SRT No room to store incoming packet

[metaswirl]

Description

I have 2 instances of Liquidsoap running, one at home which is a SRT caller, one on a remote VPS which is a SRT listener. The stream works flawlessy for roughly about 12 hours, until the remote VPS SRT listener crashes and the log is filled with:

2024/09/19 10:08:08 [srt:4] 10:08:08.076563/SRT:RcvQ:w1!W:SRT.qr: @466951504: No room to store incoming packet seqno 1089222595, insert offset 16427. iFirstUnackSeqNo=1089214359 m_iStartSeqNo=1089206168 m_iStartPos=6182 m_iMaxPosOff=8191. Space avail 0/8192 pkts. (TSBPD ready in -112483ms, timespan 56120 ms). GETTIME_MONOTONIC drift 0 ms.

Steps to reproduce

Home server (caller)

enc = %ffmpeg(format="s16le",%audio(codec="pcm_s16le", ac=2, ar=48000))

output.srt(host="X.X.X.X", port=9010, 
           passphrase="********", 
           enforced_encryption=true, on_connect=srt_connect, id="srt", enc, playlist_safe)

VPS (listener)

raw_srt_input = input.srt(
    content_type="application/ffmpeg; format=s16le, channels=2, sample_rate=44100",
    passphrase="********", enforced_encryption=true, bind_address="X.X.X.X", port=9010)

radio = blank.strip(stereo(raw_srt_input))

Expected behavior

Possibly the application does not read the packets fast enough and I would need to increase the receive buffer on the listener? re: Haivision/srt#409

Is there a way to add values to rcvbuf on input.srt ?

Liquidsoap version

Liquidsoap 2.2.5+dev
Copyright (c) 2003-2024 Savonet team
Liquidsoap is open-source software, released under GNU General Public License.
See <http://liquidsoap.info> for more information.

Liquidsoap build config

* Liquidsoap version  : 2.2.5+dev

 * Compilation options
   - Release build       : false
   - Git SHA             : (none)
   - OCaml version       : 5.2.0
   - OS type             : Unix
   - Libs versions       : angstrom=0.16.0 asn1-combinators=0.2.6 astring=0.8.5 base64=3.5.1 bigarray-compat=1.1.0 bigstringaf=0.10.0 bos=0.2.1 bytes=[distributed with OCaml 4.02 or above] ca-certs=v0.2.3 camlp-streams camomile.lib=2.0 cry=1.0.3 cstruct=6.2.0 ctypes=0.23.0 ctypes-foreign=0.23.0 ctypes.stubs=0.23.0 curl=0.9.2 domain-name=0.4.0 dtools=0.4.5 dune-build-info=3.16.0 dune-private-libs.dune-section=3.16.0 dune-site=3.16.0 dune-site.private=3.16.0 duppy=0.9.4 eqaf=0.9 eqaf.bigstring=0.9 eqaf.cstruct=0.9 ffmpeg-av=1.1.11 ffmpeg-avcodec=1.1.11 ffmpeg-avdevice=1.1.11 ffmpeg-avfilter=1.1.11 ffmpeg-avutil=1.1.11 ffmpeg-swresample=1.1.11 ffmpeg-swscale=1.1.11 fileutils=0.6.4 fmt=0.9.0 fpath=0.7.3 gen=1.1 gmap=0.3.0 hkdf=1.0.4 integers ipaddr=5.6.0 ladspa=0.2.2 liquidsoap-lang=2.2.5 liquidsoap-lang.console=2.2.5 liquidsoap_builtins liquidsoap_core liquidsoap_ffmpeg liquidsoap_ladspa liquidsoap_optionals liquidsoap_oss liquidsoap_runtime liquidsoap_srt liquidsoap_stereotool liquidsoap_taglib liquidsoap_tls logs=0.7.0 macaddr=5.6.0 magic-mime=1.3.1 menhirLib=20240715 metadata=0.3.0 mirage-crypto=0.11.3 mirage-crypto-ec=0.11.3 mirage-crypto-pk=0.11.3 mirage-crypto-rng=0.11.3 mirage-crypto-rng.unix=0.11.3 mm=0.8.5 mm.audio=0.8.5 mm.base=0.8.5 mm.image=0.8.5 mm.midi=0.8.5 mm.video=0.8.5 pbkdf pcre=7.5.0 posix-base=2.0.2 posix-socket=2.0.2 posix-socket.constants=2.0.2 posix-socket.stubs=2.0.2 posix-socket.types=2.0.2 ppx_string.runtime=v0.17.0 ptime=1.1.0 ptime.clock.os=1.1.0 re=1.12.0 rresult=0.7.0 sedlex=3.2 seq=[distributed with OCaml 4.07 or above] sexplib0=v0.17.0 srt=0.3.0 srt.constants=0.3.0 srt.stubs=0.3.0 srt.stubs.locked=0.3.0 srt.types=0.3.0 stdlib-shims=0.3.0 stereotool str=5.2.0 stringext=1.6.0 taglib=0.3.10 threads=5.2.0 tls=0.17.3 unix=5.2.0 uri=4.4.0 x509=0.16.5 zarith=1.14
   - architecture        : amd64
   - host                : x86_64-pc-linux-gnu
   - target              : x86_64-pc-linux-gnu
   - system              : linux
   - ocamlopt_cflags     : -O2 -fno-strict-aliasing -fwrapv -pthread -fPIC -pthread
   - native_c_compiler   : gcc -O2 -fno-strict-aliasing -fwrapv -pthread -fPIC -pthread -D_FILE_OFFSET_BITS=64
   - native_c_libraries  : -lm -ldl -lpthread

 * Configured paths
   - mode              : default
   - standard library  : (set by dune-site)
   - scripted binaries : (set by dune-site)
   - rundir            : (set by dune-site)
   - logdir            : (set by dune-site)
   - camomile files    : (set by dune-site)

 * Supported input formats
   - MP3               : no (requires mad)
   - AAC               : no (requires faad)
   - Ffmpeg            : yes
   - Flac (native)     : no (requires flac)
   - Flac (ogg)        : no (requires ogg)
   - Opus              : no (requires opus)
   - Speex             : no (requires speex)
   - Theora            : no (requires theora)
   - Vorbis            : no (requires vorbis)

 * Supported output formats
   - FDK-AAC           : no (requires fdkaac)
   - Ffmpeg            : yes
   - MP3               : no (requires lame)
   - MP3 (fixed-point) : no (requires shine)
   - Flac (native)     : no (requires flac)
   - Flac (ogg)        : no (requires ogg)
   - Opus              : no (requires opus)
   - Speex             : no (requires speex)
   - Theora            : no (requires theora)
   - Vorbis            : no (requires vorbis)

 * Tags
   - Taglib (ID3 tags) : yes
   - Vorbis            : no (requires vorbis)

 * Input / output
   - ALSA              : no (requires alsa)
   - AO                : no (requires ao)
   - FFmpeg            : yes
   - GStreamer         : no (requires gstreamer)
   - JACK              : no (requires bjack)
   - OSS               : yes
   - Portaudio         : no (requires portaudio)
   - Pulseaudio        : no (requires pulseaudio)
   - SRT               : yes

 * Audio manipulation
   - FFmpeg            : yes
   - LADSPA            : yes
   - Lilv              : no (requires lilv)
   - Samplerate        : no (requires samplerate)
   - SoundTouch        : no (requires soundtouch)
   - StereoTool        : yes

 * Video manipulation
   - camlimages        : no (requires camlimages)
   - FFmpeg            : yes
   - frei0r            : no (requires frei0r)
   - ImageLib          : no (requires imagelib)
   - SDL               : no (requires tsdl-image & tsdl-ttf)

 * MIDI manipulation
   - DSSI              : no (requires dssi)

 * Visualization
   - GD                : no (requires gd)
   - Graphics          : no (requires graphics)
   - SDL               : no (requires tsdl-image & tsdl-ttf)

 * Additional libraries
   - FFmpeg filters    : yes
   - FFmpeg devices    : yes
   - inotify           : no (requires inotify)
   - irc               : no (requires irc-client-unix)
   - jemalloc          : no (requires jemalloc)
   - lastfm            : no (requires lastfm)
   - lo                : no (requires lo)
   - memtrace          : no (requires memtrace)
   - mem_usage         : no (requires mem_usage)
   - osc               : no (requires osc-unix)
   - ssl               : no (requires ssl)
   - tls               : yes
   - posix-time2       : no (requires posix)
   - windows service   : no (requires winsvc)
   - YAML support      : no (requires yaml)
   - XML playlists     : no (requires xmlplaylist)

 * Monitoring
   - Prometheus        : no (requires prometheus)

Installation method

From OPAM

Additional Info

No response

[metaswirl]

I believe I have solved this issue, might have something to do with using RSAS instead of Icecast.

I changed the following settings on output.icecast:

send_icy_metadata=false

mksafe(buffer(stream)

The stream has been running for 3 days without any issues! :)

[toots]

I'm glad you were able to fix the problem.

The SRT log you are seeing usually happens when the listener is not able to process packets fast enough.

With regular icecast server, output.icecast is not blocked by the server's reception when sending source data. However, using RSAS, it's possible that you are experiencing some latency from the server that was causing your script to not be able to process incoming SRT packets fast enough.

Using a buffer, the SRT input is actually never blocked. Every now and then one packet might get dropped by you will always process them fast enough.