Script for MPEG-DASH playlist (audio)

[DigiBC]

Setting up HLS streams with Liquidsoap (ffmpeg) for adaptive streaming is quite well documented and I’ve implemented it successfully.
I use output.file.hls with 4 HLS AAC audio streams (Liquidsoap 2.1.2):

aac_1 =
  %ffmpeg(
    format="mpegts",    
    %audio(codec="libfdk_aac", samplerate=44100, channels=2, b="32k", profile="aac_he_v2", afterburner=1))

aac_2 =
  %ffmpeg(
    format="mpegts",    
    %audio(codec="libfdk_aac", samplerate=44100, channels=2, b="64k", profile="aac_he", afterburner=1))

aac_3 =
  %ffmpeg(
    format="mpegts",    
    %audio(codec="libfdk_aac", samplerate=44100, channels=2, b="128k", profile="aac_low", afterburner=1, cutoff=20000))

aac_4 =
  %ffmpeg(
    format="mpegts",    
    %audio(codec="libfdk_aac", samplerate=44100, channels=2, b="192k", profile="aac_low", afterburner=1, cutoff=20000))

hls_streams = [("aac_1", aac_1), ("aac_2", aac_2), ("aac_3", aac_3), ("aac_4", aac_4)]

output.file.hls(id="output_hls", playlist="radio.m3u8", segment_duration=2.0, segments=5, segments_overhead=5, "~/radio/hls", hls_streams, s)

I would prefer a similar setup for MPEG-DASH. I know that Liquidsoap can output an MPEG-DASH playlist (output.file.dash / output.file.dash.ffmpeg), but so far, I haven’t found any script or real-world example of how it works.

Any assistance would be greatly appreciated.

[DigiBC]

After some trial and error, I've finally found a solution:

output.external(%wav(samplerate=44100, channels=2, samplesize=16, header=false), "ffmpeg -f s16le -ar 44100 -ac 2 -i pipe:0 -map 0 -map 0 -map 0 -map 0 -c:a libfdk_aac -b:a:0 32k -profile:a:0 aac_he_v2 -afterburner 1 -b:a:1 64k -profile:a:1 aac_he -afterburner 1 -b:a:2 128k -profile:a:2 aac_low -afterburner 1 -cutoff 20000 -b:a:3 192k -profile:a:3 aac_low -afterburner 1 -cutoff 20000 -use_timeline 0 -use_template 1 -window_size 5  -adaptation_sets \"id=0,streams=a\" -f dash ~/radio/dash/radio.mpd", fallible = true, s)

Unfortunately, Liquidsoap doesn't have built-in support for MPEG-DASH yet (?), but this script seems to work quite well so far.

The similar Liquidsoap functions output.file.dash / output.file.dash.ffmpeg are quite hardcoded and therefore limited, so they didn't work in my case. However, I was able to use them as an orientation.

So, I can close this discussion.