Playing MP3 files will always re-encode stream because there is missing a null-codec. No way to keep quality.
Output of pulseaudio-dlna while streaming MP3:
...
pulseaudio_dlna.streamserver INFO Starting processes "parec --format=s16le -d my_dlna.monitor | lame -b 192 -r -"
...
LAME 3.100 64bits (http://lame.sf.net)
Using polyphase lowpass filter, transition band: 18671 Hz - 19205 Hz
Encoding to Encoding as 44.1 kHz j-stereo MPEG-1 Layer III (7.3x) 192 kbps qval=3
...
pulseaudio-dlna does double re-encoding. Each MP3 stream is re-encodec by parec to PCM (s16le wave) and then piped to lame and re-re-encoded back to MP3 (192 bit). This will reduce sound quality.
It's easy to keep quality with a null codec. In case of MP3 streams/files you should replace selected MP3 encoder by your '_pulseaudiodlna.encoders.NullEncoder' as you've already done with OGG streams/files.
felagund
commented
5 years ago
Playing MP3 files will always re-encode stream because there is missing a null-codec. No way to keep quality.
Output of pulseaudio-dlna while streaming MP3:
pulseaudio-dlna does double re-encoding. Each MP3 stream is re-encodec by parec to PCM (s16le wave) and then piped to lame and re-re-encoded back to MP3 (192 bit). This will reduce sound quality.
It's easy to keep quality with a null codec. In case of MP3 streams/files you should replace selected MP3 encoder by your '_pulseaudiodlna.encoders.NullEncoder' as you've already done with OGG streams/files.