │ vp09.00.50.08 14620k video only
313 webm 3840x2160 24 │ 332.22MiB 7649k https │ vp09.00.50.08 7649k video only 2160p, webm_dash
There are video resolutions of 320p, 480p, 720p, etc. all the way to 2160p (4K). Additionally, there are multiple audio options available, with some useful information providing a high-level quality such as "low" and "medium". In my case, I will prefer the highest quality available for both audio and video, and make some preferential decisions on the formats. Let's go with the Opus audio codec in medium-quality and WebM video format in 2160p, or format IDs 251 and 313 respectively.
I will use yt-dlp to download each of these formats to separate files before joining them together.
# download the audio file
yt-dlp -f 251 -o wedding.audio.webm 'https://www.youtube.com/watch?v=deadbeef'
# download the video file
yt-dlp -f 313 -o cwedding.video.webm 'https://www.youtube.com/watch?v=deadbeef'
These are both saved to WebM files, as it is only a container format that supports various video and audio formats within itself. With both files downloaded, our next task will be to join the two files together into a single, 4K AV file.
Splicing our audio and video together
A renowned tool for working with audio and video files is ffmpeg. We will use this to pull the audio from the audio-only WebM file and the video from the video-only WebM file. The command we will run for this is:
ffmpeg \
-i wedding.video.webm \
-i wedding.audio.webm \
-c:v copy \
-c:a copy \
-map 0:v:0 \
-map 1:a:0 \
carrio-wedding.webm
I split out the lines mostly for readability, as the command becomes more self-describing to me with this logical grouping.
We take two input files, first the video and then the audio file.
We copy over any video and audio codecs as in- no transcoding will be performed. This retains the Opus audio codec and the VP9 video codec used in these files.
We provide two mappings which dictate explicitly video and audio. For the first video (0, in a zero-index tool like ffmpeg), which had the video, we will pull the video. For the second video (1), which had the audio, we will pull the audio. The target for both is 0, the output file.
Lastly, we tell ffmpeg where to save the video: at wedding.webm.
Since there was no transcoding necessary for this, the operation should complete very quickly. In my case: 468ms.
Verifying your content
Load your content in a compatible video player for your content! If you decided to go with WebM & Opus and targeted a high resolution like 4K, make sure you use a hardware-accelerated tool. You can also upload your content to something like Google Drive and the web player in the preview tool should automatically work for playback as well. In my case, I loaded up mpv to watch this beautiful moment as it included the necessary hardware acceleration libraries for my system to playback 4K content.
nix-shell -p mpv --run 'mpv ./wedding.webm'
