Cookbook¶

List available formats with yt-dlp¶

Before choosing which formats to download, it helps to see what’s available. Every YouTube’s MPEG-DASH representation has an itag value that identifies it. For a playing live stream, you can find these in the browser’s Stats for nerds popup. To show all available formats, running yt-dlp with -F is helpful:

$ yt-dlp --live-from-start -F STREAM
ID  EXT  RESOLUTION FPS CH │    TBR PROTO │ VCODEC         VBR ACODEC      ABR ASR MORE INFO
───────────────────────────────────────────────────────────────────────────────────────────────────
140 m4a  audio only      2 │   144k dashG │ audio only         mp4a.40.2  144k 44k medium, m4a_dash
160 mp4  256x144     15    │   212k dashG │ avc1.42c00b   212k video only          144p, mp4_dash
...
137 mp4  1920x1080   30    │  5019k dashG │ avc1.640028  5019k video only          1080p, mp4_dash
248 webm 1920x1080   30    │  2896k dashG │ vp9          2896k video only          1080p, webm_dash

Play a saved manifest with mpv¶

mpv can play a saved MPEG-DASH manifest (MPD) directly, without downloading anything first.

The manifest’s SegmentTemplates reference http://localhost:9000/... segments, but by default ffmpeg’s demuxer only allows the file and crypto protocols for local files. Whitelist the ones the manifest needs:

mpv --demuxer-lavf-o='protocol_whitelist="file,crypto,data,http,https,tcp,tls"' \
  manifest.mpd

To pick a specific stream, use mpv’s interactive track selector: press g then v for video, or g then a for audio. Each opens a console menu listing the available tracks to choose from.

Pass the output name to external programs¶

ypb serve’s JSON response includes metadata.outputName, the same name ypb download would use for the same input. Reuse it when running another tool against the stream:

$ ypb serve STREAM
$ response=$(curl -s -H 'Accept: application/json' http://localhost:9000/mpd/10s--now)
$ filename=$(printf '%s' "$response" | jq -r '.metadata.outputName')

yt-dlp can read the manifest off disk instead of fetching it again, so save it and pass filename for the output location:

$ printf '%s' "$response" | jq -r '.mpd' > /tmp/manifest.mpd
$ yt-dlp --enable-file-urls -o "${output_name}.%(ext)s" "file:///tmp/manifest.mpd"

Download multiple formats from one saved manifest¶

Requesting /mpd from ypb serve lets you rewind once and save the manifest, then run yt-dlp against it as many times as you like. Each run reads the same saved segments instead of triggering a new rewind, as ypb download would:

$ ypb serve STREAM
$ response=$(curl -s -H 'Accept: application/json' http://localhost:9000/mpd/10s--now)
$ printf '%s' "$response" | jq -r '.mpd' > /tmp/manifest.mpd

$ yt-dlp --enable-file-urls -o "output.f%(format_id)s.%(ext)s" -f 137 "file:///tmp/manifest.mpd"
$ yt-dlp --enable-file-urls -o "output.f%(format_id)s.%(ext)s" -f 140 "file:///tmp/manifest.mpd"

You could get the same files with a single -f "137,140" call, but keeping the manifest around lets you work incrementally.