2014-02-21, 20:31
Hi,
Before posting here, I did extensive tests and all lead to the same result so I now assume there's a bug in the MP3 audio rendering in XBMC specifically on output volume.
My environment :
- HTPC with OpenELEC 3.2 - Audio out with HDMI connected to a high end receiver and then to a flat TV screen
- Desktop with Ubuntu 13.10 Saucy Salamander - Audio (pulseaudio) out with analog jack connected to a high end stereo amplifier
- XBMC OpenELEC : Frodo 12.2 + GIT commits
- XBMC Desktop : 12.2 stable from Nathan Rennie-Waldock PPA and 12.3~git20131213.0944 from “XBMC for Linux” team
- XBMC Settings : No replain gain anywhere (not within audio tags nor within XMBC itself)
Short description : MP3 files sound much lower in volume than any other tested format
Long description :
I was testing some new songs (OGG) on my living room with my HTPC and I immediately noticed they sounded "very loud" compared to all my usual music collection (fully in MP3 VBR 320). I came back to my desktop to make a quick test and it turned out that these songs sounded as loud as my other files in the music collection, give or take.
I pushed further the tests. I took 2 songs which sound loud right from the begining and I decoded the OGG files back to WAV and re-encoded them in WAVPACK, FLAC and MP3 in 3 flavours : 1/ Custom script using GStreamer 2/ lame -b 320 -h and 3/ same as "2/" but with --noreplaygain in case there could be any difference.
All 7 files (OGG, WAV, WAVPACK, FLAC, MP3 in 3 flavours) sounded exactly the same on my desktop in various players (DeadBeef, VLC, Clementine, MPlayer)
On my HTPC, in XMBC, there was a difference : WAVPACK, FLAC and OGG sounded all the same and all the MP3 variants sounded quite lower than the other formats (they sound exactly the same between all variants)
Ok, back to the desktop. Install XBMC 12.2 from Nathan's PPA, redo the same tests => Same results. Replace XMBC with the XBMC Team version, redo the same tests => Same results.
So, unless there's something pretty messed up here, I narrowed the problem to the MP3 decoding engine in XBMC which, for some reason, produces an output volume for MP3 files considerably lower than any other format I tested!
Can some XMBC developper take a look and confirm the issue ?
Before posting here, I did extensive tests and all lead to the same result so I now assume there's a bug in the MP3 audio rendering in XBMC specifically on output volume.
My environment :
- HTPC with OpenELEC 3.2 - Audio out with HDMI connected to a high end receiver and then to a flat TV screen
- Desktop with Ubuntu 13.10 Saucy Salamander - Audio (pulseaudio) out with analog jack connected to a high end stereo amplifier
- XBMC OpenELEC : Frodo 12.2 + GIT commits
- XBMC Desktop : 12.2 stable from Nathan Rennie-Waldock PPA and 12.3~git20131213.0944 from “XBMC for Linux” team
- XBMC Settings : No replain gain anywhere (not within audio tags nor within XMBC itself)
Short description : MP3 files sound much lower in volume than any other tested format
Long description :
I was testing some new songs (OGG) on my living room with my HTPC and I immediately noticed they sounded "very loud" compared to all my usual music collection (fully in MP3 VBR 320). I came back to my desktop to make a quick test and it turned out that these songs sounded as loud as my other files in the music collection, give or take.
I pushed further the tests. I took 2 songs which sound loud right from the begining and I decoded the OGG files back to WAV and re-encoded them in WAVPACK, FLAC and MP3 in 3 flavours : 1/ Custom script using GStreamer 2/ lame -b 320 -h and 3/ same as "2/" but with --noreplaygain in case there could be any difference.
All 7 files (OGG, WAV, WAVPACK, FLAC, MP3 in 3 flavours) sounded exactly the same on my desktop in various players (DeadBeef, VLC, Clementine, MPlayer)
On my HTPC, in XMBC, there was a difference : WAVPACK, FLAC and OGG sounded all the same and all the MP3 variants sounded quite lower than the other formats (they sound exactly the same between all variants)
Ok, back to the desktop. Install XBMC 12.2 from Nathan's PPA, redo the same tests => Same results. Replace XMBC with the XBMC Team version, redo the same tests => Same results.
So, unless there's something pretty messed up here, I narrowed the problem to the MP3 decoding engine in XBMC which, for some reason, produces an output volume for MP3 files considerably lower than any other format I tested!
Can some XMBC developper take a look and confirm the issue ?