In JDownloader 2, you can set a global filter to automatically convert all YouTube downloads to "best available 3GP variant" – typically 144p.
For the next hour, he watched a progress bar creep across the screen. Each percent felt like a gallon of water for his neighbors. When the download finally chirped “Complete,” Ibrahim didn't care that the video was a sea of moving pixels. He didn't care that the audio sounded like it was underwater. Youtube Video In 3gp 144p Quality Download
Or, if you specifically want the H.263 codec (true 3GP): In JDownloader 2, you can set a global
No software, works on Chromebooks, phones, and PCs. Cons: Pop-up ads, slower conversions, limited to 10-20 minute videos. In JDownloader 2