Internet Download Manager used to work flawlessly on YouTube for me until about a week ago when I started to get
"403 Forbidden" whenever I attempt to download anything
I've been getting "403 Forbidden" with yt-dlp a lot more since YouTube's recent attempts at blocking ads, but only over Tor. It used to work pretty well before then. So far I've been able to get around it by resetting Tor two or three times.
Haven't encountered any noticeable problems downloading on my home connection yet.
I expect any addresses used for mass downloading videos (public download websites, public Invidious instances, shared VPNs, Tor, etc.) to be heavily cockblocked going forward.
My choices now are limited to either downloading in 360p or having to pay for a "Pro" version of the downloader.
Up until about a week ago I could still download 720p at the very least but it seems that is not a thing anymore.
YouTube encodes videos in a few different ways.
It offers a few options that are audio+video, but mostly separates audio and video into different files and combines them when you watch.
Here's an example. I used yt-dlp to list the available formats for a video. Notice the options listed as "audio only" and "video only" under the RESOLUTION, VCODEC and ACODEC columns. Only option 18 has both audio and video, and it's only 360p:
Code:
[info] Available formats for 1ruVOnSxW58:
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
249-drc webm audio only 2 │ 15.44MiB 51k https │ audio only opus 51k 48k [en] low, DRC, webm_dash
250-drc webm audio only 2 │ 19.07MiB 63k https │ audio only opus 63k 48k [en] low, DRC, webm_dash
140-drc m4a audio only 2 │ 39.46MiB 129k https │ audio only mp4a.40.2 129k 44k [en] medium, DRC, m4a_dash
251-drc webm audio only 2 │ 32.83MiB 108k https │ audio only opus 108k 48k [en] medium, DRC, webm_dash
140 m4a audio only 2 │ 39.46MiB 129k https │ audio only mp4a.40.2 129k 44k [en] medium, m4a_dash
251 webm audio only 2 │ 32.48MiB 107k https │ audio only opus 107k 48k [en] medium, webm_dash
160 mp4 256x144 30 │ 16.59MiB 54k https │ avc1.4d400c 54k video only 144p, mp4_dash
134 mp4 640x360 30 │ 58.35MiB 191k https │ avc1.4d401e 191k video only 360p, mp4_dash
18 mp4 640x360 30 2 │ ≈ 99.74MiB 320k https │ avc1.42001E mp4a.40.2 44k [en] 360p
136 mp4 1280x720 30 │ 131.68MiB 432k https │ avc1.64001f 432k video only 720p, mp4_dash
137 mp4 1920x1080 30 │ 215.08MiB 706k https │ avc1.640028 706k video only 1080p, mp4_dash
If you watch this video on YouTube in one of the non-360p formats, what YouTube is doing is playing one of the video-only formats and one of the audio-only formats together at the same time.
Most video downloaders can't combine them for you, so they only offer you the full audio+video options which from what I've seen are usually only 360p and 720p.
Some other tools like yt-dlp are able to combine them. I made a
YouTube archiving guide in the YouTube thread that lists some tools if you want to try some other options.
ETA: If you're on desktop I suggest trying Tartube. It's able to combine files for you.
ETA: If you're on Android
NewPipe appears to combine them as well. I just tried it out and it worked.