Playlist metadata is lost

[audetto]

Bug report

This still happens in Fedora 35 with 0.23.5. If it is still too old, please tell me what is the version cutoff for issue reporting.

Describe the bug

With a playlist of radio streams, mpd overwrites all the metadata with information from the stream.
But it overwrites fields for which the stream provides no values.

The playlist metadata is very useful to name the stream (station, channel), as the info provided from the stream is most of the times unusable.

Example.

With
export MPC_FORMAT="%position% - %name% - %title%"

Before playing the stream I get

[andrea@fedora ~]$ mpc playlist
...
12 -  - Rai Radio 1
...

After mpc play 12 it becomes

12 - Radio1 -

As you see the title has been cleared, and the name filled from the stream. This case is still readable, but many others have unreadable names. Each stream has a different pattern.

I would like to have a field under my control, not overwritten by mpd.

This is the definition of this radio I provide:

        <track>
            <creator>RAI</creator>
            <location>http://icestreaming.rai.it/1.mp3</location>
            <title>Rai Radio 1</title>
            <album>Rai Radio 1</album>
            <trackNum>12</trackNum>
        </track>

Expected Behavior

Title should be overwritten, but not the other fields.

Actual Behavior

All fields overwritten (even with empty data).

Version

[andrea@fedora ~]$ mpd --version
Music Player Daemon 0.23.5 (0.23.5)
Copyright 2003-2007 Warren Dukes [email protected]
Copyright 2008-2021 Max Kellermann [email protected]
This is free software; see the source for copying conditions. There is NO
warranty; not even MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Database plugins:
simple proxy upnp

Storage plugins:
local udisks nfs curl

Neighbor plugins:
upnp udisks

Decoders plugins:
[mad] mp3 mp2
[mpg123] mp3
[vorbis] ogg oga
[oggflac] ogg oga
[flac] flac
[opus] opus ogg oga
[sndfile] wav aiff aif au snd paf iff svx sf voc w64 pvf xi htk caf sd2
[audiofile] wav au aiff aif
[dsdiff] dff
[dsf] dsf
[hybrid_dsd] m4a
[faad] aac
[wavpack] wv
[openmpt] mptm mod s3m xm it 669 amf ams c67 dbm digi dmf dsm dtm far imf ice j2b m15 mdl med mms mt2 mtm nst okt plm psm pt36 ptm sfx sfx2 st26 stk stm stp ult wow gdm mo3 oxm umx xpk ppm mmcmp
[modplug] 669 amf ams dbm dfm dsm far it med mdl mod mtm mt2 okt s3m stm ult umx xm
[mikmod] amf dsm far gdm imf it med mod mtm s3m stm stx ult uni xm
[sidplay] sid mus str prg P00
[wildmidi] mid
[ffmpeg] 16sv 3g2 3gp 4xm 8svx aa3 aac ac3 adx afc aif aifc aiff al alaw amr anim apc ape asf atrac au aud avi avm2 avs bap bfi c93 cak cin cmv cpk daud dct divx dts dv dvd dxa eac3 film flac flc fli fll flx flv g726 gsm gxf iss m1v m2v m2t m2ts m4a m4b m4v mad mj2 mjpeg mjpg mka mkv mlp mm mmf mov mp+ mp1 mp2 mp3 mp4 mpc mpeg mpg mpga mpp mpu mve mvi mxf nc nsv nut nuv oga ogm ogv ogx oma ogg omg opus psp pva qcp qt r3d ra ram rl2 rm rmvb roq rpl rvc shn smk snd sol son spx str swf tak tgi tgq tgv thp ts tsp tta xa xvid uv uv2 vb vid vob voc vp6 vmd wav webm wma wmv wsaud wsvga wv wve rtp:// rtsp:// rtsps://
[pcm]

Filters:
libsamplerate soxr

Tag plugins:
id3tag

Output plugins:
shout null fifo pipe alsa ao oss openal pipewire pulse jack httpd snapcast recorder

Encoder plugins:
null vorbis opus lame twolame wave flac

Archive plugins:
[bz2] bz2
[zzip] zip
[iso] iso

Input plugins:
file io_uring archive alsa qobuz curl ffmpeg nfs mms cdio_paranoia

Playlist plugins:
extm3u m3u pls xspf asx rss soundcloud flac cue embcue

Protocols:
file:// alsa:// cdda:// ftp:// ftps:// gopher:// hls+http:// hls+https:// http:// https:// mms:// mmsh:// mmst:// mmsu:// nfs:// qobuz:// rtmp:// rtmpe:// rtmps:// rtmpt:// rtmpte:// rtp:// rtsp:// rtsps:// scp:// sftp:// smb:// srtp://

Other features:
avahi dbus udisks epoll icu inotify ipv6 systemd tcp un

[audetto]

I was wondering if there is any merit in this Issue, or it is not interesting enough?

[MaxKellermann]

It is interesting (all bugs are interesting), but nobody had time to investigate yet.