What does --youtube-include-dash-manifest do?

[mysteryx93]

I'm currently updating some code to download from YouTube and am having some issues with format code 141. Apparently, youtube-dl can download a 256kb AAC audio stream with the --youtube-include-dash-manifest option, while if you open the web page and search "itag=141", the video stream definitely isn't there.

What exactly are you doing to get this 141 stream?

Here's a video
https://www.youtube.com/watch?v=Q3oItpVa9fs

itag=141 definitely isn't in the page. Yet, another download tool was able to get it at this URL. I want to know how to extract that URL.

https://r3---sn-j5caxh5nj5o-j0oe.googlevideo.com/videoplayback?id=437a08b6955af5fb&itag=141&source=youtube&requiressl=yes&ms=au&mv=m&mm=31&pl=21&mn=sn-j5caxh5nj5o-j0oe&ratebypass=yes&mime=audio/mp4&gir=yes&clen=11226600&lmt=1421394143029494&dur=352.107&upn=HrcakPuKNVc&mt=1435344694&key=dg_yt0&sver=3&fexp=9407141,9408142,9408420,9408710,9412491,9413006,9413155,9413503,9415052,9415560,9415828,9416048,9416126,9416144,9416456,9416729,9416846,952640&signature=0FE155AE3EBD09030F8EC53D102863736A5E52E2.2C58359C108562726726BEA8E0F0326322879DEE&ip=189.221.249.135&ipbits=0&expire=1435366409&sparams=ip,ipbits,expire,id,itag,source,requiressl,ms,mv,mm,pl,mn,ratebypass,mime,gir,clen,lmt,dur

Thanks!

[dstftw]

--youtube-include-dash-manifest option is noop for quite a while now since it's enabled by default. It downloads DASH manifest and extracts DASH formats from it.